TURNING
AND
MECHANICAL MANIPULATION.
BY
CHARLES HOLTZAPFFEL,
ASSOCIATE OF THK INSTITUTION OF CIVIL ENGINEERS, LONDON ;
HONOBART MEMBER OP THE ROYAL SCOTTiSH SOCIETY OW ARTS, EDINBURGH ,
CORRESPONDING MEMBER OF THE AMERICAN INSTITUTE OP NEW TOUK ;
ALSO Or THE FRANKLIN INSTITUTE, PHILADELPHIA,
ETC., ETC.
VOL. I.
MATERIALS; THEIR DIFFERENCES, CHOICE, AND PREPARATION; VARIOUS
MODES OF WORKING THEM, GENERALLY WITHOUT CUTTING TOOLS.
VOL. II.
THE PRINCIPLES OF CONSTRUCTION, ACTION, AND APPLICATION, OF
CUTTING TOOLS USED BY HAND ; AND ALSO OF MACHINES
DERIVED FROM THE HAND TOOLS.
VOL. III.
ABRASIVE AND MISCELLANEOUS PROCESSES, WHICH CANNOT BE
ACCOMPLISHED WITH CUTTING TOOLS.
VOL. IV.
THE PRINCIPLES AND PRACTICE OF HAND OR SIMPLE TURNING.
VOL. V.
THE PRINCIPLES AND PRACTICE OF ORNAMENTAL OR COMPLEX TURNING.
VOL. VI.
THE PRINCIPLES AND PRACTICE OF AMATEUR MECHANICAL
ENGINEERING.
Ercry Volume will bo complete in itaelL
x;
X
TURNING
tan
MECHANICAL MANIPULATION.
INTENDED AS
A WORK OF GENERAL REFERENCE AND PRACTICAL INSTRUCTION
ON THE LATHE,
AND THE VARIOUS MECHANICAL PURSUITS
FOLLOWED BY AMATEURS.
BY
CHARLES HOLTZAPFFEL,
ASSOCIATE OF THE INSTITUTION OF CIVIL ENGINEERS, LONDON;
HONORARY MEMBER OF THK KOTAL SCOTTISH SOCIETT OK ARTS, EDINBURGH
CORRESPONDING MEMBKR OF TUB AMERICAN INSTITUTE OF NEW TOBK ;
AU80 OF THE FRANKLIN INSTITUTE, PHILADELPHIA,
ETC., ETC.
TO BE COMPRISED IN BIZ VOLUMES.
VOL II.
THK rill NVI l-LES OF CONSTRUCTION, ACTION, AND APPLICATION,
OF CUTTING TOOLS USED BY HAND ; AND ALSO OF
MACHINES THRIVED FROM THE HAND TOOLS.
JlltutroUd fry upward* of Seven Hundred WoodcuU.
LONDON:
PUBLISHED FOR THE AUTHOR,
BY Hol.T/Al'rTKL & Co., 64, CHARINO CROSS, AND 127, LONG ACRE.
And to be had of cUl BooktcUen.
L8ML
LONDON :
BRADBURY AND EVANS, PRINTERS, WHITEFRIAR&
PREFACE TO THE SECOND VOLUME.
IN submitting'the second volume of the work on Turning and
Mechanical Manipulation to public scrutiny, two subjects call
for the Author's especial notice ; the delay in its appearance,
and the reason for the proposed augmentation of the number of
the volumes, intended to constitute the work, from five to six.
The delay has been caused principally by the unexpected
manner in which the subject matter of this volume has been
extended by additional examples and illustrations — also by great
and unavoidable interruptions caused by the Author's general
engagements — and by some domestic calamities, the most severe
of which has been the loss of the Author's eldest son.
The division of the matter that was originally meant to com-
the second volume, has been mainly caused by a desire to
lessen the disappointment, which has been repeatedly expressed
at the delay in the progress of the work. This division, although
it lias increased the number of the volumes from five to six, has
not caused any further departure from the original scheme of
the work, as will be seen on the perusal of the titles of the
distinct t of which it is proposed to consist.
viii
A few unimportant errors in the references to the several
volumes, will naturally ensue from this augmentation in their
number, but as the references to the pages, to the woodcuts,
and to the appendix notes, will be consecutive throughout the
three preliminary volumes, it is hoped that no confusion will be
experienced in consequence.
In conclusion the Author has to repeat his former request
that any omissions, errors, or ambiguities may be pointed out
for correction in the subsequent appendixes; and as he has
bestowed an equal amount of care on the production of this, as
on the first volume, a second edition of which is also this day
published, the Author hopes to be again rewarded with some
measure of public approval. He promises to use his best exer-
tions in the furtherance of the work, and as some of the matter
is in preparation, and none of the remaining volumes are ex-
pected to exceed the first in extent, he hopes not to be again
compelled to trespass so long on the patience of his readers.
CHARING CROSS, LOWDON,
November 10, 1846.
GENERAL SKETCH
or TV*
CONTENTS OF THE WORK.
VOL. I.
MATERIALS. TIIKIU I'lll IHi:v< | <. ( IKHCE. AND PREPARATION; VARIOUS
MODES OP WORKING TIIBM. OEM.ItAI.I.Y WITIHH'T < I i n\., TOOLS.
Introduction— Material* from the Vegetable, the Animal, and the Mineral Kingdom*.— ThHr
MM la the Mechanical Art* depend on their ttructural difference*, and pliynlral charactert.
The mode* of severally preparing, working, and joining the material*, with the practical deecrlp-
tioa of a variety of Procwst*. which do not, generally, require the u«e of TooU with cutting •dft*.
VOL. II.
TIIK riUNClPLKS OP CONSTRUCTION, ACTIOK. AND APPLICATION. OP CUT1 1
TOOLS L'SKD HY HAM) ; AM> ALSO OP MACHINES DERIVI |i
FROM THE HAND TOOLS.
The principle* and descriptions of Cutting TooU generally— namely . Chltcli and Plane*, Turning
Tool*, Boring Tool*, Screw-cutting TooU, Saw*. Pile*, Shear*, and Punches, The hand tooU
and their mode* of u*e are drat described ; anil subsequently various machine* In which the
hand pmce**e* are more or lew clonelr followed.
VOL. III
ABRASIVP. AND MISCELLANEOUS PROCESSES, WHICH CANNOT BE ACCOM-
H.IMIEI) WITH rCTTINO TOOLS.
Grinding and Polishing, viewed as extreme* of the came prooe**, and a* applied both to the pro-
duction of form, and the embellishment of surface. In numerous rase* to which, from the
nature of the materials operated upon, and other cause*. Cutting Tool* are altogether inappll.
cable. Varnishing and Lackering.
VOL. IV.
I UIN( Il'I.I.S AND PRACTICE OP HAND OR SIMPLE TTTRNINO.
Descriptions of various Lathe* ;— application* of numerous Chucks, or apparatu* for fixing work*
in the Lathe. Elementary instructions In turning tho soft and hard wood*, ivory and metal*,
and also In Screw-cutting. With numerous Practical Examples, some plain and aimple, other*
difficult and complex, to show how much may be done with hand tool* alone.
VOL. V.
THE PHINCII'LES AND PRACTICE OP ORNAMI NTAT, OR COMPLEX TURNING.
•Ming Re*t with Fixed Tools— Revolving Cutter*, used in the Sliding Rest with the Division
Plate and Overhead Motion. Various kind* of Eccentric, Oval, Spherical. Right-line and other
Chucks. Ibbetson's Geometric Chuck. The Row Engine, and analogon* contrivance*. Ac.
With numerous Practical Example*.
VOL. VI
THE PIMNCIPLES AND PRACTICE OP AMATEUR MECHANICAL I NO
Lathe* with Sliding Recta for metal turning. Self-acting and Screw-cutting Lathe*— Drilling
Machine*— Planing Engln^-Key-groove, Slotting and Paring Machines— Wheel cutting and
Shaping Engine*, *c.
With numerou* Practical Examples.
• Tkf Pint, Stftmd, and Tklrd I'nlumet tif t*tt teork, art teritten at aeeompanfina
book*, ami karr one Inittx in fnmmon, to at to conttitutf a ptntrai and preliminary teorft.
Ike addition to teHifk of any n/ lltt other t;,l,imrt, trill render Ike tvtyet eompltt* /or Ike tkrft
tlaitetof Amatturt rt/erred to in Ikt Introductory Chapter.
A fr<f addition*! eopiti of tkt Index kare been frinUd far Ike eonvenlfnee of tkott vko may
dttirt to bind tke Indt* tritk Volt. I. an
\l
TABLE OF CONTENTS
OF THE SECOND VOLUME.
CHAP. XXIL— GENERAL" REMARKS UPON CUTTING TOOLS.
MM
S«CT. 1 . The anylti and position* of tool* at regard* the ad of cutting —Their
division into poring, fcraping, and shearing toola-vangles and petition*
of the edges of tools ....... 457
SECT. 2. Tie form* and motion* of tool* a* reyardt thr production of line*,
tuprrfcie*, and tolidt, theoretically contidered — The guide or slide
principle may be traced both in the manual processes, and in the
machinery directed to the above purposes .... 463
CHAP. XXIII.— CHISELS AND PLANES.
SECT. 1. Introduction — The axe,hatchet, adze, baasoOlih or Indian adze, paring-
knife, drawing-knife, chisel and planing-tool for metal contrasted.
Bench-plane* of varioui kintit, or those used for flat surfaces, the
mouths of planes described, the spokeshave, planes with single and
double irons ; planes of low, middle, half, mitre and upright pitches,
and the joiner's scraper . . . . . . 472
SECT. 2. Qrooving-plane* — For cutting with the grain or across the grain —
The fillister, plough, grooving, drawer-bottom, and slit-deal planes —
The router, various gages, the cooper's croze, banding-planes, and
rounding-planes for cylindrical rods ..... 484
SECT. 3. Moulding-plane* — Their general character— difficulty of applying
them to the vertical parts of mouldings, remedy proposed by the author
— On working or sticking mouldings, explanations of the terms, the
tpring, the on and the down . . . . . . 489
SECT. 4. Remark* on the bench, and the v*e of planes — On the construction of
joiner's benches, bench-stops, hooks, and holdfasts — On sharpening,
adjusting, and using bench-planes; straight-edges, winding-sticks,
squaring thick and thin works, the shooting-board . . . 494
Srcr. 5. Plating-machine* for wood— Those invented by Bentham, Bramah,
Brunei, Muir, Paxton, Burnet & Poyer, briefly considered . . 503
CHAP. XXIV.— TURNING TOOLS.
SECT. 1. Facility of turning compared with carpentry— General remarks on the
sections of woods, and on the tools respectively used for turning and
carpentry ........ 508
SECT. 2. Turning tool* for toft wood — Gouge, chisel, hook tools ; underhand
tools, broads, side-cutting, screw-cutting and parting tools for soft
woods . 512
Xll TABLE OF CONTENTS.
PAGE
SECT. 3. Turning tools for hard wood and ivory — Gouge, side-cutting, flat,
point, bevil and parting tools — Curvilinear tools, simple and complex,
for mouldings both external and internal — Screw-cutting tools . 517
SECT. 4. Turning tool* for brass — Round or rough-out tool, square tool, planish-
ing tools, the last sometimes burnished on their edges and held in a
restless manner — Many of the other tools for brass nearly resemble
those used for ivory. The arm-rest and its employment . . 520
SECT. 5. Turning tools for iron and steel — Triangular tool, graver, flat chisel ;
heel ancl hook tools — nail-head tools — cranked or hanging tools . 523
SECT. 6. Fixed or machine tools for turning and planing — By comparison with
hand toolstheirformsrequire more rigid observance of principle — Fixed
tools for soft wood — for hard wood and ivory — for brass — for iron —
general principles — Nasmyth's tool-gage — Cutter-bars or tool-holders
with small changeable cutters — finishing, hanging, or springing tools . 527
CHAP. XXV.— BORING TOOLS.
SECT. 1. Soring bits for wood — Various kinds of awls — fluted or semi-tubular
bits — center bits — English, American and German screw augers — or-
dinary braces and angle braces for wood . 539
SECT. 2. Drills for metal used by hand — Small double cutting drills used with
the drill-bow — larger single cutting drills used in the hand-brace and
in boring machines — including pin-drills, and also square and cone
countersinks of each kind . . . . . . 646
SECT. 3. Methods of working drills by hand-power — Watch-drills, various
drill-bows and drill-stocks— Smith's old press-drill ; outline of modern
contrivances for the same purpose — Ratchet and lever-drills — Corner-
drill with bevil pinions — Shanks' a differential screw-drill . . 553
SECT. 4. Drilling and boring machines — The lathe very much used for boring
with fixed drills of numerous kinds — Sketch of the general characters
of drilling machines for small holes — and also of boring machines, with
revolving and sliding cutter-bars, such as are uaed for the largest
steam cylinders . . . . . . . 563
SECT. 5. Broaches for making taper holes — Broaches and rimers of various trans-
verse sections, for making taper and cylindrical holes, both in woods
and metals — Comparison between the actions of drills and broaches . 572
CHAP. XXVI.— SCREW CUTTING TOOLS.
SECT. 1. Introductory remarks — Observations on the screw both elementary
and descriptive — Division of the subject of screw cutting . . 577
SECT. 2. On originating screws — Simple methods invented by Pappus, (see foot
note, page 635,) by Plumier, Robinson, Maudslay, Allan, Walsh, etc. . 579
SECT. 8. On cutting internal screws with screw-taps — Old and modern taps
of numerous transverse sections ; on their longitudinal sections ; and
their general applications — Taps with loose cutters— Original taps and
cutters, for cutting the dies of diestocks, the teeth of worm wheels,
and screw tools. Screw taps and cutters for wood . . . 583
TABLE OP CONTENTS. Mil
SICT. 4. On cutting crtsriMtl ttnm with tertw dm, tie.— Screw-box for cutting
wood screws Screw plaU* for small metal screws— Old and modern
•crewstocks or diestocka — Proportions of original or master Up* ustd
for cutting the dies of dieetoeks — Various forms of dies considered ;
•far John Robiaon's dice, also Heir's and Jones's dies, with detached
cutters — On producing left-band screws from right-hand apparatus —
W hit worth's, and Bodmer's, patent sorew-stocks — screwing machines
—concluding remarks . . . . . . . 693
Sicr. 5. On cutting scnwt by hand in ike common lathe — Explanation of the
causes of failure in cutting screws flying, or in striking threads by hand rt J 1
SlCT. 6. On cutting icrnct in lathet with trarrrtiny mandrels — Sketch of old
and modern apparatus for this purpose, and their applications . 012
SECT. 7. O» cutting screw in lathe* «i'M trarcrtiny tool* — Various simple
contrivances for cutting short screws, invented by Besaon, Grandjean,
Thiout, Henley, and Varley — Machinery for cutting long and accurate
screws by the modern syntem of guide-screws and change-wheels — the
smaller application used as an addition to the ordinary slide-rest — the
larger constitutes the screw-cutting or slide-lathe — Mode of computing
the pitches of screws from the wheels and guide-screws employed — Screw
tools or chasing tools of ordinary kinds used in slide-rests and nlide-
lathes ; those by Clement, Bodmer, and the Author — Roberta's tool-
slide— Shanks'* tool-slide for cutting both in the to-and-fro movement
— Backstay for supporting long and slender screws whilst being cut . 615
SECT. 8. Various modesof originating and improving screws,etc. — First as regards
screw tackle for ordinary and general purposes — Secondly, the appa-
ratus for regulating and micrometrical screws, required to agree in pitch
with Standard Measure— Method of originating screws with theinclined
plane, used in some fusee cutting engines, and improved by Reid.
Modes of perfecting the screw, introduced by Ramsden, Maudalay,
Barton, Allan, and Clement, fully explained — Account of the con-
struction of Mr. Donkin's rectilinear dividing engine, in which the
micrometrical errors in the best screws, due principally to the want of
homogeneity in the materials, may be discovered and compensated for 635
SECT. 9. Screw threads considered m respect to their proportions, forms, and
general characters — Relative strengths of screws and nuta ; comparison
of square and angular threads ; split nuts to compensate for wear ;
different sections of screw threads, and their purposes — Inconvenience
experienced from the dissimilarity of screws — System of screws to
agree with Standard Measure, proposed by Mr. Whit worth for universal
adoption ; this proposal surrounded by various and almoot insurmount-
able difficulties — Modes of formingscrews, differing from all those before
noticed ; namely by Wilks, Warren, Perkins, Scott, and Rand . 656
CHAP, xxvn.— s.\
SECT. 1. Division of the sufyect ; forms of saw teeth— Introduction; descriptions
of the teeth used in various kinds of saws, and their several purposes 682
SECT. 2. Marymiay and setting tout Fully explained as regards the five
usual modes employed. The tools used, namely, the horses, files,
stakes, and set hammers; the ordinary saw-net, plier saw-set, and saw-
set for circular saws . . . <88
XIV TABLE OF CONTENTS.
PAGE
SECT. 3. Rectilinear saws used by hand — Table of the dimensions of rectilinear
saws in three divisions. — Pint division — Taper saws mostly without
frames — Felling saws, cross cutting saws, various pit saws, some of
them with frames — Instructions for marking out and sawing round
and squared timber — Hand saws, panel saws, compass, keyhole and
pruning caws, and directions for their use. — Second division — Parallel
saws with backs — Tenon, sash, carcase, and dovetail saws; sawing
block ; cutting tenons and mortises, and also dovetails of all kinds —
Smith's screw-head saw, comb-makers' saw, double saws for cutting
racks. — Third division — Parallel saws used in frames; and instructions
for their application — Mill saw blades, pit veneer saw, chair-maker's
saw, wood-cutter's saw, Continental frame saw, turning or sweep saw
— The smith's frame saw, side frame saw, piercing saw, buhl saw ; the
practice of buhl and marquetry work fully explained . . 698
SKCT. 4. Rectilinear or reciprocating saw machines — Those at the Govern-
ment and City saw-mills — American and Continental fire-wood saw
machine — Vertical saw mills for deals; also those for square and
round timber — Small vertical machine from the Manuel du Tourneur.
Mac Duff's, Lunds", and Professor Willis's vertical sawing machines
for small purposes, including buhl works .... 739
SECT. 5. Common applications of the circular saw to small worlcs — Smallest
circular saws mounted on the lathe for telescope tubes, screw heads,
making joints, &c. — Small saw spindle; platforms of wood and iron;
saw stops, parallel and angular guides — Sawing rectangular pieces ;
grooves; rebates; cross-cutting the ends of pieces square or bevil.
Sawing bevilled edges, and oblique prisms, fully exemplified by
the formation of the various Mosaic works of the Tunbridge turner.
Sawing regular and irregular prisms ; also regular, irregular, single,
double and mackled pyramids — The subject minutely illustrated by
the formation, with the circular saw. of the five regular bodies, or
platouic solids, and a variety of other solids that occur in mineralogy
and crystallography ; with all the angles critically given . . 751
SECT. 6. Common applications of circular saws to large works — Table of
dimensions of circular saws, given in three divisions, with the speed
and power severally required for them — Various general conditions
— Spindles for large saws; benches and platforms; stops and parallel
guides for the same — Sawing rectangular pieces . . . 783
SECT. 7. Lea common or specific applications of circular saws to large works
— Sawing grooves, rebates and tenons — Pow & Lyne's sawing machine
for combs — Cross cutting the ends of pieces square or at angles —
Sawing works with bevilled edges; Eastman's machine for feather
edged boards; sawing hexagonal and other wood pavement — Professor
Willis's mode of blocking out architectural mouldings — Sawing works
bevilled in both planes, Mr. Donkin's saw bench — Curvilinear saving
— Trephine saw and various others used in surgery; cylindrical or
drum saws, used for felloes of wheel?, backs of chairs, brushes, &c. —
Smart's machinery for sawing the curvilinear staves of casks . 792
SECT. 8. Circular tawt and machinery for cutting veneers — Veneers known to
the Roman*, and until recently cut by the pit sawyers — Brunei's split-
ting machine for veneers — Modern veneer paws — Thesmallerapplication
with single plate*, for leaves of ivory and small veneers of wood — The
TAB1 oNTENTS.
r*ot
larger application, or the modem veneer mill ; iu action fully
plained wad figured — Conclusion of the chapter — Additional illu»tra-
lioim of circular saw* ; for cutting off pile* under water; sawing (late;
and Hawing eiuU of railway ban whilst rod hot . . . 805
CHAP. XXV11L— FILES.
SECT. 1. General and dttcriptive view of Jilts of untal kindt— Explanation of
the rix principal features in filea — Description and purpose* of the
files principally used ; namely, taper, hand, cotter, pillar, half-round,
triangular, cross, round, square, equalling, knife, and slitting files.
Description of other files less frequently used — Sketch of the manu-
facture of files and rasps — Different means of grasping the file to adapt
it to various specific uses ...... 817
SECT. 2. General und detcriptivi: view of filet of let» tuual kindt — Rioters for
sculptors and others — Float* or single cut files u&ed for ivory, horn,
and tortoiscahell ; the quauuett — White's perpetual file — Raoul's and
Ericcson's machines used for cutting the teeth of files — Sir John
Robison's concave half-round files, and also hia project for file cutting 837
SECT. 3. Preliminary remark* on uting filet and on holding workt that are to
be filed — The three positions of the individual, corresponding mode*
of holding the file, and general observations on filing — Chipping,
pickling, or grinding works preparatory to filing — On cleaning files.
Modes of grasping works to be filed, the taper vice, tail vice, vice
benches, tripod vice stand, table and parallel vices, wood and metal
vice clamps — Pin vice and sliding tongs, used for small works, espe-
cially those of cylindrical forms — Filing boards, and Sheffield flatting
vice, used for thin plates ...... 844
SECT. 4. I Httructiont for filing a fiat turface under the guidance of the tlraiyht
edge, and of the trial plate, or planometer — The concluding steps to be
accomplished by scraping and not by grinding — Same care partially
necessary in works that require less accuracy ; chipping chisel now
less used than formerly — Impolicy of finishing metallic surfaces by
grinding them together ...... 865
SECT. 5. fnttructions for originating ttraight tdgtt and trial platet or piano-
mttert — Joiner's method of preparing wooden straight edges ; these
employed in commencing steel straight edges ; which latter are after-
wards delicately corrected by working on a series of three— On origi-
nating plane surfaces in iron, or planometers . . . 872
SCOT. 6. Inttructiont for filing rectilinear workt in uhicft ttveral or all the
tuperficiet have to be wrought — Works with plane surfaces and square
edges; works with bevilled edges ; works with rebates and grooves, some
these filed up in different pieces for the facility of manipulation.
:ug mortises and aperture* — Drifts or punches used in combina-
. with files, in completing square and other mortises and holes, the
key ways in wheels, Ac. ...... 873
SECT. 7. Instruction! for filing cutvUinear workt according to the three ordi-
nary modt» The operation lew difficult than filing flat surfaces ; the
file often nearly a counterpart of the work ; its position incessantly
XVI TABLE OF CONTENTS.
PAGE
changed — Filing curved works, that are moulded or formed, prior to
the application of the file — Filing curved works, that are moulded or
formed almost entirely with the file — Filing curved works that are
shaped with the file, under the guidance of templets or pattern plates
of hardened steel ; including the making of joints of various kinds . 886
SECT. 8. Comparative sketch of the application* of the file, and of the engineer's
planing machine, <tc. —Intended to show, by way of contrast, how
several of the pieces advanced in sections 4 to 7, in illustration of
works executed with files, are produced in the engineer's planing
machine, key groove machine, slotting and paring machines, shaping
machines, &c. ........ 896
CHAP. XXIX.— SHEARS.
SECT. 1. Introduction — Cutting nippers and pliers of various kinds for cutting
wires — Bursill's cutting nippers with removable cutters . . . 904
SECT. 2. Scissors and shears for soft flexible materials — Principles upon which
they act, their blades always curved and elastic, importance of the
riding parts — Scissors of various peculiar forms, explained — Pruning
scissors and shears — Sliding shears — Card-maker's shears — Revolving
shears for cloth, and for grass lawns ..... 907
SECT. 3. Shears for metal worked by manual power — Hand shears, bench
shears ; purchase shears with secondary lever ; modes of using them
— Collett's tag shears — Shears for making stationer's ruling pens —
Chisel and hammer used instead of shears for curved and some
straight works ...... . . 914
SECT. 4. Engineer's shearing tools generally worked by steam power — These
may be considered as massive copies of the foregoing tools, but are
moved by eccentrics and cams — Barton's double shears — Roberts'
shearing and punching engines for boiler-makers, the one with lever,
the other with slide — Thorneycraft's shearing machine for cutting
wide plates of iron — Nasmyth & Co's cutting vice for wide plates —
Renton's hydraulic machine for cutting off copper bolts — Rotary
shears for cutting thin metal, in straight and curved lines . . 919
CHAP. XXX.— PUNCHES.
SECT. 1. Introduction, punches used without guides — Single hollow punches
for gun-wadding, pasteboard, wafers, confectioners' lozenges ; double
punches for leather washers; figured punches — Solid and hollow
punches for thin iron, tinned plate, copper, &c. used upon lead.
Smith's punches for red-hot iron, used with counterparts or bottom
tools, known as bolsters — Harpmaker's punch for cutting mortises . 926
SECT. 2. Punches, used with simple guides — Plier punches for leather straps —
Instrument for making quill pens — Hammer press for holes, circular
mortises, &c. — Portable screw press or clamp, for the leather straps
of machinery ; a similar portable instrument on a larger scale used
for punching boiler plate ... . 930
SECT. 3. Punches used t» fly presses, and miscellaneous examples of their pro-
ducts— General characters of the fly press — Some peculiarities in fly
presses, and machinery of analogous kinds — Productions of presses —
TAIU \\11
MM
I Juki fur coin, ingenious compensatory method of ensuring thoir critical
•quality of weight — Punching disks for button* ; wiuhen with ruuml
and square holes. The link* fur chain* of various kind* for machinery,
including chain* for pin wheels, and Oldham's chain fur oommon spur
wheels, intended to act M leather bands. Peculiar punching tool* used
for making watch chain*— Punching the teeth of straight and circular
saw* — Punching copper caps and steel pens— Lariviere's perforated
motals for colanders, and various domestic purposes — Punches used in
the manufacture of Jeffrey's patent respirators — Buhl work made by
punching or stamping — Sketch of the mode uf cutting brads, tacks, and
nails by punching or shearing tools ..... 984
Sect. 4. Punching machinery uted by engineer*— Nearly the same iu general
arrangement M the shearing tools — The punching engine commonly
used for cutting curvilinear liuos in thick plates — Colthurst's,and Hick's
comparative experiments on the force required in using punches . 950
APPENDIX.
NOTES REFERRING TO THE FIRST VOLUME.
RdentoVol. I.
Not*. Page.
II Payne's Patent process for preserving timber from decay . . 953
I 25. The bassCClah or Indian adze (by the late Sir J. RobUon). . 953
J 46. Irving's Patent carving machine, principally applicable to mouldings 954
K 46. Jordan's patent carving machine, principally applicable to figures 954
L 46. Tomes's patent dentifactor, for carving artificial teeth and gums . 955
M 121. Straightening stag horn and buck horn for knife handles . 957
N 155. Making isinglass glue (by the late Sir J. Robison) . . . 957
O 160. Prosser's patent process for works made of dry clay with dies . 957
P 191. Clay's patent process for manufacturing wrought iron . . 953
Q 196. Nasmyth's patent direct action steam hammer (by the Patentee). 958
R 196. Nasmyth's patent steam pile driving engine (by the Patentee) . 961
202. The "Oliver" or small lift hammer worked by the foot . . 962
T 226. The manufacture of wrought iron tubes (explained by Mr. Pros-
ser's Synoptical table — followed by brief professional notices of
the several patents) . . . . . .963
U 256. Remarks on Sir J. Robisoo's workshop blowpipe (by the Inventor) 970
V 283. Amalgams used by dentists for stopping teeth . . . 970
W 323. Babbett's patent anti-friction metal for bearings of machinery . 970
802. Craufurd's patent process for making galvanised iron . .971
V 802. Morewood 4 Rogers's patent for making galvanized tinned-iron . 972
Z 808. Portable brass furnace by HolUapffel & Co. . . . . 978
AA 374. Berlin method of moulding delicate and complicated objects . 974
AB 424. Fluid employed in India for lubricating draw-plates . . . '.'71
AC 410. Foxall's patent method of raising vessels in sheet metal . . 974
AD 431. Drawing taper brass tubes for locomotive engines . - . 976
431. Rand's patent method of making collapsable tubes for oil colors . 977
AF 433. Clay prup* used by the Asiatic* instead of binding wire in soldering 977
AG 444. Pumice stone used by dentuts, instead of charcoal in soldering . 978
XV111 TABLE OF CONTENTS.
NOTES REFERRING TO THE SECOND VOLUME.
Refers to VoL II.
Note. Page. PAGE
All 482. Silcock & Lowe's patent planes for joiners and cabinet-makers . 978
AI 487- Lund's screw router plane for working recesses in cabinet work . 979
AJ 488. Falconer's improved circular plough for joiners . . . 979
AK 495. Franklin's screw bench hook for carpenters . . . 979
AL 495. De Beaufort's vice, or atop for joiner's benches . . . 979
AM 495. S. Nicholl's stop or clamp for joiner's benches . . . 980
AN 504. Esdaile & Margrave's machine for cutting scale boards for boxes 981
AO 505. On machines for planing wood, by Paxton, and by Burnett &Poyer 981
AP 505. Mayer's patent machine for cutting splints for chemical matches 982
AQ 533. Side cutting tool for iron to be used in the slide rest . . 983
AR 538. On lubricating metal turning tools with water . . . 983
AS 538. Paper on the principles of tools for turning and planing metals (by
Charles Babbage, Esq., F.R.S., &c.) . . . . 984
AT 538. The author's description of tools and tool holders for turning and
planing metals, constructed by C. Babbage, Esq. . . 987
AU 538. Paper on the principles of tools for turning and planing metals (by
the Rev. Prof. Willis, of Cambridge, A.M., F.R.S., &c.) . . 991
AV 538. Paper on a new form of tool holder, with detached blades for
turning or planing metals, and on a new mode of fixing tools
upon the slide rest (by Prof. Willis) . . . 996
AW 542. Franklin's expanding center bits for holes of various diameters . 1001
AX 544. The American screw auger, patented by Mr. Ash . . . 1002
AY 554. Freeman's registered drill tool, for actuating small drills . 1002
AZ 557. Mac Dowall's Archimedean screw drill stock . . . 1003
BA 557. MacDo wall's rectangular Archimedean drill stock for dental surgery 1003
BB 557. Capt D. Davidson's rectangular drill stock for dental surgery . 1004
BC 563. G. Scott's apparatus for boring and tapping cast iron main pipes 1004
BD 567- Collas' lathe drill for boring holes out of the solid . . 1006
BE 567. C. Holtzapffel's boring bit with changeable cutters, for the lathe . 1006
BF 567. The Cornish boring bit with loose cutters, for the lathe . 1007
BG 567. Maudulay's boring bit with loose cutters, for the lathe . . 1008
BH 567. Stiven's registered lathe drill . . . . 1008
BI 567. Kittoe's expanding half round bit, for the lathe . . . 1009
BJ 572. G. Wright inventor of the modern system of boring large cylinders 1010
BK 580. Mallett's method of describing regular and irregular spirals . 1010
BL 696. On sharpening the teeth of saws by means of grindstones . . 1011
BM 789. On the gages at present used for measuring the thicknesses of
she«t metals and wires — and proposals for anew system of gages
founded on the decimal subdivision of the standard inch . 1011
UN 751. Bodmer's patent for making the tires of locomotive wheels . lu_M
BO 803. Harvey 'a patent curvilinear saws for long or short works . 1022
BP 827. Cutting the teeth at the ends of files . . . . 1022
BQ 839. Michael Kelly's Quauuett for tortoiseshell, used also for zinc . 1023
BB 841. Inventors of various file cutting machines . . . 1023
BS VoL L 299. Table of decimal proportions of the pound avoirdupois . 1023
BT Vol. I. 46. Gibb's Carving Machine patented 1829 . . . 1025
THE KND OF THE TABLE OF CONTENTS.
TURNING
MECHANICAL MANIPULATION.
VOL. II.
THE PRINCIPLES OF CONSTRUCTION, ACTION, AND APPLICATION
OF CUTTING TOOLS USED BY HAND; AND ALSO OP
MACHINES DERIVED FROM THE HAND TOOLS.
CHAPTER XXII.
GENERAL REMARKS UPON CUTTING TOOLS.
INTRODUCTION.
THE title of the present volume appears to be sufficiently
descriptive without additional explanation, consequently the
author will alone offer a few words on the notions which led to
the division of the volume into the eight chapters enumerated
in the table of contents, and on their particular arrangement.
The chisel was selected as the subject of the first chapter, as
from the simplicity of its form and action, it may be viewed as a
keen wedge, sometimes employed with quiet pressure, at other
times used with percussion, as in tools of the character of axes
and adzes ; and the straight chisel mounted in a stock for its
guidance becomes the plane. Further, the carpenter's chisel may
be ii-ril as a turning tool, and many tools of this kind, the second
in the classification, follow the condition of chisels and planes, if
we imagine the tool to be held at rest, and the work to revolve
against it, on a fixed axis. The practice of turning is naturally
associated with that of boring holes, although in most cases, the
boring tool revolves whilst the work remains at rest. Turning
and boring, each circulatory processes, led to the selection of the
screw as the subject of the next chapter, for revolution combined
\ul.. II. II II
458 THE ANGLES AND POSITIONS OF TOOLS.
with rectilinear advance, are exhibited in all the numerous modes
of producing screws.
Saws were ideally compared with some of the scraping chisels,
but with a multiplication of points, and these sometimes arranged
in continuous order as in the circular saw. The file from its vast
assemblage of scraping teeth, was likened to a multiplication of
the saw ; but unfortunately the file has not been engrafted upon
any machine, embodying the manipulation of the unassisted
instrument. Shears and punches are next considered in great
measure as parallel subjects, and the rectilinear edges of shears
although mostly duplicated, nevertheless bear some resemblance
to simple chisels, although from their duplication they act on
both sides of the material; and lastly the ordinary punch is
comparable with the rectilinear edges of the shears and chisels,
if we do but conceive these to be bent into the circular form.
Should these grounds for the arrangement adopted be deemed
fanciful or visionary, it may be added that some order or selec-
tion was imperative, and it is hoped the present will serve as
efficiently as any other that could be selected.
SECT. I. THE ANGLES AND POSITIONS OF TOOLS, AS REGARDS
THE ACT OF CUTTING.
THE section now to be commenced, refers exclusively to the
principles and construction of cutting tools, which will be
considered in a general manner, and without reference to any
particular branches of mechanical art, the tools and applications
being selected by their characters and principles alone.
All edged tools may be considered to be wedges formed by
the meeting of two straight, or of two curvilinear surfaces, or
of one of each kind, meeting at angles varying from about 20
to 120 degrees.
Some few tools are pointed, from the meeting of three or
more planes or surfaces.
Occasionally, as in the hatchet, the chipping chisel, and the
turner's chisel for soft wood, the tool is ground from both sides,
or with two bevils or chamfers; at other times, as in the
carpenter's chisels and plane irons, the tool is ground from one
side only, and in such cases, the general surface or shaft of the
tool constitutes the second plane of the wedge ; this difference
does not affect the principle.
DIVISION INTO rviUNG, SCRAPING, AND .SHEARING TOOL*. I.V.t
general characters of cutting tools, namely, the -ir angles,
and their relations to the surfaces to be produced, depend upon
the hardness of the opposed substances, and the direction and
naturv <>f their fibres ; these primary characters require especial
Moderation.
The particular or specific characters of cutting tools, namely,
tin forms of their blades, stocks, or handles, are adapted to the
convenience of the individual, or the structure of the machine
by which they are guided; these secondary characters, the less
require or admit of generalization.
It will be now attempted to be shown that, granting the
latitude usual in all classifications, cutting tools may be included
in three groups, namely, Paring Tools, Scraping Tools, and
• ring Tools.
First — Paring or splitting tools, with thin edges, the angles of
which do not exceed sixty degrees ; one plane of the edge being
: ly coincident with the plane of the work produced (or with
the tangent, in circular work). These tools remove the fibres
principally in the direction of their length, or longitudinally;
and they produce large coarse chips or shavings, by acting like
the common wedge applied as a mechanical power.
Secondly — Scraping tools with thick edges that measure from
sixty to one hundred and twenty degrees. The planes of the
edges form nearly equal angles with the surface produced ; or else
the one plane is nearly or quite perpendicular to the face of the
work (or becomes as a radius to the circle). These tools
remove the fibres in all directions with nearly equal facility,
and they produce fine dust-like shavings by acting superficially.
Tlilrilly — Shearing, or separating tools, with edges of from
to ninety degrees, generally duplex, and then applied on
opposite sides of the substances. One plane of each tool, or of
•ngle tool, coincident with the plane produced.
4>lanation of these views, the diagram, fi g. 3 16, is supposed
to represent seven different tools, the bevils or edges of which
are all at the angle of sixty degrees, this may be considered as
the medium angle of the paring, scraping, and shearing tools.
:md scraping tools are supposed to be moving
which line represents the face of the work; or the
may be considered to be at rest, and the work to be moving
from B to A.
n H 2
460
DIVISION INTO PARING, SCRAPING, AND
Or, in turning, the tool may be supposed to remain fixed, and
the circle to represent the moving surface of the work ; one
plane of the tool then becomes a tangent or radius.
The shearing tools, if in pairs, are proceeding towards each
other on the line C D, whilst A B still represents the face of the
work. The single tools act on the same principle, but the body
of the material, or the surface of the bench or support, supplies
the resistance otherwise offered by the second tool.
The tools a, c, f, are bevilled or chamfered on both sides, the
others from one side only; in these latter, the general face of the
tool forms the second side of the angle, and allowing for exag-
geration, both as to excess and deficiency, the diagram may be
considered to represent the edges of the following tools.
[a, b, c, d, Splitting and Paring Tools, proceeding from A to B.]
a — The axe, or the cleaver for splitting.
b — The side hatchet, adze, paring and drawing knives, paring
chisels, and gouges, the razor, pen-knife, spokeshave, the engra-
ver's graver, and most of the engineer's cutting, turning and
planing tools for metal.
Fig. 316.
c — The turning chisel, for soft wood ; the chipping chisels, for
iron, stone, &c.
d — The joiner's chisels, and carving tools, used with the bevils
downwards, the joiner's planes, the cross-cut chisel for metal,
and some other metal tools.
[e, f, Scraping Tools, proceeding from A to B.]
e — When single, the scraping tools for turning the hardwoods,
ivory, and brass, the hand-plane for metal, and when multiplied,
the various saws, and files.
/ — When single, a triangular scraper for metal, and when
8IIEAUIN NOLES Of THE EDGES. II
n.ultiplied, the cross-cut saw for wood, and also polygonal
lies or rimers with any number of sides, for metal.
[e,f, Shearing Tools, proceeding from C to D.]
e — "When duplex, shears \uth edges from eighty to ninety
i ccs, commencing with delicate lace scissors for single threads,
and ending with the engineer's shears for cutting iron bars and
plates upwards of two inches thick ; also duplex punches with
rectangular edges, for punching engines and fly-presses.
e — When single, the carpenter's firmer and mortise-chisels,
the paring-knife moving on a hinge, and cutting punches for
gnu wadding and thin materials.
/—When duplex, common nippers for wire; more generally,
however, the blades are inclined, so that one bevil of each blade
in one and the same plane, and which is vertical to A B, as
at g //.
/—When single, the smith's cutting-off chisel.
In practice, the tools differ from the constant angle of sixty
degrees assumed in the diagram for the convenience of explana-
tion, as the angles of all tools are determined by the hardness,
and the peculiarity of fibre or structure, of the several substances
upon which they are employed. The woods and soft fibrous
materials, require more acute angles than the metals and hard
bodies ; and the greater or less degree of violence to which the
tools are subjected, greatly influences likewise the angles adopted
for them.
Thus, under the guidance of a little mechanism, the thin edge
of a razor, which is sharpened at an angle of about 15 degrees,
i - used to cut minute slices or sections of woods, in all directions
of the grain, for the purpose of the microscope. But the car-
penter and others require more expeditious practice, and the
change is to thicken the edges of the tools to range from
about 20 to 45 degrees, to meet the rough usage to which they
•re then exposed, whether arising from the knots and hard places
in the woods, or the violence applied.
In tools for iron and steel from 60 to 70 will be found a very
common angle, in those for brass 80 to 90, in hexagonal broaches
for metal it increases to 120, and in the octagonal broach some-
times employed the angle is still greater ; in the circular broach
462 POSITIONS OF THE EDGES OF TOOLS.
required by clock and watchmakers, the angle disappears and
the tool ceases either to cut or scrape, it resolves itself into
an instrument acting by pressure, or becomes a burnisher.
To a certain extent, every different material may be considered
to demand tools of a particular angle, and again the angle is
somewhat modified by the specific mode of employment : these
conditions jointly determine the practical angles suited to every
case, or the angles of greatest economy, or most productive effect.
The diagram shows that, independently of the measure of the
angle of the tool, we have to consider its position as regards the
surface of the work, the broad distinction being that, in the
paring tools, the one face of the wedge or tool, is applied nearly
parallel with the face of the work ; and in the scraping tools, it
is applied nearly at right angles, as explained in the foregoing
definitions. Indeed the paring tools, if left to themselves, will
in some cases assume the position named ; thus, for example, if
we place a penknife at an elevated angle upon a cedar pencil,
and attempt to carry it along as a carpenter's plane, the pen-
knife if held stiffly will follow the line of its lower side and dig
into the wood ; but if it be held slenderly, it will swing round in
the hand until its blade lies flat on the pencil, and it will even
require a little twisting or raising to cause it to penetrate the
wood at all. This disposition appears to be equally true, in the
thin edges of the penknife or razor, and in the thick edges of
the strong paring tools for metal.
The action of a cutting tool in motion is twofold. The moving
force is first exerted on the point of the wedge, to sever or divide
the substance particle from particle ; the cohesion of the mass
now directly opposes the entry of the tool, and keeps it back.
But the primary motion impressed on the tool having severed a
shaving, proceeds to bend or curl it out of the way ; the shaving
ascends the slope of the wedge, and the elasticity of the shar'uiy
confines the tool in the cleft, presses it against the lower side,
disposes it to pursue that line, and therefore to dig into the
substance.
In pursuing the more detailed examination of different cutting
tools employed in the mechanical arts, amongst the several classi-
fications which might be adopted, it appears to the author to be
the more generally useful to consider the various tools in separate
FORMS AND MOTIONS OP TOOLS.
chapters under the f..llo\\ in£ heads, nnmcly, Chisels and Planes
— Turning tools — Boring tools — Screw-cutting tools — Saws —
- Shears and Punches — as some of all these kinds of tools
may be found in e\ery work-room.
The several chapters and sections will be commenced with the
tools for the woods, which are perhaps the more commonly used
by the amateur, the corresponding tools for metal will generally
lie then considered, and lastly some illustrations will be given <>f
the same tools applied to various machines, still further to prove
the uniformity of principle upon which they act, throughout
these several circumstances.
e comparative views may serve to show the similitude of
principle in tools for like purposes, whether the tools be large or
small, whether they be used for wood or metal, and either by
hand or machinery ; and in cases of indecision or difficulty, a
glance through any one section or chapter may denote, either
the most appropriate of the ordinary tools, or may occasionally
suggest some new modification to suit a particular case, in imita-
tion of the numerous conversions which will be already found to
exist amongst the tools used in the constructive arts.
SECT. II. — THE FORMS AND MOTIONS OF TOOLS, AS REGARDS Tin:
PRODUCTION OF LINES, SUPERFICIES, AND SOLIDS.
THE principles of action of all cutting tools, and of some
others, whether guided by hand or by machinery, resolve them-
selves into the simple condition, that the work is the combined
copy of the form of the tool, and of the motion employed. Or
in other words, that we exactly put into practice the geometrical
definitions employed to convey to us the primary ideas of lines,
superficies, and solids ; namely, that the line results from the
ion of a point, the superficies from the motion of a line,
and the solid from the motion of a superficies.
It therefore follows, as will be shown, that when the tool is a
point having no measurable magnitude, that two motions must
he impressed upon it, one equivalent to the breadth, and another
equivalent to the length of the superficies. When the tool is
wide, so as to represent the one dimension of the superfi
its breadth, then only one motion is to be impressed, say a
motion equivalent to the length of the superficies ; and these two
are either rectilinear or curvilinear, accordingly as straight or
curved superficies are to be produced.
464 MOTIONS REQUIRED FOR THE PRODUCTION
To illustrate this in a more familiar way than by the ideal
mathematical conceptions, that a point is without magnitude,
a line is without breadth, aud a superficies without thickness ;
we will suppose these to be materialised, and to become pieces
of wood, and that the several results are formed through their
agency on soft clay.
Fig. 317.
tp
Thus supposing g g, to be two boards, the edges of which are
parallel and exactly in one plane, and that the interval between
them is filled with clay ; by sliding the board p, along the edges
of g g, the point in p, would produce a line, and if so many lines
were ploughed, that every part of the clay were acted upon by
the point, a level surface would at length result. The line I, such
as a string or wire, carried along g g, would at one process
reduce the clay to the level of the edges of the box.
Either the point or the line, might be applied in any direction
whatever, and still they would equally produce the plane, pro-
vided that every part of the material were acted upon ; and this,
because the section of a plane is everywhere a right line, and
which conditions are fulfilled in the elementary apparatus, as the
edges of g g are straight and give in every case the longitudinal
guide ; and with /, the second line is formed at once, either with
a string, a wire, or a straight board ; but in p, the point requires
a second or transverse guide, and which is furnished by the
straight parts of the board p, rubbing on the edges of g g, and
therefore the point obtains both a longitudinal and a transverse
guide, which were stated to be essential.
The board c, with a circular edge, and m, with a moulding,
would respectively produce circular and moulded pieces, which
LINKS, SUPERFICIES, AND SOLIDS. I' «
would be straight in point of length in virtue ..!'// //, the line of
; in, and curved in width in \irtue of c or m, the lines of tin;
c, and m, must always advance parallel with
their Mailing positions, or tin- \\iiltli of tin; moulding would \;i
and this is true, \\hetic\cr curved guides or curved tools
mi ployed, as the angular relation of the tool must be then
-tantly maintained, \\hiehitis supposed to be by the external
piece or guide attached to m.
Supposing g g, each to have circular edges, as represented
by the dotted arc a a, or to be curved into any arbitrary mould-
ing, the same boards pt /, c, m, wonld produce results of the
former transverse sections, but the clay would in each case pre-
sent, longitudinally, the curved figure of the. curved longitudinal
boanls n a ; here also the line of the tool and the line of the
motion would obtain in the result.
If, to carry out the supposition, we conceive the board a a, to
be continued until it produced the entire circle, we should obtain
a cylinder at one single sweep, if the wire /, were carried round
at ritjht angles to a a. But to produce the same result with the
point j>, it must be done either by sweeping it round to make
circular furrows very near together, or by traversing the point
from side to side, to make a multitude of contiguous lines,
parallel with the axis of the cylinder. In either case we should
apply the point to every part of the surface of the cylinder,
which is the object to be obtained, as we copy the circle of a a,
(which is supposed to be complete,) and the line /; or the trans-
verse motion of /), which is equivalent to a line.
Hut it is obvious that, in every case referred to, there is the
ce of moving either the clay or the tool, without variation
in the ell'eet. If iii respect to the circular guide a a, we set tin-
to rotate upon its center, we should produce all the results
without the necessity for the guide boards a a, as the axis bein^
fixed, and the tool also fixed, the distance from the circuin-
to the center \\ould be everywhere alike, and we should
obtain the condition of the circle by motion alone, instead of by
;iiiil<' : and »uch. in cH'eet, is turning.
An r\ cry-day Example of this identical supposition is seen in
tht- potter's wheel; and the potter also, instead of always
•nbini; the lines of hi> \\ orks with his hands, as in sketchini:,
occasionally resorts to curved boards or templets, as for making
n n
406 MOTIONS REQUIRED FOR THE PRODUCTION
the mouldings for the base of a column, or any other circular
ornament. But here, as also in ordinary turning, we have choice,
either to employ a figured tool, or to impress on a pointed tool
a path identical with the one section ; for example, the sphere
is turned either by a semicircular tool applied parallel with the
axis, or else by sweeping a narrow or pointed tool around the
sphere, in the same semicircular path.
Having shown that in every case, the superficies is a copy of
the tool and of the one motion, or of the point and the two
motions, it will be easily conceived that the numerous super-
ficies and solids, emanating from the diagonal, spiral, oval,
cycloid, epicycloid, and other acknowledged lines, which are
mostly themselves the compositions of right lines and of circles,
may be often mechanically produced in three different ways.
First, by the employment of tools figured to the various shapes,
and used with only one motion or traverse; secondly, by the use
of figured guides, cams, or shaper-plates, by which the motion
is constrained, just the same as p makes a right or a curved
line, in virtue of its straight or curved guide ; and thirdly, by
the employment of a point actuated by two motions, by the
composition of which most geometric lines are expressed.
Thus when uniform motions are employed, two rectilinear
motions produce a diagonal to themselves ; one circular and one
continued right-line motion, give the spiral, the screw, and the
cycloid ; also if during one circular revolution, either the circle
or the point make one oscillation in a right line, we obtain the
oval ; by two circular movements we obtain the epicycloid, by
three motions the compound or double epicycloid, and so on.
And when one or both of the rectilinear or circular generating
motions, are variable as to velocity, we obtain many different
kinds of curves, as the parabola, hyperbola, and others; and
thence the solids, arising from the revolutions of some of these
curves upon an axis.
produce the practical composition of any two lines or
movements, whether regular or irregular, by impressing these
movements on the opposite extremities of an inflexible line or
rod ; from which rod we obtain a compounded*/?';*?, if \ve trace
tin- motion of a point inserted in any part of the rod, and we
obtain a compounded superficies, if we copy the motion of the
entire line. This may need explanation.
Or LINES, SUPERFICIES, AND SOLIDS. !•'.?
Supposing that i: !, guide ff g, to rcmuin :i
;-l»t line, tin- front t«. : iivular arc a a, the board
/<, In in- now traversed in contact both with the- straight and
cm\ ;nt i> would describe a line if it were el
against tlu- line // // ,• or an arc it' close against the arc a a; mid-
way it would iK scribe an arcof about half the original curvature.
On the other hand, the line b would cut off the clay in a super-
fines possessing at the three parts these same conditions, and
merging gradually from the right line to the arc a a.
Hut a similar composition of the two lines or motions would
ir, were the lines ff ff, a a, to be exchanged for any others,
similar or dissimilar, parallel or oblique, or irregular in two
directions; and in mechanical practice we combine, in like
manner, two motions to produce a compound line or a com-
pound superficies. Indeed in many cases there is no alternative
but to impart to two edges ff a of a block, the marginal outlines
of the superficies, and then, generally by hand-labour, to reduce
all the intermediate portions under the guidance of a straight
edge applied at short intervals upon the two edges, which thus
become compounded or melted together in the superficies. Num-
bers of irregular surfaces can be produced by this mode alone.
lu fine, in mechanical processes, we translate the mathe-
matical conceptions vf the rectilinear, circular, and mixed motion*.
of points and lines, into the mechanical realities of rectilinear,
circular, and mixed motions of pointed or linear tools.
not imperative, however, that the tools should have but
1 point or edge, as without change of principle a succcs-
ot' similar points may be arranged in a circle, to constitute
\ol\ing cutter, which by its motions will continually present
a new point, and multiply the rapidity of the effect. In most
« introduction of a tool with a figured outline, cancels
tor the means otherwise required to generate such
line by the motion of a point; and a tool with a figured
B8, cancels also the remaining motion required to pro-
duce tin superficies, and the tool is simply impressed as a stamp
In tracing the method of applying these theoretical views
the explanation of the general employment of cutting tools,
or the practice of the workshop, we may safely abandon all
n i
468 GENERAL METHODS OF PRODUCING
apprehension of complexity, notwithstanding the almost bound-
less variety of the elements of machinery, and other works ot
cutting tools. For although all the regular figures and solids
referred to, are in reality met -with, besides a still greater
number of others of an irregular or arbitrary character, still
by far the greater majority of pieces resolve themselves into
very few and simple parts, namely, solids with plane superficies,
such as prisms, pyramids, and wedges, and solids with circular
superficies, such as cylinders, cones, and spheres. These are
frequently as it were strung together in groups, either in their
entire or dissected states ; but as they are only wrought one
surface at a time, the whole inquiry may be considered to resolve
itself into the production of superficies.
And it may be further stated that, the difference between
the modes of accomplishing the same results, by hand tools
or by machinery, bears a very close resemblance to the difference
between the practices, of the artist who draws the right line and
circle by aid of the unassisted hand, and of the mechanical
draftsman, who obtains the same lines with more defined exact-
ness, under the guidance of the rule and compasses.
The guide principle is to be traced in most of our tools. In
the joiner's plane it exists in the form of the stock or sole of
the plane, which commonly possesses the same superficies as it is
desired to produce. For instance, the carpenter's plane used for
flat surfaces is itself flat, both in length and width, and there-
fore furnishes a double guide. The flat file is somewhat under
the same circumstances, but as it cuts at every part of its
surface, from thousands of points being grouped together, it is
more treacherous than the plane, as regards the surface from
which it derives its guidance, and from this and other reasons,
it is far more difficult to manage than the carpenter's plane.
In many other cases the cutting instrument and the guide
are entirely detached; this is strictly the case in ordinary
turning, in which the circular guide is given by the revolution of
the lathe mandrel which carries the work, the surface of which
becomes the copy of the tool, or of the motion impressed upon
the tool, either by the hand of the workman under the guidance
of his eye alone, or by appropriate mechanism.
AVhcn the lathe is cm ployed under the most advantageous
circumstances to produce the various geometrical solids or
1. 1 MS, -i i-i iu ;< IBS, AND SOLIDS. l''-'.l
figures, the tool is placed under the guidance of a ruler Of
rati -lide. by \\hieh its path is strictly limited to a recti-
linear motion. Thus for a cylinder, the slide is placed exactly
parallel with the rotary axis of the mandrel, and tor a plain flat
thfl to . .1 is in, >\ i'd on a slide at right angles to the axis.
• •rally two slides fixed in these positions are attached to the
lathe to cany and guide the tool, the machine being knowu
as the sliding rest; hut mostly the one slide only is used as a
traversing or directional slide for guiding the tool, the other as
an adjusting or position slide, for regulating the penetration of
the tool into the work.
Sometimes the two slides are moved simultaneously for the
production of cones, but more generally the one slide is placed
oblique and used alone. The lathe is employed with great effect
in producing plane surfaces, but the more modern engine, the
pianino-machine, the offspring of the slide or traversing lathe
iitly adverted to, is now also very much employed for all
kinds of rectilinear works.
The planing-machiue being intended principally for rectilinear
solids of all kinds, its movements are all rectilinear, and these
are in general restricted to three, which are in the same relation
to each other as the sides of a cube ; namely, two are horizon-
tal and at right angles to each other, and the third is vertical,
and therefore perpendicular to the other two. The general
outline of the machine will be conceived by imagining a
horizontal railway to take the place of the revolving axis of the
lathe, and the slide rest of the lathe to be fixed vertically
.st the face of a bridge stretching over the railway.
In the general .structure of this most invaluable machine, the
railway is the cutting slide, upon which the work is slid to and
r producing a horizontal surface, the horizontal slide
;'.)!• traversing the tool across the face of the work',
which is thus reduced by ploughing a series of parallel grooves,
not exceeding in distance the width of the pointed tool, so that
the line, and then the surface arise, exactly as in the geome-
1 suppositions. For vertical planes, the vertical is the
traversing slide, the hori/.ontal the adjusting; and for oblique
planes, th.- vertical slide is swivelled round to the assigned
angle, the imaginary railway being employed in all cases to
ion.
170 GENERAL METHODS OF PRODUCING
To advance into greater detail would be to encroach on the
subject of the succeeding chapters ; although it may be added,
that when we examine into almost any machine employed in
cutting, it will be found that the end to be obtained is always a
superficies, either plane or curved, and which superficies reduced
to its elementary condition, presents length and breadth.
When, therefore, we have put on one side the mechanism
required for connecting and disconnecting the engine with the
prime mover, whether animal, steam, or other power ; it will be
found that when the superficies is produced by a pointed tool,
the primary motions resolve themselves into two, which may be
considered representative of length and breadth. The velocity
of the one primary motion, is suited to the speed proper for
cutting the material with the most productive effect, which for
the metals is sometimes as low as ten or twenty feet per minute,
measured at the tool, and for the woods, the speed is above ten
or twenty times as great.* The velocity of the other primary
motion is generally very small, and often intermittent ; and it
becomes a mere creep or traverse motion, by which the pointed
tool is gradually moved in the second direction of the superficies,
under formation.
In producing circular bodies, one of these primary motions
becomes circulating or rotary, and in complex or irregular forms,
an additional movement, making in all three, or sometimes four
are compounded ; and lastly, when linear or figured tools are
employed, one of the motions is generally expunged.
* The principal limit of velocity in cutting machines, appears to be the greatest
speed the tool will safely endure, without becoming so heated by the friction of
separating the fibres, as to lose its temper or proper degree of hardness.
The cohesion of iron being very considerable, a velocity materially exceeding
ten to twenty feet per minute, would soften and discolour the tool, whereas in
general the tools for iron are left nearly or quite hard. Brass having much less
cohesion than iron, allows a greater velocity to bo used, lead and tin admit of still
more speed, and the fibrous cohesion of the soft woods is so small, that when the
angles of the tools are favourable, there is hardly a limit to the velocity which may
bo used. Water, soap and water, oil, milk, and other fluids, are in many cases
employed, and especially with the more fibrous metals, for the purpose of lubri-
cating the cutting edges of the tools to keep down the temperature, the fluids
reduce the friction of separating the fibres, and cool both the tool and work,
thereby allowing an increase of velocity ; and at the same time they lessen the
deterioration of the instrument, and which when blunted, excites far more friction,
and is likewise more exposed to being softened, than when keen and in perfect
working order. There are, however, various objections to the constant use of
lubricating fluids with cutting tools.
I INKS, SUPERFICIES, AND SOLIDS. 171
The utlu T movements of cutting machines may be considered
M secondary, and introduced cither to effect the adjustment of
position nt starting, or the changes of position during the
_rress of the work; or the resetting* by which the same
superficies is repeated, as in the respective sides of a prism, or
the teeth of a spur wheel, which may be viewed as a complex
prism.
The above two or three movements may in general be im-
pressed wholly upon the tool, wholly upon the work, or partly
upon each ; and which explains the very many ways which,
in cases of simple forms, may be adopted to attain the same
result.
In numerous instances likewise, all the movements arc as it
were linked together in a chain, so that they may recur at
proper intervals, without the necessity for any other adjustment
than that \\hich is done prior to the first starting, such are very
appropriately called self-acting machines, and these, in many
cases, give rise to very curious arrangements and combinations
of parts, quite distinct from the movements abstractedly required
to produce the various superficies and solids, in which the
mathematician and mechanician from necessity exactly agree,
when their respective speculations are sifted to their elementary
or primary laws, which are few, simple, and alike for all.
Mr. Nasniyth has written an interesting paper, entitled,
" Remarks on the Introduction of the Slide Principle, in Tools
and Machines employed in the production of Machinery." *
This principle, although known for a far greater period, has
within less than half a century, and in many respects even within
1< H than the fourth of a century, wrought most wonderful
changes in the means of constructing mechanism, possessed of
nearly mathematical accuracy. The whole of this is traced to
the employment of the two, or the three slide movements, to
which method Mr. Nasmyth has judiciously applied the term
</r I'rinciple," but the object in this place is rather to
examine in detail the principles and practices, than to refer to
the influence these have had on manufacturing industry, and
thence on the general condition of mankind, and upon our own
n in particular.
• See Buchanau'a Mill Work, by O. Rennio, F.R.& 1841. Page 398.
472
CHAPTER XXIII.
CHISELS AND PLANES.
SECT. i. — INTRODUCTION; BENCH PLANES.
IF we drive au axe, or a thin wedge, into the center of a
block of wood, as at a, fig. 318, it will split the same into two
parts through the natural line of the fibres, leaving rough
uneven surfaces, aud the rigidity of the mass will cause the rent
to precede the edge of the tool. The same effect will partially
occur, when we attempt to remove a stout chip from off the side
of a block of wood with the hatchet, adze, pariug or drawing
knife, the paring chisel, or any similar tool. So long as the chip
is too rigid to bend to the edge of the tool, the rent will precede
the edge ; and with a naked tool, the splitting will only finally
cease when the instrument is so thin and sharp, and it is applied
to so small a quantity of the material, that the shaving can bend
or ply to the tool, and then only will the work be cut or will
exhibit a true copy of the smooth edge of the instrument, in
opposition to its being split or rent, and consequently sho\viug
the natural disruption or tearing asunder of the fibres.
In fig. 318 are drawn to one scale several very different paring-
tools, which agree however in similitude with the type, b, fig.
81 G, page 460, and also corroborate the remark on page 462,
that " in the paring-tools, the one face of the wedge or tool is
applied nearly parallel with the face of the work." In tools
ground with only one chamfer, this position not only assists in
giving direction to the tool, but it also places the strongest line
of the tool exactly in the line of resistance, or of the work to
be done.
For example, the axe or hatchet with two bevils, a, fig. 318,
which is intended for hewing and splitting, when applied to
pariny the surface of a block, must be directed at the angle a
uliich would be a much less convenient and less strong position
than b, that of the side hatchet with only one chamfer; but for
paring either a very large or a nearly horizontal surface, the side
MOIM > OK III I
;;;-.
'net in it> turn is greatly inferior to the adze C, in which the
haiullc i> clt-\atcd like a ladder, at some (50 or 70 degrees from
the -round, th.- preference being grtcn to the hon/.>nt:il portion
for tlu- surface to In- wrought.
Tin- iiistruuiriit is lii-lil in both
hands,whibttheo] unK
upon h;s \\ork in a stooping
:on, the handle being from
twenty-four to thirty inches
long, ami the weight of the
blade from two to four pounds.
Th'- ad/e i> swung iu u cir-
enlar path almost of the same
rnrvature as the blade, the
shoulder-joint being the center
.otion, and the eutire arm
and tool forming as it were one
indexible radius; the tool there-
ton- makes a succession of small
are-, and in each blow the arm
of the workman is brought in
contact with the thigh, which thus serves as a stop to prevent
lent. In coar>e preparatory works, the workman din
the ad/.e through the space between his two feet, he thus sur-
priM-s us by the quantity of wood removed; in tine works, he
frequently places his toes over the spot to be wrought, and the
adze penetrates two or three inches beneath the sole of the
, and he thus surprises us by the apparent danger
pei feet working of the instrument, which in the hands of the
shipwright in particular, almost rivals the joiner's plane; i
with him the nearly universal paring instrument, and is i
upon work> in all positions.
The small Indian adze OrBanMlXh d, fig. 3 18, in place of being
circular like the Kuropcan ad/e, is formed at a direct angle of
aboi Mi degrees; its handle is very short, and it is i.
with givat precision bj thfl marly cxchiMve motion of the elbow
joint.* In nnl.T to ^lind either of these adzes, or percussive
• " TLi» very tuvful iuatr umuut (says Sir Jolm liubioou), v*rie« a little iu different
i weight and iu the angle which the cutting face forma with the line of
tin- handle, but the funn ahown is the most gcueral, and the weight averages abuut
-471 MODIFICATIONS OF THE CHISEL.
chisels, it is necessary to remove the handle, which is easily
accomplished as the eye of the tool is larger externally as in the
common pickaxe, so that the tool cannot fly off when in use,
but a blow on the end of the handle easily removes it.
The chisel e, admits of being very carefully placed, as to posi-
tion, and when the tool is strong, -very flat, and not tilted up, it
produces very true surfaces as seen in the mouths of planes. The
chisel when applied with percussion, is struck with a wooden
mallet, but in many cases it is merely thrust forward by its
handle. It will shortly be shown that various other forms of the
handle or stock of the chisel, enable it to receive a far more
defined and effective thrust, which give it a different and most
important character. The paring-knife, fig. 8, p. 26, Vol. I, exhibits
also a peculiar but most valuable arrangement of the chisel, in
which the thrust obtains a great increase of power and control ;
and in the drawing-knife, the narrow transverse blade and its
two handles form three sides of a rectangle, so that it is actuated
by traction, instead of by violent percussion or steady thrust.
The most efficient and common paring-tool for metal, namely/,
has been added to fig. 318 for comparison with the paring-tools
for wood ; its relations to the surface to be wrought are exactly
the same as the rest of the group, notwithstanding that the angle
of its edge is doubled on account of the hardness of the material,
and that its shaft is mostly at right angles, to meet the construc-
tion of the slide rest of the lathe or planing machine.
The chisel, when inserted in one of the several forms of stocks
or guides, becomes the plane, the general objects being, to limit
the extent to which the blade can penetrate the wood, to provide
a definitive guide to its path or direction, and to restrain the
splitting in favour of the cutting action.
In general, the sole or stock of the plane is in all respects an
1 lb. 12oz. The length of handle is about twelve or thirteen inches, and in use
it is grasped so near the head, that the forefinger rests on the metal, the thumb
nearly on the back of the handle, the other fingers grasp the front of it, the nails
approaching the ball of the thumb. The wrist is held firmly, the stroke being
made principally from the elbow, the inclination of the cutting face being nearly
a tangent to the circle described by the instrument round the elbow joint as a
center, the exact adjustment being made by the grasp and the inclination of the
wrist, which is soon acquired by a little practice. In this way very hard woods
may be dressed for the lathe with a degree of ease and accuracy not attainable
with the small axe used in this country."
(iKNKRAL KORM8 OK r:
475
counterpart of the form it is intended to produce, and
it therefore combine* in itself tin- longitudinal and the transvene
•ecti 'hi- two guides referred to in the theoretical diagram,
page 4<>1, and the annexed figure :;!'.", the parts of which are
all drawn to one scale, may he considered a parallel diagram to
•')!?, page 404, so far as regards planes.
Thus, although convex surfaces, such as the outside of a hoop,
may be wrought by any of the straight planes, applied in the
direction of a tangent as at a, it is obvious the concave plane,
//, would be more convenient. For the inside of the hoop, the
radius of curvature of the plane must not exceed the radius of
the work : thus c, the compass plane, would exactly suit the
curve, and it might be used for larger diameters, although in a
lc-s perfect manner. For the convenience of applying planes to
very small circles, some are made very narrow or short, and
uith transverse handles such as d, the plane for the hand-rails
of staircases, the radius of its curvature being three inches ; it
resembles the spokcshave e, as respects the transverse handles,
although the hand-rail plane has an iron, wedge, and stop, much
like those of other planes.
sections of planes, are also either straight, concave,
com i A. or mixed lines, and suited to all kinds of specific
mouldings, but we have principally to consider their more
common to;: :nely, the circumstances of their edges and
guides ; first, of those used for flat surfaces, called by the
join | secondly, the growiny planes; and thirdly,
the innnldinii planes.
476 SURFACING, OR BENCH PLANES.
The various surfacing planes are nearly alike, as regards the
arrangement of the iron, the principal differences being in their
magnitudes. Thus the maximum width is determined by the
a vi1 rage strength of the individual, and the difficulty of main-
taining with accuracy the rectilinear edge. In the ordinary
bench planes the width of the iron ranges from about 2 to 2£
inches.*
The lengths of planes are principally determined by the degree
of straightuess that is required in the work, and which may be
thus explained. The joiner's plane is always either balanced
upon one point beneath its sole, or it rests upon two points at
the same time, and acts by cropping off these two points, with-
out descending to the hollow intermediate between them. It is
therefore clear, that by supposing the work to be full of small
undulations, the spokeshave, which is essentially a very short
plane, would descend into all the hollows whose lengths were
greater than that of the plane, and the instrument is therefore
commonly used for curved lines. But the greater the length of
the plane, the more nearly would its position assimilate to the
general line of the work, and it would successively obliterate the
minor errors or undulations ; and provided the instrument were
itself rectilinear, it would soon impart that character to the edge
or superficies submitted to its action. The following table may
be considered to contain the ordinary measures of surfacing
planes.
Names of Planes. Lengths, Widths, Widths
in inches. in inches. of Irons.
Modelling Planes, like Smoothing Planes . 1 to 5 — ^ to 2 — TV t° H
Ordinary Smoothing Planes . . . 64 to 8 --2|to3J — If to2|
lie-bate Planes 94 - - f to 2 - - j| to 2
Jack Planes 12 to 17 - 2J to 3 •— 2 to 2$
Panel Planes 14J -34 - 2J
Trying Planes 20 to 22 — 3} to 3| — 2| to 24
Long Planes 24 to 26 -- 3| - 2$
Jointer Plauea 28 to 30 — 3j — 2}
Cooper's Jointer Planes . . .. 60 to 72 -- 5 to 5$ — 34 to 3J
The succession in which they are generally used, is the jack
plane for the coarser work, the trying plane for finer work and
trying its accuracy, and the smoothing plane for finishing.
* The " iron," u scarcely a proper name for the plane-iron, which is a cutter
or blade, composed partly of iron and steel ; but no confusion can arise from the
indiscriminate use of any of these terms.
GENERAL STRUCTURE or ri . \M«.
diagram, iig. •">-<), is one quarter the full size, and may
be considered to represent the ordinary surfacing planes, tin-
mouths of which arc alike, generally about one-third from tin-
front <>f the plane, and t Ims const it uted. The line a, b, is culled
the tolt : ' . '/, upon which the hlnde is supported, is the bed, and
this, in planes of common pitch, is usually at an angle of 45°
with the perpendicular.
Fig. 320.
The month of the plane is the narrow aperture between the
fare of the iron, and the line c, f, which latter is railed the >'•<
the anu'lc between these should be as small as possible, in order
that the wearing away of the sole, or its occasional correction,
may cause but little enlargement of the mouth of the plane ; at
the same time the angle must be sufficient to allow free egress
•he shavings, otherwise the plane is said to choke. The line
//. is called the front, its angle is unimportant, and in pra>
it is usually set out one quarter of an inch wider on the upper
surface than the width of the iron.
'?/<• of the plane which fixes the iron is commonly at
an angle of 10°, and it is slightly driven between the face of the
. and the shoulder or nhiitment, C, e. It is shown by the two
detached views, that t he wedge w, is cutaway at the central part,
both to clear the screw which connects the double iron, and to
allow room for the escape of the shavings. The wedge is loosened
by a moderate blow, either on the end of the plane at h, on the
478 GENERAL STRUCTURE OF PLANES.
top at i, or by tapping the side of the wedge, which maybe then
pulled out with the fingers ; a blow on the front of the plane
at jt sets the iron forward or deeper, but it is not resorted to.
In all the bench planes, the iron is somewhat narrower than
the stock, and the mouth is a wedge-formed cavity; in some of
the narrow planes the Cutting edge of the iron extends the full
width of the sole, as in the rebate plane/, fig. 319, page 475 ; in
these and others, the narrow shaft of the iron and the thin wedge
alone proceed through the stock, and there is a curvilinear mouth
extending through the plane ; the mouth is taper, to turn the
shavings out on the more convenient side. When the planes
only cut on the one part of the sole, as in fig. 332, page 485, the
angular mouth extends only part way through the plane, and the
curvilinear perforation is uncalled for.
In the diagram, fig. 320, when the stock terminates at the
clotted line, *, *, it represents the smoothing plane ; when it is
of the full length, and furnished with the handle or toat, it is
the jack plane or panel plane ; the still longer planes have the
toat further removed from the iron, and it is then of the form
shown in fig. 330, page 483.
Fig. 321 represents, one-eighth the full size, a very effective
plane, which is commonly used on the continent for roughing
out, or as our jack plane, the horn h, being
intended for the left hand, whilst the right
is placed on the back of the stock. The
Indians and Chinese bore a hole through
the front of the plane for a transverse
stick, by which a boy assists in pulling
the plane across the work. When the
plane is very large, it is by the Chinese,
and others, placed at the end of the bench at an angle, and
allowed to rest on the ground, whilst the work is slid down its
face ; and a similar position is employed by the coopers in our
own country, for planing the staves of casks, the plane being in
such cases, five or six feet long and very unwieldy, the upper
part is supported on a prop, and the lower rests on a transverse
piece of wood or sleeper.
The amount of force required to work each plane is dependent
on the angle and relation of the edge, on the hardness of the
material, and on the magnitude of the shaving ; but the required
( Ol I UK PLANE-IKON.
479
force is in addition greatly influenced by tin- degree in which
the -having \* l>i-iit for its n-moval in tlir most ; tanner.
I :',-2-2 to .".Jil represent, of their full size, parts of
the irons and mouths of various plant -s, each in the act of rc-
;nu' a >hav in:;. Tin1 sole or surface of the plane rests upon
the face of tin- work, and the cutter stands as much in advance
of the sole of tin- plane, a.s the thickness of the shaving, which
U in each cax- so In nt as to enable it to creep up the face of
the inclined iron, through the narrow slit of the plane, called its
mouth, tin- width of which determines the extent to which the
fibre of the wood can tear up or split with the jjrain.
The spokeshave, fig. 322, cuts perhaps the most easily of all
the planes, and it closely assimilates to the penknife; the angle
of the blade is about 25 degrees, one of its planes lies almost in
contact with the work, the inclination of the shaving is slight,
and the mouth is very contracted. The spokeshave works very
easily in the direction of the grain, but it is only applicable
to small and rounded surfaces and cannot be extended to suit
larire tlat superficies, as the sole of the plane cannot be cut away
for such an iron, and the perfection of the mouth is compara-
tively soon lost in grinding the blade.
.
Fig. 323.
The diagrams, figs. 323, 4, and 5, suppose the plane irons to
be ground at the anirle of 25°, and to be sharpened on the more
refined oilstone at 35°, so as to make a second bcvil or slight facet,
as shown by the dotted lines a, in each of the figures ; the irons
•O ground are placed at the an^lc of 45°, or that of common pitch ,-
it t i : -llovv ^. that the ultimate bev il which should be \
nai elevation of 10° from the surface to be planed.
its the mouth of an old jack plane, from the
sole of which about half an inch of wood has been lost by wear
480
ACTION OF THE PLANE-IRON.
and correction, which is no uncommon case. The wide mouth
allows a partial splitting of the fibres before they creep up the
face of the single iron ; this plane works easily, and does not
greatly alter the shavings, which come off in spiral curls, but
the work is left rough and torn.
Fig. 324.
Fig. 325.
Fig. 326.
Fig. 324, a similar but less worn plane with a closer mouth,
allows less of the splitting to occur, as the shaving is more sud-
denly bent in passing its narrower mouth, so that the cutting
now begins to exceed the splitting, as the wood is held down by
the closer mouth : the shaving is more broken and polygonal,
but the work is left smoother.
The same effects are obtained in a much superior manner in
the planes with double irons, such as in fig. 325, the top iron is
not intended to cut, but to present a more nearly perpendicular
wall for the ascent of the shavings, the top iron more effectually
breaks the shavings, and is thence sometimes called the break
iron.
Now therefore, the shaving being very thin, and constrained
between two approximate edges, it is as it were bent out of the
way to make room for the cutting edge, so that, the shaving is
removed by absolute cutting, and without being in any degree
split or rent off.
The compound or double iron is represented detached, and
of half size in fig. 327 : in this figure the lower piece e, is the one
Fig. 327.
used for cutting, the upper piece t or the top iron, has a true
of THE PLANB-IK I M
edge, which is also moderately sharp, the top iron is placed
from one.sKteenth to oiir-tini. th of an inch from the edge of
the cutter, the two are held together so closely by the screw
which passes through a l«m- mortise in C, and tits in a taj
hole in /, that no shaving can tret l)et\veen tliein.
The constant employment of the top iron in all available cases,
shows the value of the improvement; and the circumstance
the plane working the smoother, hut harder, when it is added.
and the more so the closer it is down, demonstrate that its
action is to break or bend the fibres. This is particularly
rvablc in the coarse thick shavings of a double-iron jack
<•, compared with those of the same thickness from a single-
iron plane; the latter are simply spiral and in easy curves,
whereas those from the double-iron are broken across at short
intervals, making their character more nearly polygonal ; and
the same difference is equally seen in thinner shavings, although
of course less in degree.
represents the iron of a plane intended " for the use
of cabinet-makers and others, who require to cut either hard
or coarse-grained wood," the upper bevil given to the iron,
being considered to dispense with the necessity for the top-iron ;
but it is obviously much more difficult to produce a true right-
lined edge, by the meeting of two planes, each subject to error
in .sharpening, than when one exists permanently flat as in the
broad surface of the blade.
same edge may be obtained by a blade with a single
chamfer, the flat side of which is placed in either of the dotted
tions of fig. -'5 2»'.. The first, or b, is that previously in common
in the ordinary moulding planes for mahogany, and c is almost
the position of the bed for the iron of the mitre-plane, also pre-
\ iou>l\ e Miimon : in all three planes, the ultimate angle of the
face of the cutter is just GO degrees from the horizontal.
its the mouth of the mitre plane full size,
and the entire instrument one-eighth size. The stock
is much less in height than in ordinary planes, and the iron lies
at an angle of about 2~)°, and is sharpened at about the ordinary
, making a total elevation of 60°, which, together
the delicate metallic mouth, render the absence of the top
• Soe Tntn artioiw of tl.e Society of Arts, 1825, rol. zliiL p. 85.
I I
MITKi: PLANE. ANGLES OF PITCH.
iron unimportant, even when the plane is used lengthways of the
fibres, although its ostensible purpose is to plane obliquely
across their ends, as in the formation of mitre joints.
r
329.
In all ordinary planes the mouth gets wider as the iron is
ground away, because of the unequal thickness or taper form of
the blade as seen at c, fig. 327. In the mitre plane this is avoided
by placing the chamfer upwards, now therefore the position of
the blade is determined by its broad flat face which rests on the
bed of the instrument d, and maintains one constant position as
regards the mouth, uninfluenced by the gradual loss of thickness
in the iron.
The smoothing and trying planes are also made with metal
soles, and with single irons of ordinary angles, as one great pur-
pose of the top iron is to compensate for the enlargement of
the mouth of the plane by wear, this defect is almost expunged
from those with iron soles, and which are gradually becoming
common, both with single and with double irons. See Appendix,
Note A.H., page 978.
Some variation is made in the angles at which plane irons are
inserted in their stocks. The spokeshave is the lowest of the
series, and commences with the small inclination of 25 to 30
degrees; and the general angles, and purposes of ordinary planes,
are nearly as follows. Common pitch, or 45 degrees from the
horizontal line is used for all the bench planes for deal, and
similar soft woods. York pitch, or 50 degrees from the hori-
zontal, for the bench planes for mahogany, wainscot, and hard
or stringy woods. Middle pilch, or 55 degrees, for moulding
planes for deal, and smoothing planes for mahogany, and similar
woods. Half pitch, or 60 degrees, for moulding planes for
mahogany, and woods difficult to work, of which bird's-eye
maple is considered one of the worst.
. PI It II.
Mxxl, mid other close hard woods, may be smoothly
il, if not cut, in any direction of the grain, when the angle
•mi: the pitch entirely disappears ; or with a common
••tiling-plane, in which the cutter is perpendicular, or «
Ell slightly forward; this tool is railed a scrnjiiiiy ji/ane, and
is used for scraping the i\ory keys of piano-fortes, and works
inlaid with ivory, brass, and hardwoods; this is quite analogous
lie process of turning the hardwoods.
cabinet-maker also employs a scraping-plane, with a
perpendicular iron, which is grooved on the face, to present a
es of fine teeth instead of a continuous edge; this, which is
called a tool/iiny plane, is employed for roughing and scratc/iint/
veneers, and the surfaces to which they are to be attached, to
make a tooth for the better hold of the glue.
The smirh's-plane for brass, iron, and steel, fig. 330, has
likewise a perpendicular cutter, ground to 70 or 80 degrees; it
justed by a vertical screw, and the wedge is replaced by an
end screw and block, as shown in the figure, which is one-eighth
In the planes with vertical irons, the necessity for the
narrow mouth ceases ; and in the smith's plane some of the
irons, or more properly cutte;
No grooved on the faces, by Fig 330.
which their edjres are virtually
divided into several narrow
pieces; this the instru-
ment to be more easily employed "yUj
in rou^hin^-out works, by abs- I —
•in:; so much of the width
of the iron, and by giving it a greater degree of penetration, but
the finishing is done with smooth-edged cutters, and those not
exceeding from five-eighths of an inch to one inch wide.
well known that most pieces of wood will plane better
from the one end than from the other, and that when such
: in ued over, they must be changed end for end
likewise; the necessity for this will immediately appear, if we
the shade-lines under the pi:,. . 331, to
repiv-rii! the natural til ires of the wood, which are rarely parallel
with the face of the work. The pi. me a, working triM t/ie ff
i '
484
SCRAPER. GROOVING PLANES.
would cut smoothly, as it would rather press down the fibres
than otherwise; whereas b would work against the grain, or
would meet the fibres cropping out, and be liable to tear them up.
It was explained in
Fig. 331. Chap. IV., Vol. I., that
\ >•-"" / / / the handsome characters
,/...-•' / / / of showy Avoods, greatly
:
6 depend on all kinds of ir-
regularities in the fibres:
so that the conditions a
and b, fig. 331, continually
occur in the same piece of wood, and in which we can therefore
scarcely produce one straight and smooth cut in any direction.
Even the most experienced workman will apply the smoothing-
plane at various angles across the different parts of such wood
according to his judgment ; in extreme cases, where the wood
is very curly, knotty, and cross-grained, the plane can scarcely
be used at all, and such pieces are finished with the steel scraper.
This simple tool was originally a piece of broken Avindow-glass,
and such it still remains in the hands of some of the gun-stock
makers ; but as the cabinet-maker requires the rectilinear edge,
he employs a thin piece of saw-plate, which is represented black
and highly magnified at *, fig. 331. The edge is first sharpened
at right angles upon the oilstone, and it is then mostly bur-
nished, either square or at a small angle, so as to throw up a
trifling burr, or wire-edge. The scraper is held on the wood at
about 60°, and as the minute edge takes a much slighter hold,
it may be used where planes cannot be well applied. The
scraper does not work so smoothly as a plane in perfect order
upon ordinary wood, and as its edge is rougher and less keen,
it drags up some of the fibres, and leaves a minute roughness,
interspersed with a few longer fibres.
SECT. II. — GROOVING PLANES.
We may plane across the grain of hard mahogany and box-
wood with comparative facility, as the fibres are packed so
closely, like the loose leaves of a book when squeezed in a press,
that they may be cut in all directions of the grain with nezirly
equal facility, both with the flat atid moulding planes. But
the weaker and more open fibres of deal and other soft woods,
•IDB-riLUtTKR.
i-r,
cannot withstand ;i cutting edge applied to them /iarallrl with
thfiHselvet, or lat > they are torn up, ami ha\earough
unfuii«.hcd n 1 he jnim-r UM-> then.- fore, for deal and soft
/.v. a very keen plane of low pitch, and slides it across
obliquely, so as to attack the fibre from the one end, and
virtually to remove it in the direction of its length; so that
the force is divided :uul applied to each part of the fibre in
succession.
Tin1 moulding planes cannot be thus used, and all mouldings
le in deal, and woods of similar open soft grain, are con-
sequently always planed lengthways of the grain, and added
as separate pieces. As however many cases occur in carpentry,
in which rebates and grooves are required directly across the
u of deal, the obliquity is then given to the iron, which is
rtnl at an angle, as in the skew-rebate and fillister, and the
stock of the plane is used in various ways to guide its transit.
.Many of these planes present much ingenuity and adaptation
to their particular cases : for example fig. 332 is the side view,
and ti;:. -i-i-i the back of the side-fillister, which is intended to
Figs. 332. 333. 334.
n
a 6
plane buth with and across the grain, as in planing a re!
around the margin of a panel. The loose slip, or the fence./) is
adjusted to expose so much of the oblique iron as the width
of the rebate; the screw-stop *, at the side, is raised as much
above the sole of the plane as the depth of the rebate, and the
little tooth t, or scoring point (shown detached, in two views a, b],
•cdes the bevelled iron, so as to shear or divide the fibres as
with the point of a penknife, to make the perpendicular edge
i and square. This plane is then-fore a four-fold combina-
tion of two measures and two cutters. The oblique iron, and
the tooth or cutter, are pretty constantly met with in the p!:i
kfl jrrain.
Others of these planes have less power of adjustment; for
486
GROOVING PLANES; PLOUGH, ETC.
instance the grooviug-plane fig. 334, for planing across the
grain, has two separate teeth, or else a single tooth with two
points c, in addition to the cutting-iron which is commonly
placed square across the face of the plane ; the groove is only
used for the reception of a shelf, its sides are therefore the more
important parts, and the obliquity of the iron maybe safely
omitted. The fence can no longer be a part of the instrument,
as it is often used in the middle of a long piece, a wooden
straight-edge s, is therefore temporarily nailed down to guide
the plane ; and the stop is sometimes a piece of boxwood fitted
stiffly in a mortise through the stock, at other times it is
adjusted by a thumb- screw, as in the figure 334.
The plough, fig. 335, is a grooving-plane, to work with the
grain ; it has similar powers to the fillister, but with a greater
horizontal range. The width of the groove is determined by
that of the blade, of which each plough has several ; they are
retained in the perpendicular position by a thin iron plate,
which enters a central angular groove in the back of the biade.
The teeth or scoring points are now uncalled for, as the iron
works perfectly well the lengthway of the fibre. The screw-stop
is the same as before; but the fence f, is built upon two trans-
verse stems s s, one only seen, passing through mortises in the
body of the plane, and fixed by wedges. In the German plough
the position of the fence/, is determined and maintained by two
wooden screws, instead of the stems s s, and there are two wooden
nuts to each screw, one on each side of the stock of the plough.
Figs. 335. 336. 337. 338.
Other grooving-planes for working with the grain are also
made without teeth, examples of which may be seen in the
(Irawrr-hottom plane 330, and the slit deal planes, of which \\-\7
tin- gi-.Mivr, ;iiid 338 the tongue, used for connecting
, lint I I 1C, < UU'KNTERH '
boards for partitions and other purposes, with the groove and
oint MO. The- planes of this class bcin^ generally used
for out* specific purpose and measure, arc nnprmided with loose
parts, as they arc worked until the sole of the plane, or some of
dges come in contact with the wood, and stop the further
pn>t;rcsx of the .utter.
Fig. o in, the re-let plane, is of this kind, it derives its name
from being employed in making the parallel slips of wood, or
i\f//i 7. used by the printer for the wide separation of the lines of
metal type, the adjustable fences are screwed fast, as much in
aihance of the sole of the plane as the required thickness of the
re-lets or rules, which are then planed away until, from the slips
j on the bench, the tool will cut no Ion
Fig*. 340.
11 is a router plane ; it has a broad surface carrying in
its centre one of the cutters belonging to the plough, it is n>» d
for levelling the bottoms of cavities, the stock must be more than
the \\idth of the recess, and the projection of the iron
determines the depth, the sides of the cavities are prepared
before-hand with the chisel and mallet. The ordinary name for
this plane is not remarkable for its propriety or elegance, it is
ally called the " old woman's tooth." See Appendix,
Note A. I., page 979.
The carpenters' gages, for setting out lines and grooves parallel
\\ith the margin of the work, are closely associated with the
ui of fences or rails. The stem of the gage, fig. 3t2, is
retained in the head, or stock, l>y means of a small wedge, and
the cutter is fixed in a hole at right angles to the face of tin-
stem, by another wedge. The warkiny-gage, for setting out
lines, has a simple conical point ; the cut tiny -gage, for cutting
and thin wood, has a lancet--»ha:>ed knit. . and is a
488 GAGES, BANDING PLANE, AND ROUNDER.
very effective tool ; the router-gage, for inlaying small lines of
wood and brass, has a tooth like a narrow chisel.
There are other forms of gages, some of these have screw
adjustments ; in the most simple, the stem is a wooden screw,
flattened on one side, and the head of the gage consists of two
wooden nuts, which become fixed when screwed fast against
each other. The mortise-gage, which is much used, has two
points that may be adjusted to scribe the widths of mortises and
tenons. In the bisecting gage there are two sliding pieces or
heads, which are made to embrace the object to be bisected, and
the scribing point is in the center of two equal arms jointed
respectively to the two sliding heads.*
The cooper's croze is used for making the grooves for the
heading of casks, after the ends of the staves have been levelled by
a tool called a sun plane, like a jack-plane, but of a circular plan.
The croze is similar to the gages, except that it is very much
larger; the head is now nearly semicircular, and terminates
in two handles; the stem, which is proportionally large, is also
secured by a wedge, but the cutter is composed of three or four
saw-teeth, closely followed by a hooked router, which sweeps
out the bottom of the groove.
The banding -plane-f is allied to the gages, and is intended for
cutting out grooves, and inlaying strings and bands in straight
and circular works, as in the rounded corners of piano-fortes
and similar objects. It bears a general resemblance to the
plough, fig. 335, but it is furnished in addition with the double
tooth c, of the grooving plane, fig. 334. In the banding plane,
the central plate of the plough is retained as a guide for the
central positions of the router and cutter, which are inserted, so
as to meet in an angle of about 80 degrees, between two short
projections of the central plate ; the whole of the parts ent jring
the groove are compressed within the length of one inch, to
> through curvatures of small radius ; there are various
cutters and fences, both straight and circular, according to the
nature of the work. See Appendix, Note A.J., page 979.
Fig. 343 is a plane which is the link betwixt carpentryand
* Seo H. It. Palmer's ga-e for marking center Hues. — Trails. Soc. of Arts, 1813,
vol. xxxi. p. 248.
t Mr. It. Ouwin'a Landing plane.— Trans. Soc. of Arts, 1817, vol. xxxv. p. 122.
Mo II . \M>, AM) Til Kill IMPERKEITIONS.
turning; the conical hole in the plain- is furni-hed w iih a cutter
placed as a tangent to tin- circle, so that the \\ootl enters in the
:h octagonal form, and lea uuled, lit for a broom, an
umbrella handle, or an oilier rnlcr; sometimes either the work
or plane i by machinery, with the addition of one or two
preparatory gouges, for removing the rougher parts.
SECT. III. — MOULDING PLANES.
All the planes hitherto considered, whether used parallel with
the Mirt'aco, as in straight works, or as tangents to the cui
as in curved works, are applied under precisely the same circum-
stances, as regards the angular relation of the mouth, because
the edge of the blade is a right line parallel with the sole of the
plane; but when the outline of the blade is curved, some new
conditions arise which interfere with the perfect action of the
instrument. It is now proposed to examine these conditions in
respect to the semicircle, from which the generality of mould-
ing may be considered to be derived.
In the astragal, a, b, c, d, e, fig. 844-, a small central portion
at c, may be considered to be a horizontal line; two other
small portions at b, and d, may be considered as parts of the
ical dotted lines, b,f, and d, g ; and the intermediate parts
of the semicircle are seen to merge from the horizontal to the
• •al line.
The reason why one moulding plane figured to the astragal
cannot, under the usual construction, be made to work the \ei-
tical parts of the moulding with the same perfection as the hori-
zontal, consists in the fact, that whereas the ordinary plane iron
PIVM ut> an angle of some 15 to 60 degrees to the sole of the
plane, which part is meant to cut, it presents a right angle to
the side of the plane, which part is not meant to cut. Thus if
the parts of the iron of the square rebate plane, which protrude
thronirh the sides of the stock, were sharpened ever so keenly,
they would only scrape and not cut, just the same as the scraping
plane with a perpendicular iron.
\Vhen, however, the rebate plane is meant to cut at the side,
it is called the si <lt -rebate plain-, and its construction is then.
. as >ho\vu in the three views, fig. 346 j that is, the
iron is ins-Tit d perpendicularly to the sole of the plane, but ait
a hoi i/ontal angle x x, or obliquely to the tide of the plane, so
IMPERFECTIONS OF
that the cut is now only on the one side z z, of the plane, and
which side virtually becomes the sole. A second plane sloped
the opposite way, is required for the opposite side, or the planes
are made in pairs, and are used for the sides of grooves, and
places inaccessible to the ordinary rebate plane.
In the figures 344 and 345, the square rebate planes 1 and 2,
will cut the horizontal surfaces a, b, and c, perfectly, because the
irons present the proper slopes to these surfaces ; but in attempt-
ing to plane the vertical line b f, with the side of 1, we should
fail, because the cutter is at right angles to that superficies, and
it would only scrape, or be said to drag. The plane 3, when laid
on its side, would act perfectly on the vertical face, but now it
would be ineffective as regards the horizontal. The square
rebate plane, if applied all around the semicircle, would be
everywhere effective so long as its shaft stood as a radius to the
curve, in fact as at 2, and 3, as then the angle of the iron would
be in the right direction in each of its temporary situations.
But in this mode ;i plane to be effective throughout, demands
M<il I.I.I
cither numerous positions of the plane, or mi iron of sin
kind as to combine these several position
rctically speaking then fore, the face of the cutter suit-
able to working the entire semicircle or bead, would become ;i
cone, or like a tube of steel bored with a hole of the same dia-
meter as the bead, turned at one end externally like a cone, ami
split in two p.u:-. Fig. 317 would represent such a cutter, and
which just resembles a half round gouge applied horizontally and
sharpened externally. But this theoretical cutter would present
all the difficulties of the spokcshave iron ; as to the trouble of
tixiiiir if, its interference with the sole of the plane, and the dilli-
culty of maintaining the form of the mouth of the instrun.
it* made as a spokcshave, owing to the reduction of the cutter in
.sharpening.*
Hut as the iron 3, and also the side-rebate, fig. 31G, work
perfectly well in their respective positions, or when the cutters
are inclined horizontally, whilst the central iron 2, only requi
to be inclined vertically, it occurred to me that by employing a
cutter in all respects as usual, except that its face should be
I'd as in the arc coiuu'dini/ the three irons in fig. 315, the one
tool would cut equally well at every point of the curve ; and
rieuce proved the truth of the supposition. The precise
form of the iron will be readily arrived at, by cutting out in card
the diagram, fig. 318, and bending it to a circular sweep, until
the parts exterior to the dotted lines bf, — d g, just meet the
spring of the bead, at about the angle of half or middle pitch, or
30 or 35 degrees from the right angle, and it will be then found
necessary to cut away the corners to the lines b s, — d 9, or so
much of them as dip below the straight surface of the fillet, as
seen in fiir. -'519.
author had a plane constructed exactly in agreement with
the above particulars, that is, with an iron curved to about the
third of a circle, the mouth of the plane was curved to cor-
•nd, and in every other respect the instrument was as usual;
it \\as found entirely successful.
inclination of the tool to each part of the work is \ery
• The cutter 347, i« uwxl fur making the cylindrical rollers upon which ribbon*
arc wound ; tho cutter is fixed at the end of a slide, and is worked by a lorcr,
.linden are made at two cuts in length* of 8 or 10 inches, and afterward*
492 IMPERFECTIONS OF
nearly alike, and it assimilates at different parts to each of the
ordinary rebate planes, all of which work well. Namely, at the
crown of the moulding c, to the square rebate plane ; at the
spring b and d, to the side rebate planes ; and at the fillets a b,
d e, to the skew rebate. And notwithstanding the fluted form
of the iron, no greater difficulty is experienced in sharpening the
iron in the new form like a gouge, than in the old like a chisel,
the figure of the end being nearly alike in each case.*
As all the imperfections in the actions of moulding-planes occur
at the vertical parts, there is a general attempt to avoid these
difficulties by keeping the mouldings flat or nearly without ver-
tical lines. For example, concave and convex planes, called hol-
Ifjivs and rounds, include generally the fifth or sixth, sometimes
about the third of the circle ; and it is principally in the part
between the third and the semicircle that the dragging is found
to exist ; and therefore, when a large part of the circle is wanted,
the plane is applied at two or more positions in succession.
In a similar manner large complex mouldings often require to
be worked from two or more positions with different planes, even
when none of their parts are undercut, but in which latter case
this is of course indispensable. And in nearly all mouldings the
plane is not placed perpendicularly to the moulding, but at an
angle so as to remove all the nearly vertical parts, as far towards
the horizontal position as circumstances will admit.
* The above forms of cutters suggested for mouldings, are each applicable to
most mouldings, but from their nature they are too troublesome for ordinary use.
For instance, we may employ a cutter such as 347, the lower surface of which,
as in 350, is the astragal or any other moulding, \he general slope or chamfer,
will cause the tool to cut at the fillets and at c, which parts are horizontal ; but
the lines of the mouldings, which are vertical, require the tool to be fluted to
obtain the horizontal angle, x, shown in dotted lines in 351, and there is all the
inconvenience of the nearly horizontal position of the spokeshave iron.
The iron, when sloped at the accustomed angle of pitch, requires to be convex
for a convex moulding, and to be sharpened behind ; and by the converse, for a
concave moulding the tool must be also concave and sharpened in front, and all
vertical lines in the moulding require the cutter to be fluted as in fig. 351, at x.
Mixed or flowing mouldings will require, on the same principle, the cutter to have
nearly the sections of the mouldings, and to be sharpened always in front, in the
apokeahave form of iron ; but partly in front and partly behind in the sloping
irons ; but these conditions are far too complex except in some favourable cases.
The cutters are always made flat on the face, and to lessen the difficulty, the
mouldings are drawn shallow, with but few or no vertical parts, or else they are
wrought by two or more different planes.
Mot . RS. | '.»:',
Tims the pl-me for the moulding, fig. 852, would Imvc it* stock
perptBcBadat to the dotted line « //. eonm -ctiiii: tin- extreme parts
of the moulding, the angular
deviation being generally called f \
the 'I'he spring is al>o
partly determined by the position
which is in irahle to the
maintenance of the form of the
cutter in sharpening it; as the
obliquity of the sole of the plane
causes the cutter, when advanced
through it, also to shift sideways,
and cause a disagreement betv
their figures.
In the act of working, or as it is called in sticking the mould-
ing, the wood is always first accurately squared to its dimensions
to serve as a guide, and it is then sometimes roughly bevelled
nearly to the line a b ; the plane is applied in the dotted posi-
tion, the blank edge o, of the plane, rests against the edge of
the prepared wood, and determines what is called the "on" of
the moulding, that is, how far the plane can proceed upon the
wood; and the planing is continued vertically until the blank
edge d stops the further action, or determines the " down," by
resting upon the solid wood beneath it. In some cases where
the planes are unprovided with fences or blank edges, or that
they are applied in places where fences in the ordinary form
are inapplicable, a slip of wood is nailed down for their guid-
as in fig. -'1-5-t, page 485.
Wide moulding planes have been occasionally worked by two
individuals, one to guide and thrust as usual, the other to pull
with a rope. The top iron is however absent from the whole of
the group, if we except the c<ij>/)i/it/ jtfane used for the upper
surfaces of staircase rails, which are faintly rounded. The
absence of the top iron is partly compensated forj by the pitch
of moulding planes being as stated on page 482, about 10
degrees more upright than in bench planes for the same m;
nirle.s and edges of many of the small planes are
box slipped, that is, slips of boxwood arc inlaid in the beech-
wood, in order that the projecting edges or the quirks may
possess greater durability.
494
CABINET-MAKER'S BENCH.
SECT. IV. — REMARKS ON THE BENCH, AND USE OF THE PLANE.
It is not the present intention to resume the consideration of
the joiner's planes in this work, it therefore appears desirable
before quitting the subject to add a few instructions respecting the
modes of keeping them in order, and of using them, in which
some kind of bench or support for the work is always required.
The benches are made in various Avays, from a few rough
boards nailed together, to the structure shown in fig. 353, which
represents one of the most complete kind of cabinet-makers'
benches, carefully connected by screw-bolts and nuts : its surface
is a thick plank planed very flat and true, with a trough to
receive small tools, without interfering with the surface of the
bench.
353.
The wood to be planed is laid on the bench, and is stayed by
an iron bench-hook a, which is fitted in a mortise, so that it
may be placed at any required elevation, or flush with the sur-
face of the bench. The bench-hook has teeth projecting from its
face, intended to stick into the wood, and retain it from moving
ideways ; but to avoid the injury which would be inflicted by
the teeth on nearly finished works, there is also a square wooden
stop b, fitted tight into a square mortise. These are shown
c \niSKi-.MAKi:u's HKNCII. !'.'.'•
removed, and OB a much larger scale, sit the toot of the
the same letters of reference hcin^ repeated.
The two Bide screws c, d, constitute with the chope, n kind of
; the screw r, simply compresses, the .screw d, has a pit<
called a //<//•/<•/• (shown detached), which enters a groove in the
cylindrical neck of the screw d, so that when the screws are both
opened. <o hriii^ the chop e outwards. The chops are
greatly used for fixing work by the sides or cdLr'-s and as they
open many inches, small boxes, drawers, and other works, may
be pinched between them.
There arc other constructions of benches which it is unneces-
sary to describe ; some have only one of the screws c, d, the
other being replaced by a square bar fixed in e, and many are
not furnished with the end screw g, which draws out the sliding
• /i, that i> \. TV carefully fitted. The end screw serves also
as a vice for thin works which are more conveniently held at
i -i^ht angles to the position of the side screws ; but its more
valuable purpose is for holding work by the two ends, which
mode is exceedingly convenient, especially in making grooves,
rebates, and mouldings, as the work is in no danger of slipping
away from the tools. There are several square holes along the
front of the bench, for an iron stop i, which has a perpendicular
and slightly roughened face, and a similar stop j, is also placed
in //, and as the latter slides a quantity not less than the interval
ecu the holes, pieces of any length below the longest may
be securely held.
For holding squared pieces of wood upon the bench, as in
making mortises or dovetails, the holdfast k, is used in the
manner shown, it is an L formed iron, the straight arm of which
fits loosely in a hole in the bench; the work is fixed by driving
on the top at k. and it is released by a blow on the back at /.
Sometimes also the holdfast is made in two parts jointed toge-
ther like the letter T, with a screw at the one end of the
transuTM- piece, by which the work can be fixed without the
hammer, but tin mode is far more common and is suf-
ficiently manageable. And /// is a pin which is placed in any
of the holes in the leg of the bench, to support the end of long
boards, win. d at their other extremity by the screws, /•, </.
\\ V iriH n m proceed to the manairement of the planes. See
Appendix, notes A K, A L, and A Iff, ] 'MS and 980.
496 SHARPENING AND ADJUSTING.
Of the bench planes enumerated in the list on page 476, the
following are most generally used, namely, the jack plane for
the coarser work, the trying plane for giving the work a better
figure or trying its straightuess and accuracy, and the smooth-
ing plane for finishing the surface, without detracting from the
truth obtained by the trying plane. Sometimes when the wood
is very rough and dirty, two jack planes are used still more to
divide the work, and these instruments are managed in the
following manner.
The remarks on pages 477-8 explain that, for long planes, the
iron is released by a blow of the hammer on the top of the plane
at the front ; the smoothing, and all short planes, are struck at
the back of the plane, and never on the top, or the wedge may
be tapped sideways, and pulled out with the fingers.
The top iron is then removed, by loosening the screw, and
sliding it up the mortise, until its head can pass through the
circular hole in the cutting iron.
The plane iron having been ground to an angle of some 25
degrees, with the stone running towards the edge, it is next
sharpened at an angle of about 35 degrees on the oilstone. The
iron is first grasped in the right hand, with the fore finger only
above and near the side of the iron, and with the thumb below;
the left hand is then applied with the left thumb lapping over
the right, and the whole of the fingers of that hand on the sur-
face of the iron ; the edge should be kept nearly square across
the oilstone, as when one corner precedes the other the foremost
angle is the more worn.
When the iron is required to be very flat, as for the finishing
planes, the surface of the oilstone should be kept quite level, and
the blade must be held at one constant angle ; but when it is
required to be round on the edge, a slight roll of the blade is
required edgeways ; lastly, the flat face of the iron is laid quite
flat on the oilstone, to remove the wire edge, and if required,
the edge is drawn through a piece of wood to tear off this film,
after which the iron is again touched on the oilstone, both on
the chamfer and flat surface, as the edge when finished should
be perfectly keen and acute.
The iron is frequently held too high to expedite the sharpen-
ing ; it is clear, that should it be elevated above 45°, or the pitch
of the plane, the bevil would be in effect reversed, and it could only
TII IKONS. 497
act as a burnish' • ly at i:> the keen (•<!;;<• \\ould be soon
worn away, :uul tin condition of tin- hurnishi r would remain ;
and, within certain limits, the lower or thinner the edge is sharp-
i the better. lYrhaps the an^le of '•'>'>' which is assumed, is
as favourable as any, a> if the edge be too acute the durability
greatly decreases, and therefore some regard is also shown to the
degree of wear and fatigue the iron is called upon to endure.*
The edge of the iron is likewise ground to different forms ac-
cording to the work ; thus, the jack plane is found to work n
easily when the iron is rounded as an arc, so that whether it
project in the center more or less than one-sixteenth of an inch,
the common measure, the angles of the iron should sink down
to the sole of the plane at the corners of the month.
The ease thus afforded appears more or less due to three causes.
The rounded iron makes its first penetration more easily, a
commences as it were with a point, or very narrow edjre : the
iron has to penetrate the wood as a wedge, first to cut and then to
/ the shaving; and it is likely that the reduction of labour in
the cut tiny, by the narrow portion of the edge being employed,
is greater than the increase, in hcml'iny a thicker but narrower
shavinir; and lastly, the curved iron di.-tantly approaches the
condition of the skew-iron, and in all inclined blades there is a
partial sliding or saw-like motion, which is highly favourabl
cutting. The irons for the finishing planes, although sharpened
as flat as possible at other parts, arc faintly rounded at the
corners to prevent their having marks upon the wood.
The cutting iron having been sharpened, the top-iron is
screwed fast at the required distance from the edge, say for
se works one-sixteenth, and for fine work, one fortieth or
fiftieth of an inch. The compound iron is placed in the mouth
of the plane, and the eye is directed from the front along the
sole, to see that it projects uniformly and the required quantity ;
the wedge is then put in with the right hand, and slightly tapped
with the hammer. If this should by chance carry forward the
iron also, a blow on the back of the plane at h, fig. 320, p. 477,
* When the minute chamfer of the plane-iron w a I moat parallel with the sole
of the plane, it will for a short time be entirely effective. Thus, as an experiment.
the iron a very small quantity through the aole, and aharpen it by allowing
the oilstone to rub both on the edge and on the wood behind ; this will produce a
very accurate edge, and the iron when set back, will cut beautifully.
K K
498 MODIFICATIONS OF THE DOUBLE IRON.
or on the upper surface of the long planes at i, partially with-
draws the iron, and in this manner, by a few slight hlows on the
end or either edge of the iron, and on the end of the wedge, the
adjustment is readily effected. Violence should be avoided, as
the wedge if overdriven might split the plane, and long before
that it would distort the sole and drive the back wood up, which
means, that the wood behind the iron would be driven so as to
stand slightly in advance of that before the iron, the two parts
of the sole becoming slightly discontinuous or out of line. The
iron should be always so slenderly held, that one or two mode-
rate blows would release the iron and wedge.
There is a very ingenious modification of the double iron
plane,* in which the cutter is a thin unperforated blade of steel
placed between a brass bed and an iron top-piece ; the cutter,
instead of being fixed and adjusted in the ordinary manner by
taps of the hammer, is managed by the quiet action of various
screws.
In a plane patented in America, in 1832, the bottom or cutting
iron is made as usual, but without any mortise ; the top iron has
a thumb-screw at its upper end, and moves on two lateral pins or
fulcrums f -inch from its lower edge ; the pins fit into two grooved
pieces of metal let into the sides of the plane, the lengths of the
grooves exactly determine the situation of the top iron. When
therefore the cutter is placed in its required position, the thumb-
screw is turned, it bears on the upper part of the cutter, and
tilts the top iron, until its lower edge also bears hard against the
usual part of the cutter, and thereby fixes it without a wedge.
The main hindrances to the general employment of these
constructions appear to be their increased cost, and the great
dexterity with which the required adjustments are accomplished
by the accustomed hand with the apparently rude, yet sufficient,
means of the haminer.f
The planes being respectively in good working condition, the
board to be planed is laid on the bench, and if it should be
obviously higher, either at the opposite corners from being "in
iri a ili ay" or in the middle, or at the edges from being "cast and
• Invented by Mr. H. Bellingham. See Trans. Soc. of Arts, 1836, vol. li.
t The same remark applies to Mr. F. E. Franklin's Screw Bench Hook, (idem,
vol. liii,) intended to supersede a orj, fig. 353, page 494.
PLANING A PLAT SURFACE. 499
roum/in>/," these partial prominences arc first removed with the
jack plane; hut in general the shavings should be of the full
ii of the work, or at any rate a yard long.
toat of the plane is held in the right hand, the front
ig grasped with the left hand, the thumb towards the work-
man ; the planes require to he pressed down on the work during
the cut, this is done 1. -ss by an exertion of the muscles, than by
slightly inclining tin: body, to cause its weight to rest partly
upon the plane. During the return stroke, the pressure should
he discontinued to avoid friction on the edge, which would be
thereby rounded, and there is just an approximation to lifting
the heel of the plane off the work: or in short pieces it is
entirely lifted. The general attempt should be to plane the
«ork somewhat hollow, an effect which cannot however really
occur, when the plane is proportionally long and quite straight.
The sole of a long plane is in a great measure the test of the
straightness of the work ; thus when the rough outside has
:i removed with the jack-plane, the trying-plane is employed,
which is set with a much finer cut, and the workman will in a
great measure tell the condition of the surface by the continuity
and equality of the shavings. It is however also needful to
nine its accuracy with a straight-edge; the edge of the
plane applied obliquely across the board is in general the
primary test, but as the work approaches to perfection, the
straight-edge is laid parallel with the sides of the work, and also
diagonally across it; and towards the last, the work if small is
raised to the level of the eye, or in large pieces, the workman
stoops to attain the same relative position.
In using the straight-edge the workman is partly guided by the
eye, or the line of light that is observable between the instru-
ment and the work, and partly by the sense of touch, as he
s whether the straight-edge, when it is very slightly rotated
as on a center, bears hardest at the ends or in the middle, and
he applies the plane accordingly.*
* The straight-edge U simply a wide thin bar of wood or nieUl, made aa accu-
rately straight aa possible ; the tnith of a straight-edge can be only proved by the
examination of a series of at least three. Thus, supposing A to be perfect, B to
be slightly concave, and C to be slightly convex ; it might happen that B and C
exactly agreed, but .1 could not agree with either of them.
Or supposing A to be concave exactly like B, or to become If, then B and C
K K 2
500 WINDING STICKS.
The foregoing mode refers to surfaces of moderate width, but
when the pieces are narrow, or two or more distant parts alone
are required to be in one level, the winding sticks are employed.
These are two straight-edges, say twenty to thirty inches long,
which are placed transversely upon the ends of the work and
parallel with each other, they receive their direction from the
respective ends or transverse sections, and should these be
inclined to each other, or in winding instead of parallel, the
winding sticks would magnify the error. This is explained by
the diagram fig. 354, the eye placed on the level of the imagi-
nary plane, bounded by the edges a b, c d, of the winding sticks,
would find the edge of a b exactly parallel with that of c d, but
if c d were situated as in the dotted lines, the disagreement of
position arising from the twist or inclination of the edge would
be immediately apparent. It is important that the winding
sticks should be parallel, as then the eye may be directed to
their upper edges, thereby avoiding the interference of the work
itself. If the work be perfect, the two sticks appear in exact
parallelism, when from the foreshortening, c d, is nearly eclipsed.
Figs. 354. 355.
^1 /
ll d A A
7
/
Nearly all the works in carpentry are first prepared as paral-
lelograms of various proportions, whether they are to be subse-
quently used in that simple form, or to be worked with grooves,
rebates, or mouldings ; or to be connected by joints of various
kinds. We will now follow up the formation of one flat surface,
by explaining the order in which to produce the three pairs of
parallel rectangular surfaces in fig. 355, namely, A a, the two
faces, B b, the two sides, and C c, the two ends ; and in this
and every work possessing flat surfaces, it is of the utmost
consequence that one face A, should be first wrought in the
most careful and exact manner as above described, to serve
would also agree, but B and B' would disagree ; therefore the rectilinear form can
only be proved to exist when A, B, and C will bear a strict comparison in i-ach
binary combination.
MCI \.. I Itll k AM» ll« IN WORKS.
aa tlu- foundation or Imse, from which all the other measures
are to be successively derived.
Tin- works are generally sawn out a trifle above the required
sixes, aild tlic Mil»-<-.|Ui-nt modes of proeeedmg, depend upon
the proportions of the pieces, or whether they are thick as in
rarpentry, or thin as in joinery and cabinet making. In thick
pieces, after the face A, has l)t en planed quite flat, the side B is
next wrought, and a short square is used to examine whether
the two are exactly at right angles, for this purpose the stock
of tin- square is rested against A, and the blade on B ut various
parts of the work ; or indeed the square is slowly traversed to
ascertain that the angle is everywhere in agreement with the
square. The angle A B, is then marked with pencil lines
extending on the face and side, to denote that this angle is to
as the foundation for the subsequent measures.
Before proceeding to plane the second face a, the marking
gage, fig. 342, p. 487, is adjusted until its point stands exactly
as far from the head of the gage as the intended thickness of
the work. The gage is then rubbed forcibly against the finished
face A, so as to scratch a line on the edges of B b, indicative of
the intended new surface a, and which is then worked with the
same care and precaution as its companion A^ After this b, is
similarly worked, when the width of the faces A a, have been
also scored by the marking gage applied against the true side B.
In planing a and b, the square is applied from B and A respec-
tively, to ensure the rectangular forms of the edges, and the
gage is also used together with the square to test the parallelism
of the work ; and lastly, the ends C c are marked on all four
I with the square, preparatory to the use of the saw, or the
formation of the tenons, mortises, or dovetails by which the parts
are attached. When the works are planed with rebates, grooves,
or moulding, the squaring up of the four sides is always the
preliminary step, although in some cases the principal attention
d to the two surfaces A B, especially when they are only
required to serve for the attachment of other parts of the work.
juariu^ up works cut out of thin plank, the mode is dif-
ferent, the pit-saw leaves the hoard nearly parallel, and when
the piece has been cut out with the hand-saw, the face A is first
/ mi, that is, corrected with the trying plane, the piece is
next gaged to thicknets, either at the ends only, or on all four
502
SHOOTING BOARDS.
edges, and the second face a, is planed up. The rectangular
piece is next fixed in the screw clamp of the bench, with the
edge B upwards, and which is made quite straight with the
trying plane in its ordinary position, and tested with the square ;
the two ends C c, are next marked off with the square, and
planed from the corrected edge B, and lastly b is gaged and shot
down to the width. By these means, should the fibres have
been split, or spoiled off in shooting the ends, the removal of
the edge b, as the last process would correct the evil. There
are some very useful contrivances employed in planing the edges
of thin works, and which will be next adverted to.
In squaring or shooting the edges of boards, the shooting board
drawn in figs. 356 and 357, is very much used; it is a contriv-
ance to enable the side A, of the work (the ends of which are
shaded in each of these views), to be laid flat on a bed e, whilst
the plane lies on its side, either on the bench, or upon the
additional piece /; and provided the shooting board is parallel
and straight, and that the sole of the plane is at right angles to
its side, the rectangular forms of the edges are much more
readily attained. The work is, nevertheless, examined with the
square, as if the set of the iron be imperfect it will introduce a
little error, and which is corrected by tapping the iron sideways,
to correct its position.
357.
In squaring the ends C c, the transverse block g of the shooting
board, is the rectangular gage, and the cross piece also partly
supports the fibres from tearing away ; for bevils, corresponding
blocks are fitted to it as represented at /*, but the mitre, or the
I'l. \\l\ti MVCII1NE8 FOR WOOD HKNTIIAX's.
angle of forty-five degrees there shown is the on .illy
required. To plane tin- edges, B or C, to the mitre or other
angle, the respective heds upon wliieii the work and plane are
supported, are reijuireil to be to each other in that particular
angular relation, :i* in ti^s. :i:>^ and Ji59 which represent the
mitre block tor angles of forty-live degrees.
•s of external fences materially assist in pieces
much narrower than the face of the plane, and the order in which
the six faces are dressed, is very closely followed, although with
ilitti rent tools, in other arts, in which the works consist of like
surfaces requiring a similarly strict relation to each other.
SECT. V. PLANING MACHINES FOR WOOD.
In nsinu' hand-tools the instrument rests immediately upon
the face of the work under formation; and in repeating any one
ilt, the same careful attention is again required in every
successive piece. But it was explained in the last chapter, that
in the machines acting by cutting, the accuracy is ensured far
more readily, by running either the work or the tool, upon a
straight slide, an axis, or other guide, the perfection of which has
In t-n carefully adjusted in the first formation of the machine; and
the slide or movement copies upon the work, its own relative
degree of perfection. The economy of these applications is there-
fore generally very great, and they are frequently most interesting,
on account of the curious transitions to be observed from the
hand-processes to the machines, in some cases with but little, in
others with considerable change in the general mode of procedure.
The first planing machine for wood is supposed to have been
that invented by General Bentham, who took out a patent for
it in 1701 ; it was based on the action of the ordinary plane,
the movements of which it closely followed. This contrivance
reduced the amount of skill required in the workman, but not
that of the labour; it appears to have been but little used.
hoard to he planed was sometimes laid on a bench, at other
times fixed by long cheeks having teeth which penetrated its
edges, the iron of the plane extended the full width of the board,
and the stock of the plane had slips to rest on the bench and
check the cutting action, when the board was reduced to the
intended thickness, muchthe same as in the reglet plane, fig. 8 HI.
-edged boards, the two slips were of unequal
501 BRAMAH'S PLANING MACHINE.
thicknesses; for those intended to be taper in their length, the
guide rails had a corresponding obliquity, and were fixed to the
bench. The plane was moved to and fro by a crank, it was
held down to its work by weights, and the plane was lifted up in
the back stroke to remove the friction against the cutter.*
The scale-board plane, abbreviated into scabbard-plane, for
cutting off the wide chips used for making hat and bonnet boxes,
is, in like manner, a plane exceeding the width of the board ; it
is loaded with weights, and dragged along by a rope and wind-
lass, the projection of the iron determines the thickness of each
shaving or scale-board. This construction is also reversed, by
employing a fixed iron, drawing the wood over it, and letting the
scale-board descend through an aperture in the bench ; each of
these modes is distinctly based on the common plane. See
Appendix, Note A. N., page 981.
The late Mr. Joseph Bramah took out a patent in 1802 for
a planing machine for wood ; one of which may be seen in the
Gun Carriage Department, Woolwich Arsenal. The timber is
passed under a large horizontal wheel, driven by the steam-
engine at about ninety revolutions per minute ; the face of the
wheel is armed with a series of twenty-eight gouges, placed hori-
zontally and in succession around it ; the first gouge is a little
more distant from the center, and a little more elevated than the
next, and so on. The finishing tools are two double irons, just like
those of the joiner, but without the advantage of the mouth.
Mr. Bramah employed the principle of his famous hydrostatic
press (patented in 1791), both for raising the cutter wheel to suit
the different thicknesses of wood, and also for traversing the
timber under the cutters upon guide rails ; the latter, by means
of an endless chain connected with the piston of the pump, by a
rack, pinion, and drum. The bottom of the axis of the cutter
wheel is cylindrical to the extent of its vertical adjustment, and
is fitted in a tube terminating at its upper part, in a cupped
leather collar, impervious to oil or water, as in the hydrostatic
press. The injection of water into the tube by a small force-
pump, lengthens the column of fluid, upon which the wheel is
supported as on a solid post ; the descent of the wheel is effected
by allowing a portion of water to escape by a valve.f
* See the Encyclopedia Metropolitans, &c. &c.
t Mr. Bramah's patent includeR tnnny modifications of fixed and revolving
Ml Ill's 1M. \ M M. M \t III •
A more recent machine tor planing flooring hoards, and other
wood works, consists of a M in ^ of knives placed parallel with,
and around the axis of, a small cylinder ; the hoard is passed
underneath the cutter ulul>t it is in rapid motion ; this may be
called an adzing machine, and the Unives arc of the full width
of the Ix .
In Mr. Mnir's patent planing machine for flooring boards, a
i y adze roughly planes the bottom, another operates on the
top of the board ; afterwards, two oblique fixed cutters, like the
skew-n bate irons, but with top irons, remove each a shaving of
the full length and width of the deal; two cutters make the
sides parallel, and two others groove the edges for the tongues,
or in fact, these are four revolving planes or saws in order to
expedite their effect. The board enters the machine as left from
the saw-mill, it is thrust forward by the engine, and comes out
\ery speedily in a condition nearly ready for fixing, the eight
operations being simultaneous ; but sometimes a little finishing
with the hand-smoothing plane is required at those parts where
the grain is unfavourable to smooth cutting. Other machines,
by Paxton, by Burnett and Poyer, and others, are used for
preparing sash-bars, and similar works.* See Appendix, Notes
A.O., & A.P., pages 981 & 9^
The preceding machines are mostly intended to work irith the
grain ; and I am only acquainted with one rectilinear planing
machine that is exclusively intended for cutting across the grain,
namely, the mortising engine, one of the series of machines
erected at Portsmouth in 1807, by Mr. Brunei, for the manu-
facture of ships' blocks.f
A hole is first bored through the block at the commencement
of the intended groove for the sheave, and it is extended by the
successive action of a mortising or paring tool, which rides
cutter*, for planing and cutting wood and metal works ; also a machine for turning
spheres, and for cutting wooden bowla one out of the other, and likewise other
mechanical contrivances. See Specification, Gregory's Mechanics, vol. ii. p. 415.
* See tho description of Paxton's machine, Trans. Soc. of Arts, voL liii. p. 97 ;
see also specification of Burnett and Foyer's patent
The reader is likewise referred to tho foot-note, page 32, voL i, on Taylor's
patent machine for chopping out the staves for casks ; a similar mode was pre-
viously employed for chipping into fragments the dye-woods, the logs of which
fell against the revolving disk through an inclined shoot
+ Now Sir Mark Isambard Brunei.
506 BRUNEL'S MORTISING AND SCORING ENGINES.
perpendicularly up and down ; just before the tool descends, the
block is traversed a quantity equal to each cut or shaving.
The cutter is made cylindrical, and is formed just like a
quill pen, but solid and with an elliptical cutting edge instead of
the points. " The chisels are provided with small teeth, which
are fitted into dove-tailed notches formed in the blade of the
chisel. These are called scribers, they have a sharp edge pro-
jecting a short distance beyond the inside edge of the chisel,
and therefore in descending through the mortise, the scribers cut
the sides of the mortise fair, and make two clefts which separate
the chip (which will be cut out at the next stroke), at its edges
from the inside of the mortise, so that the chip comes out clean
without splitting at the edges, and this makes the inside of the
mortise as clean and smooth as possible."* A hole is drilled
nearly in the axis of the cylinder, for the insertion of a pin, by
which the shavings are thrust out when they happen to clog
the hole.
By forming the tool of a semicircular section and with two
small fins, or edges projecting at right angles from the ends of
the diameter, and then sharpening it so that the diameter
becomes a straight chisel-edge, the scribing points are formed
in the solid with the chisel, and are continually restored as the
tool is sharpened. The tool is then perfectly analogous to fig. 334,
page 485, if we suppose the plane condensed into a long chisel
of semicircular section, equal to the diameter of the hole, the
progressive elongation of which it has to effect.
There are many useful applications of revolving figured planes,
moving through curved paths, by which we obtain figures of
double curvature, as explained in the theoretical diagram,
fig. 317, page 464. Mr. Brunei introduced an example of this
in the scoring engine, one of the machines recently adverted
to, for the manufacture of ships' blocks.
It is intended to form the groove around the block, for the
rope by which it is attached to the rigging. The revolving plane
is a disk of brass with a round edge and two cutters, inserted
at an angle of about 30° with the radius; it traverses around
the one side of the block, and receives its direction from a
shaper plate or pattern placed parallel with the block, by which
* Rees'a Cyclopedia, article " Machinery for manufacturing Ships' Blocks."
COMPARISON OP HAND AND MACHINE PLANING. 507
11-,'finciit tin- ruth i ma ,cs the groove deep at the ends, but
-!i:i!l,.u win •!•«• it passes the pin or axis of the sheave. Thcsame
method has been subsequently extended to shaping the entire
block with cutters of the full width, applied at four times.*
These several machines are compounds of slides and guides,
and of fixed or revolving planes : the relative degrees of perfec-
tion :itt:iim-il, depend on the stability of the machines, and their
respective agreement with the principles of the ordinary hand
tools, which are generally themselves, the last stages of a long
series of gradual improvements.
But the absence of some of the true characters of the plane,
iu nearly the whole of the machines for wood, namely, the proper
obliquities of the iron, the frequent want of the mouth of the
plane, and of the top or breaker iron, which so greatly restrains
the splitting and tearing up of the fibres, prevent the machines
from producing, in the softer woods, the smooth finished work
of hand tools, in the management of which the judgment of the
operator can be employed to combat the peculiarities of fibre.
But the enormous productive powers of such machines, out-
Ji these drawbacks, and the more especially so, as the
general forms or outlines are repeated by them in a most exact
manner, and a little after-trimming by hand imparts the neces-
sary finish.
In speaking of the apparatus for ornamental turning, there
will be occasion to show that these same principles arc strictly
embodied in miniature, in the various parts of the complex lathe
for ornamental turning; but as the hardwood and ivory therein
generally used, admit of the employment of scraping-tools, not
requiring either the obliquity of the cutter, or the mouth of the
plane, the above objections do not apply to them, and their several
results exhibit a much nearer approach to perfection.
* Iu revolving planes for wood, the cutters should always present an obliquity
of about 80° to the radius, otherwise, or when the cutters are placed radially, they
only scrape, or act like saws. Some of these planes are made of one disk of steel,
in which oa*e there are four, five, or six openings, like the mouths of rebate
planes; the one ai<le of each wedge or cutter is now a part of the circumference,
the other is elevated some 20 or 30 degrees, thereby resembling the spokeshave
iron. This form of cutter, although nearly perfect, is very expensive, and difficult
to maintain in order.
508
CHAPTER XXIV.
TURNING-TOOLS.
SECT. I. FACILITY OF TURNING COMPARED WITH CARPENTRY.
THE process of turning is accomplished with considerably
more facility, truth, and expedition, than any other process
requiring cutting tools, because in the most simple application
of the art, the guide principle is always present, namely, that of
rotation. The expedition of the process is due to its being un-
interrupted or continuous, except as regards the progressive
changes of the tool, and which is slowly traversed from part to
part, so as to be nearly always in action.
To choose the most simple condition, let us suppose the
material to be in rotation upon a fixed axis, and that a cutting
tool is applied to its surface at fifty places. Provided the tool
remain quiescent at one place, for the period of one revolution of
the material, the parts acted upon will each become one circle ;
because the space between the tool and the axis is for a period
constant, and the revolution of the material converts the distance
of the tool from the center, into the radius of one circle ; and the
same is equally true of the fifty positions.
The fifty circles will be concentric, or parallel with each other,
because the same axis extended, or continued as a line, remains
constant, or is employed for each of them, arid therefore con-
ceiving the fifty circles to be as many parts of the outline of a
vase or other object, simple or complex, it will be strictly
symmetrical, or equidistant from the central line at correspond-
ing parts.
Each of the fifty circles will also become the margin of a
plane at right angles to the axis, and which axis being a straight
line, the whole of the circles will be parallel, and therefore the
top and bottom of the vase will be also exactly parallel. And yet
all these accurate results must inevitably occur, and that without
any measurement, provided the material revolve on one fixed
FACILITY <T M UMNO COMPARED WITH CARPENTRY. 509
axis, and t hut t he tool is for a short period constant or stationary
.ich part of tin- surface; conditions inseparable from the
tunii -r'>
Tin- principle of rotation upon a fixed axis, removes the
necessity for many of the steps and measurements required to
.:!(••• with accuracy the various angular solids employed in
carpi -ntry and many other arts. For example, at page 501 the
methods were explained by which the joiner produces the three
pairs of parallel surfaces A a, B b, C c, of fig. 855, and which
-enerally required in each separate piece of his work. And
in making a box he has to combine six such pieces with the
same relations of parallelism, and therefore thirty-six various
surfaces have to be operated upon, to obtain the hollow cube, or
the carpenter's box.
The turner's box consists of two pieces, in place of six ; as the
bottom and its four sides are resolved into one piece ; when of
wood, by nature in the forest; when of metal, by man in the
crucible. The surfaces are therefore reduced from thirty-six to
eight, namely, the inner and outer surfaces of the bottom and
lid amounting to four, and the inner and outer sides or margins,
amounting to four also, and the revolution of the work upon one
axis, places the eight in exact and true relation with extreme
rapidity.
For example, the ends or terminal planes of the box, are from
necessity at right angles to the axis of rotation, and parallel
with each other. In each of these superficies the question of
being in or out of winding ceases; as if straight, they can only
be planes or coucs, and which the one straight-edge immediately
points out.
The principle of rotation ensures circularity in the work, and
perpendicularity or equality as regards the central line ; it only
remains, therefore, to attend to the outline or contour. The
riu'lit line serves to produce the cylinder, which is a common
outline for a box ; and the employment of mixed, flowing, and
arbitrary lines, produces vase* and ornaments of all kinds, the
beaut \ of which demands attention alone to one single element,
or i 11, namely, that of form; and in the choice and
production of \\hich a just appreciation of drawing and propor-
tion greatly assist.
In the art of drawing, it is almost essential to the freedom of
510 PRACTICE OF TURNING,
the result, that the lines should be delineated at once, and
almost without after correction; in the art of turning, it is
always desirable to copy a drawing or a sketch, but having
nearly attained the end, the tool may be continually re-applied,
partially to remove any portions which may appear redundant,
until the most scrupulous eye is satisfied.
The combining of the several parts of turned objects, as the
separate blocks of which a column or other work is composed,
is greatly facilitated from the respective parallelism of the ends
of the pieces of which turned objects consist ; and the circular
tenons and mortises, whether plain or screwed, place the differ-
ent pieces perpendicular and central with very little trouble.
These several, and most important facilities in the art of
turning, are some amongst the many reasons, for its having
obtained so extensive and valuable an employment in the more
indispensable arts of life, as well as in its elegances.
The relative advantages of the different sections of the tree,
as regards the works of the turner and carpenter, were explained
with figures in the fifth chapter of Vol. I., at pages 49 and 50,
where it is shown that, from various reasons, the transverse
section of the entire tree or branch is the most generally proper
for the lathe ; and therefore, in turning the tops and bottoms of
works, as in figs. 13 and 14, page 49, Vol. I., we are cutting
across the ends of the fibres, and in turning the sides of the
same we are, as it were, proceeding across the width of a plank
or board.
The tools used in turning the woods act much in the manner
of the blades of the carpenter's planes ; but as we have now, at
all times, a circular guide in the lathe-mandrel, we do not
require the stock of the plane or its rectilinear guide. Although
if we conceive the sole of the plane applied as the tangent to
the circle, the position it would give is nearly retained, but we
are no longer encumbered with the stock or guide. In turning-
tools for soft woods, the elevation of the tool, and the angle of
its edge, are each of them less than in ordinary planes, and in
those for the hard woods both angles are greater.
For example, the softest woods are turned with tools the
acute edges of which measure about 20 to 30 degrees, and are
applied nearly in coincidence with the tangent, as in fig. 360.
\\llll CARPENTRY. Ml
These tools closely assimilate to the spokcshaxc, which 1-, the
plant- of tlir lowest pitch and keenest edge. Oil tlu; nmtran,
the hardest woods may he turned with the above soft-wood tools.,
applied just as usual; but on the score of economy and general
convenience, the edges are thickened to from 60 to 80 degrees,
and the face of the tool is applied almost horizontally on the
lathe-rest, or as a radius to the circle, as in fig. 361, thus
agreeing with the opposite extreme of the planes, in which the
cutter is perpendicular and much less acute, as in the scraping
and toothing-planes, which are only intended to scrape and not
to cut.
The hard-wood tools may be figured, and employed as scrapers
in turning the members of the capital or the base of a column,
or Minilar object in hard word or ivory; but if we try the same
tools on deal, ash, and other soft woods, we shall in vain attempt
to produce the capital of a column, or even its cylindrical shaft,
with a thick horizontal tool as in hard wood; for the fibres would
not he cut, but forcibly turn asunder, and the surface would be
left coarse and ragged.
But a reference to the planes with which the joiner proceeds
•>ss the fibres of deal, will convey the particulars suited to the
present case; the iron is always thin and sharp, and applied in
an oblique manner, so as to attack the fibre from the one end,
and \irtually to remove it in the direction of its length.
It is proposed now to describe some of the more important of
512 TURNING TOOLS FOR SOFT WOOD.
the turning-tools, commencing with those employed on the soft
grained woods, but it would be both hopeless and unnecessary
to attempt the notice of all the varieties which are to beVmet
with in the hands of different individuals; and as their prac-
tical applications will be entered upon in detail in the suc-
ceeding volume, only so much will be here advanced as, it is
hoped, may serve to explain the modifications of the general
principles of cutting tools, to some of the more usual purposes
of turning. To avoid repetition, it may be observed, that in
general the position of the tool for turning the cylinder, and
secondly that for the flat surface or plane, will be alone de-
scribed. For works of intermediate angles, whether curves or
flowing lines, the position of the tool slides from that for the
cylinder to that for the plane, or the reverse ; and these changes
will be readily made apparent, when the reader gradually moves
either a tool or even a rod of wood, from the one to the other
of the described positions.
It may be added, that most of the tools for metal are applied
direct from the grindstone, the oilstone being used for such tools
only as are employed for the more delicate metal works, or for
the last finish of those of stronger kinds ; all the tools for wood,
ivory, and similar materials, are invariably sharpened on the
oilstone. It may be desirable to remark, in addition, that the
rough exterior faces of all works should be turned with narrow
or pointed tools, and only a narrow portion at a time, until
the surfaces are perfectly true or concentric ; as wide flat tools,
applied to rough irregular surfaces, especially of metal, would
receive a vibratory, or rather an endlong motion, quite incom-
patible with truth of work.
SECT. II. TURNING TOOLS FOR SOFT WOOD.
Angle 20° to 30°. — Figures generally half-size.
The tools most generally used for turning the soft woods, are
the gouge and chisel, figs. 3(52 to 365, wherein they are shown
of one-fourth their medium size; they vary from one-eighth to
t\\<> inches wide; and as they are never driven with the mallet,
they do not require the shoulders of the carpenter's tools, they
an: also ground differently. The turning-gouge is ground exter-
nally and obliquely, so as to make the edge elliptical, and it is
M aXINU OOfGE AND CHISEL.
511
l>rincijmlly the inidillc portion of the edge which is used; the
clusrl is ground from both sides, and with an oblique edge,
and figs. 366 and 367 represent the full thickness of the chisel
and its. ordinary angles, namely, about 25 to 30 degrees for soft,
and HI fur hard woods. The gouges and chisels wider than one
inch an- almost invariably fixed in long handles, measuring with
tin- blades from 1 :> to 24 inches; the smaller tools have short
handles, in all from 8 to 12 inches long.
Fig. 860 shows the position of the gouge in turning the
cylinder; the bevil lies at a tangent, and the tool generally
863.
Mi
Mft
367
rests on the middle of the back, or with the concave side
upwards, the extremity of the handle is held in the right hand
L L
514
TURNING GOUGE, HOOK-TOOLS FOR SOFT WOOD.
close to the person, and the left hand grasps the blade, with the
fingers folded beneath it, and in this manner the gouge is
traversed along the cylinder.
For turning the flat surface, the gouge is supported on its
edge, that is, with the convex side towards the plane of the
work, and with the handle nearly horizontal, to bring the center
of the chamfered edge in near coincidence with the plane; the
tool is inclined rather more than the angle at which its chamfer
is ground, and it is gradually thrust from the margin to the
center of the work.
The gouge is also used for hollow works, but this application
is somewhat more difficult. For the internal plane, the position
is almost the same as for the external, except that the blade is
more inclined horizontally, that it may be first applied in the
center, to bore a shallow hole, after which the tool is traversed
across the plane, by the depression of the hand which moves
the tool as on a fulcrum, and it is also rotated in the hand
about the fourth of a circle, so that in completing the margin,
or the internal cylinder, the tool may lie as in fig. 360, but with
the convex instead of the concave side upwards as there shown.
In figs. 368 and 370 are represented the plans, and in 369
and 371 the elevations, of the hook-tools for soft wood,
which may be called internal
Figs. 368. 3fi9.
ri
370.
371.
gouges; they differ some-
what in size and form, the
blades are from 6 to 12
inches long, the handles 12
to 15. They are sharpened
from the point around the
hook as far as the dotted
lines, mostly on one, some-
times on both sides, as seen
by the sections. The hook
tools follow very nearly the
motion of the gouge in hol-
lowing, the rest is placed
rather distant and oblique; the tool is moved upon it as a
fulcrum, and it is also rotated in the hand, so as always to place
the bevil of the tool at a very small inclination to the tangent.
The finishing tools used subsequently to the gouges or hook-
I Mi CHISEL, BROADS POR 8OPT \v
516
tools ha\c straight edges; tin- chisel, fi^. ;;m, is the most
position closely resembles that of the gouge, Mih-
to the modifications called for by its rectilinear edge. If,
pie, the edge of the chisel were JIM parallel with tin-
axis of the cylinder, it \vould take too wide a hold; there would
In- risk of one or other corner digging into the work, and the
edge, from its parallelism with the fihres, would he apt to tear
them out. All these inconveniences are avoided by placing the
edge oblique, as in fig. 3t>t, in which the tool may be supposed
to be seen in plan, and proceeding from right to left, fig. 860
being still true for the other view; the tool is turned over to
proceed from left to right, and both corners of the tool are
oved from the work, by the obliquity of the edge. The tool
may he ground square across, but it must be then held in a
more .sloping position, which is less convenient.
Turning a flat surface with the chisel is much more difficult.
The blade is placed quite on edge, and with the chamfer in agree-
ment with the supposed plane a, b, c, fig. 366; the point of the
chisel then cuts through the fibres, and removes a thin slice
which becomes dished in creeping up a, d, the bevil of the tool;
it then acts something like the scoring point of the planes, or the
point of a penknife. Flat surfaces, especially those sunk beneath
the surface, as the insides of boxes, are frequently smoothed
with an ordinary firmer chi-
sel, which is ground and
sharpened with one bevil,
but rather thicker than for
carpentry. The edge is then
burnished like the scraper,
p. 484, and it is applied
horizontally like a hard-
wood tool, as in liu -'Ml, but
against the face or plane
surface. The wire edp- then
:i the required position,
but it must be frequently
rein
The broad, represented in
riewl in tLp. -">7- endures much longer, but it requires to
be held downwards or underhand, at about an angle of 40 to 50
L L 2
373.
Fig*. 872.
516
SIDE-TOOLS AND SCREW- TOOLS FOR SOFT WOOD.
degrees from the horizontal, in order to bring its edge into the
proper relation to the plane to be turned. Another form of the
broad is also represented in fig. 373, it is a cylindrical stem,
upon the end of which is screwed a triangular disk of steel,
sometimes measuring 3 inches on the sides, and sharpened exter-
nally on each edge, this tool requires the same position as the
last. Broads of the forms b, c, are also used, but principally for
large works, the plank way of the grain.*
For the insides of cylinders, the side-tool, fig. 374, which is
represented in three views, is sometimes used ; it is sharpened
on both edges, and applied horizontally. The tool fig. 375, also
shown in three views, serves both for the sides and the bottoms
of deep works, but it does not admit of being turned over; and
376 is another form of the same tool for shallower works, the
cranked form of which is considered to give it a better purchase.
Figs. 374.
375.
376.
The tools used for cutting screws in soft wood, by aid of the
traversing or screw mandrel lathe, partake of the same general
characters as the others, and are represented in their relative
positions; fig. 377 is for the outside, and 378 for the inside
* Similar tools are also used for turning pewter wares.
PARTING TOOL. TOOLS FOR HARD WOOD AND IVORY.
screw. To conclude the notice of tools of this class, the pnrtint:
tool, ti_'. 379, has an angular notch or groove on its upper
surface, from which it results that u hen the tool is sharpened
on the hevil />, the upper face/, presents two points, which sepa-
rate the films by a double incision. This method wastes only
as much wood as equals the thickness of the tool, and it leaves
the work smooth and flat; whereas, when the angle of the
chisel is used for the same purpose, several cuts are required,
and the gap must present a greater angle than the bevil of the
tool, and which consumes both time and wood.
The various turning tools for soft woods which have been
described are, with the exception of the gouge and chisel, nearly
restricted to the makers of Tunbridge-ware, toys, and common
turnery ; with them they are exceedingly effective, but to others
somewhat difficult. The amateur turner scarcely uses more than
the common gouge and chisel, and even these but insufficiently,
as much may be done with them ; it has been shown, for in-
stance, that moulding tools cannot be used for the soft woods,
but they are efficiently replaced by the gouge for the concave,
and the chisel for the convex mouldings, which proceedings will,
however, be detailed in the fourth volume.
A good fair practice on the soft woods would be found very
ally to facilitate the general manipulation of tools, as all
those for the soft woods, demand considerably more care as to
their positions and management than those next to be described.
SECT. III. — TURNING TOOLS FOR HARD WOOD AND IVORY.
Angle 40° to 80°. — Figure* generally half -size.
The gouge is the preparatory tool for the hard as well as for
the soft woods, but it is then ground less acutely; the soft-wood
chi-el may indeed be employed upon the hardest woods, but
this is seldom done, because the tools with single bevils, held in
a horizontal position, as in fig. 861, page 511, are much more
manageable, and on account of the different natures of the
Figs. 380. 831.
materia are thoroughly suitable, notwithstanding that
their edges are marly as thick again as those of soft-wood tools.
518 RECTILINEAR TOOLS FOR HARD WOOD AND IVORY.
In general, also, the long handles of the latter are replaced by
shorter ones, as in figs. 380 and 381, measuring with the tools
from 8 to 12 inches; but these give in general an abundant
purchase, as from the nearly horizontal position of the tool, the
lathe rest or support can be placed much nearer the work.
The hard-wood tools are often applied to a considerable extent
of the work at one time, and the finishing processes are much
facilitated by selecting instruments the most nearly in corres-
pondence with the required shapes. Rectilinear surfaces, such
as cylinders, cones, and planes, whether external or internal,
necessarily require tools also with rectilinear edges, which are
sloped in various ways as regards their shafts ; they are made
both large and small, and of proportionate degrees of strength
to suit works of different magnitudes : the following are some
of the most usual kinds.
Figa. 382. 383. 384.
• •••
385. 386. 387. 388. 389.
\
390.
391.
The right side tool, fig. 382, cuts on the side and end, the dotted
lines being intended to indicate the undercut bevil of the edge ;
it is thus named because it cuts/rom the right hand towards the
left. The left side tool, fig. 383, is just the reverse. The flat-tool,
fig. 384-, cuts on both sides, and on the end likewise; and in all
three tools the angle seen in plan, is less than a right angle, to
allow them to be applied in rectangular corners. The point-tool,
fig. 385, is also very convenient; and bevil-tools, figs. 386 and
387, the halves of the former, are likewise employed ; figs. 388
show the general thicknesses of these tools. When any of them
are very narrow they are made proportionally deep to give suffi-
cient strength, the extreme case being the parting-tool, fig. 389,
tllt\IIINEAR TOOLS FOR HARD WOOD A\l» IVORY.
519
\\ hii-li is no longer required to be tinted, ns m the corresponding
tool for soft wood ; but the side tools, when used for small and
deep holes, necessarily require to be small in both respects, as
in tig. 890. Tin- application of the inside parting-tool, fig. 391,
has been previously slmvvn on paire I :> I , Vol. I., in respect to
the removal of rings of ivory from the interior of solid works,
in preference to turning the materials into shavings; it is also
"ill in some other undercut works.
Some of the curvilinear tools for hard wood are represented
in the annexed group; the semicircular or round tool, fig. 392,
Figs. 393. 93. 394. 395. 396. 397. 898. 399.
f
^
w
J
V
1
llll
r^
r
i
Jr V
vvAVWW
404.
405.
402.
403.
is the most general, as concave mouldings cannot be made
without it, and it is frequently divided, as in the quarter round
tools, figs. 3Uo and •'>'.' I ; it is convenient that these should be
exact counterparts of the mouldings, but they may also be used
for works larger than themselves, by sweeping the tools around
the curves. Convex mouldings are frequently made by recti-
linear tools, which arc carried round in a similar manner, so as
to place the edge as a tangent to the curve, but the bead,
. the astragal, fig. 390, or the ijmirter hollows, figs. 397
and V.1", facilitate the processes, and complete the one member
of the moulding at one sweep, and enable it to be repeated any
number of times with exact uniformity.
uently the tools are made to include several members, as
the entire base or capital of a column, as in fig. 399. Similar
figured tools, have been applied to turning profiles of about one
or one and a half inches high, by employing four different tools,
520 PROFILE TOOLS ; TOOLS FOR BRASS.
embracing each about a quarter of the profile, and applied at
four radial positions, around a ring of some three to five inches
diameter; the rings are cut up into radial slices, and turned
flat on each face prior to being glued upon tablets. Profiles
have been likewise successfully and more skilfully turned, by
the ordinary round, point, and flat tools, which processes will be
proposed as examples in the practical part of the fourth volume.
Figs. 400 to 403 represent some of the various kinds of inside
tools, which are required for hollowing vases and undercut works;
and 404 the inside screw tool, and 405 the outside screw tool
for hard wood, ivory, and the metals, these tools are made with
many points, and are bevilled like the rest of the group, they
will be further noticed in the chapter on screw-cutting tools.
The hollow tools, figs. 395 to 398, may be sharpened with a
narrow slip of oilstone used almost as a file ; but their sweeps are
more accurately sharpened by conical metal grinders, supplied
with emery, as will be explained ; most other moulding tools,
and the screw tools, are only sharpened upon the face. The
ends of these tools may be whetted at a slope, if it be more
gradual, than in fig. 406, this however, increases the angle of the
edge; but by nicking in the tools, as in fig. 407, by applying
them transversely on the grindstone, the original angle is main-
tained, and which is the better mode for screw tools more
especially.
SECT. IV. TURNING TOOLS FOR BRASS.
A ngles 70° to 90°. — Figures generally the same as (he tools for hard wood.
The turning-tools for brass are in general simple, and nearly
restricted to round, point, flat, right and left side tools, parting
tools, and screw tools ; they closely resemble the hard-wood tools,
except that they are generally ground at angles of about 60° or
70°, and when sharpened it is at an angle of 80° or 90°; some
few of the finishing or planishing tools, are ground exactly at
90°, upon metal laps or emery wheels, so as to present a cutting
edge at every angle and on both sides of the tools.
It is not a little curious that the angles which are respec-
tively suitable to brass and to iron, are definitively shown to
be about 90 and 60 degrees. For turning brass, a worn-out
square file is occasionally ground on all sides to deprive it of its
teeth, it is used as a side tool, and is slightly tilted, as in
IIM-HIM, [-OOL8 FOR BRASS. .V.'l
l|ls, just to give one of the edges of the prism sufficient
pen. hut applied to iron, steel, or copper, it only scrapes
with inconsiderable effect. A triangular file, fig. 409, similarly
ground, cuts iron with great avidity and effect, but is far less
Fig*. 408. 409. 410.
r~*>y
suited to brass; it is too penetrative, and is disposed to dig
into the work. It appears indeed, that each different substance
requires its own particular angle, from some circumstances of
internal arrangement as to fibre or crystallization not easily
accounted for.
A stout narrow round tool, fig. 392, in a long handle, serves
as the gouge or roughing out tool for brass-work, others prefer
the point, fiL' '-'<^~>. with its end slightly rounded, which com-
bines, as it were, the two tools with increased strength ; a small
but strong right side tool 382, is also used in rough-turning;
the graver, figs. 411 and 412, although occasionally employed
for brass, is more proper for iron, and is therefore described in
the next section.
The wide finishing tools should not be resorted to under any
circumstances until the work is roughed out nearly to the shape,
and reduced to perfect concentricity or truth, with narrow tools
which only embrace a very small extent of the work.
It is the general impression that in taking the finishing cuts
on brass it is impolitic, either to employ wide tools, or to support
th'-m in a rigid solid manner upon the rest, as it is apt to make
the work full of fine lines or striae. This effect is perhaps jointly
attributable to the facility of vibration which exists in brass and
similar alloys, to the circumstance of their being frequently
used in thin pieces on the score of economy, and to their being
ted more rapidly in the lathe than iron and steel, to expedite
the progress of the work.
\Yhen a wide flat tool is laid close down on the rest, and
made to cut with equal eH'ect throughout its width, lines are
vrrv likely to appear on the metal, and which if thin, rings like
a bell from the vibration into which it is put ; but if the one
522 FINISHING TOOLS FOR BRASS.
corner of the tool penetrate the work to the extent of the thick-
ness of the shaving, whilst the other is just flush with the
surface, or out of work, the vibration is lessened, and that
whether the penetrating angle or the other move in advance.
The brass turner frequently supports the smoothing tool
upon the one edge only, and keeps the other slightly elevated
from the rest by the twist of the hand, which thus appears to
serve as a cushion or spring to annul the vibrations, fig. 410
shows about the greatest inclination of the tool. Some work-
men with the same view interpose the finger between the tool
and the rest, in taking very light finishing cuts. The general
practice, however, is to give the tool a constant rotative shuffling
motion upon the supported edge, never allowing it to remain
strictly quiet, by which the direction of the edge of the tool is
continually changed, so as not to meet in parallelism any former
striae which may have been formed, as that would tend to keep
up the exciting cause, namely, the vibration of the metal. The
more the inclination of the tool, the greater is the disposition
to turn the cylinder into small hollows.
Some workmen burnish the edges of the finishing tools for
brass, like the joiner's scraper, or the firmer chisel used in soft-
wood turning. On account of the greater hardness and thick-
ness of the edge of the tool, it cannot be supposed that in these
cases any very sensible amount of burr or wire edge is thrown
up. The act appears chiefly to impart to the tool the smooth-
ness and gloss of the burnisher, and to cause it, in its turn, to
burnish rather than cut the work; the gas-fitters call it a
planishing tool, but such tools should never be used for accu-
rate works until the surface is perfectly true and smooth.
The hard-wood and brass turners avoid the continual neces-
sity for twisting the lathe rest in its socket to various angular
positions, as they mostly retain it parallel with the mandrel, and
in turning hollow works they support the tool upon an arm-
rest; this is a straight bar of iron, which resembles a long-
handled tool, but it has a rectangular stud at the end, to
prevent the cutting tool from sliding off.
The position of the arm-rest and tool, as seen in plan, are
therefore nearly that of a right angle ; the former is held under
the left arm, the latter in the right hand of the workman, the
fore-fingers of each hand being stretched out to meet near the
TOOI.8 Kill IK<>\. I HI \ \«.l I \ll Midi.. (,K\\ .',:].',
cud of the tool. This may appear a diHienlt method, but it is
in all respects exceedingly commodious, and gives considerable
iom and choice of position in managing the tool, the advan-
tage of which is particularly t'dt in guiding the first entry of
the drill, or the path of the screw-tool; and iu brass work it
likewise renders the additional service of associating the tool
with the elastic frame of the man. Hut when particular firm-
ness and accuracy are required the tool should be supported
upon the solid rest as usual.
SECT. V. — TURNING TOOLS FOR IRON, STEEL, ETC.
Anyttt 60* to 9<f.—Pi<juru generally onetixth the full tizt.
The triangular tool is one of the most effective in turning
these metals, as was adverted to at page 521; the triangular
tool is also used by the engravers and others for scraping
the surfaces of the metals, and it is then applied nearly perpen-
dicular, or ns a penknife in erasing; but when the triangular
tool is placed nearly as a tangent against the inner or outer edge
of a ring or cylinder, as in fig. 409, it seems almost to devour
the metal, and instead of scratching, it brings off coarse long
shavings. In turning the flat sides of the ring, the face of the
tool is placed almost in agreement with the plane to be turned.
The yrarer, which is also an exceedingly general tool, is
a square bar of steel ground off at the end, diagonally and
obliquely, generally at an angle of from 80 to 50 degrees. The
parts principally used are the two last portions of the edge close
to the point, and to strengthen the end of the tool a minute
facet is sometimes ground off, nearly at right angles to the broad
chamfer, or principal f
The proper position of the tool, in turning a cylinder, will be
most readily pointed out by laying the chamfer of the tool in
exact contact with the flat end of such cylinder ; it will be then
found that one of the lateral angles of the tool will touch the
. and the obliquity in the shaft of the tool, would be the
angle, at which the Braver is ground, instead of which it is 1
ire and slightly elevated above the horizontal position, as-
shown in ti;:. 111. The graver is rotated upon the supporting
angle, which sticks into the rest, much the same as the edge of
the triangular tool ; in fact, the two tools, although different in
form, remove the shaving in a very similar manner.
524.
GRAVER AND FLAT CHISEL.
In using the graver and other tools for the metals, it is the
aim to avoid exposing the end of the tool to the rough gritty sur-
face of the material. This is done by cleaning the surface, espe-
412.
413.
414.
cially the extreme edge, with an old file, and beginning at that
edge, the work is at one sweep reduced nearly to its required
diameter by a wide thin cut, which may be compared with a
chamfer, or a conical fillet, connecting the rough external surface
with the smooth reduced cylinder. Therefore after the first
entry, the point of the tool is buried in the clean metal below
the crust, and works laterally, which is indeed the general path
of pointed tools for metal.
When the graver is used in the turn-bench with intermittent
motion, as for the pivots of watches, the axes for sextants, and
other delicate works ; it is applied overhand or inverted, as in
fig. 412, but it is then necessary to withdraw the tool during
each back stroke of the bow, to avoid the destruction of the
acute point, and which alone is used. The graver, when thus
applied in lathes with continuous motion, is only moved on the
rest as on a fulcrum, and in the plane in which it lies, rather as
a test of work done, than as an active instrument.
The edge of the graver is afterwards used for smoothing the
stronger kinds of work, it is then necessary to incline the tool
horizontally, to near the angle at which it is ground, in order
to bring the sloping edge parallel with the surface. But the
smoothing is better done by a thick narrow flat tool, ground
at about sixty degrees, the handle of which is raised slightly
above the horizontal, as in fig. 413, in order that its edge may
approach the tangential position ; here also the tool is rotated
on one edge, after the manner of the brass tools or the graver.
For many slight purposes requiring rather delicacy than
strength, as in finishing the rounded edge of a washer, the flat
tool is inverted or placed bevil upwards, as in fig. 414 ; the
HEEL-TOOLS POR IRON.
528
lower side then heeoiues the tangent, and the edge the axis of
• ion of the tool, the same as in turning convex mouldings with
t lie soft-wood chisel. Indeed, many analogies may be traced be-
t \\een the loth respectively used for soft woods and iron, except
that the latter are ground at about twice the angle to meet the
increased resistance of the hard metal, and the tools are mostly
sustained by the direct support of the rest, instead of resting in
great measure against the hands of the individual.
For instance, the heel-tool, which is used for rough turning the
metals, is represented of the full size in the side-view, fig. 415,
and the front-view, fig. 416, and also on a smaller scale in figs.
417 and 418. The dotted lines a, fig. 417, denote the relative
Figs. 415.
416.
position of the fluted gouge, and although the heel or hook-tool
occupies nearly the same spot, its edge is of double the thickness,
ami the entire resistance of the cut is sustained by the heel of
the tool, which is poised upon the flat horizontal surface of the
it> of the tool is bent nearly at right angles, that it
may he held either above or below the shoulder of the workman
as preferred. Some variation is made in the form and size of
526 HEEL-TOOLS, NAIL-HEAD TOOLS FOR IRON.
the heel-tools, aud they are occasionally pointed instead of round
upon the cutting edge.
The heel-tool is slightly rotated upon its heel in its course
along the work, so that, as seen at b, its edge travels in short
arcs, and when its position becomes too inclined, a fresh footing
is taken ; on this account the straight handle, employed in ordi-
nary tools, is exchanged for the transverse handle represented.
In the best form of heel-tools the square shaft lies in a groove
in the long handle, and is fixed by an eye-bolt and nut, passing
through the transverse handle, as seen in the section 418.
Notwithstanding the great difference between the materials
upon which the gouge and heel-tool are employed, their manage-
ment is equally easy, as in the latter the rest sustains the great
pressure, leaving the guidance alone to the individual.
Fig. 419 represents another kind of hook-tool for iron, which is
curiously like the tools, figs. 368 to 371, p. 514, used for soft
wood, the common differences being here also observable, namely
the increased strength of edge, and that the one edge is placed
upon the rest to secure a firm footing or hold.
Nail-head tools are made much on the same principle, one of
these, fig. 420, is like a cylinder, terminating in a chamfered
overhanging disk, to be rolled along so as to follow the course
of the work, but it is rather a theoretical than practical instru-
ment. When, however, the tool is made of a square or
rectangular bar, and with two edges as at fig. 421, it is excel-
lent, and its flat termination greatly assists in imparting the
rectilinear form to the work. Occasionally the bar is simply
bent up at the end to present only one edge, as in fig. 422, it is
then necessary the curved part should be jagged as a file to cause
it to dig into the rest like the others of its class, and which
present some analogy to the soft-Mrood tools, figs. 372 and 373,
p. 515.
The cranked or hanging tools, fig. 423, are made to embrace
the rest, by which they are prevented from sliding away, with-
out the necessity for the points and edges of the heel-tools ;
the escape of the cranked tool sideways is prevented by the pin
inserted in one of the several holes of the rest. The direct
penetration is caused by the depression of the hand ; the side-
way motion by rotating the tool by its transverse handle, which
is frequently a hand-vice temporarily screwed upon the shaft.
CRANKED oil 1I\\(,IM. TOOLS. FIXED TOOLS. 527
To save the trouble of continually shifting tin- lathe-rest, an iron
ally introduced at a, between
rest .-111.1 the hack of the tool ; when the wedge is advanced
at intervals it sets tin- tool deeper into the work, when it is
withdrawn it allows more room for the removal of the tool.
I' -
The succeeding figure, 1.1, represents a tool of nearly similar
kind, the stock is of iron, and it carries a piece of steel, about
three or four inches long, and one inch square, which is forged
hollow on the faces by means of the fuller, to leave less to be
ground away on the stone. The rectilinear edges of this tool
are used for smoothing irou rollers, iron ordnance, and other
works tunied by hand, and to preserve the edge of the tool, thin
spills of hard wood are sometimes placed between the cutter and
the bar. Under favourable arrangements these tools also are
managed with great facility ; indeed it occasionally happens that
tin- weight of the handle just supplies the necessary pressure to
advance the tool, so that they will rest in proper action without
being touched by the hand; a tolerable proof of the trifling
muscular effort occasionally required, when the tools are judi-
eion-ly moulded and well applied.
Tin >e hand tools and various others of the same kinds,
although formerly much used by the millwrights, are now in a
: measure replaced by the fixed tools applied in the sliding
rest, some account of which will be given in the next section.
SECT. VI. — FIXED OR MACHINE TOOLS FOR TURNING AND PLANING.
Angltt at in the kaitd-toolt. — Piywet generally one-fourth to o*+cigktk
The performance of fixed tools is, in general, much more
etKetive than that of hand tools; as the rigid guides and slides
now employed, do not suffer the muscular fatigue of the man,
'hose fluctuations of position to which
his hand is liable. Therefore, as the tool pursues one constant
nnde\iating course, the corresponding results are obtained both
528
FIXED TOOLS, GENERAL REMARKS.
more economically and more accurately by the intervention of
the guide -principle, or the slide-rest) from which we derive the
slide-lathe, and thence the pianino-machine, and many other
most invaluable tools.
The cutting edges of machine tools mostly follow the same
circumstances as those of hand tools, but additional care is
required in forming them upon principle ; because the shafts of
the fixed tools are generally placed, with little power of deviation,
either at right angles to, or parallel with, the surfaces to be
wrought ; the tools are then held in the iron grasp of screws
and clamps, in mortises, staples, and grooves. The^tools do not,
therefore, admit of the same accommodation of position to
compensate for erroneous construction, or subsequent deteriora-
tion from wear, as when they are held in the hand of the work-
man, and directed by his judgment.
It must also be additionally borne in mind that, however
ponderous, elaborate, or costly the machine may be, its effective-
ness entirely depends upon the proper adaptation and endurance
of the cutting-tool, through the agency of which it produces its
results.
The usual position of the fixed turning tools is the horizontal
Fig. 425. d e f line,as at a,fig.425; and unless the
tools always lie on the radius, (or
any other predetermined line,)
various interferences occur. For
instance, the tool proceeding in
either of the lines b or c, could not
reach the center of the work, and
a portion would then escape being
wrought; the curvature of the
circle at b, would sacrifice the pro-
per angle, and expose the tool to
fracture from the obliquity of the
strain ; and at c, the edge would
be altogether out of contact, and
the tool could only rub and not
cut. These evils increase with
the diminution of the circle ; and
although the diagram is greatly
exaggerated for illustration, the want of centrality is in truth
FIXED TOOLS FOR SOFT WOOD.
an e\ il of Midi magnitude that various contrivances are resorted
iv which cither tin; entire slide-rest, or the cutter alone,
niav he adjusted for height of center.
The pinning tools for metal arc in general fixed vertically, and
the path of the work bein:r, in the majority of planing machines,
rectilinear and horizontal, the tool may be placed at d, e, or/,
indifferently, then- hi-ing no interference from curvature as in
tnrnint:.
In those modifications of the planing machine, in which as in
MrumTs mortising enjrino, the cutter travels perpendicularly,
and is also fixed perpendicularly, as in the key groove or slotting
engines, and the paring engines, the general form of the tool /,
or that of a strong paring chisel, is retained, but the blade is
slightly inclined in its length as at.;, fig. 420, to avoid touching
the surface to be wrought except with its cutting edge, and the
length of the tool supplies a little elasticity to relieve the friction
of the back stroke.
Although all the various forms of hand-turning tools are more
or less employed as fixed tools, still the greater part of the work
is done with the point tool, (such as g, in the plan fig. 426,) the
angle of which should be slightly rounded; but for working
into an angle, the point of the tool is thrown off as at h, so that
its shaft may avoid either side of the angle, and it is then called
a side-tool. For internal works, and in small apertures espe-
cially, the abrupt curvature requires particular attention to the
central position of the tool i, and a frequent sacrifice of the
most proper form of the chamfer or edge. I will now describe
a few of the slide-rest tools in the previous order, namely, those
for soft wood, for hard wood, for brass, and for iron.
The fixed tools for soft loood require the same acute edges, and
!y tangential positions, as those used by hand ; and if these
it is quite immaterial whether the tool touch
Pig* 427.
the work above or below the . hut the central line, or //.
liir. 1 •: • >, is the most usual. The soft -wood gouge, or hook-tool, is
M M
530 FIXED TOOLS FOR HARD WOOD AND IVORY.
successfully imitated by making an oblique hole in the eud of a
bar of steel, as seen in two views in fig. 427, but it is not very
lasting ; or a bar of steel may be bent to the form of fig. 428,
and sharpened internally, either rounded to serve as a gouge,
or straight and inclined as a chisel, but neither of these tools
admits in itself of adjustment for center.
The difficulty of center is combated by the use of a tool
exactly like a common gouge or chisel, but only an inch or two
long, and with a cylindrical stem also an inch or two long, by which
it may be retained at any height, in the end of abar of iron, having
a nearly perpendicular hole and an appropriate side screw for
fixing the tool; this construction is abundantly strong for wood.
The fixed tools for hardwood and ivory, follow the several forms
of the hand-tools, figs. 382 to 405, pp. 518-19, except in having
parallel stems; they are always placed horizontally, and are
treated in all respects just as before. Care should be taken, how-
ever, that the end of the tool is its widest part ; in order that, if
it be sent in below the surface of the work, as in cutting a
groove, it may clear well, and not rub against the sides.
In sharpening the tools intended for hard wood and ivory,
the oil-stone should be applied principally at the end, or on the
chamfer of the tool, as this will not reduce the height of center,
which it is always important to retain. If, however, the tools
should eventually become chamfered off, after the manner of
fig. 406, p. 519, they may be annealed, and thrown up to place
the chamfered part in the line of the general face ; they are then
re-hardened, and ground up as at first. But as most of the
slide-rests for wood-turning are fitted into pedestals by means
of a cylindrical stem with a vertical screw adjustment, the tools
may be at all times accurately centered when particular care is
required ; and this provision is of still greater importance, with
the several revolving cutters applied to the slide-rest, which will
be hereafter adverted to.
The Jixcd tools for brass and for iron, \\ hether used in the lathe
or the planing machine, will be considered in one group, the
principal difference is, that the tools for brass present an angle
of nearly 90 degrees, the tools for iron an angle of 60, to the
superficies to be wrought. Indeed the angles or edges of the
cube, may be considered as the generic forms of the tools for
brass, and the angles or edges of the tetrahedron, as the generic
FIX | Kill II H ASS AM) IKO\.
forms of the tools for iron ; (lint is, supposing the edges or
plain's of these solids to be hud almost in contact with tin: line
of motion or of the cut, in order that they may fulfil the constant
conditions of the paiing tools, described at page 462, and again
M'eil to ;it pages \r: to 174.
The fixed tools for brass and similar alloys resemble, as in hand-
turning, the more simple of the hardwood tools, except that they
are sharpened a trifle thicker on the edge; they are, howc\
nearly rest tic ted to the point tool, the narrow round tool, and
to the side tool, \\liieh is represented Atj, fig. 426. It is ground
so that the two cutting edges meet at an angle not exceeding
about 80 degrees, that in proceeding into rectangular corners
it may clear each face by about five degrees, and it will then cut
in either direction, so as to proceed into the angle upon the
cylindrical line, and to leave it upon the plane surface, or it may
be applied just in the reverse manner without intermission.
\\hen the tool is used for rough work the corner is slightly
rounded, hut in finishing it is usually quite sharp; and as it
di tiers only some ten degrees from the solid angle of a cube, it
is abundantly strong. If the tools acted upon a considerable
extent or width of the brass, they would be liable to be set in
vibration ; but as the paths of the cutters are determined by the
guide principle employed, the point fulfils all that can be desired.
The fixed tools for iron, present more difficulties than the
generality of the foregoing kinds ; first, the edges of the tools are
thinner, and more interfered with in the act of grinding, as the
vertical height of the cutting edge is reduced when cither face
of the >M _rround ; and secondly, they are exposed to far
more severe strains from the greater hardness of the material,
and the less sparing manner in which it is reduced or wrought,
owing to its smaller price and other circumstances; and there-
fore, the most proper and economic forms of the tools for iron
:ire highly deserving of attention.
The fracture of n tool when it is overloaded, commonly points
out the line of greatest resistance or strain. The tool fig. 429,
on next page, although apparently keen, is very weak, and it is
besides disp.»ed to pursue the line at which its wedge-formed
. mity meets the work, or to penetrate at an angle of some
30 degrees (see | . Figure I •.'•.». would probably break
through a line drawn nearly parallel with the face a b, of the
M II 2
532
work under formation ; that portion should therefore be made
very nearly parallel with a b, the line of resistance, in order
to impart to the tool the strength of the entire section of the
steel ; so that should it now break, it would have a much longer
line of fracture. The tool thus altered is very proper for brass,
an alloy upon which acute tools cannot be favourably employed.
Figs. 429. 430. 431. 432. 433.
But with the obtuse edge of fig. 430, other metals will be
only removed with considerable labour, as it must be remembered
the tool is a wedge, and must insinuate itself as such amongst
the fibres of the material. To give the strengthened tool the
proper degree of penetration, the upper face is next sloped as
in 431, to that angle in which the minimum of friction and the
maximum of durability of the edge most nearly meet; and
which, for iron, is shown to be about 60 degrees, as in the trian-
gular tool fig. 409. The three planes of pointed tools for iron,
meeting at 60 degrees, constitute the angle of the tetrahedron,
or the solid with four equilateral planes, like a triangular pyra-
mid, the base and sides of which are exactly alike.
But the form of 431 would be soon lost in the act of grinding ;
therefore to conclude, the tool is made in the bent form of
fig. 432, in which the angles of 431 are retained, and the tool
may be many times ground without departing from its most
proper form. This is in effect extending the angle of the tetra-
hedron, into the triangular prism ground off obliquely, or rather,
;IN seen in the front view fig. 433, into a prism of five sides, the
front angle of which varies from 60 degrees to 120 degrees, and
is slightly rounded, the latter being most suitable for rough
work, sometimes the front of the prism is half-round, at other
times quite flat, these forms are shown in fig. 439.
The extremities of figs. 431 and 432, approach very closely to
the form of the graver, used for engraving on steel and copper-
plates, than which, no instrument works more perfectly. The
slender graver, whether square or lozenge, is slightly bent, and
n\i i IKON.
has a flattened handle, M> that the riil^e behind the point may
lie s,i nearly parallel with, and MI completely buried in, the line
or groove under format ion, M to be prevented or checked, by
the surface c rom digging into tin- work. Tin-, is another
continuation of the tact, that the line of penetration is that of
the lower face of the cutter or wedge, or that touching the work.
In adopting the crank-formed tools 432, the principle must
not be carried into excess, as it must be remembered, we can
ne\er expunge r/tixlicity from our materials, whether viewed in
relation to the machine, the tool, or the work.
The tool .should be always grasped as near the end as prac-
ticable, therefore the hook or crank should occupy but little
length ; as the distance from the supposed line of the fixing
screw c, to the edge of the tool, being doubled, the flexure of the
instrument will be fourfold; when trebled, ninefold; in fact as
the square. And also as the flexure may be supposed to occur
from near the center of the bar, (that is neglecting the crook,)
the point of the tool should not extend beyond the central line
o; otherwise when the tool bends, its point would dig still
deeper into the work from its rotation on the intersection of c
and o; the point situated behind the central line would spring
airiiy from, or nut of, instead of into the work. To extend the
r of the cranked tools, they are commonly forged so that the
point is nearly level with the upper surface of the shaft, as in
ti-. I :J^ ; they then admit of being many times ground before
they reach the central line, and they are ultimately ground,
(always at the end of the prism and obliquely,) until the hook
/ 434. 436.
w
^_
x
& 1
-
\
\ 435.
!
437.
ntirely lost. This avoids such frequent recurrence to the
. but it is a departure from the right principle, to allow
the point to extend beyond the center line 0. — See Appendix,
\ U, page 8
\vorks of the lathe and planing-machiue frequently present
534
NASMYTH S TOOL GAGE.
439.
angles or rebates, chamfers, grooves, and under-cut lines,
which require that the tool should be bent about in various
ways, in order that their edges may retain as nearly as possible
the same relations to all these surfaces, as the ordinary surfacing
tools figs. 431 and 432 have to the plane a b. For instance, the
shaft of the tool 431, when bent at about the angle of 45 degrees,
becomes a side cutting and facing tool, as shoAvn in plan in fig.
434, in elevation in 435, and in perspective in 436 ; and in like
manner, the cranked tool 432, when also bent as in 434, becomes
437, and is also adapted to working into angular corners upon
either face.
Mr. Nasmyth's tool gage, shown in elevation in 438, and in
plan in 439, entirely removes the uncertainty of the angles given
c to these irregular bent
Fig?. 438. tools : for instance, when
] a the shaft of the tool is
laid upon the flat surface
and applied to the iron
cone c, whose side mea-
sures about 3° with the
perpendicular, it serves
p with equal truth for s, the
tool for surfaces ; p,f, the
* side-cutting tools, used
also for perpendicular
f cuts and fillets ; and u
for undercut works.
In applying tools to lathe works of small diameters, it is
necessary to be very exact, and not to place them above the
center, or they immediately rub ; and as this soon occurs with
tools having so small an angle, it appears desirable to make the
cone gage for small lathe works of about twice the given angle,
and to mark upon the cone, a circle exactly indicative of the
height of center; the tool can be then packed up to the center
line, with one or two slips of sheet iron, to be afterwards placed
beneath the tool when it is fixed in the lathe rest. In small
hollow works, the most lasting of the crank-formed tools,
are entirely inapplicable, indeed so much attention is required
to prevent the tool from rubbing against the interior sur-
faces, that the ordinary angles cannot be employed, and the
Ill; IR BAR. TRIANGULAR CUTTER BAR. 535
'' fPS* ceases to be useful, hut in every other case it should
uitly resorted to; tin- additional thickness a, is required
to make it applicable to the crank-formed tools.*
, represents n cutter introduced in the Block Ma-
chinery at Portsmouth, to lessen the ditliculty of making and
restoring the tools, for turning the wrought-iron pins for the
sheaves; it c< a cylindrical wire \\hich, from being ground
off obliquely, presents an elliptical edge; the tool is fixed in a
stock of iron, terminating in an oblique hole, with a binding
screw. The tool, when used for iron, in the "pin turning
lathes," was made solid, when used for turning the surfaces of
the wooden shells, in the "shaping engine/' it was pierced with
a central hole ; the latter could only facilitate the process of
sharpening, without altering the character of the edge, which
continued under the same circumstances as when solid.
Figs. 440. [ 441.
443.
442.
About sixteen years back, the author made for his own use, a
tool such as fig. 140, but found that with rough usage the cutter
was shivered away, on account of its breadth, and he was soon
led to substitute for the solid cylinder, a triangular cutter, the
final edi;e of which was slightly rounded, and placed more nearly
perpendicular, in a split socket with a side screw, as in fig. 441.
The strength of the edge was greatly increased, and it became,
in fact, nn exact copy of the most favourable kind of tool for
the lathe, or pla-iing-machine, retaining the advantage that the
•The general similitude between some of the author's figures, 429 to 439,
(engraved in Jan. 1840), and part of those in Mr. James Niwmyth's article on
Tools, in Buchanan's Mill Work (published in Deo. 1841), is solely due to their
being each indebted to the some individual (namely, to Mr. Joseph Clement), for
the general theory advanced, and which associates the principles of machine took
ftal that are of comparatively modern date, with those of cutting tools gene-
rally, oven of the most primitive kinds.
536 FINISHING OR SPRINGING TOOLS.
original form could be always kept, with the smallest expendi-
ture of time, and without continually re-forging the blade, to
the manifest deterioration of the steel from passing so frequently
through the fire ; it being only requisite to grind its extremity
like a common graver, and to place it so much higher in the
stock as to keep the edge at all times true to the center.
A right and a left hand side tool for angles, the former seen
in figs. 412 and 443, were also made; the blade and set screw
were placed at about 45°, and at a sufficient vertical angle, to
clear both the inside of a cylinder of three inches diameter, and
also to face the bottom or surface. These side tools answered
very well for cast iron; but fig. 441, the ordinary surfacing tool,
is excellent for all purposes, and has been employed in many
extensive establishments.*
In turning heavy works to their respective forms, a slow
motion and strong pointed tools are employed; but in finishing
these works with a quicker rate of motion, there is risk of putting
the lathe in a slight tremor, more particularly from the small
periodic shocks of the toothed wheels, which in light finishing
cuts are no longer kept in close bearing as in stronger cuts.
Under these circumstances, were the tools rigid and penetra-
tive, each vibration would produce a line or scratch upon the
surface, but the finishing or hanging tools, figs. 444 and 445,
called also springing tools, which are made of various curves and
degrees of strength, yield to these small accidental motions.
The first resembles in its angles the rest of the tools used for
brass, the second those for iron, their edges are rectilinear, and
* The prismatic cutters admit of the usual variations of shape : sometimes two
binding screws are used, and occasionally a tail screw, to receive the direct strain of
the cut. When the blades are only used for cutting in the one direction, say from
right to left, they may, with advantage, be ground with a double inclination ; for aa
all these pointed tools work laterally, the true inclination of some 60° to the
narrow facet or fillet operated upon, is then more strictly attained.
Considerable economy results from this and several other applications, in which
the cutter and ita shaft are two distinct parts. The small blades of steel admit of
being formed with considerable ease and accuracy, and of being hardened in the
most perfect manner. And when the cutters are fixed in strong bars or shafts of
iron, they receive any required degree of strength, and the one shaft or carriage
will serve for any successive number of blades.
The blades are sometimes made flat, or convex in the front, and ground much
thinner, to serve for soft wood ; the tools for hard wood and ivory, being more
easily ground, do not call for this application of detached blades.
I I si- n is.. I • MILS. TOOLS FOR LEAD, TIN, ETC.
sometimes nn inch \\idc. The width and elasticity of these
finishing tools, pii-MMit tlicin acting otherwise than H.S serapers,
fur n-iii<>\iii-_' tin- slight superficial roughnes-s, without det ract in-
fnnu the accuracy of form prc\ ioiisly gi\cn. In a somewhat
Minilar manner tlir broad hand flat tool, rendered elastic b;.
lal .support, as in tig. 411), page 'fl\, is frequently used for
smoothing brass works, und others turned with the slide rest.
446.
447.
448.
I'..-- ill
445.
*. 1 li'» and 1 17 represent a very excellent finishing tool,
introduced hy Mr. Clement, for planing cast and wrought iron,
and steel; it resembles the cranked tools generally, but is
!itcr, it is made smooth and Hat upon the extremity; or rather
in a very minute degree rounded. This tool is sharpened
:ily upon the oilstone, and is used for extremely thin cuts,
generally one quarter of an inch wide, and when the corners just
escape touching, the work is left beautifully smooth; the edge
should on no account stand in advance of the centre line. But
to avoid the chatters so liable to occur in brass works, Mr. Cle-
ment prefers for that material the elastic planing tool,
and -UD, its edge is situated considerably behind the- i\ uter.
In corn-hiding the notice of the turning tools, it may be ueces-
to add a few words on those used for lead, tin, zinc, copper,
and their ordinary alloys. The softest of these metals, such as
lead, tin, and soft pewter, may be turned with the ordinary
tools for soft wood; but for the harder metals, such as zinc, and
hard alloys containing much antimony, the tools resemble those
u>ed for the hard woods, and they are mostly employed dry.
Copper, whieh is much harder and tougher, is turned \u;h
tools similar to those for wrought-iron, but in general they are
sharpened a little more keenly, and water is allowed to drop
538 TOOLS FOR COPPER; LUBRICATING FLUIDS, ETC.
upon the work to lessen the risk of dragging or tearing up the
face of the copper, a metal that neither admits of being turned
or filed with the ordinary facility of most others. Silver and
gold, having the tenacious character of copper, require similar
turning tools, and they are generally lubricated with milk.
In the above, and nearly all the metals except iron and those
of equal or superior hardness, there seems a disposition to
adhere, when by accident, the recently removed shaving gets
forcibly pressed against a recently exposed surface, (the metals
at the time being chemically clean, see page 432, Vol. I.,) this
disposition to unite is nearly prevented when water or other
fluid is used.
Water is occasionally resorted to in turning wrought iron and
steel ; this causes the work to be left somewhat smoother, but
it is not generally used, except in heavy work, as it is apt to rust
the machinery, oil fulfils the same end, but is too expensive for
general purposes. — See Appendix, Note AR., page 983.
Cast iron having a crystalline structure, the shavings soon
break, without causing so much friction as the hard ductile
metals ; cast iron is therefore always worked dry, even when the
acute edges of 60 degrees are thickened to those of 80 or 90,
either from necessity, as in some of the small boring tools, or
from choice on the score of durability, as in the largest boring
tools and others. Brass and gun-metal are also worked dry,
although the turning tools are nearly rectangular, as the copper
becomes so far modified by the zinc or tin, that the alloys,
although much less crystalline than cast iron, and less ductile than
copper, yield to the turning tools very cleanly without water.
But when tools with rectangular edges are used for wrought
iron and steel, on account of the greater cohesion of these
materials, they must be lubricated with oil, grease, soap and
water, or other matter, to prevent the metals from being torn.
And the screw cutting tools, many of which present much surface
friction, and also rectangular or still more obtuse edges, almost
invariably require oil or other unctuous fluids, for all the metals.
It will be shown in the practice of metal turning, that the
diamond point, figs. G4 and 65, page 178, Vol. I., is occasionally
used in turning hardened steel and other substances; figs. 72 to
74 are constantly used in engraving by machinery, and in gra-
duating mathematical instruments. — See Appendix, Notes AS.
to AV. pages 983 to 1001.
589
( HAI'TKK \\\.
BORING TOOLS.
SECT. I. — UoKINO BITS FOR WOOD.
THK process of boring holes may be viewed as an inversion of
that of turning; generally the work remains at rest, and the tool
is revolved and advanced. Many of the boring and drilling tools
have angular points, which serve alike for the removal of the
material, and the guidance of the instrument ; others have blunt
guides of various kinds for directing them, whilst the cutting
is performed by the end of the tool.
Commencing as usual with the tools for wood, the brad-awl
fig. 450, may be noticed as the most simple of its kind ; it is a
cylindrical wire with a chisel edge, which rather displaces than
removes the material ; it is sometimes sharpened with three
facets as a triangular prism. The awl, fig. 451, used by the
\\ ire- workers, is less disposed to split the wood ; it is square and
sharp on all four edges, and tapers off very gradually until near
the point, where the sides meet rather more abruptly.
The generality of the boring instruments used in carj
are fluted, like reeds split in two parts, to give room for the
shavings, and they are sharpened in various ways as shown by
figures 152 to 456. Fig. I.V.! is known as the shell, and also as
the gouge-bit, or quill-bit, it is sharpened at the end like a gouge,
and when revolved it shears the fibres around the margin of the
hole, and removes the wood almost as a solid core. The shell-
hit •< are in very general use, and when made very small, they
are used for boring the holes in some brushes.
1 .">:;, the xii'xin-lit, is generally bent up at the end to
make a taper point, terminating on the diametrical line; it acts
something after the manner of a common point drill, except
that it possesses tin- keen edge suitable for wood. The spoon-bit
union use, the coopers' dowel-bit, and the table-bit,
for making the holes for the wooden joints of tables, are of this
540
REEDED OR FLUTED BITS FOR WOOD.
kind; occasionally the end is bent in a semicircular form,
such are called duck-nose-bits from the resemblance, and also
brush-bits from their use ; the diameter of the hole continues
undiniinished for a greater depth than with the pointed spoon-bit.
Figa 450. 451. 452. 453. 454.
455.
456.
The nose-bit, fig. 454, called also the slit-nose-bit, and auger-bit,
is slit up a small distance near the center, and the larger piece
of the end is then bent up nearly at right angles to the shaft,
so as to act like a paring chisel ; and the corner of the reed, near
the nose also cuts slightly. The form of the nose-bit, which is
very nearly a diminutive of the shell-auger, fig. 455, is better
seen in the latter instrument, in which the transverse cutter lies
still more nearly at right angles, and is distinctly curved on the
edge instead of radial. The augers are sometimes made three
O "
inches diameter, and upwards, and with long removable shanks,
for the purpose of boring wooden pump-barrels, they ai;e then
called pump-bits.
There is some little uncertainty of the nose-bits entering
exactly at any required spot, unless a small commencement is
previously made with another instrument, as a spoon-bit, a gouge,
a brad-awl, a center-punch or some other tool ; Avith augers
a preparatory hole is invariably made, either Avith a gouge,
or with a center-bit exactly of the size of the auger. When
the nose-bits are used for making the holes in sash bars, for
the wooden pins or doAvels, the bit is made exactly parallel,
and it has a square brass socket which fits the bit ; so that the
Avork and socket being fixed in their respective situations, the
y Hide-principle is perfectly applied. A. "guide tube" built up
CBNTBR-B1T8 FOR WOOD.
as n tripod which the workman steadies with his foot, has !
recently applied l»y Mr. Charles May, of Ipswich, for boring the
i- h.-lcs in railway sleepers exactly perpendicular*
The gimlet fig. l.")i; is also a tinted tool, but it terminates in a
sharp worm or screw, beginning as a point and extending to the
full diameter of the tool, which is drawn by the screw into tin-
wood. The principal part of the cutting is done by the angular
corner intermediate between the worm and shell, which acts
much like the auger, the gimlet is worked until the shell is full
of wood, when it is unwound and \\ithdrawn to empty it.
The centcr-bit, tig. 4.">7, shown in three, views, is a very
beautiful instrument, it consists of three parts, a center point or
pin, filed triangularly, which serves as a guide for position ; a thin
shearing point or iiickt-r, that cuts through the fibres like the
point of a knife; and a broad chisel edge or cutter, placed
obliquely to pare up the wood within the circle marked out by
the point. The cutter should have both a little less radius and
less length than the nicker, upon the keen edge of which last
the correct action of the tool principally depends.
Many \ariations are made from the ordinary center-bit, fig.
l.'iT ; sometimes the center -point is enlarged into a stout cylin-
1 plug, so that it may ex- Fig8. 457. 458. 459
aetly fill a hole previously made,
and cut out a cylindrical coun-
tersink around the same, as for
the head of a screw bolt. This
tool, known as the pluy Of
bit, is much used in making
frames and furniture, held toge-
ther by screw-holts. Similar
but with loose cutters
inserted in a diametrical mor-
in a stout shaft, are also used in ship-building for inhmng
the heads of bolts and washers, in the timbers and planking.
The nine-cooper's center-bit is very short, and is enlarged
behind into a cone, so that immediately a full eask has been
bored, the nme pings up the hole until the tap is inserted. The
vr-l.it deprn or possessing only the pin
.,„.! Dicker, i« railed a hntt>,n-t»ol, it is used for boring and
• See Minute* of Convention lust. Civil Engineer*. 1842, page 76.
VARIOUS CENTER-BITS FOR WOOD.
cutting out at one process, the little leather disks or buttons,
which serve as nuts for the screwed wires in the mechanism
connected with the keys of the organ and piano-forte.
The expanding center-bit, shown on a much smaller scale in
fig. 460, is a very useful instrument; it has a central stem with a
conical point, and across the end of the stem is fitted a transverse
bar, adjustable for radius. Where the latter carries only a lancet-
shaped cutter it is used for making the margins of circular
recesses, and also for cutting out disks of wood and thin materials
generally ; when, as in Mr. James Stone's modification, the
expanding center-bit has two shearing points or nickers, and one
chisel-formed cutter, it serves for making
Fig. 460. grooves for inlaying rings of metal or wood
in cabinet-work, and other purposes.* — See
Appendix, note A W., p. 1001.
The above tools being generally used for
woods of the softer kinds, and the plankway
of the grain, the shearing point and oblique chisel of the center-
bit, fig. 457, are constantly retained, but the corresponding tools
used for the hard woods assume the characters of the hard wood
tools generally. For instance, a, fig. 458, has a square point,
also two cutting edges, which are nearly diametrical, and
sharpened with a single chamfer at about 60 degrees; this is the
ordinary drill used for boring the finger-holes in flutes and
clarionets, which are afterwards chamfered on the inner side
with a stout knife, the edge of which measures about 50
degrees. The key-holes, are first scored with the cup-key tool, b,
and then drilled, the tools a, and b, being represented of corres-
ponding sizes, and forming between them the annular ridge
which indents the leather of the valve or key.
\Vhen a, fig. 458, is made exactly parallel, and sharpened up
the sides, it cuts hard mahogany very cleanly in all directions of
the grain, and is used for drilling the various holes in the small
machinery of piano-fortes ; this drill (and also the last two), is
put in motion in the lathe ; and in fig, 459, the lathe-drill for
hard woods, called by the French langue de carpe, the center-
point and the two sides melt into an easy curve, which is
sharpened all the way round, and a little beyond its largest part.
Various tools for boring wood have been made with spiral
* See Trans. Soc. of Arts, vol. xxxi. p. 250.
TWISTED OR SriltM. HITS FOR WOOD.
:.T t!i;it the -havings may be enabled to ascend the
hollow worm, and thereby sa\ ihle of so frequently with-
draw in:; the hit. implc, the shaft of fig. 461. the ringle-
tbrged as a half- round bar, nearly as in the section
above ; it is then coiled into an open spiral with the flat side
\ard>, to constitute the cylindrical surface, and the end is
foniu-d almost the same as that of the shell auge.r, fig. !
The tirixtrd-yimlrt, tiu'- l'; ', is made with a conical shaft, around
which is tiled a half-round groove, the one edge of which become-
thereby sharpened, so as gradually to enlarge the hole after the
first penetration of the worm, which, from being smaller than
in the common gimlet, acts with less risk of splitting.
Pigs. 461. 402. 403. 404. 465. 466. 467. 468.
The ordinary screw auger, fig. 463, is forged as a parallel
blade, of steel, (seen in the section, fig. 4(5 1-, which also refers
to I'- and ttj.j,) it is twisted red-hot, the end terminates in
a worm by which the anger is gradually drawn into the work,
as in the u'imlet, and the two angles or lips are sharpened to cut
at the extreme ends, and a little up the sides also.
The same kind of shaft is sometimes made as in fig. 1 t'4, with
a plain conical point, with two scoring cutters and two chisel
.es, which their obliquity from the slope of the worm:
it is as it were a double center-bit, or one with two lips grafted
on a spiral .shaft. The same shaft has been also made, as in
tiu'. I ''•"», «ith a common drill point, and proposed for metal,
but this se< cly called for; but it is in this form very
ctl'iv'm- in Hunter's pat. -boring machine, intended for
stones not harder than sandstones; the drill is worked by a
544 TWISTED OR SPIRAL BITS FOR WOOD.
cross, guided by a tube, and forced in by a screw cut upon the
shaft carrying the drill ; so that the stone is not ground to
powder, but cast off in flakes with very little injury to the drill.
Another screw auger, which is perhaps the most general after
the double-lipped screw auger, fig. 463, is known as the American
screw auger, and is shown in fig. 466 ; this has a cylindrical
shaft, around which is brazed a single fin or rib ; the eud is filed
into a worm as usual, and immediately behind the worm a small
diametrical mortise is formed for the reception of a detached
cutter, which exactly resembles the nicking point and chisel
edge of the center-bit ; it may be called a center-bit for deep
holes. The parts are shown detached in fig. 467. The loose
cutter is kept central by its square notch, embracing the central
shaft of the auger : it is fixed by a wedge driven in behind, and
the chisel edge rests against the spiral worm. Spare cutters are
added in case of accident, and should the screw be broken off,
a new screw and mortise may be made by depriving the instru-
ment of so much of its length. The instrument will be found
on trial extremely effective ; and on account of the great space
allowed for the shavings, they are delivered perfectly, until the
worm is buried a small distance beneath the surface of the hole.
The Americans have also invented an auger, said to be
thoroughly applicable to producing square holes, and those of
other forms : the tool consists of a steel tube, of the width of
the hole, the end of the tube is sharpened from within, with the
corners in advance or with four hollowed edges. In the center
of the square tube works a screw auger, the thread of which
projects a little beyond the end of the tube, so as first to pene-
trate the wood, and then to drag after it the sheath, and thus
complete the hole at one process ; the removed shavings making
their escape up the worm and through the tube. For boring
long mortises, two or more square augers are to be placed side
by side, but they must necessarily be worked one at a time.*
Fig. 468, the last of this group of spiral drills, is used in
• This is described in Gill's Technical repository, vol. xL page 317. The author
baa never seen one ; it seems far too complex an instrument for general purposes,
and its success appears to be overrated. The tools, figs. 461 to 466, are also
i'ed to America; whether truly or not it is impossible to say. Fig. 461 is in
j .;irtial use. The twisted gimlet is a good tool, but as it is somewhat more expen-
sive than the common kind, it is less used. These several instrumeuts are proba-
bly derived from the common screw auger, fig. 463, which is, I believe, English.
MODES Of ROTATIN'. It HILLS FOB WOOD. '> I .">
many, and two of the instruments were brought from that
country and deposited in the Museum of the Society of Arts, by
Mr. Bryan Donkin.* The tool acts as a hollow taper bit or
rimer, and the M-IVU -form point and shaft, assist in drawing it
into tlu> wood; but the instrument must pass entirely through
for making cylindrical holes.f
The most usual of the modes of giving motion to the various
kinds of boring bits, is by the ordinary carpenter's brace with
a crank-formed shaft. The instrument is made in wood or
IIH tal, and at the one extremity has a metal socket, called the
pad, with a taper square hole, and a spring-catch used for retain-
ing the drills in the brace when they are withdrawn from the
work, and at the other, it has a swivelled head or shield, which
is pressed forward horizontally by the chest of the workman ;
or when used vertically, by the left hand, which is then com-
monly placed against the forehead.J
The ordinary carpenter's brace is too familiarly known to
require further description, but it sometimes happens, that in
corners and other places there
, . , Fig. 469.
is not room to swing round the
handle, the angle-brace, fig. 469,
is then convenient. It is made
entirely of metal, with a pair of
l>e\il pinions, and a winch han-
dle that is placed on the axis
of one of these, at various distances from the center, according
to the power or velocity required. Sometimes the bevil wheel
attached to the winch handle, is three or four times the diameter
of the pinion on the drill ; this gives greater speed but less
power. §
The augers, which from their increased size require more
power, are moved by transverse handles ; some augers are made
with shanks, and are rivetted into the handles just like the
• See Tram., vol. xliv., p. 75.
t The cooper's bit is sometimes made with a gimlet worm, a semi-conical shell,
and a conical plug to stop the hole until the tap is inserted.
J The carpenter's brace is sometimes fixed vertically, with the power of revolv-
ing and of being depressed by a lever, in some reepects like the smith's press drill,
fig. 494, page 558. See also Manuel du Tourneur, 1816, Plate IX., vol ii.
§ Fig. 469 is reduced from Plate IX. of the Manuel du Tourneur.
N N
546 DRILLS FOR METAL.
gimlet ; occasionally the handle has a socket or pad, for receiv-
ing several augers, but the most common mode, is to form the
end of the shaft into a ring or eye, through which the transverse
handle is tightly driven. The brad-awls, and occasionally the
other tools requiring but slight force, are fitted in straight
handles ; many of the smaller tools are attached to the lathe
mandrel by means of chucks, and the work is pressed against
them, either by the hand, or by a screw, a slide, or other con-
trivance ; figs. 458 and 459, are always thus applied.
SECT. II. DRILLS FOR METAL, USED BY HAND.
The frequent necessity in metal works, for the operation of
drilling holes, which are required of all sizes and various degrees
of accuracy, has led to so very great a variety of modes of per-
forming the process, that it is difficult to arrange with much
order the more important of these methods and apparatus.
It is, however, intended to proceed from the small to the
large examples: in the present section some of the general
forms of the drills for metal will be first noticed ; in the next
section will be traced the modes of applying hand power to
drills, commencing with the delicate manipulation of the
watchmaker, proceeding gradually to those requiring the different
kinds of braces, and ending with the various apparatus for driv-
ing large drills by hand-power. In the fourth section the
machine processes will be adverted to, commencing with the
ordinary lathe, and ending with the boring apparatus for the
largest cylinders ; the concluding section of this chapter will be
devoted to the various drills, cutters, and broaches required for
making conical or taper holes.
The ordinary piercing drills for metal do not present quite so
much variety as the wood drills recently described, the drills
for metal are mostly pointed, they consequently make conical
holes, which cause the point of the drill to pursue the original
line, and eventually to produce the cylindrical hole. The com-
parative feebleness of the drill-bow, limits the size of the drills
employed with it to about one-quarter of an inch in diameter ;
but as some of the tools used with the bow, agree in kind with
those of much larger dimensions, it will be convenient to con-
sider as one group, the forms of the edges of those drills, which
cut when moved in either direction.
DOUBLE CUTTING DRILLS FOR METAL.
549
Figs. 470, 471, and 472, represent, of their largest sizes, the
usual forms of drills proper for the reciprocating motion of the
drill-bow, because their cutting edges being situated on the line
Fig*. 470. 471. 472.
478.
474.
475.
of the axis, and chamfered on each side, they cut, or rather
scrape, with equal facility in both directions of motion.
Fig. 470 is the ordinary double-cutting drill, the two facets
forming each edge meet at an angle of about 50 to 70 degrees,
and the two edges forming the point, meet at about 80 to 100 ;
but the watchmakers who constantly employ this kind of drill,
sometimes make the end as obtuse as an angle of about 120
degrees ; the point does not then protrude through their thin
works, long before the completion of their work. Fig. 471, with
two circular chamfers, bores cast-iron more rapidly than any other
reciprocating drill, but it requires an entry to be first made with
a pointed drill ; by some, this kind is also preferred for wrought
iron and steel. The flat-ended drill, fig. 472, is used for flattening
the bottoms of holes. Fig. 473 is a duplex expanding drill,
used by the cutlers for inlaying the little escutcheons and plates
of metal in knife handles; the ends are drawn full size, and the
explanation will be found at page 135 of the first volume.
I ? \- is also a double-cutting drill ; the cylindrical wire is
tiled to the diametrical line, and the end is formed with two facets.
This tool has the advantage of retaining the same diameter when
it is sharpened ; it is sometimes called the Swiss drill, and was
employed hy M. I,c Riviere, for making the numerous small
holc>, in the delicate punching machinery for mamifaetni
perforated sheets of metal and pasteboard ; these drills are Mime-
timcs made either semicircular or flat at the extremity, and
as they are commonly employed in the lathe, they will be
N N 2
548
SINGLE CUTTING DRILLS FOR METAL.
further noticed in the fourth section, under the title of half-round
boring bits.
The square countersink, fig. 475, is also used with the drill-
bow ; it is made cylindrical, and pierced for the reception of a
small central pin, after which, it is sharpened to a chisel edge, as
shown. The countersink is in some measure a diminutive of the
pin drills, fig. 482 to 485, page 550; and occasionally circular
collars are fitted on the pin for its temporary enlargement, or
around the larger part to serve as a stop, and limit the depth to
which the countersink is allowed to penetrate, for inlaying the
heads of screws. The pin is removed when the instrument is
sharpened.
By way of comparison with the double-cutting drills, the ordi-
nary forms of those which only cut in one direction, are shown in
figs. 476, 477, and 478. Fig. 476 is the common single-cutting
478.
479.
480.
481.
drill, for the drill-bow, brace, and lathe ; the point, as usual, is
nearly a rectangle, but is formed by only two facets, which
meet the sides at about 80° to 85° ; and therefore lie very nearly
in contact with the extremity of the hole operated upon, thus
strictly agreeing with the form of the turning tools for brass.
Fig. 477 is a similar drill, particularly suitable for horn, tortoise-
shell, and substances liable to agglutinate and clog the drill ; the
chamfers are rather more acute, and are continued around the
edge behind its largest diameter, so that if needful, the drill
may also cut its way out of the hole.
Fig. 478, although never used with the drill-bow, nor of so
small a size as in the wood-cut, is added to show how completely
the drill proper for iron, follows the character of the turning
tools for that metal ; the flute or hollow filed behind the edge,
llTTINC DRILL* H)K MKTAL. .', I'.l
gives the hook-formed acute edge required in this too], which is
in other respecN like f'i£. 17<s the form proper for the cutting
edge is shown more distinctly in the diagram a, fig. 482.
Care should always be taken to have ;i proportional degree of
tii;th in the shafts of the drills, otherwise they tremble and
chatter when at work, or they occasionally twist off in the
x -, the point should he also ground exactly central, so that
both edges may cut. As a guide for the proportional thickness
of the point, it may measure at b, fig. 179, the base of the cone,
about one-fifth the diameter of the hole, and at j>, the point,
about one-eighth, for easier penetration : but the fluted drills are
made nearly of the same thickness at the point and base.
In all the drills previously described, except fig. 474, the size
of the point is lessened each time of sharpening ; but to avoid
this loss of size, a small part is often made parallel, as shown in
liir- 17'.'. In fig. 4s(), this mode is extended by making the drill
with a cylindrical lump, so as to fill the hole : this is called the
re-centering drill. It is used for commencing a small hole in a
flat-bottomed cylindrical cavity ; or else, in rotation with the
common piercing drill, and the half-round bit, in drilling
small and very deep holes in the lathe : see sect. iv. p. 567.
Fig. 480 may be also considered to resemble the stop-drill, upon
which a solid lump or shoulder is formed, or a collar is tempo-
rarily attached by a side screw, for limiting the depth to which
the tool can penetrate the work.
Fig. 481, the cone countersink, may be viewed as a multiplica-
tion of the common single-cutting drill. Sometimes, however,
the tool is filed with four equi-distant radial furrows, directly
upon the axis, and with several intermediate parallel furrows
sweeping at an angle round the cone. This makes a more even
distribution of the teeth, than when all are radial as in the figure,
and it is always used in the spherical cutters, or countersinks,
known as cherries, which are used in making bullet-moulds.
On comparison, it may be said the single-chamfered drill, fig.
476, cuts more quickly than the double-chamfered, fig. 470, but
that the former is also more disposed of the two, to swerve or
run from its intended position. In using the double-cutting drills,
it is also necessary to drill the holes at once to their full sizes, as
otherwise the thin edges of these tools stick abruptly into the
metal, and arc liable to produce jagged or groovy surfaces, which
550
PIN DRILLS FOR METAL.
destroy the circularity of the holes ; the necessity for drilling
the entire hole at once, joined to the feebleness of the drill-bow,
limits the size of these drills.
In using the single chamfered drills, it is customary, and on
several accounts desirable, to make large holes by a series of two
or more drills ; first the run of the drill is in a measure propor-
tioned to its diameter, therefore the small tool departs less from
its intended path, and a central hole once obtained, it is followed
with little after-risk by the single-cutting drill, which is less
penetrative. This mode likewise throws out of action the less
favourable part of the drill near the point, and which in large
drills is necessarily thick and obtuse ; the subdivision of the
work enables a comparatively small power to be used for drilling
large holes, and also presents the choice of the velocity best
suited to each progressive diameter operated upon. But where
sufficient power can be obtained, it is generally more judicious
to enlarge the holes previously made with the pointed drills, by
some of the group of pin drills, figs 482 to 485, in which the
guide principle is very perfectly employed : they present a close
analogy to the plug center-bit, and the expanding center-bit,
used in carpentry.
The ordinary pin-drill, fig. 482, is employed for making coun-
tersinks for the heads of screw-bolts inlaid flush with the surface,
and also for enlarging holes commenced with pointed drills, by
Figs. 482.
483.
484.
a cut parallel with the surface ; the pin-drill is also particularly
suited to thin materials, as the point of the ordinary drill would
soon pierce through, and leave the guidance less certain. When
ROBERTA'S FIN DRILL.
tins tool is used for iron, it is fluted as usual, and a, represents
the form of one edge separately.
.483 is a pin-drill principally used for cutting out large
holes in cast-iron and other plates. In this case the narrow
1 er removes a ring of metal, which is of course a less laborious
process than cutting the whole into shavings. When this drill
is applied from both sides, it may be used for plates half an inch
and upwards in thickness ; as should not the tool penetrate the
whole of the way through, the piece may be broken out, and the
rough edges cleaned with a file or a broach.
Fig. 484 is a tool commonly used for drilling the tube-platei
for receiving the tubes of locomotive boilers ; the material is
about f inch thick, and the holes 1J diameter. The loose
cutter a, is fitted in a transverse mortise, and secured by a
wedge ; it admits of being several times ground, before the notch
which guides the blade for centrality is obliterated. Fig. 485 is
somewhat similar to the last two, but is principally intended for
sinking grooves; and when the tool is figured as shown by the
dotted line, it may be used for cutting bosses and mouldings on
parts of work not otherwise accessible.
Many ingenious contrivances have been made to ensure the
dimensions and angles of tools being exactly retained. In this
class may be placed Mr. Roberts's pin-drill, figs. 486 and 487 ;
in action it resembles the fluted pin-drill, fig. 482, but the iron
Fig*. 486. JL 487.
stock is much heavier, and is attached to the drilling-machine by
the square tang ; the stock has two grooves at an angle of about
10 degrees with the axis, and rather deeper behind than in
front. Two steel cutters, or nearly parallel blades represented
black, are laid in the grooves ; they are fixed by the ring and
two set screws, * *, and are advanced as they become worn
away, by two adjusting screws, a a, (one only seen,) placed at the
angle of 10° through the second ring ; which, for the convenience
552 LUBRICATION. DRILLS FOR MINERAL SUBSTANCES.
of construction is screwed up the drill-shaft just beyond the
square tang whereby it is attached to the drilling-machine.
The cutters are ground at the extreme ends, but they also
require an occasional touch on the oilstone, to restore the keen-
ness of the outer angles, which become somewhat rounded by the
friction. The diminution from the trifling exterior sharpening,
is allowed for by the slightly taper form of the blades.
The process of drilling, generally gives rise to more friction
than that of turning, and the same methods of lubrication are
used, but rather more commonly and plentifully ; thus oil is used
for the generality of metals, or from economy, soap and water ;
milk is the most proper for copper, gold, and silver ; and cast
iron and brass are usually drilled without lubrication, as described
at page 538. For all the above-named metals, and for alloys of
similar degrees of hardness, the common pointed steel drills are
generally used ; but for lead and very soft alloys, the carpenters'
spoon bits and nose bits are usually employed, with water. For
hardened steel and hard crystalline substances, copper or soft
iron drills, such as fig. 67 or 71, page 178, Vol. I., supplied with
emery powder and oil are needed; or the diamond drill-points
66, 68, and 70 are used for hardened steel, with oil alone.*
Having considered the most general forms of the cutting parts
* The boring tools used for the mineral substances, are partly adverted to in
the ninth chapter of Vol. I ; beginning with the bits used for the softest materials,
those for boring through earth, sand, and clay, in order to obtain water, are enlarged
copies of the shell, nose, and spiral bits used hi carpentry, attached to long vertical
rods which are screwed together like jointed gun rods, and are worked by a cross
at the earth's surface. The rods are drawn up by a windlass, and joint after joint
is unscrewed, until the bit, with its contained earth, is brought to the surface.
Various attempts have been made to avoid the tedious necessity for raising the
rods, by the employment of a hollow cylinder or magazine resting on the bit, to
receive the borings, and to be drawn up occasionally to be emptied.
In boring large holes the earth is generally excavated by the process of " miser-
ing up." The rods terminate in the " miter," which is a cylindrical iron case
sometimes two to three feet diameter, with a slightly conical bottom, in which
there is a slit much like the mouth of a plane, and covered with a leather flap to
prevent the escape of the earth that has been collected.
In sinking the Artesian wells, lined with cast-iron tubes attached end to end
by internal flanges or screws, a spring tool is used, which expands when it is
tbruat beneath the lower end of the series of pipea See the account of sinking
the Artesian well at Messrs. Truman, Hanbury, and Co.'s Brewery, Minutes of
Conversation, Inst. of Civil Eng., 1842, p. 192.
The common pointed drill, is used for mineral substances not exceeding in hardness
those enumerated under the terms, 1, 2, 3, of the Table of hardness, p. 158, VoL I.,
Ml I 1101)8 OF WORKING DRILLS BY HAND POWER. 553
of drills, we will proceed to explain thr. modes in which they are
put in action by hand-power, bc^innin^ « ith those for tin-
smallest diameters, and proceeding gradually to the largest.
SECT. III. METHODS OP WORK I M. DKILLS BY HAND POWER.
The smallest holes are those required in watch-work, and tin-
general form of the drill is shown on a large scale in fi;:
is made of a piece of steel wire, which is tapered off at the one
end, flattened with the hammer, and then filed up in the form
shown at large in fig. 570, p. 547 ; lastly, it is hardened in the
candle. The reverse end of the instrument is made into a conical
point, and is also hardened ; near this end is attached a little
brass sheave for the line of the drill-bow, which in watchmaking
is sometimes a fine horse-hair, stretched by a piece of whalebone
of about the size of a goose's quill stripped of its feather.
Fig. 488.
The watchmaker holds most of his works in the fingers, both
for fear of crushing them with the table vice, and also that he
may the more sensibly feel his operations ; drilling is likewise
performed by him in the same manner. Having passed the
bow-string around the pulley in a single loop (or with a round
turn), the center of the drill is inserted in one of the small
center holes in the sides of the table vice, the point of the drill
is placed in the mark or cavity made in the work by the center
punch; the object is then pressed forward with the right hand,
whilst the bow is moved with the left ; the Swiss workmen apply
the hands in the reverse order, as they do in using the turn-bench*.
and which include some of the marbles. Glass may also be drilled with fig. 470,
or 471, lubricated with turpentine. The sandstones are readily bored in Hunter's
patent stone boring-machine (see p. 54$, also Conv. Civ. Eng. 1842, p. 146), and the
granites are not bored, but crushed by the jumper, or chisel point, see p. 170, Vol. 1.
: the compact mineral*, such as 4, 5, 6 of the table, the grinding tools may
be used with sand, but emery is more effective ; this powder may be also employed
for minerals not exceeding the hardness of 7 and 8 ; but emery being somewhat
I hardness to the ruby, this gem and the diamond, marked 9 and 10 in
the table, require either diamond dust, or splinters of the diamond, the ouUide
skin and natural angles of which, are much harder than the inside substance. See
the ninth chapter of VoL I. generally, especially pages 178 to 180.
• See Vol. IV., page 18.
554 DRILL BOW AND BREAST-PLATE.
Clockmakers, and artisans in works of similar scale, fix the
object in the tail-vice, and use drills, such as fig. 488, but often
larger and longer ; they are pressed forward by the chest which
is defended from injury by the breast-plate, namely, a piece of
wood or metal about the size of the hand, in the middle of which
is a plate of steel, with center holes for the drill. The breast-
plate is sometimes strapped round the waist, but is more usually
supported with the left hand, the fingers of which are ready
to catch the drill should it accidentally slip out of the center.
As the drill gets larger, the bow is proportionably increased
in stiffness, and eventually becomes the half of a solid cone,
about 1 inch in diameter at the larger end, and 30 inches long;
the catgut string is sometimes nearly an eighth of an inch in
diameter, or is replaced by a leather thong. The string is
attached to the smaller end of the bow by a loop and notch,
much the same as in the archery bow, and is passed through a hole
at the larger end, and made fast with a knot ; the surplus length
is wound round the cane, and the cord finally passes through a
notch at the end, which prevents it from uncoiling.
Steel bows are also occasionally used ; these are made some-
thing like a fencing foil, but with a hook at the end for the knot
or loop of the cord, and with a ferrule or a ratchet, around which
the spare cord is wound. Some variations also are made in the
sheaves of the large drills ; sometimes they are cylindrical with
a fillet at each end ; this is desirable, as the cord necessarily
lies on the sheave at an angle, in fact in the path of a screw ;
it pursues that path, and with the reciprocation of the drill bow,
the cord traverses, or screws backwards and forwards upon the
sheave, but is prevented from sliding off by the fillet. Occasionally
indeed, the cylindrical sheave is cut with a screw coarse enough
to receive the cord, which may then make three or four coils for
increased purchase, and have its natural screw-like run without
any fretting whatever ; but this is only desirable when the holes
are large, and the drill is almost constantly used, as it is tedious
to wind on the cord for each individual hole. The structure of
the bows, breast-plates, and pulleys, although often varied, is
sufficiently familiar to be understood without figures. — See
Appendix, Note AY, page 1002.
When the shaft of the drill is moderately long, the workman
can readily observe if the drill is square with the work as regards
itKII.L STOCKS AND DRILLING LATIIKS.
561
the horizontal plane; and to remove the necessity for the obser-
vation of an assistant as to the vertical plane, a trifling weight
is sometimes suspended from the drill shaft by a metal ring or
hook, the joggling motion shifts the weight to the lower extre-
mity; t lie tool is only horizontal when the weight remains central*.
I ii many cases, the necessity for repeating the shaft and pulley
of the drill is avoided, by the employment of holders of various
kinds, or drill-gtockf, which serve to carry any required number
<>f drill-points. The most simple of the drill-stocks is shown
iu fig. 489; it has the center and pulley of the ordinary drill,
Figs. 489.
but the opposite end is pierced with a nearly cylindrical hole,
just at the inner extremity of which a diametrical notch is
filed. The drill is shown separately at a ; its shank is made
cylindrical, or exactly to fit the hole, and a short portion is
nicked down also to the diametrical line, so as to slide into the
gap in the drill-stock, by which the drill is prevented from
revolving ; the end serves also as an abutment whereby it may be
thrust out with a lever. Sometimes a diametrical transverse
mortise, narrower than the hole, is made through the drill-stock,
and the drill is nicked on both sides; and Mr. Gill proposes
that the cylindrical hole of 489, should be continued to the
bottom of the notch, that the end of the drill should be filed off
obliquely, and that it should be prevented from rotating, by a pin
inserted through the cylindrical hole parallel with the notch; the
taper end of the drill would then wedge fast beneath the pin.f
Drills are also frequently used in the drillinr/- lathe ; this is a
miniature lathe-head, the frame of which is fixed in the table
vice ; the mandrel is pierced for the drills, and has a pulley for
• This is Analogous to Use level of the Indian matom and carpenters ; they
squeeze a few drop* of water on the upper surface of the straight edge, which in
made exactly parallel, and the escape of the fluid from either end, denotes that to
be the lower of the two.
t See Technical Repos., 1822, voL il, p. 149; also Bees'! Cyclopedia.
556
ROBISON'S AND ALLEN'S DRILL STOCKS.
the bow, therein resembling fig. 490, except that it is used as
a fixture.
The figure 490 just referred to, represents one variety of another
common form of the drill-stock, in which, the revolving spindle is
fitted in a handle, so that it may be held in any position, without
the necessity for the breast-plate ; the handle is hollowed out to
serve for containing the drills, and is fluted to assist the grasp.
Fig. 491 represents the socket of an "universal drill-stock"
invented by Sir John Robison ; it is pierced with a hole as large
Figs. 491.
492.
493.
as the largest of the wires of which the drills are formed, and
the hole terminates in an acute hollow cone. The end of the
drill-stock is tapped with two holes, placed on a diameter ; the
one screw a, is of a very fine thread, and has at the eud two
shallow diametrical notches ; the other b, is of a coarser thread
and quite flat at the extremity. The wire-drill is placed against
the bottom of the hole, and allowed to lean against the adjust-
ing-screw a, and if the drill be not central, this screw is moved
one or several quarter-turns, until it is adjusted for centrality ;
after which the tool is strongly fixed by the plain set-screw b.
Fig. 492 is a drill-stock, contrived by Mr. William Allen : it
consists of a tube, the one end of which has a fixed center and
pulley much the same as usual ; the opposite end of the tube has
a piece of steel fixed into it, which is first drilled with a central
hole, and then turned as a conical screw, to which is fitted a
corresponding screw nut n ; the socket is then sawn down with
two diametrical notches, to make four internal angles, and
lastly, the socket is hardened. When the four sections are
compressed by the nut, their edges stick into the drill and retain
it fast, and provided the instrument is itself concentric, and the
four parts are of equal strength, the centrality of the drill is
PUMP DRILL. SMITH'S BRACE, FT 557
ice ensured. The outside of the nut. :iml the square hole
in the key k, arc enrh taper, for more ready application ; and
the drills are of the most simple kind, namely, lengths of wire
pointed at each end, as in fig. 4(.W.*
The sketch, fig. 492, is also intended to explain another
useful application of this drill-stock, as an upriyht or pump-drill,
a tool little employed in this country (except in drilling the
t holes for mending china and glass, with the diamond-drill,
fig. 70, vol. I.,) but as well known among the oriental nations as
the breast-drill. The pump-drill is figured and explained on
page 3 of the fourth volume of this work, to which the reader
is referred ; occasionally the pump-drill and the common drill-
stock are mounted in frames, by which their paths are more
exactly defined; but these contrivances are far from being
generally required, and enough will be said in reference to the
use of revolving braces, to lead to such applications, if considered
requisite, for reciprocating drills. — See Appendix, Notes A. Z.
to B.B. page 1003.
Holes that are too large to be drilled solely by the breast-
drill and drill-bow, are frequently commenced with those useful
instruments, and are then enlarged by means of the hand-brace,
which is very similar to that used in carpentry, except that it is
more commonly made of iron instead of wood, is somewhat
larger, and is generally made without the spring-catch.
Holes may be extended to about half an inch in diameter, with
the hand-brace ; but it is much more expeditious to employ still
larger and stronger braces, and to press them into the work in
various ways by weights, levers, and screws, instead of by the
muscular effort alone.
Fi^. I'.U represents the old smith's press-drill, which although
cumbrous, and much less used than formerly, is nevertheless
simple and effective. It consists of two pairs of wooden standards,
bet ween which works the beam a b, the pin near a is placed at any
height, but the weight w is not usually changed, as the greater
or less pressure for large and small drills, is obtained by placing
the brace more or less near to the fulcrum a ; and this part of
the beam is shod with an iron plate, full of small center holes
: lie brace. The weight is raised by the second lever c d, the
• See Technical Repository, vol. il, 1822, p. 147.
558
OLD PHESS DRILL FRAMES.
two being united by a chain, and a light chain or rope is also
suspended from d, to be within reach of the one or two men
engaged in moving the brace. It is necessary to relieve the
weight when the drill is nearly through the hole, otherwise, it
might suddenly break through, and the drill becoming fixed,
might be twisted off in the neck.
Fig-s. 494.
495.
The inconveniences in this machine are, that the upper point
of the brace moves in an arc instead of a right line ; the limited
path when strong pressures are used, which makes it necessary
to shift the fulcrum a; and also the necessity for re-adjusting
the work under the drill for each different hole, which in
awkwardly shaped pieces is often troublesome.
A portable contrivance of similar date, is an iron bow frame
or clamp, shown in fig. 495 ; the pressure is applied by a screw,
but in almost all cases, whilst the one individual drills the hole,
the assistance of another is required to hold the frame ; 495
only applies to comparatively thin parallel works, and does not
present the necessary choice of position. Another tool of this
kind, used for boring the side holes in cast-iron pipes for water
and gas, is doubtless familiarly known ; the cramp or frame
divides into two branches about two feet apart, and these ter-
minate like hooks, which loosely embrace the pipe, so that the
tool retains its position without constraint, and it may be used
with great facility by one individual.
Fig. 496 will serve to show the general character, of various
constructions of more modern apparatus, to be used for supply-
ing the pressure in drilling holes with hand braces. It consists
of a cylindrical bar a, upon which the horizontal rectangular
rod b, is fitted with a socket, so that it may be fixed at any height,
MODERN FRES8 DRILL FRAMES.
or in any angular ji»»itiun, l»y the set-screw c. Upon b slides a
sockt t, \\ Inch is fixed at all distances from a, by its set-screw d,
and lastly, this socket has a long vertical screw e, by which the
brace is thrust into the work.
object to be drilled having been placed level, either
upon the ground, on trestles, on the work bench, or in the \
according to circumstances, the
screws, c and d are loosened, and
the brace is put in position for
work. The perpendicularity of
the brace is then examined with
a plumb-line, applied in two posi-
tions, (the eye being first directed
as it were along the north and
south line, and then along the east
and west,) after which the whole is
made fast by the screws c and rf.
The one hole having been drilled,
the socket and screws present great
facility in rc-adjusting the instru-
ment for subsequent holes, without
the necessity for shifting the work,
which would generally be at tended
with more trouble, than altering the drill-frame by its screws.
Sometimes the rod a is rectangular, and extends from the
floor to the ceiling ; it then traverses in fixed sockets, the lower
of which has a set-screw for retaining any required position. In
the tool represented, the rod a, terminates in a cast-iron base,
by which it may be grasped in the tail-vice, or when required it
may be fixed upon the bench; in this case the nut on a is
unscrewed, the cast-iron plate, when reversed and placed on
the bench, serves as a pedestal, the stem is passed through
a hole in the bench, and the nut and washer when screwed on
the stem beneath, secure all very strongly together. Even
in est;ibli>hments where the most complete drilling-machines
driven by power arc at hand, modifications of the press-drill
are among the indispensable tools: many arc contrived with
screws and clamps, by which they are attached directly to
such works as are sufficiently large and massive to serve as a
foundation^
560
EXPANDING BRACES; LEVER DRILL.
Various useful drilling tools for engineering works, are fitted
with left-hand screws, the unwinding of which elongate the
tools; so that for these instruments which supply their own
pressure, it is only necessary to find a solid support for the
center. They apply very readily in drilling holes within boxes
and panels, and the abutment is often similarly provided by
projecting parts of the castings ; or otherwise the fixed support
is derived from the wall or ceiling, by aid of props arranged in
the most convenient manner that presents itself.
Fig. 497 is the common brace, which only differs from that in
fig. 496 in the left-hand screw ; a right-hand screw would be
unwound in the act of drilling a hole when the brace is moved
round in the usual direction, which agrees with the path of a
left-hand screw. The cutting motion produces no change in
the length of the instrument, and the screw being held at rest
for a moment during the revolution, sets in the cut ; but towards
the last, the feed is discontinued, as the elasticity of the brace
and work, suffice for the reduced pressure required when the
drill is nearly through, and sometimes the screw is unwound
still more to reduce it.
500.
49S.
501.
The lever-drill, fig. 498, differs from the latter figure in many
respects, it is much stronger, and applicable to larger holes ;
the drill socket is sufficiently long to be cut into the left-hand
screw, and the piece serving as the screwed nut, is a loop ter-
minating in the center point. The increased length of the lever
gives much greater purchase than in the crank-formed brace,
and in addition the lever-brace may be applied close against a
RATCHET-DRILL, CORNER-DIM I.
surface whnv tin; crauk-brace cannot !><• tunn-d round ; in this
case tlu- lever is only moved a half circle at a time, and i-» then
slid through for a new purchase, or sometimes a spanner or
wrench is applied duvet ly upon the square drill-sod.
1 is more conveniently fulfilled by the ratchet-
({rill, fig. 499, apparently derived from the last; it is made by
nur rate:. iu the drill-shaft, or putting on the ratchet
as a separate piece, and fixing a pall or detent to the handle;
. itter may then be moved backward to gather up the teeth,
and forward to thrust round the tool, with less delay than the
l<-\ t-r in fig. 498, and with the same power, the two being of equal
length. This tool is also peculiarly applicable to reaching into
angles and places in which neither the crank-form brace, nor the
It \i r-drill will apply. Fig. 500, the ratchet-lever, in part resem-
the ratchet-drill, but the pressure-screw of the latter instru-
ment must be sought in some of the other contrivances referred
to, as the ratchet-lever has simply a square aperture to fit on the
tang of the drill d, which latter must be pressed forward by some
independent means.
Fig. 501, which is a simple but necessary addition to the
braces and drill tools, is a socket having at the one end a
square hole to receive the drills, and at the opposite, a square
: to tit the brace; by this contrivance the length of the drill
can be temporarily extended for reaching deeply-seated holes.
The sockets are made of various lengths, and sometimes two or
three are used together, to extend the length of the brace to suit
the position of the prop ; but it must be remembered, that with
the additional length the torsion becomes much increased, and
the resistance to end-long pressure much diminished, therefore
the sockets should have a bulk proportionate to their length.
The French brace, fig. 469, page 545, is also constructed in
iron, with a pair of equal bevil pinions, and a left-hand center
screw like the tools, fig. 497, 498, and 499 : it is then called the
H-r-drill. Sometimes also, as in the succeeding figures 502
and 503, the bevil wheels are made with a hollow square or a\i .
. -net-lever, fig. 500; the driver then hangs loosely on
th Mjiiarc shank of the drill tool, or cutter bar, and when the
pinion on the handle is only one-third or fourth of the size of
the bevil wheel with the square hole, it is an effective driver for
»ns uses: the long tail or lever serves to prevent the rotation
o o
SHANK S DIFFERENTIAL SCRE\V-D1ULL.
of the driver, by resting against some part of the work or of the
work-bench.
All the before-mentioned tools are commonly found in a
variety of shapes in the hands of the engineer, but it will be
observed they are all driven by hand-power, and are carried
to the work. I shall conclude this section with the description
of a more recent drill-tool of the same kind, invented by Mr.
A. Shanks of Glasgow.
This instrument is represented of one- eighth size, in the side
view, fig. 504, in the front view, 505, and in the section 500 ; it
Figs. 504. 505. 506.
is about twice as powerful as fig. 503, and has the advantage of
feeding the cut by a differential motion. The tangent screw
moves at the same time the two worm wheels a and b ; * the
former has 15 teeth, and serves to revolve the drill ; the latter
has 16 teeth, and by the difference between the two, or the odd
* A principle first introduced iu Dr. Wollaston's Trochiometer, for couutiug
the turns of a carriage wheel.
l.iui i. it')HlN<. MACHINES.
i, advances the drill slowly and continually, which may be
thus explained.
The lower wheel a, of 15 teeth, is fixed on the drill-shaft, and
this is tapped to mvivr the center-screw c, of four threads per
inch. The upper wheel of 16 teeth is at the end of a socket d,
(which is represented black in the section fig. 506), and ia con-
nected with the center-screw c, by a collar and internal key,
which last fits a longitudinal groove cut up the side of the
screw c ; now therefore the internal and external screws travel
constantly round, and nearly at the same rate, the difference of
one tooth in the wheels serving continually and slowly to pro-
ject the screw c, for feeding the cut. To shorten or lengthen
the instrument rapidly, the side screw e is loosened ; this sets
the collar and key, free from the 1C wheel, and the center-screw
for the time be moved independently by a spanner.
The differential screw-drill, having a double thread in the large
worm, shown detached at /, requires 7$ turns of the handle to
move the drill once round, and the feed is one Olth of an inch
for each turn of the drill ; that being the sum of 16 by 4. See
Appendix, Note B C, page 1004.
SECT. IV. — DRILLING AND BORING MACHINES.
The motion of the lathe-mandrel is particularly proper for
giving action to the various single-cutting drills referred to;
they are then fixed in square or round hole drill-chucks which
screw upon the lathe-mandrel. The motion of the lathe is more
uniform than that of the hand-tools, and the popit-head, with
its flat boring flange and pressure-screw, form a most convenient
arrangement, as the works are then carried to the drill exactly
at right angles to the face. But in drilling very small holes in
t he lathe, there is some risk of unconsciously employing a greater
pn-smire with the screw, than the slender drills will bear. Some-
times the cylinder is pressed forward by a horizontal lever fixed
on a fulcrum : at other times the cylinder is pressed forward
by a spring, by a rack and pinion motion, or by a simple lev. r,
••uui ri arrangement of this latter kind is that next to be
described.
In the manufacture of harps there is a vast quantity of small
drilling, and the pressure of the cylinder popit-head is given by
ms of a long, straight, double-emit d lever, which moves
o a
564 HARP-MAKER'S DRILLING-MACHINE.
horizontally, (at about one-third from the back extremity,) upon
a fixed post or fulcrum erected upon the back-board of the lathe.
The front of the lever is connected with the sliding cylinder by
a link or connecting rod, and the back of the lever is pulled
towards the right extremity of the lathe, by a cord which passes
over a pulley at the edge of the back-board, and then supports
a weight of about twenty pounds.
Both the weight and the connecting rod, may be attached at
various distances from the fixed fulcrum between them. When
they are fixed at equal distances from the axis of the lever, the
weight, if twenty pounds, presses forward the drill with twenty
pounds, less a little friction ; if the weight be two inches from
the fulcrum and the connecting rod eight inches, the effect of
the weight is reduced to five pounds ; if, on the other hand, the
weight be at eight and the connecting rod at two inches, the
pressure is fourfold, or eighty pounds.
The connecting rod is full of holes, so that the lever may be
adjusted exactly to reach the body of the workman, who, standing
with his face to the mandrel, moves the lever with his back, and
has therefore both hands at liberty for managing the work.
Sometimes a stop is fixed on the cylinder, for drilling holes to
one fixed depth ; gages are attached to the flange, for drilling
numbers of similar pieces at any fixed distance from the edge :
in fact, this very useful apparatus admits of many little additions
to facilitate the use of drills and revolving cutters.
Great numbers of circular objects, such as wheels and pulleys,
are chucked to revolve truly upon the lathe- mandrel, whilst a
stationary drill is thrust forward against them, by which means
the concentricity between the hole and the edge is ensured.
The drills employed for boring works chucked on the lathe,
have mostly long shafts, some parts of which are rectangular or
parallel, so that they may be prevented from revolving by a
hook wrench, (page 218, Vol. I.,) a spanner or a hand-vice,
applied as a radius, or by other means. The ends of the drill
shafts are pierced with small center holes, in order that they
may be thrust forward by the screw of the popit-head, either by
hand or by self-acting motion ; namely, a connection between
either the mandrel or the prime mover of the lathe, and the
screw of the popit-head, by cords and pulleys, by wheels and
pinions, or other contrivances.
BORING BITS tSED IN Till I \MIK.
drills, figs. 476 and 478, p. 548, are used for boring
ordinary holes ; but for t |iiiring greater accuracy, or a
more U ' of the same diameter, the lathe-drills, figs.
507 to 509, are commonly selected. Fig. 507, which is drawn in
tlnv. \ u \vs and to the same scale as the former examples, is cat led
the naif-round bit, or the cylinder Int. The extremity is ground a
little inclined to the ri^ht an^'lc, both horizontally and vertically,
to about the extent of three to five degrees. It is necessary to
turn out a shallow recess exactly to the diameter of the end of
the bit as a commencement; the circular part of the bit fills
the hole, and is thereby retained central, whilst the left angle
removes the -sh.i\ing. This tool should never be sharpened on
its diametrical face, or it would soon cease to deserve its appel-
lation of half-round bit : some indeed give it about one-thirtieth
more of the circumference. It is generally made very slightly
smaller behind, to lessen the friction*; and the angle, not in-
tended to cut, is a little blunted half-way round the curve, that
it may not scratch the hole from the pressure of the cutting
edge. It is lubricated with oil for the metals generally, but is
used dry for hard woods and ivory, and sometimes for brass.
Fig«. 507.
The rose-bit, fig. 508, is also very much used for light finishing
cuts, in brass, iron, and steel ; the extremity is cylindrical, or in
the smallest degree less behind, and the end is cut into teeth
like a countersink ; the rose-bit, when it has plenty of oil, and
but very little to remove, will be found to act beautifully, but
this tool is less fit for cast-iron than the bit next to be described.
The rose-bit may be used without oil for the hard woods and
566 BORING BITS USED IN THE LATHE.
ivory, in which it makes a very clean hole ; but as the end of
the tool is chamfered, it does not leave a flat-bottomed recess
the same as the half-round bit, and is therefore only used for
thoroughfare holes.
The drill, fig. 509, is much employed, but especially for cast-
iron work; the end of the blade is made very nearly parallel,
the two front corners are ground slightly rounding, and are
chamfered, the chamfer is continued at a reduced angle along
the two sides, to the extent of about two diameters in length ;
this portion is not strictly parallel, but is very slightly largest in
the middle or barrel-shaped : this drill is used dry for cast-iron.
Fig. 509, in common with all drills that cut on the side, may,
by improper direction, cut sideways, making the hole above the
intended diameter; but when the hole has been roughly bored
with a common fluted drill, the end of the latter is used as a
turning tool, to make a»accurate chamfer, the bit 509 is then
placed through the stay as shown in fig. 510, and is lightly sup-
ported between the chamfer upon the work and the center of
the popit-head ; the moment any pressure comes on the drill,
its opposite edges stick into the inner sides of the loop, (as more
clearly explained in fig. 511,) which thus restrains its position;
much the same as the point and edges of the turning tools for
iron dig into the rest, and secure the position of those tools.
It is requisite the drill and the loop should be exactly central,
fig. 510 shows the common form of the stay when fitted to the
lathe-rest, but it is sometimes made as a swing-gate, to turn
aside, whilst the piece which has been drilled is removed, and
the next piece to be operated upon is fixed in the lathe. Some-
times also the drill 509, has blocks of hardwood attached above
and below it, to complete the circle ; this is usual for wrought
iron and steel, and oil is then employed.
These three varieties are exclusively lathe-drills, and are
intended for the exact repetition of a number of holes of the
particular sizes of the bits, and which, on that account, should
remove only a thin shaving to save the tools from wear.
The cylinder bits, however, may be used for enlarging holes
below half an inch, to the extent of about one-third their
diameter at one cut ; and for holes from half an inch to one
inch, about one fourth their diameter or less, and as the bits
increase in size, the proportion of the cut to the diameter should
decrease.
IS USBD I MB.
Tin- cylinder bit is not intended to be used for drilling
in the solid material, :uul as tin- piercing drills nrc apt to s\\.
in drilling small and very deep holes, the following rotation in
the tools is sometimes resorted to. A drill, 1L-. I7i>, p.
tlmv-s!\t. niths diameter, is first sent in to the depth of an inch
or upwards, and the hole is enlarged by a cylinder hit of one
quarter inch diameter. The center at the end of the ho!
then restored to exact truth, hy fig. tSU a re-centeriug drill, the
plug of which exactly fits the hole made by the cylinder bit ;
the extremity of the re-centering drill then acts as a fixed turn-
ing tool, and should the first drill have run out of its position,
480 corrects the center at the end of the hole. Another short
portion is then drilled with 17<>, enlarged with the half-round
bit, and the conical extremity is again corrected with the re-
centering drill; the three tools are thus used in rotation until
the hole is completed, and which may lie then cleaned out with
one continued cut, made with a half-round bit u little larger
than that previously used.
Some of the large half-round bits are so made, that the one
stock will serve for several cutters of different diameters. In the
bit used for boring out ordnance, the parallel shaft of the boring
bar slides accurately in a groove, exactly parallel with the bore
of the gun ; the cutting blade is a small piece of steel affixed to
the end of the half-round block, which is either entirely of iron,
or partly of wood ; and the cut is advanced by a rack and pinion
movement, actuated either by the descent of a constant weight,
or by a self-acting motion derived from the prime mover, i
making the spherical, parabolical or other termination to the
bore, cutters of corresponding forms are fixed to the bar.* See
Appendix, Notes B D to B I, pages 1005 to 1010.
There are very many works which from their weight or size,
cannot be drilled, in the lathe in its ordinary position, as it
is scarcely possible to support them steadily against the drill ;
but these works are readily pierced in the drilling-machine,
which may 1, \itli a vertical mandrel, and
• The outside of the gun is usually turned, whiUt the boring is going on, by the
hand-tools, figs. 423 and 424, page 527. A plug of copper U screwed into the bran
guns to be perforated fur tlio touch-hole, copper being less injured by repeated
discharge*, than the alloy of 9 parts copper and 1 part tin, used fur the general
subattiucd of the gun ; the curved bit smooths off tlio end of the plug.
568
VERTICAL DRILLING-MACHINES.
with the flange of the popit-head, enlarged into a table for the
Avork, which then lies in the horizontal position simply by gravity,
or is occasionally fixed on the table by screws and clamps. The
structure of these important machines admits of almost endless
diversity, and in nearly every manufactory some peculiarity of
construction may be observed.*
Figs. 512 and 513 exhibit NasmytVs "Portable Hand-drill,"
which is introduced as a simple and efficient example, that may
Figs.
512.
513.
serve to convey the general characters of the drilling-machines.
The spindle is driven by a pair of bevil pinions, the one is attached
to the axis of the vertical fly-wheel, the other to the drill-shaft,
which is depressed by a screw moved by a small hand-wheel.
Sometimes, as in the lathe, the drilling spindle revolves with-
out endlong motion, and the table is raised by a treadle or by a
hand-lever; but more generally the drill-shaft is cylindrical and
revolves in, and also slides through, fixed cylindrical bearings.
The drill-spindle is then depressed in a variety of ways; sometimes
by a simple lever, at other times, by a treadle which either lowers
the shaft only one single sweep, or by a ratchet that brings
it down by several small successive steps, through a greater
distance; and mostly a counterpoise weight restores the parts to
their first position when the hand or foot is removed. Friction-
clutches, trains of differential wheels, and other modes, are also
used in depressing the drill-spindle, or in elevating the table by
self-acting motion. Frequently also the platform admits of an
* Probably no individual has originated so many useful varieties of drilling-
machines, fa Mr. Richard Roberts, of the firm of Sharp, Roberts, and Co.,
Manchester.
Mill! Mi lioKlM, M MINNIE, < I TTER BARS, I
adjustment independent of that of the spindle, for the sake of
admitting larger pieces; the horizontal position of the platform
i* then retained by a slide, to which a rack and pinion move-
ment, or an elevating screw, is added.*
Drilling-machines of these kinds are generally used with thp
ordinary piercing-drills, and occasionally with pin-drills; the lat-
ter instrument appears to be the type of another class of boring
tools, namely, cutter-bars, which are used for works requiring
holes of greater dimensions, or of superior accuracy, than can
be attained by the ordinary pointed drills.
The small application of this principle, or of cutter-bars, is
shown on the same scale as the former drills, in fig. 514; the
cutter c, is placed in a diametrical mortise in a cylindrical
boring bar, and is fixed by a wedge; the cutter c extends
equally on both sides, as the two projections or ears embrace the
sides of the bar, which is slightly flattened near the mortises.
Cutter-bars of the same kind, are occasionally employed with
cutters of a variety of forms, for making grooves, recesses,
mouldings, and even screws, upon parts of heavy works, and
those which cannot be conveniently fixed in the ordinary lathe.
Fig. 515 represents one of these, but its application to screws
will be found in the chapter on the tools for screw-cutting.
Figs. 514. I
3-e
-KSh
TZP *=-
The larger application of this principle is shown in fig. 516, in
which a cast-iron cutter-block is keyed fast upon a cylindrical
liar, the block has four, six, or more grooves in its periphery.
• The platform in a drilling-machine, at Messrs. Perm's, Greenwich, is placed
between two aide frames, with fillets a few inches apart, so that it is supported at
any height, like a single drawer in an empty tier. The traverse of the drill-abaft
ia rather more than equal to the space between the fillets.
Figures 512 and 513 are transcribed from plate 29 of" Buchanan's Mill Work."
by Rennie, 1841 ; and plates 29 to 33 a, of that work, contain various other
drilling-machines, similar to, and explanatory of, those in general use.
570 BORING MACHINES FOR
Sometimes, the work is done with only one cutter, and should the
bar vibrate, the remainder of the grooves are filled with pieces
of hard-wood, so as to complete the bearing at so many points of
the circle ; occasionally cutters are placed in all the grooves, and
carefully adjusted to act in succession, that is, the first stands a
little nearer to the axis than the second, and so on throughout,
in order that each may do its share of the work ; but the last
of the series takes only a light finishing cut, that its keen edge
may be the longer preserved. In all these cutters the one face
is radial, the other differs only four or five degrees from the right
angle, and the corners of the tools are slightly rounded.
These cutter-bars, like the rest of the drilling and boring
machinery, are employed in a great variety of ways, but which
resolve themselves into three principal modes :
First, the cutter-bar revolves without endlong motion, in fixed
centers or bearings, in fact, as a spindle in the lathe; the work
is traversed, or made to pass the revolving cutter in a right line,
for which end the work is often fixed to a traversing slide-rest.
This mode requires the bar to measure between the supports,
twice the length of the work to be bored, and the cutter to be
in the middle of the bar, it is therefore unfit for long objects.
Secondly, the cutter-bar revolves, and also slides with endlong
motion, the work being at rest ; the bearings of the bar are then
frequently attached in some temporary manner to the work to
be bored, and are often of wood.*
In another common arrangement, the boring bar is mounted
in headstocks, much the same as a traversing mandrel, the
work is fixed to the bearers carrying the headstocks, and the
cutter-bar is advanced by a screw. The screw is then moved
either by the hand of the workman ; by a star- wheel, or a
ratchet-wheel, one tooth only in each revolution ; or else by a
system of differential wheels, in which the external screw has a
wheel say of 50 teeth, the internal screw a wheel of 51 teeth,
and a pair of equal wheels or pinions drives these two screws
continually, so that the advance of the one-fiftieth of a turn
of the screw, or their difference, is equally divided over each
* Cylinders of forty inches diameter for steam engines, have been thus bored,
by attaching a cast-iron cross to each end of the cylinder; the crosses are boro.l
exactly to fit the boring bar, one of thorn carries the driving gear, and the bar is
thrust endlong by means of a screw, moved by a ratchet- or star-wheel.
I \K< 1 t \ 1 IM i;H8, ETC.
f the euttcr-har, much the same ns in the dif-
ntial inotiuii ot' the screw-drill, fig. ."."I, page 562.
Tliis second method only requires the interval between the
fixed hearings of the cutter-bar, to be as much longer than the
M as the length of the cutter-block ; hut the bar it-. If must
ha\e more than twice the length of the work, aud requires to
slide through the supports.
Cutter-bars of this kind are likewise used in the lathe; in
the act of boring, the end of the bar then slides like a piston
into the mandrel. Such bars are commonly applied to the
teal boring-machines of the larger kinds, which are usually
fitted with a differential apparatus, for determining the progress
of the cut ; the bar then slides through a collar fixed in the bed
of the machine.
In some of the large boring-machines either one or two
hori/ontal slides are added, and by their aid, series of holes may
be bored in any required arrangement. For instance, the
several holes in the beams, or side levers, and cranks of steam-
engines, are bored exactly perpendicular, in a line, and at any
precise distances, by shifting the work beneath the revolving
spindle upon the guide or railway ; in pieces of other kinds, the
work is moved laterally during the revolution of the cutters,
for the formation of elongated countersinks and grooves.
Thirdly. In the largest applications of this principle, the
boring bar revolves upon fixed bearings without traversing; and
it is only needful that the boring bar should exceed the length
of the work, by the thickness of the cutter-block, of which it
has commonly several of different
diameters. The cutter-block, now
sometimes ten feet diameter, tra-
verses as a slide down a hup'
boring bar, whose diameter is
about thirty inches. There is a
groove and key to couple them
together, and the traverse of the
cutter-block down the bar, i>
caused by a side-screw, upon the
end of u Inch is a large wheel, that engages in a small pinion,
/ to the >tHtioii:i: Of p> ilr-tal of the machine. ^ ith
;tion of the cutter-bar, the great wheel is carried
BROACHES FOR WOOD.
around the fixed pinion, and supposing these be as 10 to 1, the
great wheel is moved one-tenth of a turn, and therefore moves
the screw one-tenth of a turn also, and slowly traverses the
cutter-block.
The contrivance may be viewed as a huge, self-acting, and
revolving sliding-rest, and the diagram 517 shows that the cutter-
bars are equally applicable to portions of circles, such as the
D valves of steam-engines, as well as to the enormous interior
of the cylinder itself.* See Appendix, Note B J, page 1010.
All the preceding boring tools cut almost exclusively upon the
end alone. They are passed entirely through the objects, and
leave each part of their own particular diameter, and therefore
cylindrical; but I now proceed to describe other boring tools
that cut only on their sides, go but partly through the work, and
leave its section a counterpart of the instrument. These tools
are generally conical, and serve for the enlargement of holes to
sizes intermediate between the gradations of the drills, and also
for the formation of conical holes, as for valves, stopcocks, and
other works. The common pointed drill, or its multiplication
in the rose countersink, is the type of the series; but in general
the broaches have sides which are much more nearly parallel.
SECT. V. — BROACHES FOR MAKING TAPER HOLES.
The tools for making taper holes are much less varied than
the drills and boring tools for cylindrical holes. Thus the
carpenter employs only the rimer, which is a fluted tool like the
generality of his bits ; it is sharpened from within, as shown in
fig. 518, so as to act like a paring tool. Flutes and clarionets
Figs. 518. 620. 521. 522. 523. 524. 525. 626.
A
528. ~
are first perforated with the nose-bit, and then broached with
taper holes, by means of tools of this kind, which are very
There is generally a small intermediate wheel between the two represented ;
many other details of the large boring machines will also be found in " Buchanan's
Mill Work," as already noticed.
lll(i)\i|||:s K»H \VOOI» AM) MKTM.. 573
fully graduated a» to their dimensions. Fig. 519 represent*
mum rimer, used by wheelwright* for inlaying the boxes of
axletrees ; the loose blade is separated from the shell of the
mMrumcut, by introducing slips of leather or wood between the
two; the detached cutter fits on a pin at the front, aud is fi
t>y a ring or collar against the shaft.
A curious rimer for the use of wine-coopers, was invent
the late Mr. John Hilton, by which the holes were made more
truly circular, and the shavings were prevented from dropping
into the cask. The stock of the instrument consisted of a
hollow brass cone, seen in section in fig. 520 ; down one side
there was a slit for containing a narrow blade or cutter, fixed by
three or four screws placed diametrically. The tube was thus
converted into a conical plane; the shavings entered within the
tube, and were removed by taking out a cork from the small
end of the cone.*
The broaches for metal are made solid, and of various
sections; as half-round, like fig. 521, the edges are then rectan-
gular, but more commonly the broaches are polygonal, as in
fig. 522, except that they have 3, 4, 5, 6, and 8 sides, and their
edges measure respectively 60, 90, 108, 120, and 135 degrees.
The four, five, and six-sided broaches are the most general, and
the watchmakers employ a round broach in which no angle
exists, and the tool is therefore only a burnisher, which com-
presses the metal and rounds the hole.
Ordinary broaches are very acute, and fig. 528 may be con-
sidered to represent the general angle at which their sides meet,
namely, less than one or two degrees; the end is usually
chamfered off with as many facets as there are sides, to make a
penetrating point, and the opposite extremity ends in a square
/'/////. or shank, by which the instrument is worked.
Square broaches, after having been filed up, are sometimes
twisted whilst red hot; fig. 527, shows one of these, the rectan-
gular section is but little disturbed, although the faces become
slightly concave. The advantage of the tool appears to exist
in its screw form: when it is turned in the direction of the spiral,
it cuts with avidity and requires but little pressure, as it is
• Soe Tnutt. Soc. of Arts. 1880, vol. xlriii. pagi •
574 PARALLEL BROACHES FOR METAL.
almost disposed to dig too forcibly into the metal : when turned
the reverse way, as in unscrewing, it requires as much or more
pressure than similar broaches not twisted. This instrument, if
bent in the direction of its length, either in the act of twisting
or hardening, does not admit of correction by grinding, like
those broaches having plane faces. It is not much used, and is
almost restricted to wrought iron and steel.
Large countersinks that do not terminate in a point, are
sometimes made as solid cones ; a groove is then formed up one
side, and deepest towards the base of the cone, for the insertion
of a cutter, see fig. 523. As the blade is narrowed by sharpen-
ing, it is set a little forward in the direction of its length, to
cause its edge to continue slightly in advance of the general
surface, like the iron of a plane for cutting metal.
Fig. 529 represents Mr. Richard Roberts' broach, in which
four detached blades are introduced, for the sake of retaining
Fig. 529.
===1
the cone or angle of the broach with greater facility. The bar
or stock has four shallow longitudinal grooves, which are nearly
radial on the cutting face, and slightly undercut on the other.
The grooves are also rather deeper behind, and the blades are
a little wedge-form both in section and in length, to constitute
the cone, and the cutting edges. In restoring the edges of the
blades, they are removed from the stock, and their angles are
then more easily tested : when replaced, they are set nearer to
the point, to compensate for their loss of thickness.
Broaches are also used for perfecting cylindrical holes, as well
as for making those which are taper. The broaches are then
made almost parallel, or a very little the highest in the middle;
they are filed, with two or three planes at angles of 90 degrees,
as in figs. 524 or 525. The circular part not being able to cut,
serves as a more certain base or foundation, than when the tool
is a complete polygon; and the stems are commonly made
r \H\I.I.KI. Huouiir.s. I>KIM.> AND BROACHES COM PA it i i»
small eiion;h to pass entirely through t! which thru
agree very exactly a- Such tools are then-tun- rather
entitled to the name of finishing drills, than broaches.
The size of the parallel broaches is often ^li^htly increased,
by placing a piece or two of paper at the convex part; leather
and thin metal are also used for the same purpose. Gun-barrels
are broached uith square broaches, the cutting parts of which
are about eijrht to ten inches long; they are packed on the four
sides with slips or spills of wood, to complete the circle, as in
fiu'. r>'2(), in which the tool is supposed to be at work. The size
of the bit is progressively enlarged by introducing slips of thin
paper, piece by piece between two of the spills of wood and the
broach; the paper throws the one angle more towards the
center of the hole, and causes a corresponding advance in the
opposite or the cutting angle. Sometimes, however, only one
spill of wood is employed.
A broach used by the philosophical instrument makers in
finishing the barrels of air pumps, consisted of a thin plate of
steel inserted diametrically between two blocks of wood, the
whole constituting a cylinder with a scraping edge slightly in
advance of the wood ; slips of paper were also added.
According to the size of the broaches, they are fixed in
handles like brad-uwls they are used in the brace, or the tap
wrench, namely, a double-ended lever with square central holes.
Sometimes, also, broaches are used in the lathe just like drills,
and for large works, broaching machines are employed ; these
are little more than driving gear terminating iu a simple kind
of universal joint, to lead the power of the steam-engine to the
tool, which is generally left under the guidance of its own edges,
according to the common principle of the instrument.
In drills and broaches, the penetrating angles are commonly
more obtuse than iu turning tools; thus in drills of limited
dimensions, the hook-form of the turning tool for iron is inap-
plicable, and in the larger examples, the permanence of the tool
is of more consequence than the increased fiction. But on account
of the additional friction excited by the nearly rectangular edged,
it is commonly necessary to employ a smaller velocity in boring
than in turning corresponding diameters, in order to avoid soft-
ening the tool by the heat generated ; and in the ductile fibrous
576 DRILLS AND BROACHES COMPARED.
metals, as wrought iron, steel, copper and others, lubrication
with oil, water, &c., becomes more necessary than in turning.
The drills and broaches form together a complete series.
First the cylinder bit, the pin-drills, and others with blunt sides,
produce cylindrical holes by means of cutters at right angles to
the axis ; then the cutter becomes inclined at about 45 degrees,
as in the common piercing-drill and cone countersink ; the angle
becomes much less in the common taper broaches ; and finally,
disappears in the parallel broaches, by which we again produce
the cylindrical hole, but with cutters parallel with the axis of
the hole.
Still considering the drills and broaches as one group, the
drills have comparatively thin edges, always less than 90 degrees,
yet they require to be urged forward by a screw or otherwise,
the resistance being sustained in the line of their axes. The
broaches have much more obtuse edges, never less than 90, and
sometimes extending to 135 degrees ; and yet the greater force
required to cause the penetration of their obtuse edges into the
material, is supplied without any screw, because the pressure in
all these varied tools is at right angles to the cutting edge.
Thus, supposing the sides of the broach extended until they
meet in a point, as in fig. 528, we shall find the length will very
many times exceed the diameter, and by that number will the
force employed to thrust forward the tool be multiplied, the
same as in the wedge, whether employed in splitting timber or
otherwise ; and the broach being confined in a hole, it cannot
make its escape, but acts with great lateral pressure, directed
radially from each cutting edge ; and the broach under proper
management leaves the holes very smooth and of true figure.
( IIAPTER XXVI.
SCREW-CUTTINO TOOIA
SECT. I. — INTRODUCTORY REMARKS.
AN elementary idea of the form of the screw, or helix, is ob-
tained by considering it as a continuous circular wedge; and it
is readily modelled by wrapping a wedge-formed piece of paper
around a cylinder; the edge of the paper then represents the
line of the screw, and which preserves one constant angle to
the ;t.\is of the contained cylinder, namely, that of the wedge.
The ordinary wedge, or the diagonal, may be produced by the
composition of two uniform rectilinear motions, which, if equal,
produce the angle of 45°, or if unequal, various angles more or
less acute; and in an analogous manner, the circular wedge or
the screw, may be produced of every angle or coarseness, by the
composition of an uniform circular motion, with an uniform
rectilinear motion. And as either the rectilinear or the circular
motion may be given to the work or to the tool indifferently,
tin-re are four distinct modes of producing screws, and which
arc all variously modified in practice.
The screw admits of great diversity ; it may possess any dia-
meter; it may al>o have any angle, that is, the interval between
the threads may be either coarse or fine, according to the ai.
of the wedge, or the ratio of the two motions ; and the wedge
may be wound upon the cylinder to the right hand or to the
left, so as to produce either right or left-hand screws.
The idea of double, triple, or quadruple screws, will be con-
veyed by considering two, three, or four black lines drawn on the
un< Ige of the wedge-formed paper, or likewise by two,
three, or foin - or wires placed in contact, and coiled as a
flat band around the cylinder, the angle remains unaltered, it is
only a multiplication of the furrows or threads; and lastly, the
screw may have any section, that is, the section of the worm or
p P
578 INTRODUCTORY REMARKS.
thread may be angular, square, round, or of any arbitrary form.
Thus far as to the variety in screws.
The importance of this mechanical element, the screw, in all
works in the constructive arts, is almost immeasurable. For
instance, great numbers of screws are employed merely for con-
necting together the different parts of which various objects are
composed, no other attachment is so compact, powerful, or
generally available; these binding or attachment screws require,
by comparison, the least degree of excellence. Other screws are
used as regulating screws, for the guidance of the slides and the
moving parts of machinery, for the screws of presses and the like ;
these kinds should possess a much greater degree of excellence
than the last. But the most exact screws that can be produced,
are quite essential to the good performance of the engines
employed in the "graduation of right lines and circles and of
astronomical and mathematical instruments; in these delicate
micrometrical screws, our wants ever appear to outstrip the
most refined methods of execution.
The attempt to collect and describe all the ingenious con-
trivances which have been devised for the construction of screws,
would be in itself a work of no ordinary labour or extent : I must,
therefore, principally restrict myself to those varied processes
now commonly used in the workshops, for producing with com-
parative facility, screws abundantly exact for the great majority
of purposes. It has been found rather difficult to arrange these
extremely different processes in tolerable order, but that which
seems to be the natural order has been adopted, thus :
There appears to be no doubt, but that in the earliest production
of the apparatus for cutting screws, the external screw was the
first piece made ; this plain circular metal screw was serrated and
thus converted into the tap, or cutting tool, by which internal
screws of corresponding size and form were next produced ; and
one of these hollow screws, or dies, became in its turn the means
of regenerating, with increased truth and much greater facility,
any number of copies of the original external screw. In these
several stages there is a progressive advance towards perfection,
as will be hereafter adverted to.
These hand processes are mostly used for screws, which
are at least as long, if not longer than their diameters. The
rotatory and rectilinear guides, and the one or several series of
l>l\l>l'.\ OK TUB SUIUK 579
eutt in- ('"nits, are then usually combined within the tool.
Thi» fii->t -rroup \\ill be considered in three sections, namely:
1 1. On originating screws.
111. On cutting internal screws, with screw-taps.
1\ . On (in tin- external screws, with screw-dies.
Suhx (|iu nt improvements have led to the employment of the
lathe, in producing from the above, and in a variety of ways, still
more accurate screws. These methods are sometimes used for
screws which possess only a portion of a turn, at other times for
screws twenty or thirty feet long and upwards. The rotatory
guide is always given by the mandrel, the rectilinear guide is
variously obtained, and the detached screw-tool or cutter, may
ha\e one single point, or one series of points which touch the
circle at only one place at a time. This second group will be
also considered in three sections, namely :
V. On cutting screws, in the common lathe by hand.
\ I. On cutting screws, in lathes with traversing mandrels.
VII. On cutting screws, in lathes with traversing tools.
It may be further observed that the modes described in the
six sections are in general applied to very different purposes,
and are only to a limited extent capable of substitution one for
the other; it is to be also remarked that it has been considered
convenient, in a great measure to abandon, or rather to modify,
the usual distinction between the tools respectively used for
wood and for metal. The eighth and concluding section of this
chapter describes some refinements in the production of screws
which are not commonly practised, and it is in some measure a
sequel to the second section.
SECT. II. — ON ORIGINATING SCREWS.
It appears more than probable, that in the earliest attempts
at making a screw, a sloping piece of paper was cemented around
the iron cylinder ; this oblique line was cut through with a stout
knife or thiu-edgcd file, and was then gradually enlarged by
hand until it gave a rude form of screw. Doubtless, as soon as
the application of the hit i ally known, the work was
mounted bet uters, so that the process of filing up the
groove could be more easily accomplished, or a pointed turning
tool could be employed to assist. Such, in fact, is one of the
modes recommended by Plnmier, tor cutting the screw upon a
580 VARIOUS MODES FORMERLY
lathe-mandrel for receiving the chucks, even ill preference to
the use of the die-stocks, which he urged were liable to bend
the mandrel in the act of cutting the screw.*
Nearly similar modes have been repeatedly used for the pro-
duction of original screws; one account differing in several
respects from the above, is described as having been very suc-
cessfully resorted to, above fifty years back, at the Soho works,
Birmingham, by a workman of the name of Anthony Robinson,
before the introduction of the screw-cutting lathe.
The screw was seven feet long, six inches diameter, and of a
square triple thread ; after the screw was accurately turned as a
cylinder, the paper was cut parallel exactly to meet around the
same, and was removed and marked in ink with parallel oblique
lines, representing the margins of the threads; and having
been replaced on the cylinder, the lines were pricked through
•with a center-punch. The paper was again removed, the dots
were connected by fine lines cut in with a file, the spaces were
then cut out with a chisel and hammer and smoothed with a
file, to a sufficient extent to serve as a lead or guide.
The partly-formed screw was next temporarily suspended in
the center of a cast-iron tube or box strongly fixed against a
horizontal beam, and melted lead mixed with tin was poured
into the box to convert it into a guide nut ; it then only remained
to complete the thread by means of cutters fixed against the
box or nut, but with the power of adjustment, in fact in a kind
of slide-rest, the screw being handed round by levers f-
Another very simple way of originating screws, and which is
sufficiently accurate for some purposes, is to coil a small wire,
around a larger straight wire as a nucleus; this last is fre-
quently the same wire, the one end of which is to be cut into the
screw. The covering wire, whose diameter is equal to the space
required between the threads of the screw, is wound on close
and tight, and made fast at each end. The coiled screw, being
enclosed between two pieces of hard wood, indents a hollow or
counterpart thread, sufficient to guide the helical traverse, and
a fixed cutter completes this simple apparatus. See Appendix,
Note 15 K, page 1010.
* L' Art du Tourneur, by Plumier, 1701, pages 15 — 19.
+ This mode, which is described in Gill's Tech. Repos. vol. vi. p. 261, is said
to have excited at the time great admiration from its success. It is probable a
gun-metiil nut wat» cast upon this screw for use, after the screw was finished.
EMPLOYF.D FOB OBICJI SCREWS.
MlM.-hold purp'.M--, bftYQ been
made of tinned iron wire; two covering wires are rolled on
together, the one being r< n a space such as the
ordinary hollow of tin- thread, and when these screws are
dipped in a little melted tin, the two wires become sold
;icr.
Other in de> have heen resorted to for making original s.
by indenting a smooth cylinder, \\ith a sharp-ed^ed cutter placed
across the same at the required angle ; and trusting to the sur-
face or rolling contact, to produce the rotation and traverse of
the cylinder, with the development of the screw. In the most
simple application of this method, a deep groove is made along a
piece of board, in which a straight wire is buried a little beneath
the surface; a second groove is made, nearly at right angles
across the first, exactly to fit the cutter, which is just like a
table knife, and is placed at the angle required in the screw.
The cutter when slid over the wire, indents it, carries it round,
and traverses it endways in the path of a screw ; a helical
Hue is thus obtained, which, by cautious management may be
perfected into a screw sufficiently good for many purposes.
The late Mr. Henry Maudslay employed a cutter upon cylin-
ders of wood, tin, brass, iron, and other materials, mounted to
revolve between centers in a triangular bar lathe; the knife \\;ts
hollowed to fit the cylinder, and fixed at the required angle on
a block adapted to slide upon the bar; the oblique incision
carried the knife along the revolving cylinder. Some hundreds
of screws were thus made, and their agreement with one another
was in many instances quite remarkable ; on the whole he gave
the preference to this mode of originating screws.*
Mr. Allan's apparatus for originating screws for astronomical
and other purposes is represented in plan in fig. 580, in side
elevation in fi£. Ji.'ll, and .VJ-.i is the front elevation of the cutter-
frame alone. The piece intended for the screw, namely, a a fig.
530, is turned cylindrical, and with two equal and cylindi
necks; it is supported in a metal frame with two semi-circnlnr
• The reader is also referred to the Trans. Sue. of Arta, vol. xlii., page :
the description of Mr. Walsh's method of making original screws by rolling con-
tact, or with a abort screw mounted as a milling-tool, to act only by pressure, (see
abx> figs. 637 and 588, page 604 of this volume,) the method appears, however, to
be circuitous, difficult, and very questionable. The instrument, fig. 80, page
vol. i.. for cutting snakes in horn, is virtually an originator of screws.
5S2
ALLAN'S APPARATUS.
bearings, b b, which are fixed on a slide moved by an adjusting
screw c ; speaking of the apparatus the inventor says :
" The instrument generates original screws perfectly true, of
any number of threads, and right or left handed. In this case,
the stock and cutter are made as in figs. 530, 531, and 532 ;
the back of the stock is made into the segment of a circle, s ;
aud the top of the cutter is continued into an index, t. The
cutter is a single thread^ and moves on its edge, v, as a center.
This must fit true, and the stock fit close to the cutter, to keep
it perfectly steady : u, u, two screws, to adjust and fasten the
cutter to any required angle. The cutter should be rather
elliptical, for it is best to fit well to the cylinder at the greatest
angle it will be ever used. When one turn has been given to
Figs. 533.
634.
535.
636.
the cylinder, fig. 530, a tooth, w, is put into the cut, and
screwed fast; this tooth secures the lead, and causes every
following thread to be a repetition of the first ; and, though it
might do without, yet this is a satisfactory security/' *
* See Trans. Soc. of Arts, 1816, vol. xxxiv., p. 206. The engravings are copied
from figs. 6 to 12 of plate 23. An instrument based on the same general plan is
described in the Mech. Mag., 1836, vol. xxv., p. 377 ; but it is greatly inferior to
the above.
In cutting ordinal \ screws, the dies, shown separately in figs.
533 to 586, the consideration of which is for the present deferred,
take the place of the oblique cutter in tin igures.
The screw is also originated, In traversing the tool in a right
line alongside a plain revolving cylinder. Sometimes the tool
has many points, and is guided by the hand alone; at other
times the tool has but one single point, and is guided mechani-
cally so as to proceed, say one inch or one foot in a right line,
whilst the cylinder makes a definite number of revolutions. The
tool is then traversed either by a wedge placed transversely to
the axis, by a chain or metallic band placed longitudinally, or by
another screw, connected in various ways with the screw to be
produced, by wheel-work and other contrivances.
It would be injudicious to attempt at this place the explana-
tion of these complex methods of originating screws ; some of
them will, however, be introduced in the course of this chapter,
whilst, for greater perspicuity, others will be deferred unto its
latter pages. The next section will be now proceeded with, on
the supposition that a screw of fair quality has been originated
by some of the means referred to.
SECT. III. — ON CUTTING INTERNAL SCREWS, WITH SCREW-TAPS.
The screw is converted into the tap, by the removal of parts
of its circumference, in order to give to the exposed edges a
cutting action; whilst the circular parts which remain, serve
for the guidance of the instrument within the helical groove, or
hollow thread, it is required to form.
In the most simple and primitive method, four planes were
filed upon the screw as in fig. 537, but this exposes very obtuse
edges which can hardly be said to cut, as they form the thread
partly by indenting, and partly by raising or burring up the
metal ; and as such they scarcely produce any effect in cast iron
or other crystalline materials. Conceiving, as in fig. 537, only
a very small portion of the circle to remain, the working edges
of squared taps, form angles of (90 -f 45 or) 135 degrees with
the circumference, and the angle is the greater, the more of the
circle that remains. It is better to file only three planes as in
fig. 538, but the angle is then as great as 120 degrees c\cn
under the most favourable circumstances.
584
COMPARISON OF THE
In taps of the smallest size it is imperative to submit to these
conditions, and to employ the above sections. Sometimes small
intermediate facets or planes, are tipped off a little obliquely
with the file, to relieve the surface friction ; this gives the instru-
ment partly the character of a six or eight-sided broach, and
improves the cutting action.
Figs. 537. 538
540.
541.
542
There appears to be no doubt, but that for general purposes,
the most favourable angle for the edges of screw taps and dies,
is the radial line, or an angle of 90 degrees. This condition
manifestly exists in the half-round tap fig. 539, which is advo-
cated in the annexed quotation from Sir John Robison, who in
speaking of the tap, says, " I propose that this should be made
half-round, as it will be found that a tap formed in this way
will cut a full clear thread (even if it may be of a sharp pitch),
without making up any part of it by the burr, as is almost
universally the case, when blunt-edged or grooved taps are
used."
" It has sometimes been objected to me by persons who had
not seen half-round taps in use, that, from their containing
less substance than the common forms do, they must be very
liable to be broken by the strain required to turn them in the
work. It is proved, however, by experience, that the strain in
their case is so much smaller than usual, that there is even less
chance of breaking them than the stouter ones. Workmen are
aware that a half-round opening bit makes a better hole and
cuts faster than a five-sided one, and yet that it requires less
force to use it." *
Fig. 540, in which two-thirds of the circle are allowed to remain,
has been also employed for taps; this, although somewhat less
penetrative than the last, is also less liable to displacement with
the tap-wrench. It is much more usual to employ three radial
cutting edges instead of one only ; and, as in the best forms of
* Select Papers read before the Soc. of Arts for Scotland, vol. i., page 41.
vNSVEIlSE SECTIONS OP TAP*.
tin y an- only required to cut in the one direction, or when
they :uv sere\\ed into the nut, the *>ther edges are then cham-
1\ -red to make room for the shaving ; then -hy giving the tap a
section somewhat like that of a ratchet-wheel, with either tli
tour, or five teeth, aa in figs. 5H and f> 1'.).
It is more common, however, either to file up the side of the
tap, or to cut by machinery, three concave or elliptical flutes, as
in ."H2; this form sufficiently approximates to the desideratum
of the radial cutting edges, it allows plenty of room for the
shavings, and is easily wiped out. What is of equal or greater
importance, it presents a symmetrical figure, little liable to
accident in the hardening, either of distortion from unequal
section, as in figs. 539 and 510, or of cracking from internal
angles, as in 540 and 5-41.*
Still, considering alone the transverse section of the tap, it
will be conceived that before any of the substance can be re-
moved from the hole that is being tapped, the circular part of
the instrument must become embedded into the metal a quantity
equal to the thickness of the shaving; and in this respect figs.
537 and 538, in which the circular parts are each only the tenth
or twelfth of the circumference, appear to have the advantage
over the modern taps 511 and 542, in which each arc is twice as
long. Such, however, is not the case, as the first two act more
in the manner of the broach, if we conceive that instrument to
have serrated edges; but figs. 541 and 542 act nearly as turning-
tools, as in general the outer or the circular surface is slightly
relieved with a file, so as to leave the cutting edges a, somewhat
in advance of the general periphery; which is equivalent to
chamfering the lower plane of the turning tool some 3 degrees
(see page 534), to produce that relief which has been appro-
priately named the angle of separation.
But in the tup fig. 543, patented by Mr. G. Bodmer of Man-
ehe>h-r, this is still more effectually accomplished. The instru-
ment, instead of being turned of the ordinary circular section
* In fluting tap*, as in cutting the teeth of wheels, the tap or wheel is fre-
quently chucked in the lathe, just aa in turning ; but the mandrel is held at re»t
by the dividing-plate, and the tool ia a cutter, revolving horizontally, and tra-
versed through the groove by the slide-rest screw. The round flutes are made
with cutters having semicircular edges and placed centrally ; the ratchet-form
flutes are made with thick saws or square-edged cutters, the one edge of these is
placed to intersect the center of the tap, and leave the radial edge.
58t) COMPARISON OP THE TRANSVERSE SECTIONS OP TAPS.
in the lathe (or as the outer dotted line), is turned with three
slight undulations, by means of an alternating radial motion
given to the tool. From this it results, that when the summits
of these hills are converted into the cutting edges, that not only
are the extreme edges or points of the teeth made prominent,
but the entire serrated surface becomes inclined at about the
three degrees to the external circle, or the line of work, so as
exactly to assimilate to the turning tool ; and therefore there is
little doubt but that, under equal circumstances, Mr. Bodmer's
tap would work with less friction than any other.
546.
The principle of chamfering, or relieving the taps, must not
however, be carried to excess, or it will lead to mischief; in ex-
planation of which the diagrams 544, 545, and 546 may be con-
sidered parallel with the forms 429, 430, and 431, of page 532.
For example, the tap, if sloped behind the teeth as in 544, would
be much exposed to fracture; and the instrument being entirely
under its own guidance, the three series of keen points would
be apt to stick irregularly into the metal, and would not produce
the smooth, circular, or helical hole, obtained when the tool 545
is used, which may be considered parallel with the turning tool
fig. 430. The relief should be slight, and the surfaces of the
teeth' then assimilate to the condition of the graver for copper-
plates (see page 532), and thereby direct the tap in a very
superior manner.
The teeth sloped in front, as in figs. 546, would certainly cut
more keenly than those of 545, but they would be much more
exposed to accident, as the least backward motion or violence
would be liable to snip off the keen points of the teeth ; and
of THE i vL SECTIONS OF TAP*.
therefore, on the score of general y and usefulness, the
radial and slightly rdirvnl teeth of fig. 545, or rather of
are proper for working tups.
It appears further to be quite impolitic, entirely to expunge
the surface-bearing, or squeeze, from the taps and dies, when
these are applied to the ductile metals; as not only does it,
when slight, greatly assist in the more perfect guidance of the
instrument, but it also serves somewhat to condense or compress
the metal.*
The transverse sections hitherto referred to, are always used
for those taps employed in screwing the inner surfaces of the
nuts, and holes required in general mechanism. The longi-
tudinal section of the working tap, is taper and somewhat like a
broach, the one end being small enough in external diameter
to enter the blank hole to be screwed, and the other end being
as large as the screw for which the nut is intended.
•
Fig. 547.
c 6
t d
f
648.
In many cases a series of two, three, or four taps must be used
instead of only one single conical tap, and the modifications
in their construction are explained by the above diagrams;
namely, fig. 547, the tap formerly used for nuts and thorough-
fare holes, and fig. 548 the modern tap for the same purposes ;
the dotted lines in each represent the bottoms of the threads.
•M the taps cut very freely, it i* the general aim to avoid the necessity
for tapping cast-iron, which is a granular and crystalline substance, apt to crumble
away in the tapping, or in the after use. The general remedy is the employment
of bolts and nuts made of wronght-iron, or fixing screwed wrought-irou pins in the
work, by means of transverse keys and other contrivances, and sometimes by the
insertion of plugs of gun-metal, to be afterwards tapped with the screw-threads.
In general also, the mall screws for cast-iron, are coarse and shallow in the thread
compared with those for wrought-iron, stoel, and brass.
MODERN FORMS OF TAPS.
In the former kind, the thread was frequently finished of a
taper figure, with the screw tool in the lathe ; after which either
the four or three plane surfaces were filed upon it, as shown by
the section at s ; the neck from ftoff was as small as the bottom
of the thread, and the tang from g to h was either square or
rectangular for the tap-wrench. The tang, if square was also
taper, the tap-wrench then wedged fast upon the tap ; the sides
of the tang, if parallel, were rectangular, and measured as about
one to two, and there were shoulders on two sides to sustain the
wrench.
In the modern thoroughfare taps for nuts, drawn to the
same scale in fig. 54-8, the thread is left cylindrical, from the
screw-tool or the dies : then from a to b, or about one diameter
in length, is turned down cylindrical until the thread is nearly
obliterated ; from d to /, also nearly one diameter in length
at the other end, is left of the full size of the bolt, and the
intermediate part, b to d equal to three or four diameters, is
turned to a cone, after which the tap is fluted as seen at s.
The neck fff, as before, is as small as the bottom of the thread,
and the square g h, measures diagonally the same as the turned
neck.
In using the modern instrument fig. 548, the hole to be
tapped is bored out exactly to fit the cylindrical plug a b, which
therefore guides the tap very perfectly in the commencement ;
the tool is simply passed once through the nut without any
retrograde motion whatever, and the cylindrical part d f, takes
up the guidance when the larger end of the cone enters the
hole ; at the completion, the tap drops through, the head being
smaller than the bottom of the thread. The old four square
taps could not be thus used, for as they rather squeezed than
cut, they had much more friction; it was necessary to move
them backwards and forwards, and to make the square for the
wrench larger, to avoid the risk of twisting off the head of the
tap. In taps of modern construction of less than half an inch
diameter, it is also needful to make the squares larger than the
proportion employed in fig. 548.
In tapping shallow holes, as only a small portion of the end
of the tap can be used, the screwed part seldom exceeds two
diameters in length, and as they will not take hold when made
too conical, a succession of three or four taps is generally
MODES OF WORKING OR 1 > PS. 589
required. The M-iru. d part of the first may be considered to
IK! from « to A <>i , of the second, from c to d, of the
thinl from e to /; so that the prior tap may, in each case,
prepare for the reception of the following one. The taps are
generally made in sets of three ; the first, which is also called the
entering or taper tap, is in most cases regularly taper throughout
length; the second, or the middle tap, is sometimes tap* r,
hut more generally cylindrical, with just two or three threads at
the end tapered off; the third tap, which is also called the />/////
orjinix/iinf/ tap, is always cylindrical, except at the two or three
: i reads, which are slightly reduced.
Taps arc used in various ways according to the degree of
strength required to move them. The smallest taps should
have considerable length, and should be fixed exactly in the axis
of straight handles ; the length serves as an index by which the
true position of the instrument can be verified in the course of
work ; with the same view as to observation, and as an expeditious
mode, taps of a somewhat larger size are driven round by a
hand brace, whilst the work is fixed in the vice. Still larger
taps require tap wrenches, or levers with central holes to fit the
square ends of the taps; for screw-taps from one to two inches
diameter, the wrenches have assumed the lengths of from four
to eight feet, although the recent improvements in the taps
have reduced the lengths of the wrenches to one-half.
Notwithstanding that the hole to be tapped may have been
drilled straight, the tap may by improper direction proceed
obliquely, the progress of the operation should be therefore
watched; and unless the eye serve readily for detecting any
falseness of position, a square should be laid upon the work,
and its edge compared with the axis of the tap in two positions.
In tapping deeply-seated holes, the taps are temporarily
lengthened by sockets, frequently the same as those used in
drilling, which are represented in fig. 501, page 560; the tap
•ich can then surmount those parts of the work which would
otherwise prevent its application.
SometiiiH s, for tapping two distant holes exactly in one line,
the ordinary taper tap, fig. 548, is made with the small cylin-
diical part a b exceedingly long, so as to reach from the one
590
JONES'S TAP WITH LOOSE CUTTERS.
hole to the other and serve as a guide or director. This is only
an extension of the short plug a b, fig. 548, which it is desirable
to leave on most taps used for thoroughfare holes.
Some works are tapped whilst they are chucked on the lathe
mandrel ; in this case the shank of the tap, if in false position,
will swing round in a circle whilst the mandrel revolves, instead
of continuing quietly in the axis of the lathe. Sometimes the
center point of the popit-head is placed in the center hole in the
head of the tap ; in those which are fixed in handles it is better
the handle of the tap should be drilled up to receive the cylinder
of the popit-head, as in the lathe taps for making chucks ; this
retains the guidance more easily.
Taps of large size, as well as the generality of cutting instru-
ments, have been constructed with detached cutters. For those
exceeding about l\ incn diameter, Mr. Richard Jones recom-
mends two steel plugs a a, to be inserted within taper holes in
the body of the tap, as represented in fig. 519, and in the two
sections b and c ; the whole is then screwed and hardened.
Fig. 549.
The advance of the cutters slightly beyond the general line
of the thread, is caused by placing a piece of paper within the
mortises a a, and to relieve the surface friction, each alternate
tooth in the middle part of the length of the tap is filed away.
Sometimes the cutters are parallel, and inserted only partway
through, and are then projected by set-screws placed also on
the diameter as in the section c*
The cutter-bar, fig. 515, p. 569, may also be viewed as a tap
with detached cutters. The cylindrical bar is supported in tem-
porary fixed bearings, one of which embraces the thread (some-
times by having melted lead poured around the same), the bar
moves therefore in the path of a screw. In cutting the external
* See Trans. Soc. of Arts, 1829, vol. xlvii., p. 135.
MASTER TAPS; SClii < I TTERS.
501
tin-fail, tin- . 1 is shifted inwards with the pro-
gress of the work; or a straight cutter shifted outwards, serves
f»r making an internal screw: pointed instead of serrated
(•utters may be also used, they are frequently adjusted by a set-
screw instead of tlu> hammer, and are worked by a wrench.
This screw-cutter bar, independently of its use for large
awkward works, is also employed for cutting, in their respective
situations, screws required to be exactly in a Hue with holes or
ti\< tl bearings, as the nuts of slides, presses, and similar works.
Some taps or cutters are made cylindrical, and are used for
cutting narrow pieces and edges, such as screw-cutting dies,
screw-tools, and worm-wheels ; therefore it is necessary to leave
much more of the circle standing, and to make the notches
narrower than the width of the smallest pieces to be cut. But
the grooves should still possess radial sides, and when these are
connected by a curved line, as in fig. 550, there is less risk of
accident in the hardening. The number of the notches increases
\\ith the diameter, but the annexed figure would be better pro-
portioned if it had one or two less notches, as inadvertently the
teeth have been drawn too weak.
Fig* 550. 651.
S ft ft ft ft ft ft ft ft ft ft ft ft
When the tool, figs. 550 and 551, is used for cutting the dies of
die-stocks it is called an original tap, of which further particulars
will be given in the succeeding section ; the tool is then fixed in
the vice, and the die-stock is handed round, as in cutting an
ordinary screw. When 55 1 is used for cutting up screw-tools,
or the chasing-tools for the use of the turning-lathe, (figs. 404
and 405, page 519,) the cutter is then called a hob, or a screw-
tool cutter, and its diameter is usually greater ; it is now mounted
to revolve in the lathe, and the screw-tool to be cut, is laid on
the rest as in the process of turning, and is pressed forcibly
592 WORM-WHEEL CUTTERS; TAPS FOR WOOD.
against the cutter.* Fig. 551 is also used as a worm-wheel
cutter, that is, for cutting or for finishing the hollow screw-form
teeth, of those wheels which are moved by a tangent screw ; as
in the dividing-engine for circular lines, and many other cases in
.ordinary mechanism. The worm-wheel cutter is frequently set to
revolve in the lathe, and the wheel is mounted on a temporary
axis so as to admit of its being carried round horizontally by the
cutter ; sometimes the wheel and cutter are connected by gear.f
Attention has been hitherto exclusively directed to the forms
of the taps used for metal, but those for wood are very similar,
the tap fig. 542, p. 584-, with three or four flutes, being the most
common ; those of largest size are cast in iron, and require only
a little filing up to sharpen the teeth.
Different taps with loose teeth, have been adopted for wood-
screws of moderately large size, say exceeding \\ or 2 inches
diameter. In the one case, shown in fig. 552, an ordinary wood-
screw t, is first made, and at the bottom of the angular thread,
a narrow parallel groove is cut in the lathe with a parting-tool ;
the screw is then turned down to the size of the hole to be
tapped, leaving it as a plain cylinder with the square helical
groove represented in the piece t.
The next process is to insert a pointed cutter c, in a diame-
trical mortise, and when the wooden tap is in use, it is guided
by the block g, which is bored to fit, and has two iron plates
p, which enter the groove. The guide g is fixed to the work w,
which is to be tapped; the bar glides forward in virtue of
* In cutting up the inside screw-tool, fig. 404, in which the slope and the curva-
ture of the teeth should be reversed, an internal screw-cutter has been recom-
mended ; it is made like a screwed nut, notched longitudinally on its inner surface.
Another method is proposed ; the inside screw-tool is laid in a lateral groove in
a cylindrical piece of iron, and the tool and cylinder are cut up with the die-stocks as
a common screw ; by which mode the inside screw-tool obviously becomes the exact
counterpart of the hollow thread of that particular diameter. See Technological
Repository, 1821, vol. vi., p. 292. The right-hand inside screw-tool is sometimes
cut over a tolid left-hand hob, which is a more simple way of reversing the angle.
t The contact of the ordinary tangent screw with the worm-wheel, resembles
that of the tangent to the circle, whence the name ; but Hindley, of York, made
the screw of his dividing-engine to touch 15 threads of the wheel perfectly, by
giving the screw a curved section derived from the edge of the wheel, and smallest
in the middle. See Smeaton's Miscellaneous Papers, p. 183. Prof. Willis, in hig
Elements of Mechanism, 1841, p. 163—5, explains the mode of cutting such a
tangent screw, but shows that ita advantages are more apparent than re.il.
CM, -i WOOD.
593
tin* screu t!r each succeeding passage the cutter is
advanced a small distance, until the work is tapped of the full
diameter; the hollow space between the guide g, and the work
w, allows the cutter to pass entirely through the latter, the
space being wider than the cutter.
Another structure is shown in the Mum/rl du Tournevr. A
hollow iron screw is made like fig. 553, and a hole is drilled at
tin- termination of the thread, the extreme end of which is cham-
fered on the inner surface with a file, to make a keen angular
edge of the shape of the thread ; in its action the tool therefore
somewhat assimilates to the plane, and the shavings escape
through the center of the tube.
This appears to be much less serviceable than the contrivance
fig. 552, in which the helical guidance is perfectly at the com-
mencement, and continues so until the end, notwithstanding the
gradual formation of the thread, which may be cut at several
repetitions instead of in one single cut, or in two cuts when two
teeth are on opposite sides of the tube, fig. 553. The arrange-
ment of fig. 552 may be considered as quite analogous to t
of the sc: « T liar, (fig. 515, page 569,) whereas the hollow
tap, fig. 55:i, is just the converse of the screw box described at
the beginning of the following section.
SECT. IV. ON i 1 tllS(. I \ I I K\AL8CREWS,WITII SCREW DIES, 1
For the convenience of arrangement, this section will be com-
menced \\ it li t he description of the instrument which is commonly
employed lor makinir loni: screws in the softwoods, namely, the
screw box, of which fig. 554 is the section, tL'. .',:>:> the plan of
the principal piece through the line a, and fig. 556 the cutter,
shown the full size for a two-inch sc:
Q Q
59 i
SCREW BOX FOR WOOD SCREWS.
The screw box consists of two pieces of wood, accurately
attached by two steady pins and two screws, so as to admit of
separation and exact replacement; the ends of the thicker
piece are frequently formed into handles, by which the instru-
ment is worked. A perforation is made through the two pieces
of wood; the hole in, the thinner piece is cylindrical, and
exactly agrees with the external diameter of the screw, or o^.
the prepared cylinder; and the hole in the thicker piece is
screwed with the same tap that is to be used for the internal
screws or nuts, and which is shown in three views in fig. 557.
The cutter or V, has a thin cutting edge sloped externally to
the angle of the thread, usually about 60 degrees, and thinned
internally by a notch made with a triangular file ; the cutter is
inlaid in the thicker piece of wood, and fastened by a hook-form
screw bolt and nut.
In placing the cutter, four different conditions require strict
attention. Its angular ridge should lie as a tangent to the inner
circle ; its edge should be sharpened on the dotted line b, or at
an angle of about 100 degrees with the back; its point should
exactly intersect the ridge of the thread in the box ; and it
should lie precisely at the rake or angle of the thread, for which
purpose it is inlaid deeper at its blunt extremity.
555.
The piece of wood for the screw is turned cylindrical and a
little pointed ; it is then twisted into the screw box, the cutter
makes a notch, which catches upon the ridge of the wooden
worm immediately behind the cutter, and this carries the work
forward, exactly at the rate of the thread. The whole of the
•OBt.w r.«i\ ; s, in \\ i-j. \ i | .
material is n-uu. \.-.l the shavings make tin n
escape at tin- aprrtmv or m.>u:
lu cutting the smallest screws, with this well-contrived and
efft-t , inn. lit. the screw box is held in tin* Kit hand, and
tlio work is screwed in with the right ; or the box is applied
whiUt the work remains upon the mandrel of the lathe. V*
thread is required to be continued close up to a shoulder,
tlu- screw is cut up as far as the entire in>trument \\ill allow:
tin- screw box is then removed, in order that the loose piece
may be taken off from it, after which the screw is completed
without impedim,
Screws of half an inch diameter and upwards, are generally
fixed iu the vice, whilst the screw box is handed round just like
the dit jstoek. Tor large screws exceeding two or three inches
diameter, two of the V's or cutters are placed in the box, so as
to divide the work ; thereby lessening the risk of breaking the
delicate edge of the cutter, the exact position of which is a
matter of great nicety. The screw-box has been occasionally
used for wooden screws of 4, 6, and 8 inches diameter, and
upwards, and such large screws have been also made by hand,
with the saw, chisel, mallet, and ordinary tools; but these large
screws are now almost entirely superseded by those of metal,
which, for most purposes, are greatly superior in every point of
view.
In cutting the metal screw, or the bolt, the tools are required
to be the converse of the tap, as they must have internal instead
of external threads, but the radial notches are essential alike in
each. For small works, the internal threads are made of fixed
sizes and in thin plates of steel, such are called screw plates ;
for larger works, the internal threads are cut upon the edges of
t \N o or three detached pieces of steel, called dies, these are fitted
into grooves within diestocks, and various other contrivances
which admit of the approach of the screwed dies, so that they
may be applied to the decreasing diameter of the screw,
from its commencement to the completion.
The thickness of the screw plate is in general from about
t \\o-thirds to the full diameter of the screw, and mostly several
holes are made in the same plate ; from two to six holes are
Q '
596
SCREW PLATE.
intended for one thread, and are accordingly distinguished into
separate groups by little marks, as in fig. 558. The serrating
of the edges, is sometimes done by making two or three small
holes and connecting them by the lateral cuts of a thin saw, as
in fig. 559. The notches alone are sometimes made, and when
the holes are arranged as in fig. 560, should the screw be broken
short off by accident, it may be cut in two with a thin saw, and
thus removed from the plate.
In making small screws, the wire is fixed in the hand-vice,
tapered off with a file, and generally filed to an obtuse point ;
then, after being moistened with oil, it is screwed into the one
or several holes in the screw plate, which is held in the left
hand. At other times, the work fixed in the lathe is turned or
filed into form, and the plate is held in the right hand ; but the
force then applied is less easily appreciated. The harp-makers
and some others, attach a screw plate with a single hole to the
sliding cylinder of the popit-head. See page 564.
559.
560.
Figs. 558.
The screw plate is sometimes used for common screws as large
as from half to three-quarters of an inch diameter; such screws
are fixed in the tail vice, and the screw plate is made from about
15 to 30 inches long, and with two handles ; the holes are
then made of different diameters, by means of a taper tap, so
as to form the thread by two, three, or more successive cuts, and
the screw should be entered from the large side of the taper
hole. It is, however, very advisable to use the diestocks, in
preference to the screw plates, for all screws exceeding about
one-sixteenth of an inch diameter, although the unvarying
diameter of the screw plate has the advantage of regulating the
equal size of a number of screws, and as such, is occasionally
used to follow the diestocks, by way of a gage for size.
The diestock, in common witli other general tools, has received
a great many modifications thot it would be useless to trace in
gri- 1, than M> far as respects the \arietics in common
use, or those which introduce any peculiarity of action in the
cutting edges. A notion of the early contrivances for cutting
metal screws will he gathered from the figures 561 to 5(51, which
are copied half-size from Leopold's Thcatrura Machinanun
• erale, 1724.* For instance, fi-. 561 is the screw plate
divided in two, and jointed together like a common rule; the
inner edges are cut with threads, the lar-cr of which is
judiciously placed near the joint, that it may be more forcibly
compressed : there is a guide, a, a, to prevent the lateral dis-
placement of the edges, which Mould be fatal to the action.
Similar instruments are still used, but more generally for screws
made in the turning lathe.
Figs. 561.
In one of these tools, the frame or stock is made exactly like
a pair of flat pliers, but with loose dies cut for cither one or two
sizes of threads. Plier diestocks are also made in the form of
common nut-crackers, or in fact, much like fig. 5C1, if we consider
it to have handles proceeding from a a, to extend the tool to
about two or three times its length ; the guide a a is retained,
and removable dies are added, instead of the threads being cut
in the sides of the instrument. Screwing tools arc also made
of one piece of steel, and to spring open, something like fig. 131,
page 232, Vol. I., but shorter and stronger : the threads are cut
on the sides or ends of the bosses, which are flat externally, for
the convenience of compression in the tail vice.
In general, however, the two dies are closed together in a
straight line, instead of the arc of a circle: one primitive
method, fig. o*'- J-, extracted from the work referred to, has b<
thus remodelled; the dies are inserted in rectangular taper
• Moxon, Plumier, and others, describe similar took, and alto the screw box.
598
MODERN FORMS OF DIESTOCKS.
holes in the ends of two long levers, which latter are connected
by two cylindrical pins, carefully fitted into holes made through
the levers, and the ends of the pins are screwed and provided
with nuts, which serve more effectually to compress the dies
than the square rings represented in fig. 564.
The diestock in its most general form has a central rectangular
aperture, within which the dies are fitted, so as to admit of
compression by one central screw ; the kinds most in use being
distinguished as the double chamfered diestocks, figs. 565 and 566 ;
Figs. 565,
566.
567.
569.
and the single chamfered diestock, figs. 568 and 569, the handles
of which are partly shown by dotted lines. In the former, the
aperture is about as long as three of the dies ; about one-third
of the length of the chamfer is filed away at the one end, for the
removal of the dies laterally, and one at a time. In the single
chamfered diestock 569, which is preferable for large threads,
the aperture but little exceeds the length of two dies, and these
'are removed by first taking off the side plate b a, which is either
attached by its chamfered edges as a slide, or else by four screws ;
these, when loosened, allow the plate to be slid endways, and it
will be then disengaged, as the screws will leave the grooves at a,
and the screw heads will pass through the holes at b.
Sometimes dies of the section of fig. 567 are applied after the
manner of 566, and occasionally the rectangular aperture of
INI DP CURVATURE IK DIBS. 5M
fig. Jc parallel on its inner ed^e*, and without tin
j>!:ite ba\ the dies arc tlu n d by steel plates either ri\
or screwed to the diestock, as represented in fig. 570, or else by
two steel pins Imried half- \\ ay in the sides of the stock, and the
remaining half in the die, as shown in fig. 571. These variations
arc of little moment, as are also those concerning the general
form of the stock ; for instance, whether or not the handles
proceed in the directions shown (the one handle *, being occa-
sionally a continuation of the pressure screw), or whether tin-
handles are placed as in the dotted position /. In small die-
stocks, a short stud or handle is occasionally attached at ri<:ht
angles to the extremity, that the diestock may be moved like a
winch handle : and sometimes graduations are made upon the
pressure screw, to denote the extent to which the dies are closed.
These and other differences are matters comparatively unimpor-
tant, as the accurate fitting of the dies, and their exact forms,
should receive the principal attention.
In general only two dies are used, the inner surface of each
of which includes from the third to nearly the half of a circle,
and a notch is made at the central part of each die, so that the
pair of dies present four arcs, and eight series of cutting points
or edges : four of which operate when the dies are moved in the
one direction, and the other four when the motion is reversed ;
that is when the curves of the die and screw are alike.
The formation of these parts has given rise to much investiga-
tion and experiment, as the two principal points aimed at require
directly opposite circumstances. For instance, the narrower the
edges of the dies, or the less of the circle they contain, the more
easily they penetrate, the more quickly they cut, and the less
they enmpress the screw by surface friction or squeezing, whieh
last tends to elongate the screw beyond its assigned length. But
on the other hand, the broader the edges of the dies, or the more
of the circle they contain, the more exactly do they retain the
true helical form, and the general truth of the screw.
The action of screw cutting dies is rendered still more diHicnlt,
because in -reneral, one pair of dies, the curvatures and angles of
whieh admit of no change, are employed in the production of a
screw, the dimensions of which, during its gradual transit from
the smooth cylinder to the finished screw, continually change,
1 or instance, the thread of a screw necessarily possesses two
600
PROPORTIONS OF MASTER TAPS.
magnitudes, namely, the top and bottom of the groove, and also
two angles at these respective diameters, as represented by the
dotted lines in the diagrams, figs. 572, 574, and 576, (which are
drawn with straight instead of curved lines). The angles arenearly
in the inverse proportion of the diameters ; or if the bottom were
half the diameter of the top of the thread, the angle at the bottom
would be nearly twice that at the top. (The mode of calculating
the angles, is subjoined to figs. 614 — 618, page 657.)
The figures show the original taps, master taps, or cutters, from
which the dies, figs. 573, 575, and 577, are respectively made;
and in each of the three diagrams, the dies a are supposed to be
in the act of commencing, and the dies b in finishing, a screw of
the same diameter throughout, as that in fig. 572.
Figs. 572.
SMALL MASTER TAP.
Same diameter at Screw.
674.
MEDIUM MASTER TAP.
One depth larger than Screw.
576.
LARGE MASTER TAP.
Two depths larger than Screw.
Of course the circumstances become the more perplexing the
greater the depth of the thread, whereas in shallow threads the
interference may be safely overlooked. As the dies cannot have
both diameters of the screw, it becomes needful to adopt that
curvature which is least open to objection. If, as in. fig. 573, the
curved edges of the dies a and b have the same radii as the
finished screw, in the commencement, or at a, the die will only
touch at the corners, and the curved edges being almost or quite
out of contact, there will be scarcely any guidance from which to
get the lead, or first direction of the helix, and the dies will be
IM i KI KRENCB or C' i: IN i>r . 601
likely to cut false screws, or else parallel grooves or rings.* In
iiiltlitic.ii to • . (1 edges present, at the commencement,
a greater angle than that proper for the top of the screw, but at
completion of the screw, or at b, the die and screw will be
t counterparts, and will be therefore perfectly suitable to
If, as in fig. 577, the inner curvature of the dies a and /> bo
the same as in the blank cylinder, a will exactly agree both in
diameter and angle at the commencement of the screw, but at
the conclusion, or as at b, each will be too great, and the die and
screw will be far from counterparts, and therefore ill adapted to
each other.
The most proper way of solving the difficulty in dies made in
two parts, is by having two pairs of dies, such as 577 and
and which is occasionally done in very deep threads, a mode that
was first published by Mr. Allan, see figs. 535 and 536, page 582.
But it is more usual to pursue a medium course, and to make
the original tap or cutter, fig. 574, used in cutting the dies, not
of the same diameter as the bolt, as in figs. 572 and 573, not to
exceed the diameter of the bolt by twice the depth of the thread,
as in figs. 576 and 577, but with only one depth beyond the
exact size, or half-way between the extremes, as in figs. 574 and
575, in \\ liieh latter it is seen the contact, although not quite
perfect either at a or b, is sufficiently near at each for general
practice.
The obvious effect of different diameters between the die and
screw must be a falsity of contact between the surfaces and
angles of the dies; thus, in 573, the whole of the cutting falls
upon e, the external angles, until the completion of the screw in
b, when the action is rather compressing than cutting. In fig.
577, the first act is that of compressing, and all the work is soon
thrown on », the internal angles of the die, which become
* Sometimes tho dies cut a fine, single-thread screw, of one-half or one-third
the coarseness of that of the dies ; at other times, a fine double or triple screw,
of the same rake or Telocity as the dies ; and occasionally the dies cut concentric
rings. These accidental results are mainly to be attributed to the dicstocks being
closed upon the screw-bolt obliquely, instead of at right angles ; the edges of the
dies do not then approach in the required relationship, and the two dies each cut
a distinct thread, instead of one thread in common. In the act of placing the
dies the stock should be slightly " wriggled," or mored vertically, to allow the
die* to select their true position on the bolt to be cut.
602 INTERFERENCE OF CURVATURE IN DIE*.
gradually more penetrative, but eventually too much so, being
in all respects the reverse of the former. In the medium and
most common example, fig. 575, the cut falls at first upon the
external angles e, it gradually dies away, and it is during the
brief transition of the cut from the external to the internal angles
/, that is, when the screw is exactly half formed, that the com-
pression principally occurs.
The compression or squeezing, is apt to enlarge the diameter
of the screw, (literally by swaging up the metal,) and also to
elongate it beyond its assigned length, and that unequally at
different parts. Sometimes the compression of the dies, makes
the screw so much coarser than its intended pitch, that the screw
refuses to pass through a deep hole cut with the appropriate tap ;
not only may the total increase in length be occasionally detected
by a common rule, but the differences between twenty or
thirty threads, measured at' various parts with fine pointed
compasses, are often plainly visible.
Other and vastly superior modes for the formation of long
screws, or those requiring any very exact number of threads
in each inch or foot of their length will be shortly explained.
Yet notwithstanding the interferences which deprive the die-
stocks of the refined perfection of these other methods, they are
a most invaluable and proper instrument for their intended use ;
and the disagreement of curvature and angle is more or less
remedied in practice, by reducing the circular part of the dies
in various ways; and also in some instances, by the partial sepa-
ration of the guiding from the cutting action.
The most usual form of dies is shown in fig. 578, but if every
measure be taken at the mean, as in fig. 579, the tool possesses
a fair, average, serviceable quality; that is, the dies should be
cut over an original tap of medium dimensions, namely, one
depth larger than the screw, such as fig. 574 ; the curved surface
should be halved, making the spaces and curves as nearly equal
as may be; and the edges should be radial. Fig. 580, nearly
transcribed from Leupold's figure, 502, has been also used, but
it appears as if too much of the curve were then removed.
Sometimes the one die is only used for guiding, and the other
only for cutting : thus a, fig. 581, is cut over two different
diameters of master taps, which gives it an elliptical form. A
large master tap, fig. 576, is first used for cutting the pair of
: , i n.\ v i M..I.I i , l\ nil -
dies, this leaves the large parts of the curve in a: the
subsequently cut over a small manf
Fig*. 578. 579.
ISO,
In beginning the screw, the die a, serves as a bed with guiding
edges, these indent without cutting, and also agree at the tl
start, with the full diameter of the bolt ; with the gradual reduc-
tion of the bolt, it sinks down to the bottom of a, which con-
tinually presents an angular ridge, nearly agreeing in diameter,
and therefore in angle with the nascent screw. The inconveni-
ences of the dies, fig. 581, are, that they require a large and a
small master tap for the formation of every different sized pair of
dies, and which latter are rather troublesome to repair. The dies
also present more friction than most others, apparently from
the screw becoming wedged within the angular sides of the die a.
In fig. 582, a construction advocated by Sir John Robison,
the dies are first cut over a small master tap, fig. 573, the thn
are then partially filed or turned out of b, to fit the blank cylinder;
which therefore rests at the commencement upon blunt triangu-
lar, curved surfaces, instead of upon keen edges; and as the
screw is cut up, its thread gradually descends into the portions
of the thread in b, which are not obliterated. About one-third
of the thread is turned out from each side of the cutting die a,
leaving only two or three threads in the center, as shown in tin-
last view ; and the surface of this die is left flat, that it may be
ground up afresh when blunted, and which is also done with
other dies having plane surfaces.*
Mr. Peter Krirand .Mr. William Jones have each proposed
to assist the action of dies for large screws, by means of cult
tlu-ir plans will be sufficiently explained by the diagrams, figs.
583 and .".M. Mr. Keir applied this mode to large screws of
square threads for gun carriages ; the dies were cut very shallow,
• Select Papers of the Society of ArU for Scotland, vol. i., p. 41.
DIES WITH LOOSE CUTTERS; LEFT HAND SCREWS.
say one-third of the full depth, and they were serrated on their
inner faces to act like saws or files. The dies were used to cut
up the commencement of the thread, but when it filled the shal-
low dies, their future office was not to cut, but only to guide the
ascent and descent of the stocks, by the smooth surfaces of the
dies rubbing upon the top of the square thread. The remaining
portion of the screw was afterwards ploughed out by a cutter
like a turning tool, the cutter being inserted in a hole in the one
die, and advanced by a set screw, somewhat after the manner
represented in the figures 583 and 584.*
Mr. Jones employed a similar method for angular thread screws,
and the cutter was placed within a small frame fixed to the one
die. The screw bolt was commenced with the pair of dies which
were closed by the set screw a, 583, the cutter being then out of
action. When the cutter was set to work by its adjusting
screw b, it was advanced a little beyond the face of the die, and
not afterwards moved ; but the advance of a, closed the dies upon
the decreasing diameter of the screw, the cutter always continu-
ing prominent and doing the principal share of the work.f
Figs. 583.
585.
587.
584.
586.
588.
Fig. 585 is the plan, and 586 the side elevation, of an old
although imperfect expedient, for producing a left-handed screw
from a right-handed tap. It will be remembered the right and
left hand screws only differ in the direction of the angle, the
thread of the one coils to the right, of the other to the left hand ;
and on comparing a corresponding tap and die, the inclinations
of the external curve of the one, and the internal curve of the
* Technical Repos., vol. viiL, pages 182 and 193.
t Trans. Soc. of Arts, 1829, vol. xlvii., p. 135.
WlimVnUTIl's SCREW STOCKS.
oth< Airily diller in like manner as to direction. The
!o employnl therefore is to carry a ri^ht-hand tap ar<>
tin- screw to be cut; the temporary screw-cutter possesses the
same interval or thread as before, but the cutting angles of the
havini: the reu-rse direction of those of the die, the screw
becomes left-handed.
The one die in 585 and 5S6 is merely a blank piece of brass
or iron without any grooves, the other is a brass die in which
the tap is fixed ; as may be expected, the thread produced is not
very perfect, but iu the absence of better means, this mode is
available as the germ for the production of a set of left-hand
taps and dies. Fijjs. 587 and 588 represent a different mode of
originating a left-handed screw, proposed by Mr. Walsh; tin-
tool is to be a small piece of a right-handed screw, which is
hardened and mounted in a frame like an ordinary millinff or
HH /-liny tool, and intended to act by pressure alone ; the diameter
of the tool and cylinder should be like.*
The screw stock first patented by the Messrs. Whitworth of
Manchester, is represented in fig. 589 : three narrow dies were
fitted in three equidistant radial grooves in the stock, the ends
of the dies came in contact with an exterior ring, having on its
inner edge three spiral curves, (equivalent to three inclined
planes,) and on its outer surface a scries of teeth into which
worked a tangent screw, so that on turning the ring by the
screw, the three dies were simultaneously and equally advanced
towards the center.
These screw stocks were found to cut very rapidly, as every
circumstance was favourable to that action. For instance, on
the principle of the triangular bearing, all the three dies were
constantly at work ; the original tap being slightly taper, every
thread in the length of the die was performing its part of the
work, the same as in a taper tap every thread of which removes
its shaving, or share of the material ; and the dies were narrow,
with radial edges, which admitted of bein^ easily sharpened.
Thisdiestock has been abandoned by the Messrs. Whitworth,
• Sea Trans. Soe. of Arts, voL xliii., p. 127 ; this scheme is referred to likewue
in the foot-note on page 581 of this volume.
Some methods of making the tame taps and dies, serve for cutting rithrr right
or left-hand screws, will be found in Trans. Soe. of Arts, vol. xli., p. 115 ; Ma»*<l
rfu Tourntur, vol. i., plate 23; and Mechanic's Magazine, 1836, voL xxv., p. 370*
These contrivances appear, however, to possess little or no value.
606
WHITWORTH'S AND BOOMER'S SCREW STOCKS.
in favour of their screw stock subsequently patented, which is
represented in fig. 590. The one die embraces about one-third
of the circle, the two others much less; the latter are fitted into
grooves which are not radial, but lead into a point situated near
the circumference of the screw-bolt ; the edges of the dies are
slightly hooked or ground respectively within the radius, and
they are simultaneously advanced by the double wedge and nut:
the dies are cut over a large original, such as fig. 576, that is,
two depths larger than the screw. The large die serves to line
out or commence the screw, and the two others act alternately;
the one whilst the stock descends down the bolt, the other
during its ascent.
Figs. 589.
590.
The last screw stock that will be here noticed is Mr. G. Bod-
mer's of Manchester, for which he also has obtained a patent.
It is seen that the one die embraces about one-third the screw,
the other is very narrow ; the peculiarity of this construction is
that a circular recess is first turned out of the screw stock, and a
parallel groove is made into the same, the one handle of the stock,
(which is shaded,) nearly fills this recess, and receives the small
die. If the handle fitted mathematically true, it is clear it
would be immovable, but the straight part of the handle is nar-
rower than the width of the groove ; when the stock is turned
round, say in the direction from 2 to 1, the first process is to
rotate the handle in the circle, and to bring it in hard contact
with the side 1, this slightly rotates the die also, and the one
corner becomes somewhat more prominent than the other. When
MODES OF USING DIES; BOLT-SCREWING MM
tin- motion of the stock is reversed, tin- handle leaves the side
1, of the groove, and strikes against the other side 2, and then
the opposite angle of the die becomes the more prominent ; and
that without any thought or adjustment on thr part of the
workman, as the play of the handle in the groove 1, 2, is exactly
proportioned to cause the required angular change in the die.
cutting edges of the die act exactly like turning tools,
and therefore they may very safely be bevilled or hooked as
such ; as when they are not cutting, they are removed a little
way out of contact, and therefore out of danger of bein^
snipped oil', or of being blunted by hard friction. The opposite
die affords during the time an ctiicicnt guidance for the screw,
and the broad die is advanced in the usual manner, by the
pressure screw made in continuation of the second handle of
the diestock; the dies are kept m their places by a side pi
which is fitted in a chamfered groove in the ordinary manner.
There is less variety of method in cutting external screws with
the diestocks, than internal screws with taps, but it is desirable,
in both cases, to remove the rough surface the work acquires
in the foundry or forge, in order to economise the tools; and
the best works are either bored or turned cylindrically to the
true diameters corresponding with the screwing tools.
The bolt to be screwed is mostly fixed in the tail vice ver-
tically, but sometimes horizontally, the dies are made to apply
fairly, (see foot-note, page 601,) and a little oil is applied prior
to starting. As a more expeditious method suitable to small
screws, the work is caused to revolve in the lathe, whilst the
die-stock is held in the hand ; and larger screws are sometimes
marked or lined out whilst fixed in the vice, the principal part
of the material is then removed with the chasing tool or hand-
screw tool, fig. 405, p. 519, and the screw is concluded in the
diestocks. In cutting up large screw bolts, two individuals are
required to work the screw stocks, and they walk round the
e or screwing clamp, which is fixed to a pedestal in
the middle of the workshop.
For screwing large numbers of bolts, the engineer employs
the bolt-screwing machine, which is a combination of the ordinary
taps and dies, with a mandrel, driven by steam power. In tin-
machine invented by Mr. Fox, the mandrel revolves, traverses,
608 ROBERTS'S SCREWING TABLE, ETC.
and carries the bolt, whilst the dies are fixed opposite to the
mandrel ; or else the mandrel carries the tap, and the nut to be
screwed is grasped opposite to it. In the machine invented by
Mr. Roberts, the mandrel does not traverse, it carries the bolt,
and the dies are mounted on a slide ; or else the mandrel carries
the nut, and the tap is fixed on the slide. The tap or die gives
the traverse in every case, and the engine and strap supply the
muscle; of course the means for changing the direction of
motion and closing the dies, as in the hand process, are also
essential.*
Mr. Roberts' screwing table is a useful modification of the bolt
machine, intended to be used for small bolts, and to be worked
by hand. The mandrel is replaced by a long spindle running
loosely in two bearings ; the one end of the spindle terminates
in a small wheel with a winch-handle, the other in a pair of jaws
closed by a screw, in other respects like fig. 85, p. 201, vol. I.
The jaws embrace the head of the bolt, which is presented
opposite to dies that are fixed in a vertical frame or stock, and
closed by a loaded lever to one fixed distance. In tapping the
nut, it is fixed in the place before occupied by the dies, and the
spindle then used, is bored up to receive the shank of the tap,
which is fixed by a side screw. This machine ensures the rect-
angular position of the several parts, and the power is applied
by the direct rotation of a hand wheel.
It will be gathered from the foregoing remarks, that the die-
stock is an instrument of most extensive use, and it would
indeed almost appear as if every available construction had been
tried, with a general tendency to foster the cutting, and to
expunge the surface friction or rubbing action ; by the excess
of which latter, the labour of work is greatly increased, and
risk is incurred of stretching the thread.
• Sec Buchanan's Mill Work, by Rennie, 1841. Plates 38 to 88 c.
In Wright's Patent Machine for making " wood screws" for joinery work, the
traverse of the mandrel is assisted by a screw guiilo of the same degree of ci
ness as the fixed dies, and the blanks are advanced to the latter through the hollow
mandrel, at the end of which they are retained by nippers, until the machine has
screwed the former, and nupplies a new blank. In a former machine the traversing
mandrel and a fixed turning tool were used ; the thread is cut from base to point,
whilst the screw is supported in a back stay. For other modifications, see
Lardner's Cyclopedia, Manufactures in metal, vol. i., pp. 201 — 9.
OEM It VI UEMAKK8 ON DIE8TOCK8. ''"'•'
In tin p.:, -it diestocks tin- cutting is so much facilitated,
that th. .ineed perhaps to less than the half of
that i. quired with the old-fashioncu irly semicircular dies,
; hut when the guidance is too far sacrificed, the greedy
action of the dies is a source of mischief. For instance, the in-
strument, fig. 5SO, with three dies moving simultaneously, has
ded hccause of its risk of cutting irregular or
"drunken " screws : for if, from the dies being improperly placed,
the thread does not exactly meet, or lead into itself in the first
revolution of the dies, hut finds its way in with a break in the
curve, this break continues unto the end ; as the three points of
••////, so to speak, bein^ narrow, they may pursue the irregular
line, thus giving to the dicstock a rolling or "wabbling" motion,
instead of a steady quiet descent. This fault is also liable to occur
in every diestock, in which there is any risk of the blank cylinder
not being placed truly axial, from the dies touching only by
points or narrow edges, instead of against a fair proportion of
the curve; but, when the dies are moderately broad, there is
more chance of the defect being afterwards corrected.
Subsequently to the introduction, by Messrs. Whitworth, of
their screw-stock, shown in fig. 589, they invented a diestock
with four dies, the one side of each of which was radial. The
dies acted two at a time, just like turning tools, they were quite
free from rubbing, and were simultaneously advanced by two
wedges yoked together by a cross piece, and moved by one screw.
This ingenious plan was not however regularly adopted, on
account of the deficiency of the guiding power, as the screw was
supported between four series of points ; but it gave rise to the
mode explained in tig. 590, in which the broad guide is judi-
ciously introduced.
It is difficult, however, to decide fairly and impartially upon
the respective merits of diestocks, many of which approach very
nearly to one another ; as whether the facility of cutting, or the
truth of the screw, or any other point be made the standard of
iparison, it is a judgment which must necessarily be given
rather by opinion than by measure ; and the conditions which arc
aimed at in all screw-stocks, arc in strictness unattainable in any,
owing to the varying dimensions of the object to be produced.
From many reasons, it appears needless to strain the applica-
tion of the diestock to the production of long screws, which
K R
610 GENERAL REMARKS ON DIESTOCKS.
require either a very precise total length, or a very precise equa-
lity in their several parts. The main inconvenience results from
unavoidably mixing the guiding and cutting in the same part of
the one instrument ; an instrument which acts by producing a
series of copies of the few threads in the dies, and which copies
become collectively the long screw. This mode of proceeding
is equally as impolitic, as setting out a line of 50 or 100 inches
long, with a little rule measuring only one or two inches.
Neither can it be desirableto cut long,and consequently slender
screws, by an instrument used as a double ended lever, in the
application of which, the screw, supported generally at the one
end in the vice, is very liable to be bent ; as any small disturbing
force at the end of the stock, is multiplied in the same proportion
as the difference between the radii of the work and instrument.
The liability to bend the screw is reduced to the minimum, in
Mr. Allan's simple apparatus, (p. 582,) for cutting the screws
for dividing engines and other superior works, but which mode
is not adapted to ordinary screws ; the machines for screwing
bolts entail also little risk of bending the screw.
On the whole it appears questionable whether for short screws,
which are the legitimate works of the diestock, some of the
better forms of the two part dies are not as good as any ;
and on the other hand it appears quite certain that for those
screws in which particular accuracy is of real importance, that
the screw cutting engine or turning lathe is beyond comparison
more proper. This valuable engine will be soon referred to, and
in it the distinct processes of guiding and of cutting are com-
pletely detached, and each may independently receive the most
favourable conditions ; whereas in all the modifications of the
screw-stock they are more or less intimately commingled, and
are to a certain degree antagonists.
The screw-cutting lathe has also the advantage that one good
screw having been obtained as a guide, its relative degree of
perfection is directly imparted to the work, and it may be em-
ployed for cutting very coarse or very fine screws, or in fact any
of the various kinds referred to in the preliminary description.*
• Some remarks will be offered in the laat section, on the proportions aud
forms of screws of a variety of kinds.
. i in: ' i \ in |, »1 1 I
• ECT. V. — OX SCREWS CUT BY DAM* IN TUP. I.ATHF.
Great numbers of screws nrc required in works of wood, ivory
and metal, that cannot he cut u ith the tnps and dies, or the other
apparatus hitherto considered. This arises from the nature
of the materials, the weakness of the forms of the objects, and
the accidental proportions of the screws, many of which are com-
paratively of very large diameter and inconsiderable length.
These and other circumstances, conspire to prevent the use of
the diestocks for objects such as the screws of telescopes and
other slender tubes, those on the edges of disks, rings, l>oxes,
and very many similar works.
Screws of this latter class are frequently cut in the lathe with
the ordinary screw tool, and by dexterity of hand alone ; there'
is little to be said in explanation of the apparatus and tools,
which then consist solely of the lathe with an ordinary mandrel
incapable of traversing endways, and the screw tools or the
chasing tools figs. 404 and 405, page 519, with the addition of
the arm rest ; the details of the manipulation will be found in
the practical section.
The screw tool held at rest would make a series of i
because at the end of the first revolution of the object, the points
A B C of the tool would fall exactly into the scratches ABC
commenced respectively by them. But if in its first revolution,
the tool is shifted exactly the space between two of its teeth, at
the end of the revolution, the point B of the tool, drops into the
groove made by the point A, and so with all the others, and a
true screw is formed, or a continuous helical line, which appears
in steady lateral motion during the revolution of the screw in
the lathe.
It is likely the tool will fail exactly to drop into the groove,
but if the difference be inconsiderable, a tolerably good screw is
rtheless formed; as the tool being moved forward as equally
as the hand will allow, corrects most of the error. But if the
dilYerence be great, the tool finds its way into the groove with
an abrupt break in the curve ; and during the revolution of the
screw, as it progresses it also appears to roll about sideways,
in-tead of being quiescent, and is said by workmen to be
" drunk," this error is frequently beyond correction.
It sometimes happens that the tool is moved too rapidly, and
R 1.
612 ON CUTTING SCREWS BY HAND.
that the point C drops into the groove commenced by A ; in this
case the coarseness of the groove is the same as that of the tool,
but the inclination is double that intended, and the screw has a
double thread, or two distinct helices instead of one ; the tool
may pass over three or four intervals and make a treble or
quadruple thread, but these are the results of design and skill,
rather than of accident.
On the other hand, from being moved too slowly, the point B
of the tool may fail to proceed so far as the groove made by A,
but fall midway between A and B ; in this case the screw has
half the rise or inclination intended, and the grooves are as fine
again as the tool ; other accidental results may also occur which
it is unnecessary to notice.
The assemblage of points in the screw tools proper for the
hard woods, ivory and metals, renders the striking of screws in
these materials comparatively certain and excellent, that is as
regards those individuals who devote sufficient pains to the acqui-
sition of the manipulation; but the softwoods, require tools with
very keen edges of 20 to 30 degrees, and for these materials the
screw tool is made with only a single point, as represented in figs.
377 and 378, page 516. With such a tool, no skill will suffice
to cut a good useful screw by hand alone, as the guiding and
correctional power of the many points no longer exists ; and in
consequence those screws in soft wood which are cut in the lathe,
require the guidance to be given mechanically in the manner
explained in the following section.*
SECT. VI. ON CUTTING SCREWS IN LATHES WITH TRAVERSING
MANDRELS.
One of the oldest, most simple, and general apparatus for
cutting short screws in the lathe, by means of a mechanical
guidance, is the screw-m&ndrel or traversing -mandrel, which
* The twisted moulds for upholsterers' fringes, are frequently screwed by hand ;
a thin gouge, or a carpenters' fluted bit of the width of the groove, is ground very
obliquely from the lower side BO as to leave two long edges or fangs projecting, and
the tool is sharpened from within. An oblique notch is made by hand at the end
of the mould as a commencement, and the tool wedging into the groove is guided
along the rest at the same angle as the notch, whilst the lathe revolves slowly,
and completes the twist at one cut. To make the second groove parallel with
the first the finger IB placed beside the gouge, and within the first twist ; and so
on with the others. The process i» very pleasing from its rapidity and simplicity,
and 'w also sufficiently accurate for the end proposed.
IK\\I:USI\(. OR SCUKW-M \NURELS.
appears to have been known, almost as soon as the iron mandrel
ilM-lf wa> intn.diu
Fig. 502 is copied from an old French mandrel mounted in a
wooden frame, and with tin collars cast in two parts; the upper
halves of the collars are removed to show the cylindrical necks of
the mandrel, upon the shaft of which are cut several short screws.
In ordinary turning, the retaining key k, which is shown detac
in the \ie\v k, prevents the mandrel from traversing, as its
angular and circular ridge enters the groove in the mandrel;
but although not represented, each thread on the mandrel is
\-.-. MI
mum
provided with a similar key, except that their circular arcs are
screw-form instead of angular. In screw cutting, k is depressed
to leave the mandrel at liberty; the mandrel is advanced slightly
forward, and one of the screw-keys is elevated by its wedge until
it becomes engaged with its corresponding guide-screw, and now
as the mandrel revolves, it also advances or retires in the exact
path of the screw selected.
The modern screw-mandrel lathe has a cast-iron frame, and
hardened steel collars which are not divided ; the guide screws
are fitted as rings to the extreme end of the hardened steel
mandrel, and they work in a plate of brass, which has six scollops,
or semicircular screws upon its ed^e. \Vlien this mandrel is
used for plain turning, its traverse is prevented by a cap which
extends over the portion of the mandrel protruding through the
collars.*
• For further detail* of the construction of the old screw-mandrel lathes, the
reader is referred to Mozon, Plumier, Lcupold, Ac. ; and to pages 30 to 42 of the
G14 APPLICATION OF THE SCREW-MANDREL.
In cutting screws with either the old or modern screw-man-
drel, the work is chucked, and the tool is applied, exactly in the
manner of turning a plain object; but the mandrel requires an
alternating motion backwards and forwards, somewhat short of
the length of the guide screw, this is effected by giving a
swinging motion or partial revolution to the foot wheel. The
tool should retain its place with great steadiness, and it is there-
fore often fixed in the sliding rest, by which also it is then
advanced to the axis of the work with the progress of the
external screw, or by which it is also removed from the center
in cutting an internal screw.
To cut a screw exceeding the length of traverse of the mandrel,
the screw tool is first applied at the end of the work, and when
as much has been cut as the traverse will admit, the tool is shifted
the space of a few threads to the left, and a further portion is
cut ; and this change of the tool is repeated until the screw
attains the full length required. "When the tool is applied by
hand, it readily assumes its true position in the threads, when it
is fixed in the slide rest its adjustment requires much care.
In screwing an object which is too long to be attached to the
mandrel by the chuck alone, its opposite extremity is sometimes
supported by the front center or popit head ; but the center
point must then be pressed up by a spring, that it may yield to
the advance of the mandrel : this method will only serve for very
slight works, as the pressure of the screw-tool is apt to thrust
the work out of the center. It is a much stronger and more
usual plan, to make the extremity or some more convenient
part of the work cylindrical, and to support that part within a
stationary cylindrical bearing, or collar plate, which retains the
position of the work notwithstanding its helical motion, and
supplies the needful resistance against the tool.*
fourth volume. And also to pages 90 to 92 of the same, for the figures and
explanation of tbo modern screw-mandrel lathe, with cylindrical collars of
hardened steel ; the durability of which has been occasionally brought into ques-
tion by those who, it must be presumed, have not personally tried them. See
remarks, page 52, of Vol. IV.
* In cutting the screws upon the ends of glass smelling-bottles, and similar
works incapable of being cut with steel tools, the bottle is mounted on a traversing
mandrel, which is moved slowly by hand, and the cutting tool is a metal disk
revolving rapidly on fixed centers, and having an angular edge fed with emery
and water; in BOIUO rare cases a diamond is used as the cutting tool.
SCREW-LATHES WITH TRAVERSING ' ".
The amateur wh - dillieulty in cutting screws
flying, or with the common mandrel :ui<l hniul-tool unassistedly,
will find the screw mandrel an apparatus by fnr the most generally
convenient fur those works, in wood, ivory, and metal turning, to
which the screw box, and the taps and dies are inapplicable.
the screw-mandrel requires but a very small cli
apparatus, and whatever may be the diameter of the woiv
ensures perfect copies of the guide screws, the half dozen
varieties of which, will be found to present abundant choice aa
to coarseness, iu respect to the ordinary purposes of turning.
SECT. VII. — ON CUTTING SCREWS IN LATHES WITH TRAVERSING
TOOLS.
! cat number of the engines for cutting screws, and also of
the other shaping and cutting engines now commonly used, are
clearly to be traced to a remote date, so far as their principles
are concerned.
For instance, the germs of many of these cutting machines,
in which the principles are well developed, will be found in the
primitive rose engine machinery with coarse wooden frames, and
arms, shaper plates, cords, pulleys, and weights, described in the
earliest works on the lathe, and referred to in pages 4 to 8 of
Vol. I. ; whilst many others are as distinctly but more carefully
modelled in metal, in the tools used in clock and watchmaking,
many of which have also been published.
The principles of these machines being generally few and
simple, admit of but little change ; but the structures, which are
most diversified, nay *il most endless, have followed the degrees
of excellence of the constructive arts at the periods at which
they have been severally made, combined with the inventive
talent of their projectors.
In most of the screw-cutting machines a previously-formed
screw is employed to give the traverse, such are copying machines,
and will form the subject of the present section; and a few
other engines serve to oriyintitc screws, by the direct employ-
ment of an inclined plane, or the composition of a rectilinear
and a circular motion ; the notice of this kind of screw machi-
will be deferred until the next section.
The earliest screw-lathe Kn»\\n to the author, bears the date
of 15G9, and this curious machine, which is represented in
616
BESSON'S SCREW-CUTTING LATHE.
fig. 593, is thus described by its inventor Besson ; "Espies de
Tour en nulle part encore veiie et qui riest sans subtilite, pour
engraver petit a petit la Vis a lentour de toute Figure ronde et
solide, voire mesmes ovale." *
The tool is traversed alongside the work by means of a guide-
screw, which is moved simultaneously with the work to be
operated upon, by an arrangement of pulleys and cords too
obvious to require explanation. It is however worthy of
remark, that bad and imperfect as the constructive arrangement
is, this early machine is capable of cutting screws of any pitch,
by the use of pulleys of different diameters ; and right and left
hand screws at pleasure, by crossing or uncrossing the cord ;
and also that in this first machine the inventor was aware that
a screw-cutting-lathe might be used upon elliptical, conical, and
other solids.
The next illustration, fig. 594, represents a machine described
as " A Lathe in which without the common art all sorts of screws
and other curved lines can be made ; " this was invented by
* The figure is copied half size from plate 9 of the work entitled " Des Instru-
mentt MatMmatiquts et Mtchaniques, <kc., Inventees par Jaques Sesson." Firat
Latin and French Edit., fol. 1569. Second Edit., Lyons, 1578 ; also a Latin Edit.,
Lyons, 1582. The same copper plates are used throughout.
ORANI' NO IMIII.
M. (irnmlj.an prior to 1729.* The constructive details of tins
machine, which are also sufficiently apparent, are iu some
respects superior to those in Hcsson's; but the two are alik«-
open to tin- iniprrlVrtioii due to the transmissions of motion by
cords; and (nandjran's is additionally imperfect as the scheme
represented, will fail to produce an equable traverse of the
mandrel compared with its revolution, owing to the continual
change in the angular relations between the arms of the bent
lever, and the mandrel and cord respectively. Sometimes the
spiral board or templet *, is attached to the bent lever, to
act upon the end of the mandrel ; this also is insufficient to
produce a true screw in the manner proposed.
Several of the engines for cutting screws, appear to be derived
from those used for cutting fusees, or the short screws of hyper-
bolical section, upon which the chains of clocks and watches are
wound, in order to counteract the unequal strength of the
different coils of the spiral springs. The fusee engines, which
are very numerous, have in general a guide-screw from which
the traverse of the tool is derived, and the illustration fig. "
selected from an old work published in 17 U, is not only one of
the earliest, but also of the most exact of this kind; and it
exhibits like-wise the primitive application of change wheels, for
producing screws of varied coarseness from one original.
• Communicated to the " AcadSmic Koyale," in 17-'.', and printed in tho
u Machiutt ttppnmritt," tome v. 1735. As a matter of arrangement, tbu figure
belong* to Sect. VI., but as * specimen of early mechauum, ito preteut place
e«ui« more appropriate.
618
OLD FUSEE ENGINE WITH CHANGE WHEELS.
This instrument is nearly thus described by Thiout. "A lathe
which carries at its extremity two toothed wheels ; the upper is
attached to the arbor, the clamp at the end of which holds the
axis of the fusee to be cut, the opposite extremity is retained
by the center ; the fusee and arbor constitute one piece, and are
turned by the winch handle. The lower wheel is put in movement
by the upper, and turns the screw which is fixed in its center :
the nut can traverse the entire length of the screw, and to the
nut is strongly hinged the lever that holds the graver or cutter,
and which is pressed up by the hand of the workman. Several
pairs of wheels are required, and the smaller the size of that
upon the mandrel, the less is the interval between the threads
of the fusee " *.
Fig. 595.
In the general construction of the fusee engine, the guide-
screw and the fusee are connected together on one axis, and are
moved by the same winch handle : the degree of fineness of the
thread on the fusee is then determined by the intervention of a
lever generally of the first order j a great variety of construc-
tions have been made on this principlef, the mode of action will
be more clearly seen in the next figure, wherein precisely the
same movements are applied to the lathe for the purpose of
cutting ordinary screws.
The apparatus now referred to is that invented by Mr. Ilealey
* Tkioufi Traiti d'Horloyerie, Mechanique ct Pratique, &c., 4to, Paris, 1741,
vol. L, page 69, plate 27. The uamo of the iuventor is not given.
f Three are described in Thiout's Treatise : namely, in plates 25, 26, and 27,
the first by Regnaud de Chaalon. Other examples will be found in Heed's Cyclo-
pedia, Article Fusee, Plates Horology, 36 and 37.
. A I' I'll:
619
9o o o| *
of Dublin, an amateur;* it is universal, or capable within
iiu limits of cutting all kinds of screws, either right or left
handed, and i in plan in tig. 590, in which C is the
chuck which carries the work to be screwed, and / is the tool
which lies upon r r the lathe-rest, that is placed at right angles
lie bearer, and is always free to move in its socket *, as on a
center because the binding screw is either loosened or rcm<>\< .1.
On the outside of the chuck C is cut a < .ide screw,
which we will suppose to be right-handed. The nut n n, which
fits the screw of the chuck, is extended into a long arm, ami
the latter communicates with the lathe-rest by the connecting
rod c c. As the lathe revolves backwards and forwards the
arm n (which is retained horizontally by a guide pin g),
traverses to and fro as regards
the chuck and work, and cai
the lathe-rest r r, to oscillate in
its socket *. The distance s t
being half s r', a right hand screw
of half the coarseness of the guide
will be cut; or the tool being
nearer to, and on the other side
of, the center 8, as in the dotted
position /', a finer and left haud
screw will be cut.
The rod c c may be attached in-
differently to any part of n ny but
the smallest change of the re-
lation of * / to * r, would mar
the correspondence of screws cut at different periods, and there-
fore t and r should be united by a swivel joint capable of being
fixed at any part of the lathe r. -t / /•', which is omitted in Mr.
llealcy's perspective drawing of the apparatus.
•:ie of the least perfect of the modes of originating
screws, it should therefore be only applied to such as are
short; as owing to the variation in the angular relation of the
parts, tin motion given to the tool is not strictly constant or
equable; when in the midway position, the several parts should
lie - tt right angles to each other, in order, as far as
possible, to :i\oid the error. The inequality of the screw is
:ot described iu Tilloch's Philosophical Hag. for 1804, Vol. zu . \-\
620
VARLEY'S SCKEW-CUTTIXG LATHE.
imperceptible in the short fusee, and it would be there harmless
even if more considerable ; but a perfect equality of coarseness
or of angle, is imperative in longer screws, and those to be fitted
one to the other, a condition uncalled for in the fusee, which
has only to carry a chain.
The apparatus invented by the late Mr. S. Varley, and repre-
sented in plan in figs. 597 and 598, although it does not present
the universality of the last, is quite correct in its action and far
more available ; it is evidently a combination of the fixed man-
drel, and the old screw-mandrel, fig. 592, p. 613. Four different
threads are cut on the tube which surrounds the mandrel, and
the connection between the guide screw and the work, is by
the long bar b b, which carries at the one end a piece g filed
to correspond with the thread, and at the other, a socket in
which is fixed a screw tool /, corresponding with the guide at
the time employed.
598.
' r
* r
| OO
::V
— r — r
The lathe revolves with continuous motion; and the long bar
or rod being held by the two hands in the position shown, the
guide g, and the tool /, are traversed simultaneously to the left
by the screw guide ; and when the tool meets the shoulder of
the work, both hands are suddenly withdrawn, and the bar is
shifted to the right for a repetition of the cut, and so on until
the completion of the screw. The guide g, is supported upon
the horizontal plate p, which is parallel with the mandrel, and
the tool /, lies upon the lathe rest r.
Beneath the tool is a screw which rubs against the lathe rest r,
and serves as a stop, this makes the screw cylindrical or conical,
according as the rest is placed parallel or oblique. For the
internal screw, the tool is placed parallel with the bar, as in
fig. 598 ; and the check screw is applied on the side towards the
center, against a short bar, parallel with the axis of the lathe.
LATHES WITH GUIDE-SCREWS \ M> Mi\\..K WHEELS. '
As in the .srrew-inamlrel lathes, the screws heroine exact
eoptcs of the screw-guides, and to a , -lianism
fulfils the ofliee of the slide-rest; but at the same time, more
trouble is required for the adjustment of the apparatus. In
general the guide-rod must be supposed to act somewhat as an
inrumhrniice to the free use of the tool, which is applied in a
less favourable manner, when the screw is small compared with
the exterior diameter of the work, as it must then project con-
siderably from the bar: so that on the whole the traversing
mandrel is a far more available and convenient arrangement.*
None of the machines which have been hitherto described, are
proper for cutting the accurate screws, of considerable length or
of great diameter, required in the ordinary works of the en-
gineer; but these are admirably produced by the screw-cutting
lathes, in whieh the traverse of the tool is effected by a long
piide-screw, connected with the mandrel that carries the work,
by a system of change wheels, after the manner employed a
century back, as in fig. 595. The accuracy of the result now
depends almost entirely upon the perfection of the guide-screw,
and which we w ill suppose to possess very exactly 2, 4, 5, 6, or
some whole number of threads in every inch, although we shall
for the present pass by the methods employed in producing the
original guide screw, which thus serves for the reproduction of
those made through its agency.
The smaller and most simple application of the system of
change wheels for producing screws, is shown in fig. 599. The
work is attached to the mandrel of the lathe by means of a
chuck to which is also affixed a toothed wheel marked M.
therefore the mandrel, the wheel, and the work partake of one
motion iu common: the tool is carried by the slide-rest, the
principal slide of which is placed parallel with the axis of the
lathe as in turning a cylinder, and upon the end of the screw
near the mandrel, is attached a tooth wheel S, which is made
to engage in M, the wheel carried by the mandrel.
As the win els are supposed to contain the same number of
teeth, they will revolve in equal times, or make continually turn
for turn ; and therefore in each revolution of the mandrel and
• The details of this apparatus will b« found in the description of the same
by Mr. Cornelius Varley, the nephew of the inventor, in the Trans. Soo. of Art*,
TO!, zliii., p. 90, 1825.
622 FIXED SLIDE-REST AND CHANGE WHEELS.
work, the tool will be shifted in a right line, a quantity equal to
one thread of the guide-screw, and so with every coil throughout
its extent of motion. Consequently, the motion of the two axes
being always equal and continuous, the screw upon the work
will become an exact copy of the guide-screw contained in the
slide-rest, that is, as regards the interval between its several
threads, its total length, and its general perfection.
But the arrows in M and S, denote that adjoining wheels
always travel in opposite directions; when therefore the mandrel
and slide-rest are connected by only one pair of wheels, as in
fig. 599, the direction of the copy screw is the reverse of that of
the guide. The right-hand screw being far more generally
required in mechanism, when the combination is limited to its
most simple form, of two wheels only, it is requisite to make
the slide-rest screw left-handed, in order that the one pair of
wheels may produce right-hand threads.
But a right-hand slide-rest screw may be employed to produce
at pleasure both right and left hand copies, by the introduction
of either one or two wheels, between the exterior wheels M
and S, fig. 559. Thus, one intermediate axis, to be called I,
would produce a right-hand thread : two intermediate axes, I I,
would produce a left-hand thread, and so on alternately; and
this mode, in addition, allows the wheels M and S to be placed
at any distance asunder that circumstances may require.
In making double thread screws the one thread is first cut,
the wheels are then removed out of contact, and the mandrel
is moved exactly half a turn before their replacement, the second
thread is then made. In treble threads the mandrel is twice
disengaged, and moved one-third of a turn each time, and so on.
FIXED SLIDE-REST AND tll.vNGE WHEELS.
When i nt ( rmediate wheels are employed, it becomes necessary
to build up from the bearers some descript ion of pedestal, or from
tin- lathe-head some kind of bracket, which may serve to carry
the axes or sockets upon which the interim mate wheels rev<>
These parts hare received a great variety of modifications, three
of which are introduced in the diagrams 600 to 602 ; the wheels
supposed to be upon the mandrel, are situated on the dot
line M M, and those upon the slide-rest on the line S S.
i'..--. M •.
601.
602.
I t
The rectangular bracket in fig. 600, has two straight mortises ;
by the one it is bolted to the bearers of the lathe, and by the
other it carries a pair of wheels, whose pivots are in a short
piece, which may be fixed at any height or angle in the morr
so that one or both wheels, I I, may be used according to cir-
cumstances. In fig. 601, the intermediate wheel, or wheels, are
carried by a radial arm, which circulates around the mandrel,
and is fixed to the lathe head by a bolt passed through the
circular mortise. In fig. 601, a similar radial arm is adjustable
around the axis of the slide-rest screw, in the fixed bracket.
Sometimes the wheel supposed to be attached to the slide-
rest, is carried by the pedestal or arm, fixed to the bed or
headstock of the lathe; in order that a shaft or spindle may
proceed from the wheel S, and be coupled to the end of the
slide-rest screw, by a hollow square or other form of socket, so
as to enable the rest to be placed at any part of the length of
the bearer, and permit a screw to be cut upon the end of a
long rod.*
• The abaft sometime* terminates at each end In universal joints, in order to
accommodate any trifling want of parallelism in the parts, if however the shaft
be placed only a few degree* oblique, the motion transmitted ceases to be uniform,
or it is accelerated and retarded in every revolution, which is fatal in screw cutting.
TRAVERSING SLIDE-REST AND CHANGE WHEELS.
This change in the position of the slide-rest, is also needful in
cutting a screw, which exceeds the length the rest can traverse,
as such long screws may then be made at two or more distinct ope-
rations; before commencing the second trip the tool is adjusted
to drop very accurately into the termination of that portion of
the screw cut in the first trip, which requires very great care, in
order that no falsity of measurement may be discernible at the
parts where the separate courses of the tool have met. This
method of proceeding, has however from necessity, been followed
in producing some of the earliest of the long regulating screws,
which have served for the production of others by a method
much less liable to accident, namely, when the cut is made
uninterruptedly throughout the extent of the work.
In the larger application of the system of change wheels, the
entire bed of the lathe is converted into a long slide -rest, the
tool carriage with its subsidiary slides for adjusting the position
of the tool, then traverses directly upon the bed ; this mode has
given rise to the name " traversing or slide-lathe," a machine
which has received, and continues to receive, a variety of forms
in the hands of different engineers. It would be tedious and
unnecessary to attempt the notice of their different construc-
tions, which necessarily much resemble each other; more
especially as the principles and motives, which induce the
several constructions and practices, rather than the precise
details of apparatus, are here under consideration.
The arrangement for the change wheels of a screw-cutting
lathe given in fig. 603, resembles the mode frequently adopted.
The guide-screw extends through the
middle of the bed, and projects at the
end ; there is a clasp nut, so that when
required, the slide-rest may be detached
from the screw and moved independently
of the same. The train of wheels is placed
at the left extremity of the lathe ; there
is a radial arm which circulates around the
end of the main screw, the arm has one
or two straight mortises, in which are
fixed the axes of the intermediate wheels,
and there are two circular mortises, by
I SLIDE REST \M> IL1M LATHB.
whirh the arm may la- secured to the lathe bed, in any required
position, by its two binding screws.
On comparing the relative facilities for cutting screws, either
with the slide-n^t furnished with a train of wheels, or with the
tra\ersing or screw-cutting lathe, the advantage will be found
greatly in favour of the latter ; for instance :
With the slide-rest arrangement, fig. 599, the work must be
always fixed in a chuck to which the first of the change wheels
can be also attached ; the wheels frequently prevent the most
favourable position of the slides from being adopted; and in
cutting hollow screws the change wheels entirely prevent the
tool carriage of the slide-rest from being placed opposite to the
center, and therefore awkward tools, bent to the rectangular
form, must be then used. The slide-rest also requires frequent
attention to its parallelism with the axis of the lathe, or the
screws cut will be conical instead of cylindrical.
With the traversing lathe, from the wheels being at the back
of the mandrel, no interference can possibly arise from them,
and consequently the work may be chucked indiscriminately on
any of the chucks of the lathe ; every position may be given to
the slide carrying the tool, and therefore the most favourable,
or that nearest to the work, may be always selected, and the
tools need not be crooked. As the tool carriage traverses at
once on the bearers of the lathe, the adjustment for parallelism
is always true, and the length of traverse is greatly extended.
The system of screw-cutting just explained is very general
and practical : for instance, one long and perfect guide-screw
(which we will call the guide), containing 2, 4, 6, 8, 10, or any
precise number of threads per inch having been obtained, it
becomes very easy to make from it subsequent screws (or copies],
which shall be respectively coarser and finer in any determined
degree. The principal is, that whilst the copy makes one revo-
lution, the guide must make so much of one revolution, or so
many, as shall traverse the tool the space required between each
thread of the copy ; and this is accomplished by selecting change
wheels in the proportions of these quantities of motion, or, iu
other words, in the proportion required to exist between the
«:uide-«cre\v and the copy.
In explanation, we will suppose the guide to have 6 threads
8 8
626 MODES OF COMPUTING THE TRAINS OF WHEELS
per inch, and that copies of 18, 14, 12£, 8, 3, 2, 1, threads per
inch, are required : the two wheels must be respectively in the
proportions of the fractions -^, T6T, T%J> £> 1> 4> T> tne guide
beiiig constantly the numerator. The numerator also represents
the wheel on the mandrel, and the denominator that on the
guide screw ; any multiples of these fractions may be selected
for the change wheels to be employed.
For example, any multiples of -^, as •£•§•, -ff, -f £, &c., will
produce a screw of 18 threads per inch, the first and finest of
the group ; and any multiples of 4, as -f§-, '-^0°, &c., will produce
a screw of 1 thread per inch, which is the last and coarsest of
those given.
Screws 2, 4, or 6 times as fine, will result from interposing a
second pair of wheels, respectively multiples of -^, 4> •&> and
placed upon one axis.
For instance, the pair of wheels -f-f-, used for producing a
screw of 18 threads per inch, would, by the combination A,
produce a copy three times as fine, or a screw of 54 threads per
inch.*
Combination A. Combination B. Combination C.
M Interm. S M Interm. S M Interm. S
24 60 120 24 27 53
20 72 72 20 39 107
And the wheels ^ used for the screw of one thread per
inch, would, by the combination B, produce a copy three times
as coarse, or of three inches rise. Whatsoever the value of the
intermediate wheels, whether multiples of -|, •£, £, &c., they
produce screws, respectively of -|-, %, -f-, the pitches of those
screws, which would be otherwise obtained by the two exterior
wheels alone ; and in this manner a great variety of screws,
extending over a wide range of pitch, may be obtained from a
limited number of wheels.
For instance, the apparatus Holtzapffel & Co. have recently
added to the slide rest, after the manner of figs. 599 and 601, has
a series of about fifteen wheels, of from 15 to 144 teeth, employed
with a screw of 10 threads per inch; several hundred varieties
of screws may be produced by this apparatus, the finest of which
has 320 threads per inch, the coarsest measures 7-f inches in
• Fig. 601, represents the wheels referred to in combination A, and fig. 602,
those in combination B.
U»BD IN SCREW CUTTIN'.. 627
h coil or rise; and the screws may be made right or left
handed, double, triple, quadruple, or of any number of threads.
The tim-t combinations are only useful for self-acting turning,
those of medium coarseness serve for nil the ordinary purposes
of screws; whilst the very coarse pitches are much employed in
ornamental works of the character of the Elizabethan twist:
and iu cutting these coarse screws, the motion is given to the
slide-rest screw, and by it communicated to the mandrel.
The value of any combination of wheels may be calculated as
vulgar fractions, by multiplying together all the driving wheels
as numerators, and all the driven wheels as denominators,
adding also the fractional value, or pitch, of the guide-screw ;
thus iu the first example A :
24 x 20 x 1 = 480 1
or reduced to its lowest terms — .
60 x 72 x 6 = 25920 54
The fraction denotes that -jV of an inch is the pitch of the
•crew, or the interval from thread to thread ; also that it has 54
threads in each inch, and which is called the rate of the screw.
And in C, the numbers in which example were selected at
random, the screw would be found to possess rather more than
35 threads per inch.*
27 x 39 x 1 1114 1
or reduced to ita lowest terms .
53 x 107 x 6 89026 35,H,
In imitation of the method of change-wheels, the slide-rest
screw is sometimes moved by an arrangement of catgut bands,
resembling that represented in Bessou's screw lathe, page 616.
One band proceeds from the pulley on the mandrel to a spindle
overhead having two pulleys, and a second cord descends from
this spindle to a pulley on the sb'de-rest.f The method offers
• The fractions should be reduced to their lowest terms before calculation, to
avoid the necessity for multiplying such high numbers. Thus the first example
would become reduced to 4 x J x J = 4>4, and would be multiplied by inspection
aloue, as the numerators and denominators may be taken crossways if more con-
renient ; thus J J is equal to \, and £ is also equal to J, fractions which are smaller
than | and &, the lowest terms respectively of }* and fg; the second case could not
be thus treated, and the whole numbers must there be multiplied, as they will not
admit of reduction. Other details will be advanced, and tables of the combination*
of the change-wheels will be also given, in treating of the practice of cutting screws.
f This apparatus has been applied to cutting the expanding horn snakes. See
Mantel du To*nu*r, first edit, 1796, vol. iL, plate 21 ; and second edit., 1816,
voL iL, plate 16 ; see also page 124-5 of the fint volume of this work.
8 S 2
628 FIXED SCREW TOOLS FOR ANGULAR THREADS.
facility in cutting screws of various pitches, by changing the
puDeys, and also either right or left hand screws, by crossing or
uncrossing one of the bands.
The plan is unexceptionable, when applied for traversing the
tool slowly for the purpose of turning smooth cylinders, or sur-
faces (which is virtually cutting a screw or spiral of about 100
coils in the inch) ; and in the absence of better means, pulleys
and bands are sometimes used in matching screws of unknown
or irregular pitches, by the tedious method of repeated trials ;
as on slightly reducing, with the turning tool, the diameter of
either of the driving pulleys, the screw or the work becomes
gradually finer ; and reducing either of the driven pulleys makes
it coarser ; but the mode is scarcely trustworthy, and is decidedly
far inferior to its descendant, or the method of change wheels.
The screw tools, or chasing tools, employed in the traversing
lathes for cutting external and internal screws, resemble the
fixed tools generally, except as regards their cutting edges ; the
following figures 604 to 606 refer to angular threads, and 607
and 608 to square threads.
Angular screws are sometimes cut with the single point, fig.
604, a form which is easily and correctly made; the general
angle of the point is about 55° to 60°, and when it is only
allowed to cut on one of its sides or bevels, it may be used fear-
lessly, as the shavings easily curl out of the way and escape.
But when both sides of the single point tool are allowed to cut,
it requires very much more cautious management ; as in the
latter case, the duplex shavings being disposed to curl over
opposite ways, they pucker up as an angular film, and in fine
threads they are liable to break the point of the tool, or to cause
it to dig into, and tear, the work. Sometimes, also, a fragment
of the shaving is wedged so forcibly into the screw by the end
of the tool, that it can only be extricated by a sharp chisel and
hammer.
In cutting angular screws, it is very much more usual and
expeditious to employ screw tools with many points, which are
made in the lathe by means of a revolving cutter or hob, figs.
550 and 551, page 591. Screw tools with many points, are
always required for those angular threads which are rounded
CLEMENT'S AND BOOMER'S CHASING TOOLS. -'.:.!J
at the top and bottom, and which arc theucc called rounded or
round threads.41
Mr. Clement gives to the screw tool for rounded threads the
profile of tig. 605, which construction allows the tool to be
inverted, so that the edges may be alternately used for the pur-
pose of equalizing the section of the thread. In making the tool
605, the hob (which is dot led), is put between centers in the
traversing lathe, and those wheels are applied which would serve
to cut a screw of the same pitch as the hob ; the bar of steel is
thru fixed in the slide rest, so that the dotted line or the axis of
the tool intersects the center of the hob. The tool is afterwards
hollowed on both sides with the file, to facilitate the sharpening,
and it is then hardened. In using the tool, it is depressed
until either edge comes down to the radius, proceeding from
the (black) circle, which is supposed to represent the screw to
be cut ; the depression gives the required penetration to the
upper angle, and removes the lower out of contact.f
Mr. Bodmer's patent chasing tool is represented in fig. 606 ;
the cutter, c, is made as a ring of steel which is screwed internally
to the diameter of the bolt, and turned externally with an
undercut groove, for the small screw and nut by which it is held
in an iron stock, *, formed of a corresponding sweep ; for dis-
tinctness the cutter and screw are also shown detached. The
center of curvature of the tool is placed a little below the center
of the lathe, to give the angle of separation or penetration ;
and after the tool has been ground away in the act of being
sharpened, it is raised up, until its points touch a straight edge
applied on the line a a of the stock ; this denotes the proper
height of center, and also the angle to which the tool is
intended to be hooked, namely 10 degrees: each ring makes
• Mr. Clement considers the many points to act with less risk than the single
point, because in the processes of hardening, first the hob and then the tcrtic tool,
they both become slightly enlarged, or a little coarser than the pitch of the
screw; consequently port of the teeth cut on one side, and part on the other,
but none of them on both sides of the points ; which latter action gives rise to
confusion by interrupting the free escape of the shavings.
t In making a hob with rounded threads, it is usual to prove whether the top
and bottom of the thread are equally rounded, by driving two different pieces
of lead into the hob with a hammer ; the two impressions will only fit together
so as to exclude the light, when the departure from the simple angle is alike
at the top and bottom of the hob, and that the thread is perpendicular or doe*
not lean. Master taps are similarly proved.
G30
SCREW TOOLS FOR SQUARE THREADS.
four or five cutters, and one stock may be used for several
diameters of threads.
Angular thread screws are fitted to their corresponding nuts
simply by reduction in diameter; but square thread screws
require attention both as to diameter and width of groove, and
are consequently more troublesome. Square thread screws are,
in general, of twice the pitch, or double the obliquity, of angular
screws of the same diameters ; and, consequently, the inter-
ference of angle before explained as concerning the diestocks,
refers with a twofold effect to square threads, which are in all
respects much better produced in the screw-cutting lathe.
The ordinary tool for square thread screws is represented
in three views in fig. 607 : the shaft is shouldered down so as to
terminate in a rectangular part which is exactly equal to the
width of the groove ; in general the end alone of the tool is
Screw Tools for Angular Threads.
Figs. 604.
Screw Tools for Square Threads.
Figs. 607.
608.
required to cut, and the sides are bevilled according to the
angle of the screw, to avoid rubbing against the sides of the
thread. Tools which cut upon the side alone, are also occa-
sionally used for adjusting the width of the groove. In either
case it requires considerable care to maintain the exact width
and height of the tool ; the inclination of which should also
differ for every change of diameter.
i UK AUTHOR'S CUTTER-BAR FOR SQUARK THREADS. 631
To obviate these severe] incom< ni. nces, the author several
years back contrived a tool-holder, fig. 608, for carrying small
blades made exactly rectangular. In height, as at ht the blades are
alike, in width, u; they are exactly half the pitch of the threads,
and they are ground upon the ends alone. The parallel blades
are clamped in the rectangular aperture of the tool socket by the
four screws c c ; and when the screws * *, which pass through
the circular mortises in the sockets, are loosened, the swivel joint
and graduations allow the blades to be placed at the particular -
angle of the thread, which is readily obtained by calculation,
and is estimated for the medium depth of the thread, or midway
between the extreme angles at the top and bottom.*
One blade, therefore, serves perfectly for all screws of the
same pitch, both right and leffc-handed, and of all diameters ; as
the tool exactly fills the groove, it works steadily, and the width
of the groove and the height of center of the tool, are also
strictly maintained with the least possible trouble. The depth
of the groove, which is generally one sixth more than its width,
is read off with great facility by means of the adjusting screw of
the slide-rest ; especially if, as usual, the screw and its micrometer
agree with the decimal division of the inch.
The holder, fig. 60S, has been much and satisfactorily used for
screws from about 20 to 2 threads per inch; but when the screw
is coarse and oblique, compared with its diameter, the blade is
ground away to the dotted line in /*, and is sometimes bevilled
on the sides almost to the upper edge, to suit the obliquity of
the thread, but without altering the extreme width of the tool.
The tools for external screws of very coarse pitch, are neces-
sarily formed in the lathe by aid of the corresponding wheels,
and a revolving cutter bar resembling fig. 515, p. 569. The soft
tool is fixed in the slide-rest, and is thereby carried against the
revolving cutter bar, 515, which has a straight tool, either pointed
or square as the case may be. The end of the screw-tool is thus
shaped as part of an internal screw, the counterpart of that to
be cut ; the face of the screw tool is filed at right angles to the
obliquity of the thread, and the end and sides are slightly bevilled
for penetration, previously to its being hardened.
Internal square threads of small size, are usually cut with
• For the mode of calculating the angle* of screws, MO foot-note, p. 657.
632 VARIOUS SCREW TOOLS OR CUTTERS.
taps which resemble fig. 548, p. 587, except in the form of the
teeth. When internal square threads are cut in the lathe, the
tool assumes the ordinary form, of a straight bar of steel with a
rectangular point standing off at right angles, in most respects
like the common pointed tool for inside work.
For very deep holes, and for threads of very considerable
obliquity, cutter bars, such as fig. 515, p. 569, are used. The
work and the temporary bearings of the bar, are all immoveably
fixed for the time, and the bar advances through the bearings
in virtue of its screw thread ; or otherwise a plain bar, having a
cutter only, and not being screwed, may be mounted between
centers in the screw lathe, and the work, fixed to the slide-rest,
may traverse parallel with the bar by aid of the change wheels.
The cutter bar in some cases requires a ring to fill out the space
between itself and the hole, to prevent vibration, and it is neces-
sary to increase the radial distance of the cutter between each
trip, by a set screw, or by slight blows of a hammer.
Very oblique inside cutters are turned to their respective
forms with a fixed tool, in a manner the converse of that
explained above ; and some peculiarities of management are
required in using them, in order to obtain the under-cut form
of the internal thread, — but the consideration of which does not
belong to this place.
In cutting screws in the turning lathe the tool only cuts
as it traverses in the one direction ; therefore whilst the cutter
is moved backwards, or in the reverse direction, for the suc-
ceeding cut, it must be withdrawn from the work. Sometimes
the tool is traversed backwards by reversing the motion of the
lathe; and in lathes driven by power, the back motionis frequently
more rapid than the cutting motion, to expedite the process : at
other times the lathe is brought to rest, the nut is opened as a
hinge, so as to become disengaged from the screw, and the
slide-rest is traversed backwards by hand, or by a pinion move-
ment, and the nut is again closed on the screw, prior to the
succeeding cut. This mode answers perfectly for screws of the
same thread as the guide, and for those of 2, 4, 6, 8 times as
coarse or as fine ; but for those of 2|-, 4£, or any fractional times
the value of the guide screw, the clasp nut cannot in general
be employed advantageously.
Ml. limns OF ADJUSTIV. Illi: I PIOM »l -' KIW TOOLS. 633
The progressive advance of the tool between each cut, is com-
monly regulated by a circle of divisions or a micrometer on the
slide-rest screw, which should always correspond with the decimal
division of tin ini-li. The substance of the shaving may be pretty
considerable after the lir>t entry is made, but it should dw indie
away to a very small quantity, towards the conclusion of the
screw. To avoid the necessity for taxing the memory with the
graduation at \\hieh the tool stood when it was withdrawn for
the back stroke, the author has been in the habit of employing
a micrometer exactly like that on the screw, which is set to tin-
same graduation, and serves as a remembrancer ; another method
i^ to employ an arm or stop, which fits on the axis of the screw
or handle with stiff friction, but nevertheless allows the tool to
be shifted the two or three divisions required for each cut.
In Mr. Roberta's screw lathe, the nut of the slide screw,
instead of being a fixture, is made with two tails as a fork, which
embraces an eccentric spindle ; by the half rotation of which
spindle, the nut, together with the adjusting screw, the slide,
and the tool, are shifted, as one mass, a fixed distance to and
from the center, between each cut ; so as first to withdraw
and then to replace the tool. Whilst the tool is running back,
the screw is moved by its adjusting screw and divisions, the
minute quantity to set in the tool for the succeeding cut, and the
continual wear upon the adjusting screw, as well as the uncer-
tainty of its being correctly
moved to and fro by the indi- 6
vidual, are each avoided.
Sometimes, with the view
of saving the time lost in
running back, two tools are
used, so that the one may
cut as the tool slide traverses
towards the mandrel, the
other in the contrary direc-
Mr. Shanks' arrange-
ment for this purpose, as ap-
to the screwing of bolts
in the Inthe, is shown in
fig. 609 ; / represents the
front, and b the back tool, which are mounted on the one slide **,
634 LONG SLENDER SCREWS, BACKSTAY, ETC.
and all three are moved as one piece by the handle h, which
does not require any micrometer.
In the first adjustment, the wedge w, is thrust to the bottom
of the corresponding angular notch in the slide s, and the two
tools are placed in contact with the cylinder to be screwed. For
the first cut, the wedge is slightly withdrawn to allow the tool/,
to be advanced towards the work ; and for the return stroke, the
wedge is again shifted under the observation of its divisions,
and the slide s s, is brought forwards, towards the workman, up
to the wedge; this relieves the tool/ and projects b, which is
then in adjustment for the second cut ; and so on alternately.
The command of the two tools is accurately given by the
wedge, which is moved a small quantity by its screw and micro-
meter, between every alternation of the pair of tools, by the
screw h.
In cutting very long screws, the same as in turning long
cylindrical shafts, the object becomes so slender, that the con-
trivance called a backstay, is always required for supporting the
work in the immediate neighbourhood of the tool. The back-
stay is fixed to the slide plate, or the saddle of the lathe which
carries the tool, and is brought as near to the tool as possible ;
sometimes the dies or bearings are circular, and fit around the
screw; at other times they touch the same at two, three, or
four parts of the circle only. Some of the numerous forms of
this indispensable guide or backstay, will be hereafter shown.
In using the screw-lathe with a backstay for long screws, it is
a valuable and important method, just at the conclusion, to
employ a pair of dies in the place usually occupied by the tool ;
as they are a satisfactory test for exact diameter, and they
remove trifling errors attributable to veins and irregularities of
the material, which the fixed tool sometimes fails entirely to
reduce to the general surface. The tool and backstay may be
each considered to be built on the tops of pedestals more or less
lofty, and therefore, more susceptible of separation by elasticity,
than the pair of dies fixed in a small square frame. Sir John
Robison has judiciously proposed, in effect, to link the backstay
and turning tool together, by the employment of a small frame
carrying a semicircular die of lignum-vitae, and a fixed turning
MOPES 07 ORIGINATING AND IMPROVING SCREWS. 635
tool, adjusted by a pressure screw; the frame to be applied cither
in the liiiiul alone or in the slide rest, and to be inverted, so that
the shavings may fall away without clogging the cutter.
SECT. VIII. — VARIOUS MODES OP ORIGINATING AND IMPROVIM.
SCi: I< DING THOSE OF RAMSDEN, MAUU8LAY, BARTON,
ALLAN, CL1 ND OTHERS.
The improvement of the screw has given rise to many valuable
schemes and modes of practice, which have not been noticed in
the foregoing sections, notwithstanding their collective length.
These practices, indeed, could not consistently have been placed
in the former pages of this chapter, because some of them must
be viewed as refinements upon the general methods, the earlier
notice of which would have been premature; and others
exhibit various combinations of methods pursued by different
eminent individuals with one common object, and are therefore
too important to be passed in silence, notwithstanding their
miscellaneous nature.
To render this section sufficiently complete, it appears needful
to take a slight retrospective glance of the early and the modern
modes of originating screws and screw apparatus ; some account
of the former may be found in the writings of Pappus, who lived
in the fourth century.*
The progressive stages which may be supposed to have been
formerly in pretty general use for originating screws, may be
thus enumerated :
1. The first screw-tap may be supposed to have been made by
the inclined templet, the file, and screw-tool ; it was imperfect in
all respects, and not truly helical, but full of small irregularities.
2. The dies formed by the above were considerably nearer to
perfection, as the multitude of pointed edges of 1, being passed
• The author haa been told by a classical friend, that in the works of Pappus
Alexandrinus, a Greek mathematician of the fourth century, are to be found
practical directions for making screws.
The process is simply to make a templet of thin brass of the form of a right-
angled triangle, the angles of which are made in accordance with the inclination
uf the proposed screw. ThU triangle is then to bo wrapped round tho cyliu.l. r
which is to be the desired screw, and a spiral line traced along its edge. The
screw is subsequently to be excavated along this line. Minute practical direc-
tions are given not only for every step of this process, but also for the division,
setting out, and shaping the teeth of a worm-wheel of any required number of
teeth to suit the screw. (Vide Pftppi Math. Col. lib. viii.. prob. zviiL)
636 EARLY METHODS OF ORIGINATING SCREWS.
through every groove of the die, the threads of the latter
became more nearly equal iu their rake or angle, and also iu
their distances and form.
3. The screw cut with such dies would much more resemble
a true helix than 1 ; but from the irregularities in the first tap,
the grooves in the die 2 would necessarily be wide, and their
sides, instead of meeting as a simple angle, would be more or less
filled with ridges, and 3 would become the exact counterpart of 2.
4. A pointed tool applied in the lathe, would correct the form
of the thread or groove in 3, without detracting from its im-
proved cylindrical and helical character; especially if the turning
tool were gradually altered, from the slightly rounded to the
acute form, in accordance with the progressive change of the
screw. The latter is occasionally changed end for end, either
in the die-stocks or in the lathe, to reverse the direction in
which the tools meet the work, and which reversal tends to
equalise the general form of the thread.
5. The corrected screw 4, when converted into a master-tap,
would make dies greatly superior to 2 ; it would also serve for
cutting up screw tools ; and lastly,
6. The dies 5 would be employed for making the ordinary
screws and working taps ; and this completes the one series of
screwing apparatus.
One original tap having been obtained, it is often made
subservient to the production of others ; for example, a screw
tool, with several points cut over the corrected original 4, would
serve for striking, in the lathe, other master-taps of the same
thread but different diameters. The process is so much faci-
litated by the perfection of the screw-tool, that a clever workman
would thus, without additional correction, strike master-taps
sufficiently accurate for cutting up other dies larger or smaller
than 4. Sometimes also the dies 5 are used for marking out
original taps a little larger or smaller than 4.
As a temporary expedient, the screw tool may be somewhat
spread at the forge fire to make a tool a little coarser, or it
may be upset for one a little finer, and afterwards corrected
with a file ; or screw tools may be made entirely with the file,
and then employed for producing, in the lathe, master-taps of
corresponding degrees of coarseness and of all diameters.
These are in truth some of the progressive modes by which
n SI:K KM. INK \\irn I\<I.INM> M.\\K.
687
under MTV careful management, great numbers of good useful
screwing apparatus have been produced, and which answer per-
!y well for all the ordinary requirements of " binding " or
" attachment" screws ; or as the cement by which the parts of
mechanism, and structures generally, arc firmly united together,
hut \\nli the power of separation and reunion at pleasure.
In this comparatively inferior class of screws, considerable
latitude of proportion may be allowed, and whether or not their
pitches or rates have any exact relationship to the inch, is a
matter of indifference as regards their individual usefulness; but
in superior screws, or those which may be denominated " regu-
lating" and " micrometrical" screws, is does not alone suffice
that the screw shall be good in general character, and as nearly
as possible a true helix ; but it must also bear some defined pro-
portion to the standard foot or inch, or other measure. The at-
tainment of this condition has been attempted in various ways,
to some of which a brief allusion was made in the second sec-
tion, and a few descriptive particulars will now be offered.
Fig. 610.
The apparatus for cutting original screws by means of a wedge
or inclined plane, appears to be derived from the old fusee engine,
a drawing of which is given in fig. 610; in principle it is perfect,
638 FUSEE ENGINE WITH INCLINED PLANE.
and it is also universal within the narrow limitation of its
structure *.
The handle h, gives rotation to the work ; and at the same
time, by means of the rack r r, and the pinion fixed on its axis,
the handle traverses a slide which carries on its upper surface a
bar i; the latter moves on a center, and may be set at any incli-
nation by the adjusting screw and divisions; it is then fixed by
its clamping screws. The slide s, carries the tool, and the end
of this slide rests against the inclined plane z, through the inter-
vention of a saddle or swing piece ; the slide and tool are drawn
to the left hand by the chain which is coiled round the barrel b,
by means of a spiral spring contained within it.
Supposing the bar i i, to stand square or at zero, no motion
would be impressed on the tool during its traverse, which we will
suppose to require 10 revolutions of the pinion. But if the bar
were inclined to its utmost extent, so that we may suppose the
one end to project exactly one inch beyond the other, in reference
to the zero line or the path of the slide, then during the 10 re-
volutions of the screw, the tool would traverse one inch, or the
difference between the ends of the inclined bar i ; and it would
thereby cut a screw of the length of one inch, or the total incli-
nation of the bar, and containing ten coils or threads.
But the inclination of the bar is arbitrary, and may be any
quantity less than one inch, and it may lean either to the right
or left ; consequently the instrument may be employed in cutting
all right or left hand screws, not exceeding 10 turns in length,
nor measuring in their total extent above one inch, or the maxi-
mum inclination of the bar.
The principle of this machine may be considered faultless ; but
in action it will depend upon several niceties of construction,
particularly the straightness of the slide and inclined bar,
the equality of the rack and pinion, and the exact contact
between the tool slide and the inclined plane. These difficulties
augment very rapidly with the increase of dimensions; and
* The drawing is the half size of fig. 1, plate xvii. of Ferdinand Berthoud's
Eaai tur L' Horlogeric, Paris, 1763. M. Berthoud says, " The instrument is the
most perfect with which I am acquainted; it is the invention of M. le Lievre,
and it has been reconstructed and improved by M. Gideon Duval." The templet
or shaper plate determines the hyperbolical section of the fusee. Plate 37 of
Rees's Cyclopedia contains an engraving of a different modification of the fuseo
engine, also with an inclined plane, which is ascribed to Hiudley of York.
REID'S SCREW ENGINE. RAMSDEN'S DIVIDING ENGINE. 639
probably the inachiue made by Mr. Adam Reid exclusively for
cutting screws, is aa large as can be safely adopted ; the inclined
plane is 44 inches long, but the work cannot exceed ly/j inch
ilium., 24 inch long, or ten threads in total length. The ap-
plication of the iiulimil plane to cutting screws is therefore
too contracted for the ordinary wants of the engineer, which
are now admirably supplied by the screw-cutting lathes with
guide screws and change wheels.
The accuracy of screws has always been closely associated
with the successful performance of engines for graduating circles
and right lines, and the next examples will be extracted from
the published accounts of the dividing engines made by Mr.
Ramsden.*
* Thia eminent individual received a reward from the Board of Longitude, upon
the condition that he would furnish, for the benefit of the public, a full account of
the methods of constructing and using his dividing machines, and which duly
appeared in the following tracts : — " Description of an Engine for dividing Mathe-
matical Instruments, by Ramsden, 4 to, 1777." Also, "Description of an Engine
for Dividing Straight Lines, by Ramsden, 4to, 1779," from which the following
particulars are extracted : —
The circular dividing engine consisted of a large wheel moved by a tangent
screw ; the wheel was 45 inches diameter, and had 2160 teeth, so that six turns
of the tangent screw moved the circle one degree ; the screw had a micrometer,
and also a ratchet wheel of 60 teeth, therefore one tooth equalled one-tenth of
a minute of a degree. The screw could be moved a quantity equal to one single
tooth, or several turns and parts, by means of a cord and treadle, so that the
circular works attached to the dividing wheel could be readily graduated into the
required numbers, by setting the tangent screw to move the appropriate
quantities ; the dividing knife or diamond point always moved on one fixed
radial line, by means of a swing frame.
In ratching or cutting the wheel, says Mr. Ramsden, " the circle was divided
with the greatest exactness I was capable of, first into 5 parts, and each of these
into 3 ; these parts were then bisected 4 times ; " this divided the wheel into 240
divisions, each intended to contain 9 teeth. The ratching was commenced at
each of the 240 divisions, by setting the screw each time to zero by its micro-
meter, and the cutter frame to one of the great divisions by the index ; the
cutter was then pressed into the wheel by a screw, and the cutting process
was interrupted at the ninth revolution of the screw. It was resumed at the
next 240th division (or nine degrees off), as at first, and so on.
This process was repeated three times round the circle, after which the ratching
was continued uninterruptedly around the wheel about 300 times ; this completed
the teeth with satisfactory accuracy. The tangent screw was subsequently made,
as explained in the text
Thejfrrf application of the tangent screw and ratchet to the purposes of gradu-
ation, appears to have been in the machine for cutting clock and watch wheels, by
Pierre Fardoil ; see plat* 23 of Thiout's Trait c £ 1/orlvgerit, 4c. Paris, 1741. At
page 55 is given a table of ratchets aud settings for wheels from 102 to 800 Ueth.
640
RAMSDEN'S SCREW-CUTTING ENGINES.
In Mr. Ramsden's description of his dividing engine for
circles, he says : " Having measured the circumference of the
dividing wheel, I found it would require a screw about one
thread in a hundred coarser than the guide screw." He goes on
to explain that the guide-screw moved a tool fixed in a slide
carefully fitted on a triangular bar, an arrangement equivalent
to a slide-rest and fixed tool ; the screw to be cut was placed
parallel with the slide and the guide-screw and copy were con-
iiected by two change wheels of 198 and 200 teeth (numbers in
the proportion required between the guide and copy), with an
intermediate wheel to make the threads on the two screws in
the same direction. As no account is given of the mode in
which the guide-screw was itself formed, it is to be presumed
it was the most correct screw that could be obtained, and was
produced by some of the means described in the beginning of
the present section.
Mr. Ramsden employed a more complex apparatus in origi-
nating the screw of his dividing engine for straight lines, which
it was essential should contain exactly 20 threads in the inch;
a condition uncalled for in the circular engine, in which the
equality of the teeth of the wheel required the principal degree
of attention. This second screw-cutting apparatus, which may
be viewed as an offspring of the circular dividing engine, is
represented in plan, in fig. 611, and may be thus briefly ex-
plained.
Fig. 611.
The guide-screw G is turned round by the winch, and in each
revolution moves the larger tangent wheel one tooth; the
KAMSDEN'S SCREW-CUTTINO ENGINES, ETC. ''<ll
tangent wheel has a small central boss or pulley/;, to which is
attached tin- one end of an elastic slip of steel, like a watch-
spring; tin- other end of the slip is connected with the slide*,
that carries the tool /, in a right line beside the screw C, which
hitter is the piece to he cut ; and (', is connected with the gu;
A G, by a bcvil pinion and wheel, g and c, as 1 to 6.
To proportion the traverse of the tool to the interval or pitch
of the seieu, two dots were made on the slide *, exactly five
inches asunder; and in that space the screw should contain I'll)
coils, to be brought about by GOO turns of the handle. The
irnidc-screw was moved that number of revolutions, and the
diameter of p, was reduced by trial, until the COO turns traversed
the slide exactly from dot to dot ; these points were observed
at the time through a lens placed in a fixed tube, and having
a fine silver wire stretched diametrically across the same as an
index.*
The late Mr. Henry Maudslay, devoted an almost incredible
amount of labour and expense, to the amelioration of screws and
screwing apparatus; which, as regarded the works of the mill-
wright and engineer, were up to that time in a very imperfect
state. With the view of producing screws of exact values, he
employed numerous modifications of the chain or band of steel,
the inclined knife, the inclined plane, and indeed each of the
known methods, which however he remodelled as additions to the
• See " Description of an Engine for Dividing Straight Lines," pages 13 to 16.
In the construction of his dividing engine for straight lines, Ramsden very closely
followed his prior machine for circular lines, if we conceive the wheel spread out as
a rectilinear slide. On the one edge of the main slide which carried the work, was
cut a screw-form rack, with twenty teeth per inch, which was moved by a short 6xcd
•crew of the same pitch, by mean* of ratchets of 50, 48, or 32 teeth respectively; the
•crew could be moved a quantity equal to one single tooth, or to several turns and
parts, by means of a treadle. To obtain divisions which were incompatible with
the subdivision of the inch into 1000, 960 or 640 parts, the respective values of one
tooth, the scale was laid on the slide at an angle to the direction of motion ; when
the swing frame was placed to traverse the Icnife at right angles to the path of the
slide, the graduations were lengthened ; when the knife was traversed at right
angle* to the Mique position of the scale being divided, they were shortened. This
was to a small degree equivalent to having a screw of variable length. In cutting
the screw-form teeth of the rectilinear dividing engine, the entire length, namely,
25-6 inches, was first divided very carefully by continual bisection into spaces of
eight-tenths of an inch, by hand as usual, and the screw-cutter was placed at zero
at each of these divisions, pressed into the edge of the slide, and revolved
sixteen times ; after three repetitions at each of the principal spaces, the entire
length was niched continuously until the teeth were completed.
T T
G42 MAUDSLAY'S METHODS OF ORIGINATING SCREWS.
ordinary turning-lathe with a triangular bar; a natural result,
as he was then in the frequent habit of constructing that
machine, and which received great improvement at his hands.
It was noticed at page 581, that of all the methods he gave
the preference to the inclined knife, applied against a cylinder
revolving in the lathe, by means of a slide running upon the bar
of the lathe; which besides being very rapid, reduced the
mechanism to its utmost simplicity. This made the process to
depend almost alone on the homogeneity of the materials, and
on the relation between the diameter of the cylinder and the
inclination of the knife ; whereas in a complex machine, every
part concerned in the transmission of motion, such as each axis,
wheel and slide, entails its risk of individual error, and may
depreciate the accuracy of the result ; and to these sources of
disturbance, must be added those due to change of temperature,
whether arising from the atmosphere or from friction, especially
when different metals are concerned.
A rod of wood, generally of alder and about two feet long, was
put between the centers, and reduced to a cylinder by a rounder
or witchet (fig. 343, p. 487), attached to a slide running on the
bar ; the slide with the inclined knife was then applied, and the
angle of the knife was gradually varied by adjusting screws, until
several screws made in succession, were found to agree with
some fixed measure. The experiment was then repeated with
the same angle, upon cylinders of the same diameter, of tin,
brass, and other comparatively soft metals, and hundreds, or
it might almost be said, thousands of screws were thus made.
From amongst these screws were selected those which, on
trial in the lathe, were found to be most nearly true in their
angle, or to have a quiescent gliding motion ; and which would
also best endure a strict examination as to their pitch or inter-
vals, both with the rule and compasses, and also when two were
placed side by side, and their respective threads were compared,
as the divisions on two equal scales.
The most favourable screw having been selected, it was em-
ployed as a guide-screw, in a simple apparatus which consisted
of two triangular bars fixed level, parallel, and about one foot
asunder, in appropriate standards with two apertures ; the one
bar carried the mandrel and popit heads as in the ordinary bar
lathe. The slide rest embraced both bars, and was traversed
Ml : riMM.s 01 <; SCREWS.
thcrriipou by the k'liide-Ncrew placed about midway between the
bars ; the guide-screw and mandrel wcrt generally connected by
three wheels, or rKe by two or four, when the guide and copy
were required to have the reverse direction. The mandrel was
not usually driven by a pulley and cord; but on the extremity
of the mandrel was fixed a light wheel, with one arm serving as
a winch handle for rapid motion in running back ; and six or
cij;ht radial anus, (after the manner of the steering wheels of
lar^e vessels,) by which the mandrel and the screw were slowly
handed round during the cut.
In a subsequent and stronger machine, the bar carrying the
mandrel stood lower than the other, to admit of larger change
wheels upon it, and the same driving gear was retained. And
in another structure of the screw-cutting lathe, Mr. Maud>lay
placed the triangular bar for the lathe heads in the center,
whilst a large and wide slide-plate, moving between chamfer
bars attached to the framing, carried the sliding rest for the
tool : in this last machine, the mandrel was driven by steam
power, and the retrograde motion had about double the velocity
of that used in cutting the screw. Indeed these machines may
be fairly considered to be the precursors of the present screw
cutting lathes, in which the detached triangular bars or slides
have been exchanged for one strong bearer with two ridges or
fillets, upon which the slide plate moves for guiding the trav>
of the tool.
The relations between the guide-screw and the copy were
varied in all possible ways : the guide was changed end for end,
or different parts of it were successively used ; sometimes aUo
t\u> guide-town were yoked together with three equal wheels,
their nuts being connected by a bar jointed to each, and the
center of this link, (whose motion thus became the mean of that
of the guides,) was made to traverse the tool. Steel screws \\
also cut and converted into original taps, from which dies were
made, to be themselves used in correcting the minor errors, and
render the screws in all respects as equable as possible. In fact,
•licme that he could devise, which appeared likely to benefit
the result, was carefully tried, in order to perfect to the utmost,
tlu helical character and equality of subdivision of the screw.
Mr. Maudslay succeeded by these means, after great perse-
;mce, in making a very excellent brass screw about s>>.
T T 2
644 MAUDSLAY'S ADJUSTMENT FOR TOTAL LENGTH.
feet long, and which, compared with standard measure, was
less than one sixteenth of an inch false of its nominal length.
Taking the error as the one-thousandth part of the total length
of the screw, which was beyond its real quantity, to make from
it a corrected screw by the system of change wheels, would
have required one wheel of 1000 teeth, and another of one tooth
less, or 999 ; but in reality the error was much less, and perhaps
nearer the two-thousandth of an inch; then the wheels of 2000
and 1999 teeth would have been required; consequently the
system of change wheels is scarcely applicable to the correction
of very minute errors of length.
The change of the thousandth part of the total length, was
therefore given to the tool as a supplementary motion, which
might be added to, or subtracted from the total traverse of the
tool, in the mode explained by the diagram, fig. 612, in which
all details of construction are purposely omitted. The copy C,
and the guide-screw G, are supposed to be connected by equal
wheels in the usual manner; the guide-screw carries the axis of
the bent lever, whose arms are as 10 to 1, and which moves in a
horizontal plane ; the short arm carries the tool, the long arm is
jointed to a saddle which slides upon a triangular bar i i.
Fig. 612.
In point of fact, the tool was mounted upon the upper of two
longitudinal and parallel slides, which were collectively traversed
by the guide-screw G. In the lower slide was fixed the axis or
fulcrum of the bent lever, the short arm of which was connected
by a link with the upper slide, so that the compensating motion
was given to the upper slide relatively to the lower.
The triangular bar i i, when placed exactly parallel with the
path of the tool would produce no movement on the same, and
C, and G, would be exactly alike ; but if i i, were placed out of
parallelism one inch in the whole length, the tool, during its
traverse to the left by the guide-screw G, would be moved to
the right by the shifting of the bent lever one-tenth of the
displacement of the bar, or one-tenth of an inch.
MAUDSLAY, BARTON, TROi
B whiNt tin- ^'nide-screw O, from being coarser than
required, nioud the principal slid .'--thousandth part of
the total length in excess; the bent lc\er and inclined xtrftif/ht
bar i t, pulled back the upper or compensating slide, the
thousnndth part, or the quantity in excess; making the absolute
ir.se uf t : \actly seven feet, or the length reqnin-d for
the- new screw C, instead of seven feet and one-sixteenth of an
inch the length of O. To have lengthened the traverse of the
tool, the bar i », must have been inclined the reverse way ; in other
words, the path of the tool is in the diagram the difference of the
two motions; in the reverse inclination, its path would bethe*M//»
of the two motions, and t i being a straight line, the correction
would be evenly distributed at every part of the length.*
Whilst Mr. Maudslay's experiments in perfecting the screw
were being carried on, his friend Mr. Barton,f paid frequent
manufactory, and also pursued a similar course.
M r. Barton preferred, however, the method of the chain or flexible
band, for traversing the tool the exact quantity ; because the
reduction of the diameter of the pulley or drum, afforded a very
ready means of adjustment for total length ; and all the wheels
of the mechanism being individually as perfect as they could
be made, a near approach to general perfection was naturally
anticipated on the first trial. This mode, however, is subject to
the error introduced by the elasticity or elongation of the chain or
band, and which is at the maximum when the greatest length of
chain is uncoiled from the barrel.
These two individuals having therefore arrived, by different
methods, as near to perfection as they were then resj
capable of; each made a screw of the same pitch, and
inches long, and the two when placed side by side were found
exactly to agree throughout their length, and were considered
vet. The two screws were submitted in 1810 to the
scrutiny of that celebrated mathematical instrument maker, the
Mr. Kdw. Troughton, F.R.S., &c., who examined them by
means of two powerful microscopes with cross wires, such as are
used for reading off the graduations of astronomical instruments;
applied like a pair of the most refined compasses, to measure the
• The apparatus was fitted to the aeoond •crow-lathe of those described, and
the inclined bar wan placed on temporary wooden standards.
f Subsequently Sir J. Barton, Comptroller of the Mint, Ac.
016 BARTON'S APPLICATION OF TWO PAIRS OF DIES.
equality of some 20, 50, or 100 threads, taken indiscriminately
at different parts of the length of the screws.* From this
severe trial it resulted, that these screws, which to the unassisted
sight, and for almost every purpose of mechanism, were unexcep-
tionable, were found to be full of all kinds of errors, being
unequally coarse at different parts, and even irregular in their
angles, or "drunk." This rigid scrutiny led both parties to fresh
and ultimately successful efforts, but of these our limits will only
allow us to notice one, apparently derived from the use of the
two microscopes.
Mr. Barton employed two pairs of dies upon the one screw ;
the dies were fixed at various distances asunder upon one frame
or bar, and the screw was passed through them. This was found
to distribute the minute errors so completely, that little re-
mained to be desired ; as it is obvious that at those parts where
the screw was too coarse, the outer sides of the threads were
cut, and which tended to shorten the screw ; and where it was
too short, the inner sides were cut, which tended to lengthen the
screw ; in fact the two parts temporarily situated within the dies,
were continually endeavouring to approximate themselves to the
fixed unvarying distance, at which the dies were for the time
placed.f
Mr. Maudslay did not restrict his attention to the correction
of the screw for the purposes of science, J but he also effected a
great many improvements in the system of taps and dies, by
which they were made to cut instead of squeeze : as to him are
due the introduction of the three cutting edges, and the division
of the taps into the series of three, namely, the entering or
taper tap, the middle, and the plug tap, by which shallow holes
* The microscope had been long used in the process of graduating instruments,
but this invaluable mode of employing two microscopes in combination, was first
successfully practised by Mr. Trough ton.
+ Mr. Barton informed the author that he employed the screw corrected in the
above manner, in his engraving machine employed for cutting with the diamond,
the lines as fine as 2000 in the inch, on the steel dies referred to in the note on page
42, vol. i. ; and he said " that such was the accuracy of the mechanism, that if a line
were missed, the machine could be set back for its insertion without any difference
being perceptible." The author unintentionally ascribed the first application of
the diamond to turning steel, to Sir John Barton (see note, page 179, vol. i.),
whereas it had been used long before by Ramsden in cutting the hardened-
steel screw for his rectilinear dividing engine. See his tract, pages 14, 15.
£ The accuracy of a screw cut by Mr. Maudslay, and employed in Mr. Donkin's
rectilinear dividing engine, ia indisputably shown at page 654 of this volume.
MAUDSLAY'S IMPROVEMENT IN SCREWING TOOLS, i
or dead holes, in cast iron, can be safrly i ; j<cd with full
threads, a rant re impossible.
This engineer also made a scries of taps, from six i:
diameter, for attaching the pistons of steam-engines to t!
piston rods, to the smallest used in scres\ -plates for watch work.
The diameters of these taps were derived from the ordinary
subdivision of the inch into eighths and sixteenths; and their
threads were jointly dctcnninrtl by the respective strength of
each screw, and the choice of defined rates, such as -\, •'> \, I, 1 1,
6, 8, &c., threads per inch. To have employed one constant
le or proportion between the diameter and pitch, would have
introduced many fractions into the rates of pitch, and an irre-
gularity of strength in the screws themselves. The formation of
these taps was rendered comparatively easy, after he had intro-
duced the true original screw and the system of change wheels,
as a common practical apparatus ; many copies of these screw
threads have found their way to other workshops, and have
ed to influence the construction of similar tools of various
proportions.
Indeed, I believe it may be fairly advanced, that during the
period from 1800 to 1810, Mr. Maudslay effected nearly the
entire change from the old, imperfect, and accidental practice of
screw-making, referred to at page 635, to the modern, exact
and systematic mode now generally followed by engineers ; and
he pursued the subject of the screw with more or less ardour, and
at an enormous expense, until his death in 1835. The results
have been so important, and are so well appreciated amongst
mechanical men generally, that they may be considered fully
to deserve the short digression to which they have led.
In IMtl, Mr. Allan was rewarded by the Society of Arts for
his method of cutting micrometer screws with dies : the repre-
sentation and description of the instrument will be found at page
re it is shown in the act of cutting an original screw with
an inclined knitX Micrometer screws are cut in this apparatus
much in the same manner, except that about one-third of the
thread is cut with the large die, fig. 535, the inner curvature
of which agrees with the curvature of the blank cylinder, and
the screw is finished with the smaller die, 5:5(5, cut by an original
of the same diameter as the finished screw. The piece pre-
pared for the screw must always have two cylindrical ends to
CiS CLEMENT'S MODE OF ORIGINATING SCREWS.
fit the semicircular bearings b b ; this arrangement prevents the
screw from being bent in the process of cutting, but which
latter operation is accomplished entirely with the dies.*
About the year 1820, Mr. Clement devised and put in practice
a peculiar mode for originating the guide-screw of his screw-lathe,
the steps of which plan will be now described.
1. He procured from Scotland some hand-screw tools cut
over a hob with concentric grooves ; and to prevent the ridges
or points of the screw tools, from being cut square across the
end, the rest was inclined to compensate for the want of angle
in the hob or cutter.
2. A brass screw was struck by hand, or chased with the tool 1.
3. The screw 2, was fixed at the back of a traversing mandrel,
and clipped between two pieces of wood or dies to serve as a
guide, whilst
4. A more perfect guide-screw was cut with a fixed tool, and
substituted on the mandrel for 3 : as Mr. Clement considered
the movement derived from the opposite sides of the one screw,
became the mean of the two sides, and corrected any irregu-
larities of angle, or of drunkenness.
5. A large and a small master-tap m, fig. 613, were cut on the
traversing mandrel with a fixed tool, the threads were about an
inch long, and situated in the middle of a shaft eight or ten
inches long ; the small master-tap was of the same diameter as
the finished screw, the large master-tap measured at the bottom
of the thread the same as the blank cylinder to be screwed, as
in figs. 572 and 576, page 600. The master-taps m, were used
in cutting up the rectangular dies required in the apparatus
shown in fig. 613, and now to be described.
6. On the parallel bed of a lathe, were fitted two standards or
collar-heads h hf, intended to receive the pivots of the screw to
be cut, on the extremity of which was placed a winch handle, or
sometimes an intermediate socket was interposed between the
* Mr. A. Ross considers that the friction of Mr. Allan's apparatus is apt to retard
the traverse of the screw, and therefore to cut the bottom of the thread too wide or
rounding. In his practice he uses the large and small dies for a short period at the
commencement and conclusion of the process, but he cuts out the principal bulk of
the material, by a fixed tool inserted within a radial mortise in a semicircular
copper die ; the copper is indented more and more with tho progress of the work,
and serves as an efficient guiilo, whilst thecuttiug in accomplished with considerably
leas friction, and in a superior manner, by the cutter or turning-tool.
\C, 8CBBW8.
•crew and tin- winch, to carry tin end of the bed.
;ti-d had also an accurate slide plate x .«', running freely upon
'lie slide-plate had two tails which passed l>e>ide tin- head //,
and at the other end, a projection through which was made a
transverse rectangular mortise for the dies, the one end of the
mortise is shown by the removal of the front die d, and the back
die d' is seen in its proper situation ; one extremity of each die
was cut from the large master tap TO, and the other from the
small. The clamp or shackle c c, was used to close the two dies
upon the screw simultaneously ; it is shown out of its true posi-
tion in order that the dies and mortise may be seen, but when in
u>e the shackle would be shifted to the right, so as to embrace
the diew/'A. The plain extremity c' rested against the back die,
whilst the screw c bore against the front die, through the inter-
vention of the washer loosely attached to the clamp to save
the teeth from injury; the pressure screw c had a graduated
head and an index, to denote how much the dies were closed.
7. A cylinder about two feet long, prepared for the screw,
was placed between the heads h /*', and the large dies, whose inner
edges were of the same diameter as the cylinder, were closed
upon it moderately tight, and the screw was turned round with
the winch, to trace a thread from end to end ; this was repeated
a few times, the dies being slightly closed between each trip.
8. A screw-tool was next fixed on the slide * *', in a chamfer
slide / /' with appropriate adjusting screws, so as to follow the
ami remove a shaving, much the same as in turning; the
dies having arrived at one end of the screw, the same s<
tool, or a second tool, was placed on the opposite side of the
slide-plate, so as to cut dm > turn movement. With
the progress of the screw, the screw-tool was applied at a
650 CLEMENT'S MODE OF ORIGINATING SCREWS.
variety of distances from the pair of dies, as well as on opposite
sides of tlie screw, so that the metal was cut out by the tool, and
the dies were used almost alone to guide the traverse. Of course
the dies were closed between each trip, and when the screw was
about half cut up, the small dies were substituted for the large
ones used at the commencement of the process.
9. The screw thus made, which was intended for a slide-rest,
was found to be very uniform in its thread, and it was used
for some time for the ordinary purposes of turning. When how-
ever it was required to be used for cutting other screws, it was
found objectionable that its rate was nearly nine, whereas it
was required to have eight threads per inch ; it was then used
in cutting a new guide-screw by means of a pair of change
wheels of 50 and 56 teeth, which upon calculation were found
to effect the conversion with sufficient precision.
10. From 9, the screw of 24> inches in length, one of 8 feet
in length was obtained; the thread was cut one-third its
depth, with the wheels, successive portions being operated upon,
and the tool being carefully adjusted to the termination of the
part previously cut. The general truth of the entire length was
given by a repetition of the tedious mode of correction repre-
sented in the figure, with the dies and tool applied upon a bearer
rather exceeding the full length of the screw.*
Although the processes 7 and 8 will produce a most uniform
screw, Mr. Clement attaches little importance to the use of the
dies and guide-frame alone, when several screws are wanted
strictly of the same length. Of some few thus made, as nearly as
possible under equal circumstances, two screws were found very
nearly to agree, and a third was above a tenth of an inch longer
in ten inches. This difference he thinks to have arisen in mark-
ing out the threads, from a little variation in the friction of the
slide, or a difference in the first penetration of the dies.
The friction of the slide, when sufficient to cause any retard-
* Mr. Clement also made a very superior steel screw of about five feet in length
and three inches diameter, precisely by the method 10, before he had completed tho
screw lathe he now commonly uses : and Mr. Whitworth followed precisely the
same method in obtaining his standard screw, of about the length of 24 feet and
half-inch pitch ; except that a claap nut was used instead of the dies. It was
produced from a short screw cut by Mr. Clements; the correctional process
occupied two months, and was carried with a most strict regard to avoid the
unequal expansion of the screw and apparatus employed upon it
:.l\'s UK I I II I M Ml |.|\ I!)IN(, |;\.
ation, he considers to produce a constant and accumulative
cltect ; first as it were, mine-in;,' the, screw of 15 threads JHT
inch, say to tin- fineness of !."»} ; thru acting upon that of 15$-
n-.inrinu' it to 15 J, and so on; and that to such an extent, as
occasionally to place tin; screw entirely beyond the correctional
process. This cannot be the case when the thread is i
marked out with the change wheels, instead of the diea.
One very important application of the screw, is to the gradua-
tion of mathematical scales, the screw is then employed to move
a platform, which slides very freely, and carries the scale to be
graduated; and the swing frame for the knife or diamond point
is attached to some fixed part of the framing of the machine.
Supposing the screw to be absolutely perfect, and to have fifty
threads per inch, successive movements of fifty revolutions, would
move the platform and graduate the scale exactly into true
inches; but on close examination, some of the graduations will
be found to exceed, and others to fall short of the true inch.
The scales assume, of course, the relative degree of accuracy
of the screw employed. No test is more severe ; and when these
scales are examined by means of two microscopes under a mag-
nifying power of ten or twenty times, the most minute errors
become abundantly obvious, from the divisions of the scales, fail-
to intersect the cross wires of the instrument; the result
clearly indicates, corresponding irregularities in the coarseness of
the screw at the respective parts of its length. An accustomed
eye can thus detect, with the microscope, differences not exc>
in'4 the one thirty-thousandth part of an inch, the twenty-:
thousandth part being comparatively of easy observation.
From Mr. Donkin's investigation of the subject, he was led to
conclude that it is quite impossible to produce a screw which
shall be absolutely free from error, when micrometrically pro\
and in 1 S23, he was in consequence led to consider that as Mr.
.dslay's method of the bent lever and inclined straiyht bar,
would compensate the error of total length in a nearly per
screw, a similar mode might he applied to all the intermediate
errors, by the employment of :i \perimentally obtained by
ethod of continual bisection employed in hand dividing.
It having been explained i nee to the diagram on page
«'• I I, that the inclination given to the bar i i, would mince the
effective length of a screw, and the reverse inclination would
DONKI.V'S RECTILINEAR DIVIDING ENGINE.
increase it, Mr. Donkin considered that from the observed fact
of one half of the screw, (as estimated by counting the number
of threads,) being generally too coarse, and the other half too
fine, the compensation would require the one half of the bar i i,
to be inclined to the right as in the diagram, and the other half
to the left, in fact thus bending the right line into an obtuse angle.
Extending this mode, upon the presumption that the quarters,
eighths, or sixteenths, of the screw were also dissimilar, the
bar would require many flexures instead of the one only, giving
to it a more or less zig-zag character, or rather that of a gently
undulating line. The undulations being proportioned experi-
mentally, to effect such compensations, as should add to the
movement of the upper platform or supplementary table, where
the screw was too fine, and subtract from its motion, where the
screw was too coarse ; so as, from a screw known to be slightly
irregular, to produce the divisions of a scale, or the thread of
another screw, considerably nearer to equality.
He carried out this project in 1826, and he has satisfactorily
proved the existence of a correctional method, which is within
reach of any clever workman who will devote sufficient patience
to the adjustment of the engine, and which latter will be now
briefly explained.
Mr. Donkin's dividing machine consists first of a table or
platform moving on a railway, the platform being supported by
four or any greater number of wheels, that may be required
for preventing flexure and for diminishing friction. The upper
edges of the two rails on which the wheels turn, are made as
perfectly straight as possible, the rails lie in the same horizontal
plane; and they are placed at 'any convenient distance from
each other. The table or platform is guided laterally in its
course upon the rails, by four wheels, of which two are placed
on each side of one of the rails ; two wheels turn on fixed axles
on one side of the rail, whilst the two on the other side are
held tight to the rail by means of springs, thus preventing any
deviation from the rectilinear course in which the platform
ought to travel. To the under side of the platform is attached
a clasp-nut, the two parts of which are so constructed, as to be
applied to, or separated from the main screw, which lies below
the platform, and is exactly parallel with the rails, or with the
line in which the platform is made to move.
To effect the compensation, the platform or table consists
I.ONKIV'S RECTILINEAR IMVliUM. i:\..: f,.Y;
of nn upper and lower plate, which arc of a small inde-
pendent motion. The low IT plate carries the fulcrum of the
ben: .MS,, amis arc at right angles and as fifty to one,
r moves in the vertical plane, so that its longer arm lies by
gravity alone on the cunili near edge of the compensation bar; the
upper platform is pressed endlong against the shorter arm of
bent lever, by a spring which always keeps them in close contact.
The attachment of the two platforms is peculiar; the upper,
rides upon four rollers or rather sectors, and the two plates are
connected by two slight rods placed transversely between tl
the ends of the rods are fixed over the one rail to the lower, and
over the other rail to the upper platform; the bars consequently
fulfil the oilicc of the radius bars of a parallel rule, and suffice
by their flexure alone, for the very limited and exact motion
required in the upper table.
The compensating bar which is of the length of the screw, or
•2 I inches, has 48 narrow slips of metal placed like the keys of
a piano-forte, each having an appropriate adjusting and fixing
screw, by which the ends of the pieces may be placed in a con-
tinuous line, or any of them may be placed above or below the
line as required in the following mode of compensation. For
change of total length and adjustment for temperature, the curved
bar is more or less inclined, as in the former example, except
that it is placed edgeways or vertically ; it is attached to the out-
side of one of the rails, by a pivot which intersects the one end
of its curvilinear edge, and the other end is raised or depressed
by a screw, which effects the adjustment for temperature.
Conceiving the length of the guide-screw divided into 48
equal parN, denoted by the figures 0 to 48, it would be first
ascertained by two fixed microscopes, if the halves of the srr
measured from 0 to 24, and from 24 to 48, were absolutely
equal quantities; if not, the central slip or finger would be
cd or lowered until on repeated trials the due correctional
movement was applied to the table. The two halves would be
similarly bisected and corrected in the points 12 and 36, and
the quarters atrain bisected in 6, 18, 80, and 42; and the
eighths when also bisected, would extend the examination to
the points 0, 3, 6, 9, &c., to 48. The easiest method is to com-
pare the path of the slide, with the divisions of a superior scale,
fixed upon the slide or platform of the machine.
It would now be needful to divide the whole into three ;
<>.') l DONKIN'S RECTILINEAR DIVIDING ENGINE.
by the comparison of the spaces from 0 to 16, from 16 to 32,
and from 32 to 48, the points 16 and 32, being adjusted until
exactly equal, which is the most difficult part of the work ; and
then these three distances being bisected four times, every
point of the 48 would have been examined, and some of them
twice over. These adjustments having been repeatedly verified,
during which a very frequent recurrence to the total length is
imperative ; the concluding step is to file off the corners of the
48 slips very carefully, so as to convert them into a line with
undulations, slight it is true, but which represent fifty-fold the
actual errors in the guide-screw ; and therefore shift the table
simultaneously with its general traverse, so as to apply the
exact corrections for inequality, at every point examined and
found to be in error.
But the term error must be received in a very restricted sense,
as it deserves to be noticed, that Mr. Donkin first used a screw
made by Mr. Maudslay, and the maximum deflection of the
curved edge of the compensation bar from a straight line, was
very nearly the eighth of an inch, indicating the maximum error
of the screw to have been about the 400th part of an inch ; and
as the curve was nearly limited to a single undulation, or a hill
at one end, it may be presumed this minute error was in part
attributable to a difference in the material, a source of perplexity
from which no care is a sufficient protection. The dividing engine
was employed as a traversing lathe in cutting a new screw, and
which, although it had the advantage of the compensation, only
reduced the error of the new screw to about one-third the
quantity of that of the first; as shown by the new curve assumed
by the compensation bar, its deflection being -^ of an inch, when
re-adjusted in the tedious and anxious method described.*
Having at length concluded the remarks on some of the most
* In the paat year, 1842, Mr. Donkin has made a similar but enlarged dividing
engine. The length of traverse of the new machine is 42 inches, the screw has 40
threads in the inch, the compensation bar is as 60 to 1, and the value of one single
tooth in the counting wheel is equivalent to the 60,000th part of an inch ; that of
the first machine having been the 30,000th part.
It is to be hoped that Mr. Donkin will complete his labours, by publishing a
detailed account of these machines, the latter of which, in particular, exhibits
throughout its structure a most refined contrivance and execution, of which no
adequate idea can possibly be conveyed within the limits of this slender notice,
nor without exact drawings of the details, to the arrangement of which great
attention has been bestowed.
OKNERAL CHARACTERS OF SCREW THREAD*. C55
i od and scientific efforts that have been employed in pro-
ducing and i .MI;,' the screw, I shall in the next and con-
section of this already extensive chapter, proceed to the
of a variety of important considerations and con-
ditions, which practically influence the proportions, forms, and
general character of screws, to adapt them to multifarious pur-
poses in the mechanical and constructive arts.
SECT. IX. — SCREW THREADS CONSIDERED IN RESPECT TO THEIR
PROPORTIONS, FORMS, AND GENERAL CHARACTERS.
The proportions given to screws employed for attaching
together the different parts of work, are in nearly every case
arbitrary, or in other words, they are determined almost by
experience alone rnther than by rule, and with little or no aid
from calculation, as will be shown.
In addition to the ordinary binding screws, which although
arbitrary, assume proportions not far distant from a general
average, many screws, either much coarser or finer than usual,
are continually required for specific purposes ; as are likewise
other screws of some definite numbers of turns per inch, as 2,
10, 12, 20, &c., in order to effect some adjustment or movement
having an immediate reference to ordinary lineal measure.
But all these must be considered as still more distant, than
common binding screws, from any fixed proportions, and not to
be amenable to any rules beyond those of general expediency.
Neither the pitch, diameter, nor depth of thread, can he-
adopted as the basis from which to calculate the two othci
measures, on account of the different modes in which the three
influence the effectiveness of the screw ; nor can the proportions
suitable to the ordinary f inch binding screw, be doubled for the
1 £ inch screw, or halved for that of $ inch ; as every diameter
requires its individual scale to be determined in great measure
by experiment, in order to produce something like a mean
proportion between the dissimilar conditions, which will be
separately explained in various points of view.
The reasons for the uncertainty of measure in the various
fixing screws required in the const native arts, arc sufficiently
manifest ; as first, the force or strain to which a screw is exposed,
either in the act of fixing, or in the office it has afterwards to
G56 RELATIVE STRENGTHS OF SCREWS.
perform, can rarely be told by calculation ; and secondly, a
knowledge of the strain the screw itself will safely endure with-
out breaking in two, or without drawing out of the nut, is
equally difficult of attainment ; nor thirdly, can the deduction
for friction be truly made from that force the screw should other-
wise possess, from its angle or pitch, when viewed as a mecha-
nical power, or as a continuous circular wedge.
The force required in the fixing of screws takes a very wide
range, and is faintly indicative of the strain exerted on each.
The watchmaker, in fixing his binding screws, employs with great
delicacy a screw-driver, the handle of which is smaller than an
ordinary drawing pencil : while for screws, say of five inches
diameter, a lever of six or seven feet long must be employed by
the engineer, with the united exertions of as many men. But
in neither case do we arrive at any available conclusion, as to
the precise force exerted upon, or by each screw; nor of the
greatest strain that each will safely endure.
The absolute measures of the strength of any individual screw
being therefore nearly or quite unattainable, all that can be done
to assist the judgment, is to explain the relative or comparative
measures of strength in different screws, as Betermined by the
three conditions which occur in every screw; whether it be right
or left handed, of single or of multiplex thread, or of any section
whatever; and which three conditions follow different laws, and
conjointly, yet oppositely, determine the fitness of the screw for
its particular purpose, and therefore tend to perplex the choice.
The three relative or comparative measures of strength in dif-
ferent screws are : first, the mechanical power of the thread, which
is derived from its pitch ; secondly, the cohesive strength of the
bolt, which is derived from its transverse section ; and thirdly,
tfie cohesive strength of the hold, which is derived from the inter-
placement of the threads of the screw and nut.
These conditions will be first considered, principally as regards
ordinary binding screws, and screw bolts and nuts, of angular
threads, and which indeed constitute by far the largest number
of all the screws employed ; screws of angular and square threads
will be then compared.
The comparative sections, figs. 614 to 617, represent screws of
the same diameters, and in all of which the depth of the thread
is equal to the width of the groove; figs. 615 and 617 show the
RELATIVE Si OH SCREWS.
«57
nary proportions of } inch angular and squarr thrr-adscrcws ;
'• 1 I and G16 are respectively as fine and as coarse again as 615.
Fig* 014.
fv.\\\\\\\v
615.
514
617.
rr.Ln_a-Q,
\ , I V
m
A . * \ \ ' I « •
Various measures of the screws which require little further
explanation are subjoined in a tabular form ; and the relative
degrees of strength possessed by each screw under three different
points of view, are added.
IIKASU RES AND RELATIVE STRENGTHS OF THE SCREWS.
Fig.
614
Fig.
615
Fig.
616
Fig.
617
External diameters in hundredtha of an inch
•75
•75
•75
•75
;ial diameters in hundredths of an inch . .
•65
•55
•35
•55
N umber of threads per inch, or rota of the screws
20-
10-
5-
5-
• ha and widths of the threads in hundredth)*
•05
•Id
•20
•10
A nglea of the threads on the external diameters*
1° 16'
2° 33'
5° 6'
6° 5*
Angles of the threads on the internal diameters*
1° 28'
3° 28'
10" 47'
.; ;.:.
Relative mechanical powers of the threads . .
20
10
5
5
Relative cohesive strengths of the bolts . . .
4
3
1
3
Relative cohesive strengths of hold of the screws
65
55
35
274
Relative cohesive strengths of hold of the nuts .
75
75
70
* The angles "of tho threads of screws are calculated trigonomotrically, the
circumference of the bolt being considered as the base of a right-angled triangle,
snd the pitch as the height of tho same.
The author has adopted the following mode, which will be found to require the
fewest figures ; namely, to divide the pitch by the circumference, and to seek the
product in tho table of tangents; decimal numbers are to be used, and it is
sufficiently near to consider the circumference as exactly three times the
F<>r the external angle of fig. 616 say 20 -f- 2-25 = -OSS3, and this quotient by
Hutt. m's Tables gives 5 deg. 5 min.
Fur the internal angle of fig. 614 say -05 -j- 1-95=0-2564, and by Hutton's Tables,
1 dcg. 28 min.
In this method the pitch is considered a* the tangent to the angle, and the division
• s the change of the two sides of the given right-angled triangle, for two others,
the larger of which is 1 or unity, for the convenience of using the tables.
U U
C58 HELATIVE STRENGTHS OF SCREWS.
Square thread screws, have about twice the pitch of angular
threads of similar diameters, and 617 estimated in the same
manner as the angular, will stand by comparison as follows. The
square thread, 617, will be found to be equal in power to 616, the
pitch being alike in each. In strength of bolt to be equal to 615,
their transverse areas being alike. And in strength of hold, to
possess the half of that of 615, because the square thread will
from necessity break through the bottom of the threads, or an
interrupted line exactly like the dotted line in 616, that denotes
just half the area or extent of base, of the thread of 615 ; which
latter covers the entire surface of the contained cylinder, and
not the half only.
The mechanical power of the thread, is derived from its pitch.
The power, or the force of compression, is directly as the number
of threads per inch, or as the rate; so that neglecting the friction
in both cases, fig. 614 grasps with four times the power of 616,
because its wedge or angle is four times as acute.
When however the angle is very great, as in the screws of
fly-presses which sometimes exceed the obliquity of 45 degrees,
the screw will not retain its grasp at all j neither will a wedge of
45 degrees stick fast in a cleft. Such coarse screws act by
impact ; they give a violent blow on the die from the momentum
of the fly, (namely, the loaded lever, or the wheel fixed on the
press-screw,) being suddenly arrested ; they do not wedge fast,
but on the contrary, the reaction upwards, unwinds and raises
the screw for the succeeding stroke of the fly-press.
Binding screws which are disproportionately coarse, from
leaning towards this condition, and also from presenting less
surface-friction, are liable to become loosened if exposed to a
jarring action. But when, on the contrary, the pitch is very
fine, or the wedge is very acute, the surface friction against the
thread of the screw is such, as occasionally to prevent their
separation when the screw-bolt has remained long in the hole
or nut, from the adhesion caused by the thickening of the oil,
or by a slight formation of rust.
The cohesive strength of the bolt, is derived from its transverse
section. The screw may be thus compared with a cylindrical rod
of the same diameter as the bottom of the thread, and employed
in sustaining a load; that is, neglecting torsion, which if in
excess may twist the screw in two. The relative strengths are
IMI.'iu \\( K OF AQREEM PIKH. »;.V.|
-. i,t,,i ',;. the squares of the smaller diameters: in the
screws of 20, 1", and ."> angular threads, the smaller diameters
are 65, r> ; the squares of these numbers are 4225, 8"
and 1225, which may be expressed in round numbers as 4, 8, 1 ;
and therefore, the coarsest screw C 1C, has transversely only one-
fourth the area, and consequently one-fourth the strength of the
;ire-entL-d in the three diagrams.
The cohesive strength of the hold, is derived from the helical ridge
of the external screw, being situated within the helical groove of
tin- internal screw. The two helices become locked together with
a degree of firmness, approaching to that by means of which t In-
different particles of solid bodies are united into a mass ; as one
or both of the ridges must be in a great measure torn off in the
removal of the screw, unless it be unwound or twisted out.
A slight difference in the diameter or the section of a screw
and nut, is less objectionable than any variation in the coarse-
ness or pitch ; as the latter difference, even when very minute,
will prevent the screw from entering the hole, unless the screw
is made considerably smaller than it ought to be, and even then it
will bear very imperfectly, or only on a few places of the nut.
To attempt to alter a screwed hole by the use of a tap of a
different pitch, is equally fatal, as will be seen by the annexed
diagram fig. G18. For instance, the upper line a, contains exactly
•!• threads per inch, and the middle line or b, has 4J threads ; they
only agree at distant intervals. The lowest line c, shows that
which would result from forcing a tap of 1 threads such as a,
into a hole which had been previously tapped with the 4 £ thread
screw b, the threads would be said to cross, and would nearly
Fig. 618.
/vwvvy-
d< >;i i\ caeh other; the same result would of course occur from
employing 4 or 5 thread dies on a screw of 4^ threads per inch.
<-f<>re. unless the screw tackle exactly agree in pitch with
u u 2
6GO RELATIVE STRENGTHS OF SCREWS AND NUTS.
the previous thread, it is needful to remove every vestige of the
former thread from the screw or hole ; otherwise the result drawn
at c, must ensue in a degree proportionate to the difference of
the threads, and a large portion of the bearing surface, and con-
sequently, of the strength and the durability of the contact, would
each be lost. Some idea may thence be formed of the real and
irremediable drawback frequently experienced from the dis-
similarity of screwing apparatus ; nearly to agree will not suffice,
as the pitch should be identical.
The nut of a f -inch screw bolt is usually f inch thick, as it
is considered that when the threads are in good contact, and
collectively equal to the diameter of the bolt, that the mutual hold
of the threads exceeds the strength either of the bolt or nut ;
and therefore that the bolt is more likely to break in two, or the
nut to burst open, rather than allow the bolt to draw out of the
hole, from the thread stripping off.
"\Vhen screws fit into holes tapped directly into the casting's or
other parts of mechanism, it is usual to allow still more threads
to be in contact, even to the extent of two or more times the
diameter of the screw, so as to leave the preponderance of
strength greatly in favour of the hold ; that the screw, which
is the part more easily renewed, may be nearly certain to break
in two, rather than damage the casting by tearing out the thread
from the tapped hole.
Should the internal and external screws be made in the
same material, that is both of wood, brass or iron, the nut or
internal screw is somewhat the stronger of the two. For example,
in the screw fig. 615, the base of the thread is a continuous
angular ridge, which occupies the whole of the cylindrical surface
represented by the dotted line. Therefore the force required
to strip off the thread from the bolt, is nearly that required to
punch a cylindrical hole of the same diameter and length as the
bottom of the thread ; for in either case the whole of the cylin-
drical surface has to be stripped or thrust off laterally, in a
manner resembling the slow quiet action of the punching or
shearing engine.
But the base of the thread in the nut, is equal to the cylindrical
surface measured at the top of the bolt, and consequently, the
materials being the same, and the length the same, considering
the strength of the nut for 615 to be 75, the strength of the bolt
KM \ I I \M> NtTS. ''•'•!
would l> ', or tin v \vould he respeet ively as the diameters
of the tup and bottom of the thread; although when the holt
ru.lr> through the nut, the thread of the holt derives a slight
additional strength, from the threads situated beyond the nut,
and which ser\e as an almtnient.
It is however probable that the angular thread will not strip
off at the base of the threads, cither in the screw or nut, but w ill
break through a line somewhere between the top and bottom :
but these results will occur alike in all, and will not therefore
materially alter the relation of strength above assumed.
Comparing 01 4, 015, and 010, upon the supposition that the
bolts and nuts exactly fit or correspond, the strengths of the three
nuts arc alike, or as 75, and those of the bolts are as 05, .').",, and
.nid therefore the advantage of hold lies with the bolt of finest
thread ; as the finer the thread, the more nearly do the bolt and
nut approach to equality of diameter and strength.
Supposing however for the purpose of explanation, that
instead of the screws and nuts being carefully fitted, the screws
are each one-tenth of an inch smaller than the diameters of the
respective taps employed in cutting the three nuts ; Oil would
draw entirely out without holding at all; the penetration and
hold of (515 would be reduced to half its proper quantity ; and
that of i'.16 to three-fourths ; and the last two screws would strip
at a line more or less elevated above the base of the thread ; and
therefore the more easily than if the diameters exactly agreed.
The supposed error, although monstrous and excessive, shows
that the finer the thread, the greater also should be the accuracy
of contact of such screws; and it also shows the impolicy of
employing fine threads in those situations where they will be
subjected to frequent screwing and unscrewing, and also to much
strain. As although when they fit equally well, fine threads are
somewhat more powerful than coarse, in hold as well as in
mechanical power; the fine are also more subject to wear, and they
from such wear, a greater and more rapid depreciation of
•strength, than threads of the ordinary degrees of coarseness.
lu a screw of the same diameter and pitch, the ultimate
ngth is diminished in a twofold manner by the increase of
tin- tlfjith of the thread ; first it diminishes the transverse area of
the bolt, whieh i> therefore more disposed to break ill two; and
udly, it diminishes the individual strength of each thread,
: COMPARISON OF SQUARE AND ANGULAR THREADS.
which becomes a more lofty triangle erected on the same base,
and is therefore more exposed to fracture or to be stripped off.
But the durability of machinery is in nearly every case increased
by the enlargement of the bearing surfaces, and therefore as the
thread of increased depth presents more surface -bearing, the deep
screw has consequently greater durability against the friction or
wear, arising from the act of screwing and unscrewing. The
durability of the screw becomes, in truth a fourth condition, to
be borne in mind collectively with those before-named.
It frequently happens that the diameters of screwed works are
so considerable, that they can neither break nor burst after the
manner of bolts and nuts ; and if such large works yield to the
pressures applied, the threads must be the part sacrificed. If the
materials are crystalline, the thread crumbles away, but in those
which are malleable and ductile, the thread, instead of stripping
off as a wire, sometimes bends until the resisting side presents a
perpendicular face, then overhangs, and ultimately curls over :
this disposition is also shown in the abrasive wear of the screw
before it yields.
Comparing the square with the angular thread in regard to
friction, the square has less friction, because the angular edges
of the screw and nut, mutually thrust themselves into the
opposed angular grooves in the manner of the wedge. The
square thread has also the advantage of presenting a more direct
thrust than the angular, because in each case the resistance is
at right angles to the side of the thread, and therefore in the
square thread the resistance is very nearly in the line of its axis,
whereas in the angular it is much more oblique.
From these reasons, the square thread is commonly selected
for presses, and for regulating screws, especially those in which
rapidity of pitch, combined with strength, is essential ; but as
regards the ordinary attachments in machinery, the grasp of the
angular thread is more powerful, from its pitch being general I v
about as fine again, and as before explained, angular screws and
nuts are somewhat more easily fitted together.
The force exerted in bursting open a nut, depends on the
angle formed by the sides of the thread, when the latter is con-
sidered as part of a cone, or as a wedge employed in splitting
timber. For instance, in the square thread screw, the tlm ;ul
forms a line at right angles to the axis, and which is dotted in
M HI:\V NUTC, ""I n> AM> !H\ IDI:I).
868
figure 610; it is not therefore a cone, but simply compresses
the nut, or attempts to force the metal before it. In tin- deep
thread tig. <>20, the wedge is obtuse, and exerts much less
bursting effort than the acute cone represented iu the shallow
thread screw fig. <'>21 ; therefore the shallower the angular
thread, the more acute the cone, and the greater the strain it
throws upon the nut. The transverse measure of nuts, whether
they are square or hexagonal, is usually about twice the diameter
of the bolt, as represented in the figures, and this in general
suffices to withstand the bursting effort of the bolt.*
Those nuts, however, which are not used for grasping, but
for the regulating screws of slides and general machinery, are
made much thicker, so as to occupy as ranch of the length of
the screw as two, three, or more times its diameter ; this greatly
increases their surface- contact, and durability.
Should it be required to be able to compensate the nut, or to
re-adapt it to the lessened size of the screw when both have
been worn, the nut is made in two parts and compressed by
screws, or it is made clastic, so as to press upon the screw. The
nuts for angular threads are divided diametrically, and re-united
by two or more screws, as in fig. G22, in fact, like the semi-
circular bearings of ordinary shafts ; as then by filing a little of
the metal away from between the two halves of the nut, they
may be closed upon the angular ridges of the thread.
The nuts of square threads, by a similar treatment, would on
being closed, fit accurately upon the outer or cylindrical surface
of the square thread screw, but the lateral contact would not be
• red ; these nuts are therefore, divided transversely, as shown
* In the table of the dimensions of nuts, in Temploton'a Engineer's Pocket
Companion, the transforms measures decrease in the larger nuts ; the breadth of
the nut for a 4 inch bolt is stated as 1 inch, that for a 2| iuch bolt as 4 inches.
G64
NUTS CAPABLE OF BEING ADJUSTED.
in fig. 623, or they are made as two detached nuts placed in
contact. When therefore a small quantity is removed from
between them with the file, or that they are separated by one or
more thicknesses of paper, the one half of the nut bears on the
right hand side of the square worm, the other on the left.
Either of these methods removes the " end play," or the " loss
of lime," by which expression is meant that partial revolution,
to and fro, which may be given to a worn screw without pro-
ducing any movement or traverse in the slide upon which the
screw acts. It is usual, before cutting the nuts in the lathe or
with screw taps, to divide the nuts, and to re-unite them with
soft solder, or it is better to hold them together with the perma-
nent screws whilst cutting the thread.
But the screws of slides are very apt to become most worn in
the middle of their length, or at the one end, leaving the other
parts nearly of their original size : it is then best to replace
Figs. 622.
623.
624.
625.
them by new screws, as the former method of adjusting the
nuts cannot be used; although recourse may occasionally be
had to some of the various methods of springing, or the elastic
contrivances commonly employed in delicate mathematical and
astronomical instruments. Although these should be perfectly
free from shake or uncertainty of motion, they do not in general
require the firm, massive, unyielding structure of engineering
works and machinery.
Two kinds of the elastic nuts alone are shown; in fig. C>~2 1 the
saw-cut extends throughout the length of the nut, but sometimes
a portion in the middle is left uncut ; the nut is usually a little
set-in, or bent inwards with the hammer, so as to press upon the
screw. In fig. C25, the two pieces a and b, bear against opposite
DIFFERENT .SECTIONS OF SCREW Til Hi: \ Ms.
side* of tin- tin-cat!, :m<l /> only is li\. .1 t,, tin- slide, as in fig. 623;
tin- corn now accomplished hy interposing loosely around
tin- screw, and between tlie halves of the nut, n spiral spring
MiHieiently >; ome the friction of the slide upon the
fittings; the same contrivance is variously modified, sometimes
two or four spiral springs are placed in cavities parallel with the
screw.
The slide resists firmly any pressure from a to b, as the fixed
half of the nut lies firmly against the side of the thread presented
in that direction, but the pressure from b to a is sustained alone
by the spiral spring ; when therefore the pressure exceeds the
strength of the spring, the slide nevertheless moves endways to
tin- extent of the misfit in the piece A, and which, but for the
spring, would allow the slide to shake endways. In absolute
cflect the contrivance is equivalent to a single nut such as b
alone, which although possessing end play, if pulled towards b
by a string and weight, would always keep in contact with the
one side of the worm, unless the resistance were sufficient to
raise the weight. The method is therefore only suited to works
requiring delicacy rather than strength, and the spring, if
excessively strong, would constantly wear the two halves of the
nut \\ith injudicious friction and haste.
The several threads represented in figs. 620 to 638, may be
considered to be departures from the angular thread fig. 626, and
the square thread fig. 635, which are by far the most common.
The choice of section is collectively governed : First, by the
facility of construction, in which the plain angular thread excels.
Secondly, by the best resistance to strain, which is obtained in
the square thread. Thirdly, by the near equality of strength in
the internal and external screw. For similar materials the space
and thread should be symmetrical, as in the square thread, and
in fiL's. r^r, to »;:JO, which screws are proper for metal works
generally; whereas in dissimilar materials, the harder of the t\\o
»h<.nld have the slighter thread, as in the iron screws figs.
to (>:U, intended to he screwed into wood ; the substance of the
screw is supposed to lie below the line, and the head to the rijrht
hand. Fourthly, by the resistance to accidental \iolence, either
to the screws, or to the screwing tools, which is best obtained hy
the > angles or edges, as in the several rounded
666 DIFFERENT SECTIONS OF SCREW THREADS.
threads. This fourfold choice of section, like every other feature
of the screw, is also mainly determined by experience alone.
Fig. 626, in which the angle is about 60 degrees, is used for
most of the screws made in wood, whether in the screw-box or
the turning lathe ; and also
Sections derived from the for a very large proportion
,-,. ANGULAR THREAD. » ' r i
of the screw bolts of ordinary
626 v/VVVVVVVVVV mechanism. Sometimes the
points of the screw tool mea-
sure nearly 90 degrees, as in
....• the shallow thread, fig. 627,
628 /VVVVVVVV VV used for the thin tubes of
telescopes ; or at other times
J A/WWVWW they only measure 45 de-
eso AAAAAAAAAA/ grees as in the very deep
VVVVVVVVV threap, 628, used for some
031 JUU\J\JU\JU\J\_Aj mathemfic«J and other in-
struments; the angles repre-
632 AAAAAAAAAA7 sented mav be considered as
nearly the extremes.
633 xlx'lxl/lXlXl/lXlx'lXl/1 In originating accurate
screws, the angular thread is
634 \J\_J\_A_J\_A_J\_J\_J\_J\A always selected, because the
figure of the thread is still
maintained, whether the tool
Sections derived from the •> .-, • j
BQDABK THREAD. cut on one or on both sides
of the thread, in the course
635 I I I _| LJ I L I of the correctional process.
Fig. 629 is the angular
636 ^| O O ("S (~*} r~^ thread in which the ridges
LJ LJ LJ LJ LJ are more or less truncated,
to increase the strength of
\ f^i i i f i 1^1 ri 4~lif» hr^lf* • if" mnv np viPWPfl
637 \J \J \J LJ LJ I
as a compound of the square
638 _^/ u ^ ^ and angular thread.
Fig. 630 is the angular
thread in which the tops and bottoms are rounded; it is much used
in engineering works, and is frequently called a round thread.*
* See foot-note on p. 670.
DIFFERENT SECTIONS OF SCREW THREADS.
• I tin- thread is more acute, and truncated only at the
Ix.ttnm of the screw, this is used for j >rk, and greatly
increases the hold upon t lie wood; 632 is obviously derived from
631, and is used for the same purpose.
In 633, which is also a screw for wood, the face that sustains
the hold is rectangular, as in the square thread, the other is
'.led. l-'i^. 03 1 is the form of the patent wood screw, some-
times called the (ieriuan screw; it is hollowed to throw the
advantage of bulk, in favour of the softer material, or the wood,
the head of which is supposed to be on the right hand. In the
last four figures, the substance of the screw is imagined to be
situated below the line, and that of the wood above.
The screws which are inserted into wood are generally made
taper, and not cylindrical, in order that they may cut their own
nut or internal thread ; some of them are pointed, so as to pene-
trate without any previous hole being made : they merely thrust
the fibres of wood on one side. Screws hold the most strongly in
wood, when inserted horizontally as compared with the position
in which the tree grew, and least strongly in the vertical position.
Fig. 635 represents the ordinary square thread screw; the
space and thread are mostly of equal width, and the depth is
either equal to the width, or a trifle more, say one sixth.
is a departure from 635, and has been made for
-scs : and 637 has obviously grown out of the last from the
obliteration of the angles; various proportions intermediate
between 637 and 630 are used for round threads.
In some cases where the screw is required to be rapid, one
single shallow groove is made of angular, square, or circular sec-
tion, leaving much of the original cylinder standing, as in fig. '
very slight purposes, a pin only is fitted to the groove, to
serve as the nut ; should the resistance be greater, many pins, or
a comb may be employed, and this was the earliest form of nut;
otherwise a screwed nut may be used with a single thread. But
when the greatest resistance is required, the surface bearing of
the nut is extended, by making the thread, double, triple, &c. by
rnttiui: one or more intermediate grooves and a counterpart nut.
The nuts or boxes of very coarse screws for presses are now
mostly cut in the lathe, although, when the screwing i
were less perfectly understood, the nuts were frequently .
Sometimes lead, or alloys of similar fusibility, were poured iu
C68 TANGENT SCREWS, PIEDMONT SCREW WHEELS.
betwixt the screw and the framework of the machinery (see
note, p. 293, also 322-3, vol. 1) ; but for nuts of brass and gun-
metal, sand moulds were formed. The screw was always
warmed, to avoid chilling the metal ; and for brass, it was some-
times heated to redness and allowed to cool, so as slightly to
oxidize the surface, and lessen the disposition to a union or
natural soldering of the screw and nut. It was commonly
necessary to stretch the brass by an external hammering, to
counteract the shrinkage of the metal in the act of cooling, and
to assist in releasing from the screw, the nut cast upon it in
this manner. The mode is by no means desirable, as the screw
is exposed to being bent from the rough treatment, and to being
ground by particles of sand adhering to the brass.
The tangent screws used for screw wheels, have mostly angular
or truncated angular threads, fig. 629, as screws absolutely square
cannot be fitted with good contact and freedom from shake
between the thread and teeth ; and probably the same rules by
which the teeth of ordinary wheels and racks are reciprocally
set out, should be also applied to the delineation of the teeth of
worm-wheels, and the threads or teeth of their appropriate screws.
Tangent screws are occasionally double, triple, or quadruple,
in order that 2, 3, or 4 teeth of the wheel may be moved during
each revolution of the screw. In the Piedmont silk-mills, this
principle is carried to the extreme, as the screw and wheel become
alike, and revolve turn for turn ; the teeth supposing them to be
20, are then identical with those of a 20 thread screw, the angular
coils of which cross the axis at the angle of 45°, that is when
the shafts lie at right angles to each other ; other proportions
and angles may be adopted. In reality they fulfil the office of
bevel wheels, or rather of skew-bevel wheels, in which latter also
the axes, from being in different planes, may cross each other •
so that the skew-bevel wheels may be in the center of long
shafts, but which cannot be the case in ordinary bevel wheels,
the teeth of which lie in the same plane as the axis of the wheel.
The Piedmont wheels act with a very reduced extent of bearing
or contact surface, and a considerable amount of the sliding
action of screws, which is disadvantageous in the teeth of wheels,
although inseparable from all those with inclined teeth, and which
are indeed more or less distant modifications of the screw.*
* Wheii the obliquity of tlio tectU of worm-wheels is small, it gives a very
IN. \-CB8 PROM THE DISSIMILARITY OP SCREWS. 669
somewhat in detail the dillVrcnt forms of
screws, and the circumstances which adapt thorn to their several
purposes, I have now to consider some of the inconveniences
which ha\e unavoidably arisen from the indefinite choice of
proportions in ordinary screws, and also some of the means that
have heen proposed for tin ir correction. The slight discussion
of the more important of these topics will permit the introduc-
tion of various additional points of information on this almost
inexhaustible subject, the screw.
No inconvenience is felt from the dissimilarities of screws, so
l<>ii£ as the same screwing tools are always employed in effecting
repairs in, or additions to, the same works. But when it is
considered, how small a difference in either of the measi
will mar the correspondence of the screw and nut ; and further
the very arbitrary and accidental manner, in which the propor-
tions of screwing apparatus have been determined by a variety
of individuals, to suit their particular wants, and without any
attempt at uniformity of practice (sometimes on the contrary,
with an express desire to be peculiar), it is perhaps some matter
of surprise when the screws made in different establishments
properly agree. Indeed their agreement can be hardly expected,
unless they are derived from the same source, and that some
considerable pains are taken not to depart from the respective
proportions first adopted.
In a few isolated cases this inconvenience has been partially
remedied by common consent and adoption, as in the so-called
(iir-pmnp thread, which is pretty generally used by the mak
of pneumatic apparatus ; and to a certain degree also in some
of the screws used in gas-fittings and in gun-work. But the
non-existence of any common standard or scale, enhances both
the delay and expense of repairs in general mechanism, and leads
to the occasional necessity for making additional sizes of tools to
match particular work>, however extensive the supply of screw
apparatus.
Tliis perplexity is felt in a degree especially severe and costly,
as regards marine and locomotive engines, which from necessity,
have to he repaired in localities far distant from those in which
they were made; and therefore require that the packet station,
smooth action, bat at the expense of friction; but in ordinary toothed wheels, the
teeth are exactly square aerow or in the plane of the axis, and the aim is to employ
rolling contact, w i th the greatest possible exclusion of sliding, from amongst the tooth.
670
TABLES WHICH HAVE BEEN SELECTED
or railway depot, should contain sets of screwing tackle, corres-
ponding with those used by every different manufacturer whose
works have to be dealt with: otherwise, both the delay and
expense are from necessity aggravated.
Mr. Whitworth has suggested that for steam machinery and
for the purposes of engineering in general, " an uniform system
of screw threads" should be adopted, and after having used
some prior scales, he has proposed the following table, which
may be justly considered as a mean between the different kinds
of threads used by the leading engineers.
Mr. Whitworth' s Table for Angular TJiread Screws.*
Diameters in inches . . .
i
ft
3
&
1
1
I
i
1"
i|
il
ii
H
i|
1:
2"
Nos. of threads to the inch
2(i
IS
1C
14
1-2
11
lo
9
S
7
7
6
0
5
5
4!-
4*
Diameters in inches . . .
2!
-'i
2|
3"
3]
31
^
4"
M
•U
4
5"
•>l
54
H
V
Nos. of threads to the inch
4
4
Si
34
N
3-1
3
3
3j
21
N
2i
As regards the smaller mechanism, made principally in brass
and steel, such as mathematical instruments and many others,
* In selecting this scale, the following judicious course was adopted : — An
extensive collection was made of screw-bolts from the principal workshops
throughout England, and the average thread was carefully observed for dif-
ferent diameters. The J inch, £ inch, 1 and 1£ inch, were particularly selected,
and taken as the fixed points of a scale by which the intermediate sizes were
regulated, avoiding small fractional parts in the number of threads to the inch.
The scale was afterwards extended to 6 inches. The pitches thus obtained for
angular threads were as above :
" Above the diameter of 1 inch the same pitch is used for two sizes, to avoid
small fractional parts. The proportion between the pitch and the diameter varies
throughout the entire scale.
" Thus the pitch of the 1 inch screw is |th of the diameter ; that of the £ inch
ith, of the 1 inch Jth, of the 4 inches ^th, and of the 6 inches ^th.
" The depth of the thread in the various specimens is then alluded to. In this
respect the variation was greater than in the pitch. The angle made by the sides
of the thread being taken as an expression for the depth, the mean of the angle in
1 inch screws was found to be about 55°, which was also nearly the mean in screws
of different diameters. Hence it was adopted throughout the scale, and a constant
proportion was thus established between the depth and the pitch of the thread. I n
calculating the former, a deduction must bo made for the quantity rounded off,
amounting to Jrd of the whole depth, t. e., Jth from the top, "and Jth from the
bottom of the thread. Making this deduction, the angle of 55° gives for the actual
depth rather more than gths, and less than |rds of the pitch." Quoted from the
Abstract of Mr. Whilworth't Paper, given in the Proceedings of the Institution of
cert, 1841, p. 157-160. The entire paper is oho printed separately.
M HI.U 1 IIKIIAI)-.
tin- screws in the above scale below half au inch diameter are
admit t < il to be too coarse; and the acute angular threads which
are not rounded, are decidedly to be preferred from their greater
ilt licacy and durability, that is when their strengths are propor-
tioned to the resistance to which they arc exposed. In these
respects the following table may be considered preferable.
Table for Small Screwt of Fine Anyular ThrtadtS
Diameters in vulgar fractions of the inch
\
H
;
:
1
11
1
1
:
•
•
Diameter* in hundths.of the inch nearly
:,»
•17
44
11
•:;:
31
•51
•
•>:,
•
•20
Number of threads to tho inch . . .
11
1."
U
m
m
•24
u
H
•
m
M
Diameters in hundredth* of the inch .
•1>
11
•14
u
Ifl
,,;,
PI
"7
u,}
«i
•04
Number of thread* to the inch . . .
:;.;
u
u
u
t--
:,.;
;,•;
H
100
* This table was arranged by Mr. Chidson, of Liverpool, who made, first, a set
of coarse angular thread tape from J to 1 inch, agreeably to the terms of Mr.
\\ hitworth's table, giving to the screw tool the angle of 55 degrees, and also a
set of square thread taps, of tho some diameters, and, as usual, of twice the pitch.
This led Mr. Chidson to set out and construct a series of finer and deeper threads,
from 4 inch to 14 hundred ths diameter, agreeably to the arrangement in the
second table, and with screw tools of the angle of 45 degrees.
I have great pleasure in stating my individual opinion of the suitability of the
table to its intended purpose, and on comparing tho screws with those of similar
diameters used by Holtzapffel and Co., I found about one third to be nearly
identical in pitch, one third to be slightly coarser, and the others slightly finer.
As regards the workmanship of these tape, made by Mr. Chidson fur his own use,
and principally with his own hands, by means of the change wheels and single
point tools, it gives me great pleasure to report most favourably.
The tables above given, and which have been teUcUd and not calculated, will
serve to explain the inapplicability of the mode of calculation proposed in various
popular works ; namely, for angular thread screws, to divide the diameter by 8
f«>r tho pitch, when, it is said, such screws will all possess the angle of 34 degree*
nearly ; and for square threads to divide by 4, thus giving an angle of 7 degree*
nearly ; therefore
Angular thread screws of 86421 4 J inches diameter.
would have pitches of 1 I 4 i i & & inches rise.
or rates of 1 1 J 2 4 8 16 32 threads per inch.
which differ greatly from 2434(8 12 20 Whitworth's observational numbers.
By the use of the constant divisor 8, the one-inch screw agrees with Whit worth's
table, the extremes are respectively too coarse and too fine ; as instead of 8 being
employed, the actual divisors vary from about 5 to 16, and therefore a theoretical
mode would probably require a logarithmic schema Bat were this followed out
with care, tho adjustment of the fractional threads so obtained, for those of whole
numbers, would completely invalidate the precision of the rule; and the result
would not bo in any respect better than when adjusted experimentally, as at present.
G72 AGREEMENT OP SCREWS WITH STANDARD MEASURES,
There is little doubt that if we could entirely recommence the
labours of the mechanist, or if we could sweep away all the screw-
ing tools now in use, and also all the existing engines, machines,
tools, instruments, and other works, which have been in part made
through their agency, these proposed scales, or others not greatly
differing from them (as the choice is in great measure arbitrary),
would be found of great general advantage ; the former for the
larger, the latter for the smaller works. But until all these myriads
of objects are laid on one side, or that repairs are no longer wanted
in them, the old tools must from absolute necessity be retained,
in addition to those proposed in these or any other schemes. It
would be of course highly judicious in new manufacturing esta-
blishments to adopt such conventional scales, as they would, to
that extent, promote this desirable but almost impracticable end,
namely, that of unity of system ; but which, although highly
fascinating and apparently tenable, is surrounded by so many
interferences, that it may perhaps be considered both as needless
and hopeless to attempt to carry it out to the full, or to make
the system absolutely universal : and some of the circumstances
which affect the proposition will be now briefly given.
First, agreement with STANDARD MEASURE, although convenient,
is not indispensable. It may be truly observed, that as regards
the general usefulness of a screw such as 615, which was sup-
posed to measure f inch diameter, and to have 10 threads per
inch, it is nearly immaterial whether the diameter be three or
four hundredths of an inch larger or smaller than f of an inch ;
or whether it have 9, 9TV, 9|, 10£, or 11, threads per inch, or
any fractional number between these; or whether the thread
be a trifle more or less acute, or that it be slightly truncated or
rounded ; so long as the threads in the screw and nut are but
truly helical and alike, in order that the threads mutually bear
upon each other at every part ; that is, as regards the simple
purpose of the binding screw or bolt, namely, the holding of
separate parts in firm contact. And as the same may be said
of every screw, namely, that a small variation in diameter or
pitch is commonly immaterial, it follows, that the good office of
a screw docs not depend on its having any assigned relation to
the standard measure of this or any other country.
Secondly, The change of system would cause an inconvenient
SURROUNDED BY VARIOUS DIFFICULTIES. • T.i
increase in the number of icrewing tool* wed. — Great numbers
of« :md useful screws, of accidental measures, have 1-
made by various mechanieians; and the author hopes to be
excused for citing the example with which he is most familiar.
Between the years 1791—1800, the author's father m.\
few \arii ties of taps, dies, hobs, and screw tools, after the modes
explained at pages 635 and G36 ; these varieties of pitch were
ultimately extended to t\u l\e kinds, of each of which was for i
a deep and shallow hob, or screw tool-cutter. These, when
measured many years afterwards, were found nearly to possess
in each inch of their length, the threads and decimal parts that
are expressed in the following table.
Approximate Valuti of I. I. IldtzapfftPi Original Screw Thrtndt.
Number . . .
Threads in 1 inch
1
6-58
2
3
4
13-00
6
6
19-89
7
22-12
8
2571
9 1 10
23-88 36-10
11
39-83
12
Tkt aitffU <(f On d«tp thrtatU u about 50 dtgrttt ; o/UttihaUoif 00 dtgrta.
This irregularity of pitch would not have occurred had the
screw-lathe with change-wheels been then in use ; but such was
not the case. For a long series of years I. I. Iloltzapftel, (in
conjunction with his partner, I. G. Deycrlein, from 1804 to
1827,) made, as occasion required, a large or a small screw, a
coarse or fine, a shallow or deep thread, and so forth. By
which accumulative mode, their series of working taps ami die*,
together with screw tools, gages, chucks, carriers, and a variety
of subordinate apparatus, became extended to not less than one
hundred varieties of all kinds.
About one-third of these sizes have been constantly used, up
to the present time, both by II. & Co., and by other persons to
whom copies of these screw tackles have been supplied, and
consequently many thousands of screws of these kinds have
ii made : this implies the continual necessity for repairs and
alterations in old works, which can only be accomplished by
;nir the original sizes.
Since the period at which II. & Co. made their screw lathe,
they have employed the aliquot threads for all screws above half
an inch; indeed, most of the^c have also been cut in the st •:
lathe. To have introduced the same method in the small bind-
ing screws which are not made in the screw lathe, but with the
-locks and chasing tools, would have doubled the number of
x x
G7i AGREEMENT OF SCREWS WITH STANDARD MEASURES,
their working-screw tackle, and the attendant apparatus ; with
the risk of confusion from the increased number, but without
commensurate advantage as regards the purposes to which they
are applied.
Doubtless the same reasons have operated in numerous other
factories, as the long existence of good useful tools has often
lessened, if not annulled, the advantage to be derived from a
change which refers more immediately to engineering works ;
and in which a partial remedy is supplied, as steam-engines, &c.
are frequently accompanied with spare bolts and nuts, and also
with corresponding screw apparatus, to be employed in repairs ;
the additional cost of such parts being insignificant, compared
with the value of the machinery itself.
Thirdly : Unless the standard sizes of screws become inconve-
niently numerous, many useful kinds must be omitted, or treated
as exceptions. For instance, in ordinary binding screws, more
particularly in the smaller sizes, two if not three degrees of
coarseness should exist for every diameter, and which might be
denominated the coarse, medium, and fine series; and again,
particular circumstances require that threads should be of
shallow or of deep angular sections, or that the threads should
be rounded, square, or of some other kinds ; in this way alone,
a fitness for all conditions would inconveniently augment the
number of the standards.
In many cases besides, screws of several diameters are made
of the one pitch. In order, for example, that the hole when
worn may be tapped afresh, and fitted with screws of the same
pitch or thread, but a trifle larger ; * or that a partially worn
screw may be corrected with the dies or in the lathe, and fitted
with a smaller nut of the same pitch. A succession of taps of
the same pitch also readily permits a larger screw to be employed,
when that of smaller diameter has been found to break, either
from an error of judgment in the first construction of the
machine, or from its being accidentally submitted to a strain
greater than it was intended ever to bear.f
* This is dono in some of the patent screws for joinery work, so that when
the thread in the wood is deteriorated from the frequent removal of the screw,
another of the same pitch, but larger diameter, may be substituted.
t Mr. Clement has screw taps of }, J, 1, 1J, 1J, If, 1J, &c., inch diameter, and
all of seven threads per inch. Holtzapfiel and Co. have taps, &c., for screws of ten
threads per inch of fifteen different kinds, which are used for slides and adjust-
mente, besides less extensive repetitions of other threads.
SURROUNDED BY VARIOUS DIFFICULTIES. < '•'< "»
It is also in some cases requisite to li:i. and left hand
screws of the same pitch, that, amongst other purposes, they
may effect simultaneous yet opposite adjustments in machin
as in some universal chucks: and also some few screws, the
threads of which are double, triple, quadruple, and so forth, for
ng to screws of small diameters considerable rapidity of pitch
or traverse, or a fixed ratio to other screws associated with them,
in the same piece of mechanism.
I'oiirthly : Friction prevents the strict maintenance of standard
gaffes for screws. The universality of system, to be perfect, should
admit that a bolt made tl. in London, should agree with
a nut made ten or fifty years hence in Manchester, which is not
called for, nor perhaps possible, if an absolute fit be required :
in reference to this we must commence by a small digression.
In comparing the Exchequer Standard Yard Measure \\ith
the copies made from it, friction in no way interferes, as the two
measures are successively observed through two fixed micro-
scopes, as before adverted to. But we cannot thus measure a
cylinder, as either callipers, or a counterpart cylinder placed in
contact, must be employed as the test; aud each time of trial
the cylinder is absolutely, although very slightly worn, by the
traverse of the surfaces against each other; the form of the
cylindrical gage being simple, to increase its durability, it is
worked to the figure after having been hardened.
In nicaMiring a screw, the callipers are insufficient, and the
one screw must be screwed into the other: from this trial much
more motion, friction, aud abrasion arise. Further, the se.
gage cannot, from its complex form, be readily figured after
material has been hardened; and if hardened subsequently to
the helical form having been given, the measure become, m
some degree, altered, from the action of the fire and water,
ii is a fatal objection.
I'mlcr ordinary and proper management, the production of a
number of similar pieces may be obtained with sufficient exacti-
tiu! ng to the tool some constant condition. For example,
a hundred nuts tapped with the same tap, will be very nearly
alike in their thread ; and a hundred screws passed through tin-
hole of a screw-plate, \\ ill similarly agree in size, because of the
ant dimensions of the tools, for a moderate period.
In practice, the same relative constancy is given to the dies
x x 2
G7G AGREEMENT OF SCREWS WITH STANDARD MEASURES,
of die-stocks and bolt-screwing engines, and partly so to the
tools of the screw-cutting lathe. Sometimes the pressure or
adjusting screw has graduations or a micrometer ; and numerous
contrivances of eccentrics, cams, and stops, are employed to
effect the purpose of bringing the die or turning-tool to one
constant position, for each succeeding screw ; these matters are
too varied and general to require more minute notice. Part of
such modes may serve sufficiently well for ten, or a hundred
screws, provided that no accident occur to the tool ; but if it
were attempted to extend this mode to a thousand, or a hundred
thousand pieces, the same tool could not, even without accident,
endure the trial: it would have become not only unfit for
cutting, but also so far worn away as to leave the last of the
works materially larger than the first.
In respect to screws, the instrument, the size of which claims
the most importance, is perhaps the plug-tap, or that which
removes the last portion of the material, and therefore deter-
mines the diameter of the internal thread ; but as the tap is
continually, although slowly, wearing smaller, the first and last
nut made with it unavoidably differ a little in size. It is on
account of the wearing of the tap, amongst other circumstances,
that when screws and nuts are made in large numbers, and are
required to be capable of being interchanged, it becomes needful
to make a small allowance for error, or to make the screws a
trifle smaller than the nuts.
In order to retain the sizes of the taps used by Holtzapffel&Co.
Fig. 639. they some years ago made a set of original taps
exactly of the size of the proposed screws, and to
be called A ; these, when two or three times
used, to rub off the burrs, were employed for
cutting regulating dies B, of the form of fig. G39,
with two shoulders, so that the dies could be
absolutely closed, and yet leave a space for the
shavings or cuttings. In making all their plug-
taps, they are first prepared with the ordinanr
shop tools, until the taps are so nearly com-
pleted, that, grasped between the regulating dies B, the latter
close within the fortieth or fiftieth of an inch, therefore leaving
the dies B next to nothing to perform in the way of cutting,
but only the office of regulating the diameter of the working
SURROUNDED in \ VICIOUS DIFFICULTIES.
.--taps. Should the dies H moot with any accident, tlio taps
A, which have to this stage been only used for one pair of
regulating dies, exist for making repetitions of B. This method
has been loimd to fulfil its intruded purpose very ellVetually for
several years, but at the same time it is not proposed to apply
this or any other system universally.
In conclusion, it may be said that by far the most important
argument in favour of the adoption of screws of aliquot pitches
applies to steam machinery and similar large works, and that,
principally, because it brings all such screws within the province
of the screw-lathe with change-wheels, which has become, in
ueerin^' establishments and some others, a very general tool.
This valuable tool alone, renders each engineer in a great measure
independent of his neighbour, as screws of 2, 2J, 2$, 3, 10, or
20 threads in the inch, are readily measured with the common
rule, and copied with the screw-wheels, and a single- pointed tool,
or an ordinary comb or chasing tool with many points.
And therefore, with the modern facility of work, were engineers
severally to make their screw tackle from only the written mea-
sures of any conventional table, they would be at once abundantly
within reach of the adjustment of the tools, and that without any
standard gages; the strict introduction of which would almost
demand that all the tools made in uniformity with them should
emanate from one center, or be submitted to some office for
inspection and sanction, — and this would be indeed to buy the
occasiunul advantage at too dear a rate.
It must, however, be unhesitatingly granted, that the argu-
ment applies but little, if at all, to a variety of screws which from
their smaller size are not made in the screw-lathe, but with die-
stocks and the hand-chasing tools only ; and which arc employ »d
in branches of art that may be considered as almost isolated
i one another, and therefore not to require uniformity.
For instance, the makers of astronomical, mathematical, and
philosophical instruments, of clocks and watches, of guns, of locks
and ironmongery, of lamps, and gas apparatus, and a multitude
of other work*, possess, in each case an amount of skill which
appl; tically to these several occupations; so that iinle^
the works made by each are returned to the absolute makers for
repaiaiion. tiny an- at any rate.M nt to an indiv idual engaged in
the same line of business.
678 PECULIAR MODES OF MAKING SCREWS.
Under these circumstances, it is obvious that the gunmakers,
watchmakers, and others would derive little or no advantage from
one system of threads prevailing throughout all their trades ;
in many of which, as before noticed, partial systems respec-
tively adapted to them already exist. The means employed
by the generality of artizans^in matching strange threads, are, in
addition, entirely independent of the screw lathe, and apply
equally well to all threads, whether of aliquot measures or not ;
as it is usual to convert one of the given screws, if it be of steel,
into a tap, or otherwise to file a screw tool to the same pitch by
hand, wherewith to strike the thread of the screw or tap ; and
when several screws are wanted, a pair of dies is expressly made.
But at the same time that, from these manifold considerations,
it appears to be quite unnecessary to interfere with so many
existing arrangements and interests, it must be freely admitted
that advantage would ultimately accrue from making all new
screws of aliquot measures ; and which, by gradually superseding
the old irregular threads, would tend eventually, although slowly,
to introduce a more defined and systematic arrangement in
screw tackle, and also to improve their general character.
The author has now concluded the various remarks he pro-
poses to offer on the formation of the screw for the general
purposes of mechanism; on the modes pursued by various
celebrated mechanicians for its improvement ; and on various
practical considerations which influence the choice of screws :
but he is desirous briefly to advert to some few peculiar, inter-
esting and practical methods of producing this important
element of construction.
The threads of wrought-iron screws have been forged whilst
red hot, between top and bottom swage tools, having helical
surfaces like those of screw dies ; screws have been twisted
whilst red hot, out of rectangular bars, by means of the tail vice
and hook wrench; as in making screw augers. Screws intended
for ordinary vices, have been compressed whilst cold, somewhat
as with die-stocks ; the lever is in this case very long, and the die
is a square block of hardened steel, with an internal square
thread screw, left smooth or without notches. The thread is
partly indented and partly squeezed up, the diameter of the
AND WARREN'S CAST-IRON SCREWS. ••;•.'
iron cylinder being less than that of the finished screw: this
action severely teats the iron.*
A patent was taken out in 1S30 by Mr. Wilks, for making
both the boxes and screws of tail vices and presses in malleable
cast-iron. The peculiarities in the moulding processes are that
tin- core for the hollow worm, or box, is made in a brass core box,
divided longitudinally into three parts, which arc filled separately,
and closed together with a stick of wood in the center, to stiffen
the core and serve for the core print. The core box is then con-
nected by rings, like the hoops of a cask : this completes the core,
which is removed, dried, and inserted in a mould made from a
model of the exterior of the box, constructed as usual.
In moulding the solid screw, the moulding-flask is a tube with
a cap having an internal thread, exactly like that of the screw ;
the tube is filled with sand, and a plain wooden rod, nearly equal
in diameter to the axis of the screw, is thrust in the sand, to
form a cavity. The screwed tap is then attached to the flask,
and a brass screw, exactly like that to be cast, is guided into the
sand by means of the screw-cap, and taps a thread in the sand
mould very accurately. The screw-cap is then removed, and the
second part of the flask, in which the head of the vice-screw has
been moulded, is fitted on, and the screw is poured.
After having been cast, the screws and boxes arc rendered
malleable in the usual way, except that they are placed vertically ;
in general the box is slightly corrected with a screw-tap.
Large quantities of screws have been produced by .M r. Warren's
pat (lit process for manufacturing screws of malleable cast-iron
for joinery work : a most ingenious plan is employed therein for
\\ hiding the models into and out of the solid sand-mould, which
is thereby made beautifully smooth and accurate. After the last
description the general method will be readily understood, it' it
he considered that the first side of an ordinary flask is rammed
full of sand on an iron plate having conical projections like the
Is of screws, in regular lines half an inch asunder, and ribs to
form the channels by \\hich the metal is to be admitted. The
when tilled is placed in a machine, beneath a plate of metal
• Applied by the Wright*' Vice makers of Birmingham. 8e« Technological
itory, vol. vi., p. 289. For the mode of soldering the thread in the box or the
hollow screw of the rioe, M* the MUM paper, and also ToL I, p. 443, of this work.
680 PERKINS'S AND SCOTT'S SCREWS FOR CAST-IRON PIPES.
with screwed holes, also half an inch asunder, and each fitted
with a pattern screw, terminating above in a crank like a winch
handle, say of £ inch radius.
Any of these screws on being turned by its crank with the
fingers, would pierce the sand as in Wilks's process ; but by em-
ploying a crank-plate pierced with a like number of holes, to
receive the pins of all the cranks, the whole of the screw models
are twisted in at once, and removed with the same facility.
The notches of the screws are cut by a circular saw ; if large
they may be moulded. The cast-iron screws are subsequently
rendered malleable, by the decarbonizing process described in
the former volume, pages 259-260.*
Mr. Perkins's patent cast-iron water-pipes, with screw joints,
may be considered as another example. The patent pipes are
connected with right and left hand screws and loose sockets,
which draw the ends of the pipes into contact, or rather against
a thick greased pasteboard washer interposed between them.
The pipes are made entirely by foundry- work, and from patterns
and : core-boxes divided in halves, in the ordinary manner.
Mr. Perkins says that although the patent pipes possess several
advantages over ordinary cast-iron pipes with the spigot and
faucet joint, they are produced at the same price, and save much
ultimate expense in fixing.f
In Mr. Scott's subsequent patent for joining cast-iron and
other pipes for various fluids, the method commonly known as
the "union-joint" is employed, and which offers additional
facility in the removal of one pipe from the midst of a series.
Each pipe has at one end a projecting external screw, and at
the other a projecting fillet or flange ; the socket is cast loosely
around the pipe, but is prevented from being removed or lost by
the projections at each end of the same. The inside screw of the
socket cast upon the first pipe «, screws upon the external screw
of the next pipe b, until the socket comes in contact with the fillet
on a, and thus draws a and b into close contact with the washer
that is placed between them. One cast-iron pipe and its appro-
* Date of Mr. Warren's patent for an improved machine for making screws, 4th
August, 1841 ; described in Rep. of Patent Inv. for March 1843, also in the Glasgow
Mechanics' and Engineers' Mag., same date. The machine was constructed by
Mr. Ingram of Birmingham, and is successfully worked by him.
t Date of patent, 21st Sept. 1841, described in Rep. of Patent Inv. Oct. 1841.
Il\\l)'- (nMt'RESSED SCREWS, ETC.
print i« socket a iv moulded at one operation, which is curiously
accomplished by the use of two sand cores, the inner of which
is of the length of the pipe, and solid as usual; the outer core
uide aa a loose ring around th.- mm T. The union-joint is
differently produced by Mr. Scott in wrought-iron and soft
metal pipes.*
A peculiar method of making screw joints is employed in
Mr. Hand's patent collapsible tubes for preserving paints, |>n, vi-
sions, &c. The tin, whilst at the ordinary atmospheric tempe-
rature, is forced, almost as a cement, into the screwed recesses of
brass or iron moulds; and the threads arc thus made to assume
the helical form, with great rapidity, uniformity, and perfection. f
Indeed it is diflicult, nay impossible, to find the limit of the
methods employed in producing, or those of subsequently em-
ploying this interesting object, the screw; which not only enters
in endless variety into appliances and structures in metal, wood,
and other materials, but is likewise rendered available in most
different yet important modes, as in the screw-piles for sandy
foundations, screws for raising water, for blowing furnaces,
ventilating apartments, and propelling ships.
Should it appear that the formation of the screw has been
treated in greater detail than the other subjects with which
it is associated, either as regards the modes of proceeding or
the mechanism employed; the author would observe that it
appeared to him that by this mode alone he could introduce, in
something like order, a variety of interesting particulars, which
although they have occupied very many pages, are but as a
fragment of what might be said on a subject which has engrossed
so much attention.
• Date of patent, 6th July, 1842. See Mechanics' Magazine, 1843, page 104.
t Rand's second patent for making collapsible vessels, 29th Sept 1842. U in lor
the first patent the tin was drawn into tube, (sec vol. L, p. 431,) and the convex and
screwed ends were cast and soldered in ; by the improved method the entire vessel
is made from a small thick perforated disk of tin by one blow of a fly-press. The
lower part of the mould has a shallow cylindrical cup, concave and tapped at the
bane ; the upper part of the mould is a cylinder as much smaller than the cup as
the intended thickness of the metal, which, on the blow being given is compressed
into the screw, and ascends four or five inches up the cylinder or ruin. For large
•IMS a hydrostatic press is employed.
682
CHAPTER XXVII.
SAWS.
SECTION I. DIVISION OF THE SUBJECT FORMS OF SAW TEETH.
THE saw is the instrument which is almost exclusively em-
ployed for converting wood, ivory, and various other substances,
from their original forms to those shapes required in the arts ;
and in general, the thin serrated blade proceeds along the super-
ficies of the required object, whether they be plane, circular,
or irregular, and effects its office with considerable speed and
accuracy, and comparatively insignificant waste. Unless a tree
is felled with the axe, the saw is employed, first, in the forest in
separating the tree from its roots, and cutting it into lengths
convenient for transport ; the saw is next used at the saw -pit in
converting the timber into plank and scantling of various dimen-
sions ; and the saw is subsequently employed in the workshop,
by the joiner, cabinet-maker, and numerous other artisans, in
reducing the plank or board into smaller pieces, ready for the
application of the plane, the file, and other finishing tools. In
some elaborate and highly ornamental arts, the saw as will be
shown is nearly the only instrument used.
Many of the machines now employed in sawing are, as it will
be seen, derived from similar processes before executed, and in
many cases less perfectly so, by hand labour. The saw is but
little used for similar preparatory works in metal, the figuration
of which is for the most part, accomplished by the furnace,
the hammer, or rollers; matters that have been described in
the first volume.
It is proposed to consider saws in two groups, namely, recti-
linear saws, and circular saws : the precedence will be given to
the more simple kinds, or those rectilinear saws used by hand,
and generally without additional mechanism; conditions which
do not apply to the circular saw, which is always combined vitli
some portion of machinery. And for the perspicuity of the whole
subject, it has been thought best to place the general remarks
on the forms of teeth of saws, at the beginning of the chapter;
GENERAL REMARKS ON SAW!. '•-•">
from which arrangement many advantages appear to arise,
notwithstanding that it implies the necessity for adverting to
various saws, before their specific or particular descriptions have
:> given, and which objection will be in part removed by the
pivxious inspcetion of the table on page G99.
The blade of the rectilinear saw is usually a thin plnte of
sheet steel, whieh in the first instance is rolled of equal thick-
ness throughout : the teeth arc then punched along its edge,
previously to the blade being hardened and tempered, after
which it is smithed or hammered, so as to make the saw quite
flat. The blade is then ground upon a grindstone of consider-
able diameter, and principally crossways, so as to reduce the
thickness of the metal from the teeth towards the back. When,
by means of the hammer, the blade has been rendered of
uniform tension or elasticity, the teeth are sharpened with a
file, and slightly bent, to the right and left alternately, in order
that they may cut a groove so much wider than the general
thickness, as to allow the blade to pass freely through the
groove made by itself. The bending, or lateral dispersion of
the teeth, is called the set of the saw.*
The circular saw follows the same conditions as the recti-
linear saw, if we conceive the right line to be exchanged for the
circle ; with the exception that the blade is, for the most part,
of uniform thickness throughout, unless, as in the circular veneer
saws, it is thinned away on the edge, as will be explained.
It is to be observed that the word pitch, when employed by
the saw-maker, almost always designates the inclination of the
face of the tooth, up which the shaving ascends ; and not the
intrnal from tooth to tooth, as in wheels and screws.
In the following diagrams of teeth, which, for comparison, are
drawn of equal coarseness or size, some kinds are usually small,
and seldom so distant as $ an inch asunder: these are described
as having 2, 3, 4, 5, to 20 points to the inch,- and such of the
other teeth represented as are used by hand, are commonly
from about ^ to 1J inch asunder, and arc said to be of £ or 1^
inch space, although some of the circular saws are as coarse as
2 to 3 inches and upwards from tooth to tooth.
• For the mode of hardening and tempering saw*, the reader ia referred to vol. i.,
pp. 249—250, of this work : and for the principled upon which they are flattened
and rendered of uniform elasticity, to the Mine Tolume, pp. 414 — 422.
684
FORMS OF SAW TEETH.
The usual range of size or space for each kind of tooth, is
accordingly expressed beside the diagrams; as are also the angles
of the faces, and of the tops of the teeth, measured from the line
running through the point of the teeth, or the edge of the saw.
Figs.
640
644
653
ANGLES. ORDINARY
Face & Back. SPACE.
deg. deg.
110 & 70 — 1 to H
641 4JVLJVUVLMJVl_M 90 & 60
643 A/vWW 12° & 60
— 1 to
105 & 45
90 & 30
75 & 15
1 to 1J
I to 1J
— | to 1
— I to 1
— MO 24
Also from 3
to 60 points
iu each inch.
90 &
60 &
50 —
15 —
1 to 4
1 to 2
90 &
30 —
§ to 34
Sometimes
each alter-
nate tooth is
cut out, and
75 &
20 —
| to 34
then called
ski/i-tooth.
60 &
10 —
g to 34
45 &
5 —
I to 34
The angle of the point itself will be found by subtracting the
angle of the back from that of the face of the tooth, or the less
from the greater of the first two numbers.
FORMS OF SAW TEETH.
The four varieties of teeth at the commencement of the an-
nexed group, from presenting the same angK -s in cither direction
also cut in both din •» -ti.»ns; in fact, the face and back may !>••
considered to change places in each alu -nuite cut. These tenth
are u>cd t'»r such cross-cutting saws as have a handle at each
end, and are worked by two or more men; aa in cutting down
S and dividing them win -n they have been felled; and similar
saws are used for the soft building stones when they arc first
raised from the quarry. Fig. 640 is called the peg-tooth, or
Jlmm-tooth, and is much used in North America and elsewhere ;
ti.ur. 'ill, the M-tooth, which is so named from its resemblance to
the letter, is now but very rarely employed; fig. 61:2, the half-
moon-tooth, is used in South America for cross-cutting; and
fig. 043 is that commonly described as the cross-cutting-tooth,
although in England the peg-tooth or 040, the hand-saw-tooth
or 645, and the gullet-tooth 050, are also used for cross-cutting
timber, more especially the last form when sharpened more
acutely than usual, and used to cut in one direction only.
Referring to the preliminary remarks on cutting tools, pages
457 to 468 of the present volume, it will be seen that saws were
considered to belong to the group of scraping tools, and that <•
and/, fig. 816, were viewed as the generic forms of the teeth, the
le of which is commonly 60 degrees, from the circumstance
of the simple angular teeth being mostly produced by angular
notches, filed with two of the sides of an equilateral triangular
file; and therefore the points assume the same angle as the
spaces, or 60 degrees.
But the angle of 60 degrees is variously placed; for instance,
the teeth in fig. 043 are said to be upright, or to have no pitch ;
and the teeth in fig. 646 to be flat, or to have considerable
pitch : these may be considered as the extremes of this kind of
tooth, between which every inclination or pitch is more or less
used ; but, for the sake of definition, four varieties have been
assumed, the- straight lines of which are 15 degrees asunder.
Fig. 643, as already explained, is the ordinary tooth for cross-
cutting, and which, from presenting equal angles on each side,
is said to be of upright pitch. The tooth that is, however, more
t-rally used for small cross-cutting saws is fig. 644, which
i> im-limd ah. nit 15 degrees from the last. This form of
tooth, called slight pitch, is used for the cross-cutting saws for
686 FORMS OF SAW TEETH.
firewood ; those for joiners' use ; and also for those employed
in cutting up ivory ; in which latter case the blade is stretched
in an iron frame.
Fig. 645 is the tooth in most general use : it is known as
ordinary pitch or the hand-saw-tooth. The face is perpendicular,
and the back inclines at an angle of 30° from the edge of the
saw, or the line of work. Most of the saws used by cabinet-
makers and joiners are thus toothed, or rather at an inclination
intermediate between figs. 644 and 645.
The tooth, fig. 645, is likewise generally employed for saws
used for metal; for circular saws used for fine work, including
veneer-saws, and for many of the circular saws for cross-cutting.
In fig. 646 the face of the tooth is " set forward" or stretches
beyond the perpendicular, at an inclination of 15 degrees : this
kind is employed in mill-saws used abroad for soft woods, and
they are the most inclined of those teeth formed by the two
faces of the triangular file at the one process.
Nearly the same tooth as fig. 646 is also used for circular saws
and cutters for metal. The object is then to assimilate the points
to those suitable to tools for turning the metals ; therefore, the
angle of separation betwixt the end of the tooth and the plane
to be wrought, is made small. The hook form of the point is
incidental to the employment of the triangular file, and is also
proper for the material to be cut.
Fig. 647 is a form of tooth that is set forward like 646, but
the point is more acute than the last five, or it is about 45
degrees instead of 60. It is used for some circular saws,
and occasionally also for pit saws and cross-cut saws; and is
frequently employed for cutting soft Bath stone.
Sometimes the acute angular notch is not continued to an
internal angle ; a method adopted in some mill saws, both those
of ordinary or perpendicular pitch, fig. 648, and those of greater
pitch or inclination, fig. 649 ; the former being more common
for rectilinear, the latter for circular saws. Various intermediate
forms are met with.
The three kinds of teeth, figs. 647, 648, and 649, from being
more acute than 60 degrees, cannot be sharpened with the
ordinary three-square or equilateral file, as it will not reach to
the bottoms of the teeth. The mill-saw file is then used, namely,
a thin flat file with square or round edges, as the definition
FORMS OP SAW TEETH.
of the internal an^le is not needful; althougb given by the punch
in the forma1 !ic tooth. The angular mill-saw teeth arc
employed, partly because tbcy are more easily sharpened than
the gullet teeth, which conclude the series of diagrams.
The teeth, figs. 650 to fig. 653, are called yullt-t teeth, on
account of the large hollow or gullet that is cut away in front of
each tooth, in continuation of the face; and they are also known
as briar teeth. The tooth is in general cut by one punch filling
the entire space ; but two punches, an angular and a gullet
punch have been occasionally used.
The gullet is adopted to allow the tooth to be sharpened with
a round or half-round tile, by which the face of the tooth becomes
concave when viewed edgeways, and acquires a thin and nearly
knife-like edge, as will be explained. The increased curvilinear
space allows more room for the sawdust, and is less disposed to
retain it than the angular notch.
For the facility of explanation, the faces of the teeth differ
fifteen degrees in pitch, and the tops of the tooth are variously
inclined to the edge of the saw, as tabulated. The medium
kinds, figs. 651 and 652, are perhaps more common, although the
saw-maker forms the teeth originally more acute, for the facility
of first sharpening; and the sawyer sometimes neglects to
file the gullets in the same proportion as the tops, by which the
advantage attending the gullets is in a measure lost. Each
alternate tooth appears to be deeper than the others ; but this
only arises from the peculiar mode of sharpening the gullet with
a round or half-round file, which makes a broad chamfer, the
of which is elliptical.
For the general purposes of pit saws, and also for straight and
circular mill-saws, the medium teeth, 651 and 652, are suitable;
hut for hard woods, as mahogany, rosewood, and others, and also
for cross-cutting, the form should lean towards fig. 650; and
for soft woods and ripping with the grain, towards the more
inclined tooth, iig. 653. The whole of the forms of teeth may
materially diverted from those originally given by the saw-
make r, in the important process of sharpening, and which will
In- now described, as the most proper way of concluding the
remarks respecting the angles or bevils given to the edges of the
teeth, independently of their simple profiles.
CSS SHARPENING AND SETTING SAWS.
SECT. II. — SHARPENING AND SETTING SAWS.
The processes denominated sharpening and setting a saw, con-
sist, as the names imply, of two distinct operations : the first
being that of filing the teeth until their extremities are sharp ;
the second, that of bending the teeth in an equal manner, and
alternately to the right and left, so that Avhen the eye is directed
along the edge, the teeth of rectilinear saws may appear exactly
in two lines, forming collectively an edge somewhat exceeding
the thickness of the blade itself.
Circular saws require exactly similar treatment, if we con-
sider the tangent of the circle to be substituted for the right
line ; and therefore the sharpening of straight saws will be first
described, and those peculiarities alone which attach to the
sharpening of circular saws will be then separately noticed.
Setting the teeth, which in practice is always subsequent to
the sharpening, will also be placed subsequently in the section ;
the commencement of which will be devoted to the modes of
holding the saw in the operation of sharpening, and the descrip-
tion of the files used.
In sharpening the saw it is mostly fixed perpendicularly, and
with its teeth upwards, various modes being adopted according
to circumstances. The tail-vice used by the saw-maker in
sharpening the saw, measures from nine to twelve inches wide
in the chops, and also nine to twelve inches high, or above the
screw ; proportions exceeding those of tail-vices used by mecha-
nicians generally. Slips of wood, or clamps of sheet lead bent
to the figure of the jaws of the vice, are interposed between the
saw and the vice, so that the elasticity of the wood, or the
inelasticity of the lead may give a firm hold, and prevent the
disagreeable screeching noise that accompanies the action of
the file when the saw is insecurely held ; and the greater the
noise the less the amount of work that is done.
The joiner employs a wooden vice resembling that of the saw-
maker as to proportions, but it is fixed in the screw-chops of his
work-bench.
In sharpening pit-saws, the sawyer seldom finds it necessary
to remove the handles or frames. The long or whip-saw, and
others not having frames, are supported in the sawing-horse, a
trestle about five feet long and two feet high, with four or five
II \M> FILES USED IN MIMUT.MVO SAWS.
uprights or wooden pegs, sawn half-way through to receive tin:
X edge of the blade; tin- horse HUM -> the edge of the saw
about three feet from the ground.
A more convenient mode is to have ;\juin(i'ii-/ior»et fig. 654, the.
two halves of which open somewhat like the jaws of a pair of
pliers ; \vhen the saw has been inserted, the legs of the horse are
ided by the stretchers at the ends, and fix the blade.
The tiles used in sharpening saws are triangular, round, hnlf-
round, and mill saw-files. The equilateral triangular files, com-
monly designated as three-square files, vary from about three to
nine inches long; for small saws they are generally taper; for
large, sometimes nearly parallel, when they arc called blunts, a
term applied to other nearly parallel files. The triangular file
i> lAclusively used for the teeth of fiir*. t! [:'> to «'. (•'>, and more or
less for all the rectilinear teeth. For small teeth, the double-
cut Lancashire files are the most used, on account of the kcen-
of their edtres and the common size is 4$ inches long. The
generality of other saw-files are single or float-cut, that kind of
file tooth being considered to 'cut sweeter,' and do more work.
Konnd files from 5 to 8 inches long, arc used in saw-mills for
the ;;nllets of the teeth, figs. 650 to <>.">:*, and flat files for the
tops; but the pit-sawyer and some others always employ half-
round files, as the one instrument may be then applied to
both pur hesc files arc always blunt or parallel.
Mill saw- tiles are in general thin, flat and parallel, from 6 to
1 1 inches long, float-cut on the sides, and with smooth, square
\ ^
690 GENERAL REMARKS ON SHARPENING SAWS.
edges. Sometimes, however, they have round and cutting edges,
and are of taper figure.
The five ordinary modes of sharpening saws will be explained
and illustrated by enlarged diagrams in three views, which denote
the ways in which the teeth are bevelled and set ; but a few
general observations that apply to each mode will be first given.
In general, the angles of the points of the saw-teeth are more
acute, the softer the material to be sawn, agreeably to common
usage in cutting tools ; and the angles of the points, and those
at which the files are applied, are necessarily the same. Thus
in sharpening saws for metal, the file is generally held at 90
degrees, both in the horizontal and vertical angle, as will be
shown ; for very hard woods at from 90 to 80 degrees, and for
very soft woods at from 70 to 60 degrees, or even more acutely.
The vertical angle is about half the horizontal.
In general the horizontal angle of the file is alone important,
(that is, considering the saw-blade vertical and with the teeth
upward,) although to assist the action of the file it is customary
to depress the handle a little below the point of the file, and
only to file on those teeth which are bent from the operator.
When the tooth that is bent towards the individual is filed, it
vibrates with much noise, and is disposed to strip off the teeth
from the file, instead of being itself reduced.
To insure the action of each tooth, the edge of the saw should
he quite straight ; it is therefore occasionally topped, by laying
the file divested of its handle, lengthways upon the teeth,
and passing it along once or twice, to reduce these few points
which may be above the general level. The file is pressed hard
at the two ends of the saw, where the blade is less worn, and is
applied lightly in passing the middle ; the file should be held
perfectly square, to reduce the edges alike. The new point of
each tooth is then made to fall as nearly as possible upon the
center of the little facet, thus exposed by the process of topping
or ranging the teeth ; and the faces or fronts of the teeth are
always filed before the tops of the same.
When the file is perfectly square to the saw-plate, every tooth
is sharpened exactly alike, and in direct succession, that is, in the
order 1, 2, 3, 4. Whenever the file is inclined, the teeth 1, 3
UPRNINO SMITIl's-SAW Mini.
7. 9, are to tin- ri;,'ht, and the teeth :', I,
6,8, t > the lilt, after \\liich they are set in the same order;
80 as collectively to form a double line of points, somcuhat
mbling the tail of a bird, when the section is coarsely mag-
nified and exaggerated as in the several diagrams to be given.
The teeth are the more set, the softer or the uettcr the w
first (/idt/ruiti on sharpening saws, fig. i'>.~>.~>, represents in
plan and two elevations the saw-teeth that are the most easily
shai -pencil, namely. tlu»e of the frame-saw for metal, commonly
: by the smith ; the teeth of this saw are not set or bent
in the ordinary manner, owing to the thickness and hardness of
the blade, and the small size of the teeth.
Fig. 655.
The smith's >aw blade, when dull, is placed edgeways upon the
jaws of the vice, and the teeth, which are placed upwards, are
slightly hammered ; this upsets or thickens them in a minute
degree, and the hammer face reduces to a general level those
teeth which stand highest. They are then filed with a triangular
file laid perfectly square, or at ninety degrees to the blade, both
in the hori/.ontal direction h, and the vertical v, until each little
facet just disappears so as to leave the teeth as nearly as possible
in a line, that each may fulfil its share of the work.
The most minute kind of saws, those which are made of broken
watch-springs, have teeth that are also sharpened nearly as in
the diagram, fig. C55, but without the teeth being either upset
or bent; as in very small saws the trifling burr, or rough win-
edge thrown up by the file, is a sufficient addition to the thick-
ness of the blade, and is the only set they receive.
Three modes of spacing out the teeth of fine saws will be
now described, and which modes, although not employed by the
saw-maker, may assist the amateur who is less accustomed to
the use of the file.
^ I
692
MAKING AND SHARPENING FINE SAW TEET1I.
Fine saw teetb are sometimes indented with a double chisel,
fig. 656, the one edge of which is inserted each time in the
notch previously made, and the other edge makes the following
indentations the intervals thus become exactly alike, and the
teeth are completed with the file. For still more delicate saws
recourse may be had to a little bit of steel bent at the end as
a minute rectangular hook, which is magnified in fig. 657 ; the
hook or filing guide, being inserted into each tooth as it is suc-
cessively formed, regulates the distance of the file for the next
tooth, as the file is allowed to bear slightly against the blunt
and hardened end of the hook.
Figs. 6.
657.
658.
The third mode is used for piercing and inlaying saws, these
measure about one one-thirtieth of an inch wide, one one-hun-
dredth thick, and have about twenty points to the inch for wood,
thirty for ivory, forty for ebony and pearl, and sixty for metals.
They are made from pieces of watch-spring, which are straight-
ened by rubbing them the reverse way of their curvature through
a greasy rag, after which they are cut into strips with shears.
When the saw is either being made, or sharpened, it is kept
distended in its frame, and is laid in a shallow groove or kerf
in a plate of brass embedded in the wood block, fig. 658, which
is clamped to the table. First, the back of the blade is filed
smooth and round ; the edge is then smoothed ; after which the
teeth are set out, beginning near the handle of the frame.
The spaces between the teeth are determined, in this case, by
the facility with which the hand appreciates any angular position
to which it is accustomed. Thus in the act of filing the teeth,
— the file is always used, say at an horizontal angle of twenty
degrees with the blade — the file is sent once through the first
tooth, and allowed to rest for an instant without being drawn
backwards ; the file still resting in the first notch of the blade1,
as shown in elevation, is then placed two to five degrees nearer
square in the horizontal angle, or at fifteen degrees with the
SHARPENING FECj-TKETII AND MILL-RAW TBRTII. 098
blade, inMcail of • for :in instant on
the edge of the wood block, and raised out of the notch ; the
i on the block, as in the dotted line, is
:\ccd on the saw at twenty degrees, its first position. 1'y
the two l:it -nil movements it is shifted a trifle to the right, and
a second notch is made at the spot thus determined. The
routine is continued, and after each traverse of the file the
stepping process is repeated, during which the file rests alter-
nately on the saw blade, and on the edge of the block, by which
curious yet simple mode the spaces of the teeth are given with
great rapidity and exactness.
In this first range each notch has only received one stroke of
the file; but three or four ranges, commenced from the oth. r
end of the blade, are required to bring the teeth up sharp.
The second diagram, fig. 659, illustrates the peg-tooth; but it
may also be considered to apply to 641, the M-tooth, and, in part,
to the mill-saw-tooth, 648. The points of the cross-cutting
saws for soft woods are required to be acute or keen, that they
may act as knives in dividing the fibres transversely.
Fig. 659.
^ides 1, 5, 9, that is, the left of each alternate tooth, are
tiled with the horizontal angle denoted by h, and then the
opjx s of the same teeth, or 2, 6, 10, with the reverse
inclination, or h' . The other teeth arc then treated just in tin-
same manner, from the other side of the blade; that K first the
l . and then 11,7, 3, are successively filed, the work
being thus completed in four ranges. The first and second
ranges are accomplished, a few inches at a time, throughout the
re length of the saw ; after which the third and fourth are
plcted in the same interrupted order.
694
SHARPENING HAND-SAW TEETH.
The third diagram, fig. 660, may be considered to refer gene-
rally to all teeth the angles of which are 60 degrees, (or the
same as that of the triangular file,) and that are used for wood.
The most common example is the ordinary hand-saw tooth; but
teeth of upright pitch, such as the cross-cut saw, fig. 643, or of
considerable pitch, as in 646, are treated much in the same
mcinner.
Fig. 660.
The teeth having been topped, the faces 1, 5, 9, are first filed
back, until they respectively agree with a dotted line a, sup-
posed to be drawn through the center of each little facet
produced in the topping; the file is then made to take the
sides 2 and 3 of the nook until the second half of the facet is
reduced, and the point of the tooth falls as nearly as may be on
the dotted line a. The two sides 6 and 7, those 10 and 11, and
all the others, are similarly filed in pairs. The latter process
reduces the second series of faces 3, 7, 11, to their proper
positions, and therefore when the saw is changed end for end, it
only remains to file the tops or sloping lines 4, 8, 12.
The first course takes the face only of each alternate tooth ;
the second course the back of the former and face of the next
tooth at one process; and the third course takes the top
only of the second series, and completes the work. This order
of proceeding is employed, that the faces of the teeth may be in
each case completed before the tops or backs.
The fourth diagram, fig. 661, which follows next in order,
exhibits also in three elevations a somewhat peculiar form of
tooth, namely, that of the pruuing-saw for green wood. The
blade is much thicker on the edge than the back, so that the
teeth are not set at all. The teeth are made with a triangular
file, applied very obliquely as to horizontal angle, as at h,
sometimes exceeding 45 degrees, but without vertical inclination
SHARPENING PRUNING AND GULL!: KKTII.
as at r; and the facet of the teeth are nearly upright, as in the
hand -saw.
fig. Ml.
^<y ^<y "v/ ^/ ^j <
tvx"~ // \\ // — KS:
Looking at the priming-saw in profile, it appears to have large
and small teeth alternately; this only arises from the excessive
be\il employed; the large sides of the teeth are very keen, and
each vertical edge is acute like a knife, and sharply pointed ;
in consequence of which it cuts the living wood with a much
;u-r surface, and less injury to the plant, than the common
hand-saw tooth.
The fifth diagram, fig. 662, explains the method employed in
sharpening gullet or briar-teeth ; in these, as before explained,
there are large curvilinear hollows, in the formation of which
the faces of the teeth also become hollowed so as to make the
projecting angles acute.
The jru 1 lets, 3, 7, 11, are first filed, and from the file crossing
the tooth very obliquely, as at v v in the section, the point of the
tooth i \t. mis around the file, and gives the curvature represented
in the plan. The file should not be so large as the gullet;
it is therefore requisite that the file be applied in two posi-
tions, lir>t upon the face of the one tooth, and then on the
hack of the preceding tooth. The tops of the teeth, 4, 8, 1 -2,
C96
Ml TING SAWS, AND THE REQUISITE TOOLS.
are next sharpened with the flat side of the file, the position
of which is of course determined by the angles c and d ; the
former varies with the material from about 5 to 40 degrees with
the edge, and the latter from 80 to 60 degrees with the side of
the blade ; the first angles in each case being suitable for the
hardest, and the last for the softest woods. The alternate teeth
having been sharpened, the remainder are completed from the
other side of the blade, requiring in all four ranges.
The gullet-tooth accomplishes, in a different manner, and
in one possessing some peculiar advantages, that which occurs
from the horizontal inclination of the file in most other cases ;
and although the position may seem difficult, it will be found
very manageable, as the hollow forms a convenient bed for the
file. — See Appendix, Note B L, page 1011.
The saw having been sharpened, it is afterwards set, or, as
before explained, the teeth are bent. The best mode is that
which is almost always adopted by the saw-maker, who fixe:- iu
the tail-vice a small anvil or stake with a rounded edge, such as
fig. 663. The saw is held with its teeth along the center of the
ridge, and the teeth are bent upon, or rather around the curve of
the stake, with two or three light blows of a small hammer also
shown, the face of which is at right angles to the handle, and
narrow enough to strike one tooth only.
The set, or lateral curve, given to each alternate tooth, is in
measure determined by the curve of the stake, the edge of
which, for fine saws, has a ridge like a pointed gothic window.
Half the teeth having been bent, the saw is changed end for
end, and the intermediate teeth are similarly treated.
gAW-si I Pi ii Us. < ir.i i I.AB 8AWB.
Those uho HI of the saw, employ
tlu- saw-tet for bending the teeth : it consists of a narrow blade
of steel, \\itl >us width* tor dill'i rent saws; fig.
is tor larire, and fig. 665 for small saws. In u-m- the
saw-.sc't, tht: sau : i to remain in the clamp* after ha.
been tiled, and the alternate teeth are inserted a little \\;<
that notch whieh tits the blade the most exactly; and they are
bent over by applying a small force to the handle, whieh is either
d up or depressed equally for each tooth.
In some few cases saw-set pliers, fig. G6G, are used. Two
adjustments are required, respectively to determine the quantity
of the tooth which shall be bent, and the angle that shall be ^
to it. The quantity is adjusted by shifting the stop It, which
i> held by the thumb-screw c, that passes through a mortise in b;
the angle of the part bent is adjusted by the screw d. The tooth
is first giasped between the jaws of the pliers, which are then
rotated until the screw d touches the blade.
Fig. 666.
In which way soever the saw is set, it requires to be accom-
plished with great uniformity, so that the two series of points
may form two exact lines. It is proper to change ends with
the blade in order that each side may have, as nearly as possible,
the same treatment ; as unless the two sides of the saw are very
nearly in the same condition, or set alike, the saw is apt to run,
or cut a crooked instead of a straight path ; it cuts most rapidly
on the side that is most set, and consequently glances off in a
- too rapid encroachment.
The only changes in • ;he circular saw, arise from the
ditlereuee between the riirht line ami the curve; that is. the files
are applied in the same relation to the tangent of the circle, that
698
SHARPENING AND SETTING CIRCULAR SAWS.
they are to the rectilinear edge of the straight saw. When
the teeth of circular saws are topped, a small lump of grindstone
is held upon the saw-bench and against the revolving saw, and
moved continually sideways ; the highest teeth are soon rubbed
down, indeed almost in a moment, as only a very small quantity
is thus removed from them ; sometimes a file is used instead of
the stone.
In sharpening circular saws with angular teeth, and the tops
of gullet-teeth, they are clamped between two upright boards,
connected by a screw passing through the center of the saw.
For saws of small diameter the three are nipped in the vice ;
but for large saws, the boards are shaped like the letter T, and
are screwed against an upright post or the side of the bench, by
a screw bolt and nut.
In gulleting circular saws, the two boards grasping the saw
are often fixed at an angle of about 30 degrees, by which the
file is brought to the horizontal position, and the saw is turned
over when the gullets on one side have been finished.
Fig. 667.
In setting the teeth of the circular saw, all the former modes
may be employed ; and also one other little instrument which
is represented in fig. 667. It consists of a bed or anvil of steel,
which is held in the vice at a; it has an axis c, placed at such a
distance from the sloping plane on a, as suits the radius of the
saw; and the end b of the upper piece, which is somewhat elastic,
is filed to a corresponding angle, and is besides pointed so that
the blow of the hammer may only bend or set one tooth at a
time, as shown by the dotted lines in the inverted plan b'. The
axis, shown detached and in the other view at c', is a turned
block of brass having a shoulder to fit the hole in the saw, two
diametrical mortises for the pieces of steel a and b, and also five
binding screws to retain the several parts in position.
SECT. III. RECTILINEAR SAWS USED BY HAND.
Rectilinear saws used by hand, are divisible into three groups,
as arranged and tabulated on the next page.
899
TABLB OP TUB DIMENSIONS OP RKCTIUNRAR SAWS.
Thefrst column rtfrrt to (he payee *h"» the MMM and their utet an dtitribed.
Tl<e latt column refen to At Birmingham iron wire and ikttt mm gage : the comparison of
dinary linear meemtre it ffiren in At table an page 1013 of the Appendix.
•'
TAFKR SAWS, MOSTLY WITHOUT PKAMES.
m**>~«<«~*-*.
I :: •
1 .
Width at
Wi.lth »t
. .: : . , .. :
1 :
i H
:
Tooth.
'. • • •
M | ..
: -
roi
:<••.
:-:
70S
711
712
713
725
72fi
728
Cross-cut saw ....
; it, IT whip law .
4 to 10 ft.
J. 8 -
4 • 6 -
6 to 12in.
9-12-
7 - 11 •
3 to 7 in.
34-5 -
3 - 41 -
.
160 *6£
} to 1 in.
i - 1 -
I.I.
I'J - 10
15 - If-
ia - 15
'•..•• :
M
18 to 19
18 - 19
18 - lil
19 -
19 - 20
18 - 21
10 - 1'j
IS - 19
19 - 20
13 - If
•Felloe, or pit turnicg saw
WM a ka*tl< at out t*J.
4. 0 .
: • . :
] . .
3- 4-
Widthat
:
a -s -
Width at
narrow end
i • . •
; • .
! S
!' • '
2Sto30in.
20 - 28 -
•1-2 - -j-; .
•:» .14.
20 - 24 -
10 - 20 .
18 - 26 -
8-18.
6-12 -
10 - 24 -
7 to 9 in.
6 -8 -
5-74-
5-74-
44 - 74 -
4 -6 -
24 - 34 -
lj - 2. -
1 • 1 -
g - :; -
3 to 1 in.
3-84-
24.3 -
24-3 -
2 - 24 -
2 - 24
l':!4:
|: :
i-l*-
644&645
644 661
34
5
6
7
8
6 to 8
7 - 8
8 - 9
9 - 10
4 - 7
Hiklf rip uw. .
Hand saw
Broken space or fine hand
Panel saw
Fine panel saw ....
Chert saw, (for tool chests)
•Tal.K- saw
•Compass, or lock saw . .
* K« yh'.le or fret saw . .
Pruning saw ....
(2). PARALLEL SAWS WITH BACKS.
With a kanJlt atonttnJ.
i •
!.. .
Width of
i:
1 : . :
Tooth.
I'oinU per
inch.
'. •.• :
vi. • .:.
16to20in.
14-18-
lo - 14 -
6 - 10 -
8 - 8 -
31 10 4in.
?:8:
14-2-
644&645
10
11
12
21
22
23
15 to 22
Doretail
(\mili rutttr'w saw . . .
5-8-
14-24.
(3). PARALLEL SAWS USED IN FRAMES.
Gtntelktd Unfflkiray.
i, • -••: • :
i. . ..
..
I. . .
Form of
! ' .
: • ; • •
inch.
.... f
M ' ..
Mill saw . .
4 to 8 ft
4 - 6 -
4- 5-
24 - 86 -
«-22-
15 - 30 -
3 - 5 -
3- 5.
4 to 5 in.
3 -4 -
4 -r, .
2"-S4-
1 -3 -
A- 1-
14-8 .
M:
A- A-
648&651
645
644
645
644
••;•:
645
{to lin.
,:i:
3-4-
3- 4-
4 - !•_>.
10 - 20 -
4-6-
10-14-
40 - 60 -
15 - 40 -
10 to 14
Mill saw webb ....
r.» - -Ji
19 . 23
19 - -J2
19 - -J4
l:i - -'4
22 - 24
20 - 26
A to ,J,
Chair- maker's H.I
Wood-cotter's wv,
Continental frame saw . .
'Turning, or sweep saw .
Ivory saw
s frame saw . .
•I'i'-P-iiu- - iw ...
•Inlaying or bohl saw . .
• Tkote Satct marted vi*A an Atteritk are uttd for Circular and Curvilinear Work*.
700 GENERAL REMARKS ON SAWS. — FELLING-SAWS.
The first kind of saw is usually taper ; and if long, it has a
handle at each end as in the pit-saw ; but if short, or not
exceeding about thirty inches in length, it has only a handle at
the wide end, as in the common hand-saw.
The second kind of saw is stiffened by a rib placed on the
back of the saw, and parallel with the teeth ; the rib or back is
generally a cleft bar of iron or brass ; as in the tenon-saw, dove-
tail-saw, and others.
The third kind of saw is provided with an external skeleton,
by which the saw-blade is strained in the direction of its length,
like the string of a bow; as in the turning or sweep-saw for wood,
and the bow-saw or frame-saw for ivory.
These three classes of saws differ much in proportions and
details, as will be seen by the inspection of the foregoing table,
and the subsequent remarks. The longest saws are placed at
the beginning of each group, and the names mostly denote tho
ordinary purposes of the respective instruments.
Immediately subsequent to the description of the several
saws, some account will be given of the general purposes of each
instrument, and of its manipulation. The numbers prefixed to
the table, refer to these respective remarks, which are expressed
somewhat in detail, owing to the importance of the instruments
themselves, and the circumstance that many of the topics will
not be resumed. Whereas the turning, boring, and screw-cutting
tools, the subject matters of the previous chapters, will be more
or less returned to, in speaking of the practice of turning.
The saw which claims priority of notice, is that used in felling
timber, when the axe is not employed for the purpose.
The felling-saw mostly used of late years in this country, is
a taper blade about five feet long, with ordinary gullet teeth,
closely resembling the common pit-saw, except that the teeth
are sharpened more acutely.
The handle of the wide end, fig. 668, is fixed by an iron bolt
and wedge; that at the narrow end, fig. 669, is calculated for
two men, and is made of wood, except a plate of iron at the
bottom attached by rivets or screws to the wood, so as to make
a crevice for the saw, which is fixed therein by a wooden wedge
on the upper surface of the blade.
AVheu the saw has entered a moderate distance, wedges are
PELLIN'i \M> CROSS- ('
driven in to present the weight of the tree from closing the saw-
kerf and fix i lade; and it is needful the handles should
be removeable, that one or other may lie taken off, to allow
§aw to be withdrawn lengthways, which could not be done, were
the handl I on.
In cross-cutting saws, the straight handles are sometimes
attached as in fig. 670, by a piece of sheet-iron serving as a
ferrule, and extending in two flaps which embrace the saw, and
are riveted to it.
I. 671 and 672 represent two other kinds: the former is
attached by a bolt and key, and the spike is riveted through the
wooden handle. la the latter the handle is perforated for
the reception of a slender rod of iron, slit open as a loop to
receive the saw-blade, and which is drawn tight by means of the
nut and washer above the handle.
Fig*. 670
Some of the cross-cutting saws used in the colonies for
large logs, arc made as long as twelve, fourteen, and sixteen
. nine to eleven inches v.ide in the center, and six or seven
inches at the ends. The peg-tooth is commonly used for them.
The lomj saw, fiit saw, or whip saw, which follows in the table,
702
LONG, WHIP, OR PIT SAW.
is also the next saw that is commonly applied to the piece of
timber, which is then placed over the saw-pit, iu order that
the saw may be used in the vertical position by two men, called
respectively the top-man and the pit-man, the former of whom
stands upon the piece of timber about to be sawn. The positions
of the men are highly favourable, as they can give the saw a
nearly perpendicular traverse of three or four feet ; and in the
up or return stroke, the saw is removed a few inches from the
end of the saw cut, to avoid blunting the teeth, and to allow
the sawdust free escape.
The long saw varies from about six to eight feet in length,
according to the size of the timber. To adapt it to the
hands of the sawyers, it has at the upper part a transverse
handle or tiller, fig. 673, and at the lower a box, fig. 674. The
tiller consists of a bar of iron,
divided at the lower part to
receive the blade, to which it
is fixed by a square bolt pass-
ing through the two, and
fastened by a wedge ; and at
the upper end, the tiller is
sometimes formed as an eye
for a wooden stick, or else it
is made as a fork, and the
Figs. 673. 674.
handle is riveted on.
The handle at the lower
part, fig. 674, is simply a
piece of wood four or five
inches diameter, and twelve
to sixteen long, turned as a
handle at each end ; a dia-
metrical notch is made half
way through the center to
admit the saw blade, which is fixed by a wooden wedge. Some-
times the bottom handle of the long saw is a flat iron loop,
as in fig. 675, with a space for the fixing wedge, and an eye
for the wooden handle. Occasionally a screw box is used, or
one like fig. 674, but with the one handle screwed in, so that
its point may bear upon the saw, in place of the wedge. In
all cases it is desirable the lower handle should be capable of
being easily removed.
PIT FRAME-SAW. — SAWPIT.
708
Tin /jit framc-iaw, fig. 076, is commonly used for deals, and
for such pieces of the foreign hard woods as are small enough
.•H frame, which is about two feet wide,
frame-saw blade has two holes above or at the wider end,
one below, and is
the wooden
frame by two iron buckles
or loops, which are split
about half way round.
The upper buckle fits
squarely and firmly to
the top head, and re-
ceives, above its lower
side, two pins passing
through the holes in the
saw. The lower buckle
is similarly cleft, and re-
ceives one pin only ; this
buckle is drawn tight by
a pair of equal or fold-
ing wedges, beneath the
bottom transverse piece.
The blade is usually
five or six feet long, and
thinner than that of the
whip saw, which latter
although it may be used for the widest timbers, is more wasteful.
Insome few cases, where the double frame, fig. 676, is inapplicable,
as in removing a plank from outside a very large log, the single
frame, 677, is used ; but this latter is generally narrow, and
employed alone for small curvilinear works.
It is now proposed to give some few particulars of the sawpit,
and the modes employed by the sawyers in marking out the
timber preparatory to sawing.
-awpit varies from about twenty to fifty feet in length,
four to six feet in width, and five to six feet in depth ; it has two
stout timbers rnnnini: the whole length, called ride strokes, and
transverse, pieces at each end, called head (tills, upon which the
one end of the timber rests, whilst the other end is supported
704- MARKING OUT ROUND TIMBER.
on a transome, or a joist lying transversely upon the strakes :
a second transome, is used in case of the first breaking ; this is
called a trap transome.
Sometimes holdfasts, or L-formed iron brackets, are added to
the head-sills, by which thick pieces of plank are fixed horizon-
tally; screw chops are also used for fixing short pieces of hard-
Mrood vertically or edgeways, for slitting them.
In cutting deals into thin boards, three deals, which from
being as many as the frame of the saw will include, are called a
pit-full, are placed vertically against the stake, and are securely
attached to it by a rope passed once round the deals and the
lower end of the stake, and strained by a binding-stick.
Foreign timbers and hard woods are mostly squared with the
axe or adze, for the convenience of transport and close stowage on
shipboard, and such square pieces are readily marked out with
the chalk line into the scantling, or the planks and boards
required. More skill is called for in setting out the lines upon
our native timbers, which are mostly converted into plank, or
the various pieces, without being previously chopped square.
The converter determines in which direction the tree can be
cut most profitably into plank, and the section chosen is usually
that, which when opened, shows the greatest curvature or irre-
gularity ; this section is supposed to be shown longitudinally by
a, b, c, d, fig. 678, and, on a larger scale and transversely, by
e' e, fig. 679 ; the central points a and b, and the line b c, being
given by the converter, who also gives instructions as to the
thicknesses desiredin the planks. The sawyer's firstobject is accu-
rately to mark the margins of the irregular central plane, abed,
so truly, that when the lines are followed with the saw, the sur-
face shall be true and thoroughly out of winding or twist.
The sawyer gets the timber on the sawpit, with the hollow
side upwards : that being always first marked : it is plumbed
upright, or, so that the plumb-line, suspended by the hand at z,
exactly intersects the line b c, which has been marked on the
end. The butt is then secured from rotating, by dogs or staples,
s s, fig. 679, driven both into the end of the timber and into the
vertical face of the head-sill; for which purpose the two ends of
the dogs are bent at right angles, both to each other and to thr
intermediate part of the dog, the extremities of which are pointed
with steel, made chisel-form, and hardened.
i-ii i i- \K \ n>nv
s \\\ : s...
A chalk-line is now stretched in the dotted line from a to bt
r.nd pul illy upwards, exactly in the plane in which it
is desired to act . ng is then let go, as in discharging an
arrow, and striking the timher. it leaves thereupon a portion of
the white or black chalk with which the line was rubbed.
Should the curvature of the timber be such that, as in the
mple, the chalk-line would scarcely reach the hollow, it is
strained on the dotted line a, b, and left there ; the plumb-line is
held in the hand at z, and an assistant holds a piece of chalk on
the top of the timber at the point e. The principal then observes,
in the same glance, that the plumb-line z, intersects the string
a b, the line b c, and also the point of the chalk, showing them
all to be in the plane of vision ; a mark is then made at e. Marks
are similarly made at/ and g, or as many places as may be re-
quired ; and, lastly, the points a ff,fff,fe, and e b, are connected
by short lines struck with the chalk-line around the curve.
The required thickness of the planks is then taken in the
compasses, with a little excess for the waste of the saw, and two,
three or more planks are pricked off on each side the center
e' et fig. 679 ; until, from the circular section of the timber, its
surface becomes so inclined, that the compasses would measure
a slanting instead of a horizontal distance, and w Inch would
diminish the thickness assigned to the boards.
The sawyer then holds the compasses as at y, and fixing his eye
on the part of the wood perpendicularly beneath the off leg of
706 MARKING OUT ROUND TIMBER.
the compasses, he removes the instrument and pricks a mark
therewith ; after which the compasses are replaced as at y, to see
that the mark is correct. This is repeated at different points in
the length, and the chalk-line is stretched from point to point
thus set out with the compasses, and marks the edges of the
intended saw cuts with sufficient certainty.
The timber is now turned over, or with cto d, fig. 678, upper-
most and the end line exactly perpendicular as before. Should
the piece be very crooked or high-backed, the sawyer may be
unable to see over it, and observe the central marks at the ends
of the timber ; such being the case, the points e,f, g, are trans-
ferred to e',f, g', on the top of the timber, by the mode ex-
plained by the figure 679, supposed to be a section through the
plane e e'. A dog is driven into the timber near e', and from the
dog a plumb-line, x' x, is suspended ; the distance e x, is then
measured with a common rule, and measured backwards from
x' to e ' , by which process e' becomes exactly perpendicular to e ;
the points / and g are similarly treated to obtain the points/'^' ;
after which the central line is made at four operations, through
c, e',f,g', d', the plank lines are set out with the compasses as
before explained.
Large timber is usually cut into plank as in fig. 679 ; the
planks are sometimes flatted or their irregular edges are sawn
off and for the most part wasted ; but this is not generally done
until the wood is seasoned and brought into use.
When many planks are wanted of the same width, it is
a more economical mode, first to leave a central parallel balk,
as in fig. 680, by removing one or two boards from each
side, and then to flat the balk, or reduce it into planks. The
central line is in this case transferred from the lower to the
upper side, by aid of the square and rule, instead of by the
plumb-line.
According to Hassenfratz, the setting out shown in fig. 681 is
employed in large wainscot oak, in order to obtain the greatest
display of the medullary rays which constitute the principal
figure in this wood; and the same author strongly advocates
the method proposed by Moreau, and represented in fig. 682,
in which he says one-sixth more timber is obtained than by any
other mode, and also that the pieces are less liable to split and
warj) ; but on examination there does not appear to be any
SAWING STRAIGHT, AND CURVILINEAR WORKS. 707
to incur tho increased trouble in marking and
sawing the timber on this method.*
the timber has been properly marked out, the sa\
take their r places, upon the timber and in the pit:
tin- saw is sloped :i little from the perpendicular ; that is, sup-
posing tlic piece about eighteen inches through or deep, the saw
when it touches the top angle, is held off about two inches from
the bottom. A few short trip> arc then very carefully made, as
much depends on the saw entering well; and should it fail to
hit the line, the blade is sloped to the right or left at about the
angle of 15 degrees, to run the cut sideways and correct the
inei.Mon in its earliest stage. It is usual to take all the cuts as
in figs. 679 and GSO, to the depth of three or four feet, and then
the whole of them a further distance, and so on.
\Vhrn the saw has penetrated three or four feet, a wooden
heading wedge is driven iuto the cut, to separate the timber, for
the relief of the saw ; and when, from the length of the cut, the
timber is sufficiently yielding, the hanging wedge is used, which
is a stick of timber about twelve to twenty inches long and an
inch Mpiarc, with a projection to prevent the wedge from falling
through. The wedges lessen the friction upon the saw ; but if
too greedily applied they split the wood, and tear up the loose
parts sometimes observed in planks.
In sawing straight boards, it is advantageous that the saw
should be moderately wide, as it the better serves to direct the
ilincar path of the instrument; but for curvilinear works, as
tin- felloes of carriage wheels, the sawyer employs a much
narrower saw, to enable him to follow the curve. The blade of
one kind of felloe-saw is about five feet long, and it tapers from
nearly four inches at the wide, to two inches at the narrow end;
it is used with a tiller and box, exactly the same as the ordinary
long saw, and also without a frame.
The more general felloe-saw, or pit-turning gaw, has a blade
about li inch wide, and is stretched in a frame exactly like those
reprcM-ntcd in tigs. 676 and 677. The turning-saw with two
he best where it can be applied ; sometimes the
• Traits de PArt d* Ckarptntier, par J. H. Hauenfratz. 4 to. Para, 1804.
PUtelS.
• • 2
708 nir, HAND, PANEL
frame is obliged to be made single, and with a wire and screw
nuts, by which the saw is strained as in fig. 677, page 703.
In cutting-out very small sweeps, as in the small wheels or
trucks for wooden gun-carriages, no frame whatever can be used,
and slender blades about five or six feet long, five-eighths of an
inch wide, with a handle at each end, were employed for this
purpose during the late war. In using the various pit-turning
saws, the thick plank having been sawn out in the ordinary
manner, the work is marked off on one side from a pattern or
templet, and then held down, upon the head-sill of the saw-pit
and one transom, by means of the holdfast before noticed.
The rip-saw, half-rip, hand-saw, broken space, panel-saw, and
fine-panel, which, in respect to appearance, are almost alike, may
be considered to be represented by fig. 683 ; their differences of
size will be gathered from the dimensions in the table ; the
chest-saws are merely diminutives of the above, and such as are
used for small chests of tools, whence their name.
Fig. 683
This kind of saw is made taper, in order that the blade may
possess a nearly equal degree of stiffness throughout, notwith-
standing that it is held at the one end, and receives at that end,
as a thrust, the whole of the power applied to the instrument ;
the greater width also facilitates the attachment of the handle.
AVcre the blade as wide at the point, as at the handle or heel,
it would add useless weight, and instead of being a source of
strength, it would in reality enfeeble the saw, which from the
increased weight at the far end, would be more flexible near the
handle than at the point.
It will be seen that the saws in this group are progressively
smaller and finer. The rip-saw has the coarsest teeth, and
which are of slight pitch, or mid-way between the upright or
cross-cutting teeth, fig. 643, und those of ordinary pitch, fig. 645 ;
the half-rip is similar, but a little finer ; these two are used in
carpentry for ripping or cutting fir-timber rapidly with the grain.
\\D INS rut | 01 i MI:IR USE.
The hand nml fine-hand saws arc somewhat liner in tin- teeth,
which are of ordinary pitch, or the lace of the tooth i> perpen-
dicular; the hand-saws are much used hy the joiner for ordinary
purposes, ami also hy the eahinet maker, for cutting iniiho-
and other hardwoods with the grain.
panel and line-panel arc still finer saws of the same kind,
which probably derived their name from ha\inu' been made for
cutting out panels, \\hen ouk and other wainscottiug were more
common in our bouses than plastered \\alls ; and they ma;
considered as intermediate between the handsaw, by which
most of the work is done, and the tenon or back-saw hereafter
to be described.
The same workman does not require cacb of the six saws, but
commonly selects the two or three most suited to his particular
class of work; they are principally used for still further preparing
the woods to their several purposes, after they have been cut at
the sawpit into planks and boards. The outlines of the works are
marked out upon the surface of the plank by aid of the rule,
compasses and chalk line, or the straight edge and square, with
much greater facility than setting out the round timber into
planks, which has been already explained. The board having
been marked, is rested upon a sawing stool or trestle, the height
of which is about 20 inches; if the work be long two stools an
employed. The workman commonly places his right knee upon
the board to fix it, and applies the saw on the portion that o
hangs the end of the stool.
The saw is grasped in the right hand, and the left is applied
to the board, in order that the end of the thumb may be pl;i<
just above the teeth and against the smooth blade of the saw, to
ie it to the line; the saw is then drawn backwards a few
inches, with light pressure, to make a slight notch, a short gentle
down-stroke is then made almost without pressure. In the lir>t
the length and vigour of the stroke of the saw are
gradually increased, until the blade has made a cut of two to
tour inches in depth ; after which the entire force of the ridit
arm is employed, the saw is used from point to heel, and in
extreme cases, the whole force of both arms is used to urge the
saw forward. The blade is occasionally -it .,-« d to lessen the
friction, the end of a tallow candle bein- mostly used, or <
- lard smeared on leather.
710 INSTRUCTIONS FOR USING THE
In most instances little or no pressure is directed edgeways,
or on the teeth ; and when the effort thus applied is excessive,
the saw sticks so forcibly in the wood, that it refuses to yield to
the thrust otherwise than by assuming a bow or curved form,
which is apt permanently to distort the saw from the right line.
The fingers should never be allowed to extend beyond the handle,
or they may be pinched between it and the work.
In order to acquire the habit of sawing well, or in fact, of
performing well most mechanical operations, it is desirable to
become habituated to certain defined positions. Thus in sawing,
it is better the work should, as often as practicable, be placed
either exactly horizontal or vertical ; the positions of the tools
and the movements of the person will also be then constantly
either horizontal or vertical, instead of arbitrary and inclined.
In sawing, the top of the sawing stool should be horizontal,
the edge of the saw should be exactly perpendicular, when seen
edgeways, and nearly so when seen sideways ; the eye must
watch narrowly the path of the saw, to check its first disposition
to depart from the line set out for it. If however, the eye be
directed either so far from the right or left side of the blade as
to form a material angle with the line of the cut, the hand is
liable almost uuconsciously to lean from the eye, and thence to
incline the saw sideways. It is therefore best to look so far
only on the right and left of the blade alternately, as to be just
able to see the line, and thence to detect the smallest deviation
of the instrument at the very commencement of its departure.
And then, by twisting the blade as far as the saw-kerf will allow,
the back being somewhat thinner than the edge, the true line
may be again returned to ; indeed, by want of caution, the saw
may be made to cross the line and err in the opposite direction.
It is however, best to make it a habit to watch the blade so
closely as scarcely to require any application of the correctional
or steering process at all. The saw, if most set on the left side,
or having teeth standing higher on the left side, cuts more
freely on that side, and has a tendency to run or arcuate to-
wards the left ; and under the reverse circumstances the saw is
disposed to run to the right.
Thick works are almost always marked on both sides the
plank, and the piece is turned over at short intervals, so that a
portion of the work is performed from each side ; the saw-cut
IIV.ND SAW. TABLE AND COMPASS SAW. 711
trill then ns.siiinc a aeries of slight ;<» the ri.u'ht and left
altci :,iul will depart less from tin- true line, than if these
irbanees had c fleet from the one side only, and thus pro-
duced an accumulating error, or a line swerving in one d:
tion :d Mm •. or as a sweep of a large circle. The practice of
changing sides with the work will, under most circumstances,
be found to lessen the errors incidental to the process, and the
practice is therefore especially desirable for beginners.
The work is not always placed on the sawing-stool, as in some
cases it is laid on the bench, and fastened down upon the same
with the holdfast or hand screws, and with the intended cut
situated beyond the edge of the bench ; the workman then
stands erect, and uses the saw with both hands, placing the back
of the saw towards his person, and sawing from it; this with
many is a favourite position. In some cases, especially in MI, all
and thick works, the wood is fixed perpendicularly in the screw-
chops of the bench, and the saw is applied horizontally. These
modes are both good, inasmuch as they relieve the individual
from the necessity for holding the work with the knee, and he
is less restrained in the action of the limbs.
In using the hand-saw for preparing hardwood for turning, the
log is either laid on the common X-form sawing horse or else it
is fixed in the jaws of the tail- vice, which latter mode is gene-
rally more convenient. In speaking of sharpening the saw, it
was shown that the points of saw-teeth, proper for hardwoods,
are somewhat less acute than those for deal and ordinary timber.
The remarks on the hand-saws hare been given in greater
detail than those which follow, because it is considered these
instructions will assist in the manipulation of all the other saws
used by hand.
Ki-rs. r,M ;in,l r,v~> represent the narrow tujvr UMTS n-rd fur
cutting curves and sweeps, especially those required in wide-
ids. Compared with the generality of saws, these are made
thicker on the edge, and are ground thinner on the back, to
allow them more freedom in twisting round curves, the smallest
of which require the narrowest Ida*
The table-saw, and the compass or lock-saw, fig. 684, which only
differ in *i/e, resemble the hand-saws in their general structure
and in the forms of their teeth, except that the blades are smaller
and nan dow them to lie as a tangent to the curve.
712
KEY-HOLE AND PRUNING SAWS.
The key -hole or fret saw-blade, 685, which is drawn to the
same scale as the last, is held in a saw-pad, or a handle having
a stout ferrule with a mortise and screws, so that the blade may
be strongly grasped; and as the handle is perforated throughout
its length, either the whole or part only of the blade may be
allowed to project. The key-hole saws are sometimes fixed in
a handle like that for a file, which is less proper.
Figs. 684
The table, compass, and key-hole saws, all require care in
their use, for if much pressure is thrown on the teeth, they
stick fast in the material, and a violent thrust is liable to bend
and permanently injure, or indeed, to break the saws; and be-
sides, their paths are the less easily guided, the more vigorously
they are used. It would be desirable, if in the narrow taper
saws with only one handle, we more frequently copied the
Indian, who prefers to reverse the position of the teeth so that
the blade may cut when pulled towards him, instead of in the
thrust; this employs the instrument in its strongest instead
of its weakest direction, and avoids the chance of injury. The
inversion of the teeth, which in India is almost universal,
is with us, nearly limited to some few of the key-hole and
pruning saws.
Pruning-saws are often made exactly like the table and com-
pass-saws, fig. 684, recently described, but with teeth which are
coarser, thicker, and keener than those for dry wood. The forms
of teeth figs. 644, and 645, namely the hand-saw tooth, and slight
pitch, are used, and also the double teeth, fig. 661, which are
rarely employed but for living timber. An excellent modifica-
tion of the pruning-saw is to mount the blade at the end of a
light pole 4 to 6 feet long, so that the edge of the blade may
form an an^le of about 150 degrees with the handle. This saw
may be applied to branches eight or ten feet from the ground ;
the inclination of the blade just suffices for the onward pressure,
TENON, SASH, CARCASE, AND DOVETAIL SAWS. 7)3
and the saw cuts in the pull instead
of in the thrust, which is both more commodious to the indi-
vidual, and free from the risk of accident to the blade.
FSg. 666.
Many pruning-saws are made with blades nearly parallel in
width, but as thick again on the edge as on the back, and with
double teeth, fig. 661. The larger pruning-saws of this kind,
fig. 686, are mounted as carving-knives, or with straight h.-mdlcs
of buck-horn; such blades measure from 8 to 10 inches long,
and i to 5 inch wide; the smaller kind are made as clasp or
pocket-knives, and are of about half the dimensions given.
The next group of saws enumerated in the table, are Parallel
Saws with Backs; those most commonly known are in some
measure particularised by their names, as tenon-saws, sash-saws,
carcase-saws, and dovetail saws; they only difler in size, as
already shown, and they are represented by fig. 687.
Fig. 687.
The blades of the back-saws are thin, and require to be very
carefully hammered; the handle of the saw is affixed to the
blade itself by the screws. The back is either a piece of stout
sheet-iron or brass folded together, first as an angle between
tup and bottom tools, and then closed with the hammer upon a
parallel plate thicker than the saw. When the inside of the
groove has been tiled to remove the irregularities, the two edges of
the back are grasped in the tail vice, and the ridge is hammered
to make the edges spring together almost as a pair of forceps,
back is held upon the blade by this elasticity or grasp alone,
and the blade only penetrates about half-way down the groove.
The general condition of the blade depends in <;reat measure
upon that of the back, which should not be exposed to ronjrh
714 BACK SAWS. SAWING BLOCKS.
usage ; as a blow on the middle of the back tends to throw the
blade more in that part, and make it crooked on the edge, a
fault that may be in general corrected by tapping slightly upon
the back near the ends, in order to drive the blade as much
inwards at those parts as in the center, and balance the first
error. When the blade itself is buckled, which is less liable to
occur than with hand-saws, from the more careful manner in
which the back saws are used, the saw must be taken to pieces
and the blade corrected on the anvil as in other cases.
The back-saws, which are much employed for accurate works,
are often assisted or guided by sawing -blocks, in which one or
more saw-kerfs, that have been very carefully made, serve to
guide the blades ; consequently this method saves a part of
the trouble in marking out the lines to be cut, and also of the
risk of making incorrect incisions. The sawing block, fig. 688,
which is of the ordinary form, is
F- cog
a trough made parallel both inside
and out, and having three saw-kerfs,
which are all exactly vertical. The
one kerf is at right angles to the side
of the block, and serves for cutting
off pieces, the ends of which are required to be perfectly square ;
the two other saw-kerfs are at angles of 45°, and slope opposite
ways : these serve for cutting mitres, or the bevilled joints always
employed for uniting mouldings at right angles to each other,
as in picture frames and panels. The work is simply held close
to the further side of the box, and with the line of division
opposite the saw-kerf, the saw is then allowed to pursue the
direction given by the saw-kerf; and when many pieces of
similar length are wanted, stops are added to the block. The
joiner frequently uses the shooting boards represented on page
502, for sawing as well as planing, especially when the work is
to be planed immediately after on the same shooting board ; the
saw is then applied parallel with, but slightly in advance of, the
face against which the sole of the plane rubs.
Before concluding the remarks on saws with backs, fig. 687,
it appears desirable to offer some particulars on the modes of
constructing tenons and dovetails, from which most useful and
general modes of uniting materials, two of these saws have
derived their names.
TENONS AND MORTISES.
718
In a rectangular frame, represented partly finished in fig. 689,
tin .••• .us are commonly made on the shorter pieces, called the
rails, and the mortises on the longer or the styles, which arc
always left somewhat longer than ultimately requm ••!, t<>
them fr»in breaking out, either in making the mortises or in
wedging up the frame. In carpentry, the panel is fitted in a
groove, as at a, and is inserted or planted before the frame is
glued up ; but in cabinet-work the panel is fitted in a rebate, as
at b, and is fixed by slips of wood after the frame is finished.
Aft; 689.
When the styles and rails have been planed up to their
widths and thicknesses, (see pp. 498 to 503), the internal length
of the frame is marked on the styles at / /, and the width on 1 1 <•
rails at w w \ these lines are scribed on the four sides of each
piece, with the square and scriber. The additional lines ft
indicating the ultimate length of the style, are also mark
The width of the enlarged tenon t t', is from one-half to two-
thirds that of the entire rail; the inner haunch t, is required
to be lower than the groove or rebate, and the outer haunch /',
is generally about three times as wide as the inner, to leave
room for the wedges, and the end wood of the style exterior to
them. The thickness of the tenon is commonly about one-third
that of the style, but from the mode of work, its actual thiek-
ness, if not exceeding about J-inch, becomes exactly the same
as the \\idth of the mortise-chisel eniph
The appropriate ehi>» •! having been selected, the
716 TENONS AND MORTISES.
g g, corresponding with its width, are gaged on each edge of the
styles and rails. Frequently the mortise-chisel is slightly stuck
into the work to imprint its own width, by which to adjust the
gages ; and every piece is gaged from the face side, so that when
the whole are put together they may be flush with one another.
The several styles to be mortised, if small, as in cabinet work,
are placed side by side with their inner edges upwards, and are
fixed upon the bench with the holdfast ; the mortises are then
commenced near the outer end, m ', 690. The styles, if large
as in carpentry, are placed upon the stout mortising stool ; the
workman sits upon them, and begins near the inner end m.
The mortises are made half-way through from the inner side
of the rails, and are completed from the outer ; and the opera-
tion is by no means difficult, provided the mortise-chisel, which
although narrow is very thick and strong, is kept exactly per-
pendicular to the side of the wood, and truly to the gage-lines.
The chisel is mostly held with its face towards the operator, and
the first cut is perpendicular and about one-sixth from the end
of the mortise, as at a, fig. 690 ; the chisel is driven with two
or three blows of a mallet of proportionate size ; the second cut
is inclined, as at b, and between each of the inclined blows, the
chisel is moved to loosen the chips. By the two cuts a trian-
gular portion of wood or a core is loosened, and which is prized
up by thrusting the chisel backwards through the dotted arc,
the bevil or bulge of the chisel then resting upon the angle of
the wood as a fulcrum.
The neighbouring lines in fig. 690 show the successive cuts
employed in making the mortise ; some workmen prefer taking
the cuts a and b alternately, always prizing up the chips by
thrusting the chisel from them, after each cut b ; others prefer
taking most of the cut a, at an earlier stage of the work. When
the triangular incision reaches half way through the wood, it is
extended in length cither by sloping cuts with the chisel, as at b,
or Mith perpendicular cuts, as at c.
At the completion of the inner half of the mortise, the face
of the chisel must be applied exactly perpendicular at each end,
as a and c, and in releasing the shavings, the handle is moved
towards the center of the mortise, using the cutting edge as the
fulcrum, and not the angle of the wood, which would be thereby
bruised. The style is now turned over, and the remaining half
CUTTING TENONS. l>o\ r.T \ II.1. 717
of the mortise is eomph trd ; hut i cuds :u 1 for
tin- reception of the wedges, as marked in the diagram. The
moi : ostly left from the n ii-( 1, although when
the two incisions do not exactly meet, it is needful to purr d»un
the inequalities with an ordinary chisel.
• -utting of the tenon is less difficult of explanation than
the mortise. The shoulders, or tin MOM,
are generally made with the dovetail or carcase-saw, whilst the
rail lies on the bench against the sawing-stop, or a peg near
the corner of the bench; the rail maybe held with the holdfast
if preferred. The side or longitudinal cuts are usually made
with the tenon or sash-saw, the rail being then fixed perpen-
dicularly in the bench-screws.
These cuts, which remove two thin rectangular pieces called
cheeks, should be made with great accuracy, and so as just to
avoid encroaching on the gage lines ; as the tenon is left from
the saw, or at most the angle is cleared out with the corner of a
chisel applied almost as a knife.
The haunches are marked by laying the end of the rail in
contact with the gage lines on the inner side of the style, and
marking the tenon from its corresponding mortise.
Tenons and mortises do not in all cases extend through the
wood, and as they cannot be then wedged up, they have to
depend exclusively on good fitting or surface contact, and the
glue ; in many cases also, screw-bolts, straps, and wooden pins
are used to draw the tenon into the mortise in various w
subjects that are too varied to be here particularized.
In mortises that are wider or deeper than usual, it is a com-
mon practice to remove a portion of the wood with center-bits,
or nose-bits, and to complete the mortises with firmer chisels.
Dovetailed joints are employed for uniting the ends of boards
at right angles to each other, as in boxes, drawers, and nume-
rous other works. The dovetails are made of several forms ;
thus, fig. 691 is a kind of factitious dovetail, in which the boards
are first mitred, or their edges are planed at the angle of
45 degrees, and slightly attached by glue or otherwise ; a few
cuts leaning alternately a few degrees upwards and downwards
are then made with a back-saw upon the angles, pieces of
veneer are afterwards glued and drawn into the notches. This
718
SETTING OUT DOVETAILS.
method is principally employed in toys and very common works,
which are then said to be mitred and keyed ; the hold is much
stronger than might be expected.
Fig. 691.
692.
693.
Fig. 692 represents the ordinary dovetail joint ; p, fig. 693, the
pins, and d, fig. 693, the dovetails of which the same is com-
posed. In some cases the pins and dovetails are nearly alike in
size, and this makes the strongest attachment ; but in joinery
and cabinet work, the dovetails are made on the front or more
exposed part of the work, and the pins are cut of only one-
fourth or less the size of the dovetails, in order that but little
of the end wood may be seen. Usually the pins are the first
made; as in making ordinary dovetails as well as tenons,
the surfaces are left from the saw, this instrument must be well
applied to produce the close joints met with in works of the best
quality.
In setting out dovetailed works, the sides and ends of the
box are first marked across on both sides with the gage or
square at g g, which lines indicate both the inside measures of
the box and the bottoms of the pins and dovetails ; the portions
beyond the lines are left a trifle longer than ultimately required.
Very little care is taken in setting out the pins ; indeed, their
distances are usually marked with a pencil, without the rule or
compasses, and the two external pins are always left nearly as
strong again as the others.
One of the fronts, fig. 694, is fixed upright in the bench-
screws, and the pins are sawn as shown at a a. These saw cuts
are made exactly perpendicular, and terminate upon the gage
lines ; but horizontally they are sloped opposite ways, so that
v \\\ IN.. \M» ( I I MM. IH.N l.r.MI S.
;.• pili in about as wide again on tin- inner as on the on
side of t of tin- l)ox. Tin- wood between the dovetail
pins is generally cut out with the bow or turning saw, leaving the
space as at b, fig. 694; and the spaces are then pared out with
tin tinner chisel from opposite sides, as at c, i 1 being
placed exactly on the gage lines, but slightly overhanging, so
that the insides are cut hollow rather than square, to insure the
exact contact at the inner and outer edges of the dovetails.
When the wood between the pins is removed entirely with
the chisel, this instrument is driven with the mallet perpendicu-
larly into the wood just in advance of the gage-line, and sloping
cuts are then made to form a notch half-way through the wood
as at/; and when the space has been thus cleared, a more careful
vertical cut is made exactly upon the gage-line itself, as in the
former case.
The dovetails are next marked from the pins, and thus become
their exact counterparts. In marking the dovetails, the end piece
d, fig. 695, is laid upon the bench, and the pins in p are placed
exactly vertical, and in their intended positions ; and lastly, the
scriber is passed along the two sloping sides of every pin. The
gage lines are followed with the dovetail saw, the waste of the
tool being taken from the hollows, so as to leave the gage lines
almost standing: the hollows between the dovetails are now
removed with the chisel unless the work is very large, when, as
in cutting away the wood between the dovetails, the frame saw
may be previously employed.
As the gage lines are almost left in sight, the pins and dove-
tails are mutually a trifle too large, so that in driving them
together, they somewhat compress each other, and produce that
close accurate contact to be observed in good works ; and which
720
VARIOUS KINDS OF DOVETAILED JOINTS.
gives rise to so much surface-friction, that the glue might in
some cases be nearly dispensed with between the joint ; but if
the pins are left too large, they split the wood.
Whilst the chisel is being employed in dovetailing, it is usual
to lay the several pieces of wood upon the bench, with their ends
slightly extending beyond each other, like a flight of steps, an
arrangement that admits of every edge being readily seen and
operated upon ; the pieces are fixed in this position by the hold-
fast, and when they have been cut half-way through, they are
turned over, and finished from the other side.
Figs. 696 to 701 represent in plan, and in one group, the
several ways of dovetailing the edges of boxes and similar works:
fig. 696 is the mitre and key joint, and fig. 697 the common
dovetail joint already spoken of, in which the pins and dovetails
are both seen from the outside of the box. In the four other
kinds the parts are more or less concealed, and they may be con-
sidered to increase in the difficulty of construction, in the order
in which they are represented. It is supposed that the pins
which are on the upper pieces marked p, are made before the
dovetails on the pieces d, and before scribing which latter from
the pins, chalk is rubbed on mahogany and other dark woods,
to make the lines more conspicuous.
Figs. 696. 697.
698.
699.
700.
701.
Fig. 698 is the half-lap dovetail, which is much used for the
front of drawers. The pins in p, or the front of the drawer, are
first marked, and the wood is also gaged at the end to denote
how far the pins shall extend inwards : the saw can only be used
obliquely, as shown by the dotted line, and the pins are finished
with the chisel applied on the lines a and d. When, however,
the drawer front is to be veneered, the pins are often sawn quite
through on the line d, as the pins may be thus more easily cut,
and the veneer conceals the saw-kerfs in the drawer front. The
dovetails on the sides of the drawer, or d, are afterwards marked
VARIOUS KINDS OF DOVETAILED JOINTS. 721
and cut as in the first example, fig. 697, but of their exact
In fig. 699, sometimes called i\\o tecret dovetail, the pins and
dovetails are both concealed, as neither of them extend through
tin- work ; the saw can be only used at the angle of 45 degrees,
either for the pins or dovetails, and most of the work is done
with the chisel. The angle is filled in with a corner line.
The lap dovetail, fig. 700, is often used for writing-desks, and
similar works with rounded edges, and not having corner lines:
the front of tin- dt>k, or p, is first rebated out to leave the lap,
the pins are then made in this piece, and the dovetails are after-
wards scribed on d, and made as in the last case ; only a small
portion of the end wood is then seen at the ends of the desk,
and this is in great measure removed from observation when the
angle is rounded.
The mitre dovetail, fig. 701, requires each piece to be rebated
out square, as in p, fig. 700; and after the pins and dovetails
have been respectively made, the square rebates are converted
into a mitre joint with a rebate plane. When finished, neither
the pins, nor the modes of their concealment, are distinguishable
and the work appears to have a plain mitre joint.
\Vlirn the lid of a box has a dovetailed rim, or that the box
and lid only differ in respect to depth, the box is technically
said to have a tea-chest top, and four pieces of wood, sufficiently
deep to make both the box and its cover, are then dovetailed
together in either of the ways before mentioned. When the top
and bottom of the box are also added, the six pieces present the
appearance of a rectangular block, and which is known as
a carcase, a term also applied to other entire framings. The
saw used in cutting open the carcase, or in separating the top of
the box from the bottom, is thence called a carcase saw.
This mode of work, besides saving much of the labour of
dovetailing, ensures the exact agreement in size, and the general
. rspondence of the two parts; which it would be more diffi-
cult to obtain if they were separately made, especially in sloping
works, such as portable writing-desks and others of similar
character.
In every case where the box and the lid are made together,
the line of dr. .M»n is gaged on the four sides exteriorly, and
one of the dovetail pins is placed upon that line ; but it is made
3 A
722 DOVETAILED WORKS. SMITHES SCREW-HEAD SAWS.
fully as wide again as the others, to admit of division, and ye
be of the ordinary size. If the joint-pin were made as usual, or
left square, the carcase, on being cut open, would exhibit the
rectangular lines of the pin and dovetail; to avoid which the
joint-pin and dovetail should be pared away to the mitre, and
then the cover and the box will also exhibit a mitre joint.
The top and bottom are fitted in various ways : sometimes
they are glued on the square edges of the sides, but generally
the sides and the top are both rebated, just as represented in
fig. 700, on the supposition that p is the top, and d the side of
the box ; or they are rebated and mitred as in fig. 701.
A box made as above described, with mitred dovetails, with
mitred joint-pins, and with the top and bottom rebated and
mitred, would not show any joint, either within or without the
box, except those constituting the margins of the twelve super-
ficies of the work : in fact the joints would alone occur at the
several angles, and escape observation, as will be apparent from
the inspection of figure 701.
Such a box if neatly made, would be a finished specimen of
work, but so much care is seldom taken, and it is more usual to
employ corner lines and lippings to conceal the joints, or else to
cover the box with veneers, and all of which are sometimes
mitred. In these cases the interior frame or the carcase of the
box is of common mahogany, and dovetailed in the manner of
fig. 697 ; or in very inferior works, the fabric is of deal attached
by glue and brads, the principal reliance being then placed on
the veneer for uniting the parts and concealing the defects.
Having concluded this long but important digression, respect-
ing the formation of tenons and dovetails, the consideration will
be now resumed of the saws enumerated in the table on page 699.
The smith's screw head-saw, fig. 702, which, in the table,
follows the back saws last noticed, differs from them in propor-
tions, and also in the handle, which resembles that of a file ; the
blade is generally also thicker and harder, to accommodate it to
its work. Some of the screw head-saws are made considerably
smaller than those noticed in the table, the blade being a piece
of watch-spring fixed in a brass back ; but these little tools are
generally made by the watch-maker, or other artizan requiring
them.
COMB-CUTTER'S DOUBLE SAW.
723
In all screws that are made in the turning lathe, it is
desirable, in separating them from the neighbouring metal, to
the- turning tool, and to nick them in rather small behind
the head. The little neck that i» left, is broken through, just
Fig. 702.
flattened with a file, and then slightly notched with a triangular
file, as an entry for the screw-head saw; by these means the
risk of notching the head otherwise than truly diametrical is
avoided.
The comb-cutter's double saw shown in profile in fig. 704»
and in section on a larger scale in fig. 703, is called a " stadda"
and has two blades so contrived as to give, with great facility
and exactness, the intervals between the teeth of combs, from
the coarsest, to those having from 40 to 45 teeth in the inch.
The blades of the saw, or its plates, are made of thick steel,
and are ground away on the edge as thin as the notches in the
comb, either in the manner of a or b, and they have about 10
to 20 points in the inch, of slight pitch, fig. 644. The plates are
fixed in the two grooves in the wooden handle or stock, by
means of the stuffing, either two long wooden wedges, or folds
of brown paper ; the plates would rest in contact but for the
introduction of the thin slip or tongue of metal /, called a
languid, which is of the thickness of the teeth required in the
comb, the one blade is in advance of the other from -rrth to
Fig*. 70S.
of an inch. At the first process a notch nearly of the full
depth is made in the comb c, and a second notch is commenced ;
3 A 2
JM GAGE-SAW, HACK-SAW, FRAME-SAWS.
at the next process the notch in advance is deepened, and a
third commenced, and so on consecutively.
The gage-saw, or gage-vid, is used to make the teeth square
and of one depth. The saw is frequently made with a loose
back, like that of ordinary back-saws, but much wider, so that
for teeth |- f f inch long, it may shield all the blade except
£ § f inch of its width respectively, and the saw is applied
until the back prevents its further progress. Sometimes the
blade has teeth on both edges, and is fixed between two parallel
slips of steel connected beyond the ends of the saw blade by two
small thumb-screws, as in fig. 705; the less common instru-
ment is represented, because it is useful for other purposes.
Double saws, fig. 706, analogous to those of the comb-maker,
have been also frequently applied to cutting metal racks, similar
to those used in air-pumps. The blades, which in 706 are
shaded, are as thick as the widths of the spaces, and are sepa-
rated by a parallel slip of metal, represented white, exactly
equal to the thickness of the teeth; the separating slip also
serves as the stop to make the teeth of one depth from the
surface ; the three parts are strongly united by two or more
screws, or bolts and nuts. The rack-saw if carefully made
fulfils its work with considerable accuracy ; the dotted lines at a,
denote the succeeding step, those at b, the square notches when
completed, and c, the teeth when rounded, which is done after-
wards with a file. In modern practice, however, the teeth of
wheels and racks are usually cut and rounded at the one process,
which is performed in appropriate machines.
The third division of the table on page 699, refers to parallel
saws used in frames, of which the measures are tabulated.
The saw-frames of these and other kinds, keep the blades
straight, give them tension and enable the force to be applied
virtually as in the Indian saws, or by pulling the blades, thereby
avoiding the risk of buckling them. From these several reasons
the blades of frame-saws may be made very thin, consequently
they act with less labour and waste, and may in general be used
more vigorously than those saws having only a thrusting handle
at the one end. The blades are sometimes left a trifle thicker
where the pins are to be inserted, and these parts are softened
by being pinched between red-hot tongs, prior to drilling the
pin-holes by which they are attached to their frames.
MILL-SAWS, PIT VKN'XCR SAW. ' II H Il-MAKER's SAW. 725
The mill-taw, and mill-taw web, at the beginning of this group,
are used in vertical saw machines, which will be described in
the fourth section of this chapter. It will suffice here to observe,
that the first, or mill-saws, which are the larger and stouter,
are employed for sawing round timber into thick planks; and
tin- null -saw webs, for cutting deals into thin boards.
The veneer taw formerly in use at the snw-pit was, except-
ing the blade, a copy of the pit-frame saw, fig. 676, p. 708, and
skilful sawyers would therewith cut about six veneers from the
solid inch of wood. Snialli r veneer saws more nearly resembling
that shown in fig. 708 were also used by cabinet-makers, who
would cut seven or eight veneers in each inch from smaller
pieces of wood, fixed upright in the chops of the bench, two
individuals being mostly required. The hand veneer saws, are
now scarcely used in England.
The chairmaker's saw is in general a diminutive of the ordinary
pit saw, and has a central blade strained by buckles and wedges.
The work is fixed horizontally upon the bench by the hold-fast,
the saw is grasped by the side rails with both hands, and
with the teeth from the operator, who stands in the erect
posture. He can thus saw with great rapidity and accuracy all
straight and slightly curved pieces, not exceeding in width half
the span of the frame, which is sometimes nearly as wide as the
length of the blade. The wheelwright employs precisely the
same saw for cutting the felloes of wheels; the timber, wide
enough for two felloes, is then fixed in the ordinary tail-vice.
The three following figures represent different kinds of frame
saws, in which the blades are neither strained by buckles and
wedges, nor placed centrally, as in those hitherto considered.
There is a central rod or stretcher, to which are mortised two
end pieces that have a slight power of rotation on the stretcher;
the end pieces are at the one extremity variously adapted to
receive the saw, and at the other they have two hollows for a
coil of string, in the midst of which is inserted a short lever.
On turning round this lever the coil of string becomes twisted
and shortcut 1 1 •. it therefore draws together those ends of the
cross pieces to which it is attached, whilst the opposite ends
from separating, strain the sa\\ in a manner the most simple,
Tin- tension of the blade is retained by allowing
the lever to rest in contact with the stretcher, as represented,
7£6 WOOD-CUTTER'S SAW, CONTINENTAL FRAME SAW.
but wheii the saw is not in use, the string is uncoiled one turn
to relieve the tension of the blade and frame, one or other of
which may be broken by an excessive twist of the string.
In the wood-cutter s saw, fig. 707, the end pieces are much
curved, and one of them extends beyond the blade, which is
embedded in two saw-kerfs, and held by a wire at each end ;
the blade is therefore always parallel with the frame of the saw,
which is mostly used vertically. The end piece alone is grasped
at r and I, by the right and left hands respectively ; the wood is
laid in an X form sawing-horse, and is sometimes held by a
chain and lever, or less frequently in a strong pair of screw-chops.
The Continental frame-saw used abroad for the general pur-
poses of carpentry and cabinet-making, is shown in fig. 708;
in the largest of these the blades are about three feet long, one
I. SAWING HORSE.
727
and a half to three inches wide, and very thin; and others as
small as half those sites are also used. The wooden handles,
/* ft, shown also detached and of twice the size at A', have cylin-
drical stems, \\lnrh i>i» through the end pieces; they are cut
through longitudinally for admitting the sheet iron T form
clamps, \\ln .;'li In-Ill by a rivet passing through the
handle outside the frame; the blade is fastened between each
pair of clamps by a pin or screw.
The handles being cylindrical, the saw can be placed at all
angles with regard to the frame, and may therefore be employed
for cutting off pieces of indefinite length, provided they do not
exceed the width from the blade to the stretcher, which latter is
forked at the extremities to embrace the cross pieces, and this
allows it to be shifted nearer to the string when required for
wide pieces. Before using the saw it should be observed to
place the blade exactly in a plane, or out of winding.
Most of the works performed in England with the hand-saw,
the tenon, dovetail, and similar saws, are abroad accomplished
with frame-saws of various sizes ; the pieces are mostly fixed,
either to or upon the bench, and the contrivance for holding long
works, shown in fig. 709, is also general on the Continent.
Fig. 709.
rt
^
] Rg. 710.
, J \
£O
The work to be sawn is passed through the triangular opening
in a wooden frame, nearly in the form of the letter A ; when the
frame and work lie at an obtuse angle, they constitute a three-
legged stool. The upper edges of the board become wedged
fast in the angular sides of the triangle, and the lower side of
the board rests on the cross piece of the supposed letter, which
may be placed at various heights, according to the size of the
work, as it rests on two moveable pegs. In sawing small works,
the man rests his knee on the work near the top of the frame,
and the board is changed end for end when sawn through half
its length. Triangular frames, with various modifications, are
728 TURNING OR SWEEP SAW, IVORY SAW.
also commonly used abroad instead of the saw-pit ; but our own
occasional method, namely, a pair of trestles about six feet
high, is much better, as each of the sawyers is then far more
favourably situated than when the timber is placed aslant.*
The turning -saw, or sweep-saw, fig. 710, which is also called the
frame-saw, or bow-saw, resembles fig. 708, except in its smaller
size and greater proportionate width of frame j this will be
apparent, as the figures are drawn to the same scale.
Its handles have always cylindrical wires that pass through
the end rails; the wires are sawn diametrically to admit the
saw blade, and are drilled transversely for the pins ; frequently
the one handle has an undercut notch, as represented on a
larger scale, so that the saw may be removed sideways from
the one handle, and allowed to move as on a joint upon the
other, a provision that is often turned to a useful account.
In using the bow-saw the work is mostly fixed vertically, and
therefore the blade is used horizontally ; but the frame is placed
at all angles, to avoid the margin of the work, and it is fre-
quently necessary to twist the handles or pins during the cut,
to modify the position of the frame. It often happens that the
cut has to be commenced from a hole or aperture, in which case
the tension of the blade is relieved by a turn of the stretcher,
and the saw is disconnected at one end for its introduction. The
disunion of the blade is also convenient for withdrawing it side-
ways, without the tedious necessity for retracing the tortuous
course by which it may have entered the work.
It still remains to notice those saws, the frames of which
may be considered to be slightly flexible, and to form the three
sides of a rectangle. The ivory-saw, which has been already
figured and described at pages 146 and 147 of the first volume,
is the largest of this kind, and the full particulars have been
there given, of its use in the preparation of ivory. Sometimes
the frames of saws for ivory are made of iron, and without the
adjusting screw clamp ; the frame is then sprung inwards by
means of a long hook whilst the saw is inserted.
* These nnd relative matters are fully described and figured by A. R. Emy, in
hia Traiti ckl' Art de la Charpcnterie. Paris, 1837. Plates 2 to 11.
SMITH'S FRAME SAWS, JOINT SAW.
The smith's frame-taw, fijr. 7 1 1 , i*. m-:irly a copy of the saw
last referred to, and it almost always possesses a screw and nut
for stretching the blade.
The mode of using the saws, for metal, is tin- reverse of that
in saws for wood ; as for metal, the motion should be slow, and
pressure somewhat considerable, and the necessity for each
of these conditions increases with the hardness of the material.
The saw is almost invariably moistened with oil or tallow-grease,
and in the back strokes the pressure on the blade is discon-
tinued, but the saw is not raised from the bottom of the notch ;
in this respect the action resembles that of the file.
The smith's frame-saw is the common instrument used in
metal works for the removal of pieces that are in excess, and in
many cases instead of the whole substance being cut through, a
notch is made on two sides of the work, and the center part is
broken. This saw is also used for making notches and grooves,
much the same as in cabinet-work ; but except in small works,
preference is given to the figuration of materials by casting,
forging, and other modes already described.
1
713.
712.
The side frame-saw, fig. 712, although far less common, is
greatly preferred by some workmen; thus, in making the joints
of drawing instruments, much depends on the correct use of the
frame-saw, by which the notches are made for the reception of
the steel plates used in the joints, and fig. 712, in which the
blade is more immediately under observation, is preferred to
fig. 711. For routing out the concave part, a saw like fur. 713
is used, niid iiiM-rted a little way into the joint, until the holes
in the joint and tool are sufficiently opposite to admit the end of
a taper pin ; the joint -saw or router is then moved to and fro,
and as the concavity is cut auay. the pin is set forward until its
cylindrical part causes the two holes to be exactly opposite, and
then the work is completed.
730 PIERCING SAW AND PIERCED WORKS.
Piercing-saw blades commonly measure from 3 to 5 inches
long, and they are fixed in very light frames, such as fig. 714,
which are from about 2 to 4 inches deep from the saw to the
back ; in some instances piercing-saws exceed the depth of
8 inches, as in m, fig. 716. The blades are fixed between small
screw clamps, the inner sides of which are mostly cut like files.
Sometimes, as in fig. 715, the clamp near the handle is extended
as a wire through the handle, and is tightened by a nut at the
extremity, somewhat as in a violin-bow ; but in general the slide
is considered sufficient and preferable, as when it is loosened
the tension of the saw can be appreciated with the fingers, and
retained with the thumb-screw.
Fig. 714. r> 715.
Some kinds of silversmith's works are pierced with this instru-
ment, and embellished with the graver. When the design is
original, the engraving is usually first done, and the interstices
are cut out with the saw. But for the convenience of repetition,
recourse is had to brass pattern plates, pierced and engraved
like the finished work ; the brass pattern is laid on the work,
and all its interstices are marked through with a fine scriber.
In copying designs from any article of silver, the new piece is
laid upon the original, the interstices of which are smoked
through with a lamp : and in curvilinear works that cannot be
pierced while straight, the pattern is dabbed with printing-ink,
a paper is laid thereon, and rubbed on its upper surface with a
burnisher; the paper thus printed is then pasted upon the
object to be pierced. The under side of the original is printed
from, to make the copy direct and not reversed.
The outline having been obtained by one of the above modes,
a hole is made with the breast-drill in every piercing, and where
practicable, the holes form the circular terminations of the
apertures. The several curves are then followed with the saw,
which is used vertically, and with the handle downwards, whilst
the plate is held horizontally upon the pin of the jeweller's
PIERCED WORKS. SILVERSMITH'S AND JEWELLER'S BENCH. 731
bench with the fingers, in order that both the work and the saw
may be freely twisted about in sawing out the several parts.
The silver-piercer sits at the silversmith's and jeweller's ordi-
nary work-bench, formed like a round table, with four or six
semicircular scollops, about IS inches diameter around it ; the
pins, or omall filing boards, are about 3 inches square, and pro-
ject inwards into the bottoms of the hays or scollops, each of
which has a skin or a leather bag nailed around its edge, that
serves to collect the filings removed from the work.
This form of work-table is adopted, in order that a central
lamp may serve for the four or six workmen, each of whom has
a glass globe 6 to 8 inches diameter, filled with water, to act as
a condensing lens, and direct a strong light to the spot occupied
by his work. Spirits of wine are added to the water, to prevent
it from freezing and bursting the globe. The benches are fre-
quently made semicircular, and placed against a window, as the
circular bench requires a sky-light.
The amateur can employ in piercing, a small square filing-
board with a fillet beneath, by which it is fixed horizontally
in the ordinary vice. Should he prefer fixing the work, it may
be still held horizontally, provided he employs a hand-vice, and
pinches it by the half of its joint in the tail-vice, so as to place its
jaws horizontally. In passing round the small curves, the strokes
of the saw must be short, quick, and feeble; in the larger curves
the full length of the blade may be more vigorously used.
Some of the very minute pierced works are drilled and then
finished with small files, as in the plates formerly used for
covering the balances of watches, but in general the file is not
used. The piercing saw is also employed for cutting out small
escutcheons and other pieces for inlaying.
From the pierced works, appear to have been derived those
inlaid works, consisting of curved and flowing Hues, which are
produced by a method that may be called counterpart -saw inr/,
and in which two plates of differently coloured materials, whether
wood, metal, ivory, tortoise, or pearl shell, are temporarily fixed
together, and then cut through at the same time with a fine
hair-like saw. By this process the removed pieces so exactly
correspond in form with the respective perforations, that when
the two colours are separated and interchanged, the one ma-
terial forms the ground, the other the inlay or pattern, and
732 INLAYING, OR BUHL-SAW.
vice versd : and the pieces fit so nearly together, that the route
of the saw is only visible as a fine line on close inspection.
These works receive the general name of inlaid or marquetry
works; and also the specific names of buhl-works and reisner-
works, from their respective inventors.*
The saws used in piercing and inlaying scarcely differ but in
size: thus, the black line m, in fig. 716, is drawn from a large
piercing saw of metal, and the dotted line w, from an ordinary
buhl-saw of wood : the former measures eight inches from the
blade to the frame, the latter twelve or sometimes twenty inches,
to avoid the angles of large works. The wooden frames are
made of three pieces of wood, halved and glued together to con-
stitute the three sides of a rectangle, after which two pieces are
glued upon each side, each at the angle of 45 degrees across the
corners : the whole, when thoroughly dry, is cut round to the
form represented. The screws for giving tension to the blade,
although commonly added, are seldom used, as the frame is only
sprung together at the moment of fixing the saw, and by its
reaction stiffens the blade.
The buhl-cutter sits astride a horse, or a long narrow stool,
fig. 717, having near the one extremity two vertical jaws lined
with brass at the top ; the one jaw is fixed, the other is notched
* The term marquetry seems to be employed to designate all kinds of inlaid
work, known in France as marqueterie en bois, and marqueterie en mital. It
includes not only the works of counterpart sawing, in which flowers, animals,
landscapes, and other objects are represented in their proper tints, by inlaying
and without the aid of the artist's pencil ; but it also includes those geometrical
patterns composed of angular pieces, laid down in succession more after the manner
of ordinary veneering : and amongst which, the specimens of parquetage, or inlaid
floors, appear to claim a place.
Boule work, and reisner work, are considered by the virtuosi to apply exclu-
sively to the works of two celebrated fbeniates of those names, both settled in
France ; the former, an Italian, in the reign of Louis XIV., the latter, a German,
in the time of Louis XIV. to XV. Their cabinet works were as much celebrated
for their graceful forms or outlines, as for their embellishment with inlaying.
Boule, mostly employed dark-coloured tortoise-shell inlaid with brass, in flowing
patterns, occasionally ornamented with the graver. Reisner, used principally as
the ground tulip-wood (called in France bois de rose,) inlaid with flowers in dark
woods, grouped in a much less crowded manner than in ordinary marquetry.
Keisuer occasionally combined therewith bands and margins, in which the woods
were contrasted as to the direction of the grain, as well as colour.
The terms buJil or lool work appear to be corrupted from boule, and now refer
to any two materials of contrasted colours inlaid with the saw, and which, in
France, would be called by the general name of marqueterie.
It in ( I fTEa's SAWING HORSE.
w, and springs open when left to itself, hut is closed by a
strut, which is loosely 1 to the stool by a tenon and
mortise, and rests in a groove in the moveahle jaw. When the
strut is pulled downwards, by a string leading to tin? treadle, it
closes the flexible jaw of the vice. In the plan the jaws are
inclined some twenty degrees, so as to be at right angles to the
path of the workman's right hand.
Fig». 716.
In the following descriptions of counterpart sawing, the several
methods will be noticed in that order which appears to offer the
most facility of explanation, regardless of other considerations.
In buhl-work the patterns generally consist of continuous lines,
of which the honeysuckle ornament may be taken as a familiar
example. To make this, two pieces of veneer of equal size, say
of ebony and holly, are scraped evenly on both sides with the
toothing-plane, and glued together with a piece of paper between,
for the convenience of their after separation.* Another piece
of paper is glued outside the one or other veneer, and on which
* Veneers, like other thin plate*, we pinched by one corner with « screw clamp
to the table or bench ; the tooU are applied from the fixed end, in order that ttx-y
may pull the material and keep it straight Instead of forcing it up in a ware.
734- ORDINARY PRACTICE OP BUHL-CUTTING.
the design is sketched; a minute hole is then made with a
sharp-pointed awl or scriber, for the introduction of the saw,
that spot being selected in which the puncture will escape
observation.
The buhl-cutter being seated on the horse, the saw is inserted
in the hole in the veneers, and then fixed in its frame; the work,
held in the left hand, is placed in the vice, which is under
control of the foot, and the saw is grasped in the right hand,
with the fore-finger extended to support and guide the frame ;
the medium and usual position of which is nearly horizontal
and at right angles to the path of the saw.
The several lines of the work are now followed by short quick
strokes of the saw, the blade of which is always horizontal ; but
the frame and work are rapidly twisted about at all angles, to
place the saw in the direction of the several lines. Considerable
art is required in designing and sawing these ornaments, so that
the saw may continue to ramble uninterruptedly through the
pattern, whilst the position of the work is as constantly shifted
about in the vice, with that which appears to be a strange and
perplexing restlessness.
When the sawing is completed, the several parts are laid flat
on a table, and any removed pieces are replaced. The entire
work is then pressed down with the hand, the holly is stripped
off in one layer with a painter's palette-knife, which splits the
paper, and the layer of holly is laid on the table with the paper
downwards, or without being inverted.
The honeysuckle is now pushed out of the ebony with the
end of the scriber, and any minute pieces are picked out with
the moistened finger, these are all laid aside : the cavity thus
produced in the ebony is now entirely filled up with the honey-
suckle of holly, and a piece of paper smeared with thick glue,
is rubbed on the two to retain them in contact. They are
immediately turned over, and the toothings or fine dust of the
ebony are rubbed in to fill up the interstices ; a little thick glue
is then applied, and rubbed in, first with the finger, and then
•with the pane of the hammer, after which the work is laid aside
to dry.
"When thoroughly dry, it only remains to scrape the bottom
with the toothing-plane or, when the work is small, with its
iron alone, and then the buhl is ready to be glued on the box
Hfll I.- WORKS, IN TURK WOODS. 735
or furniture in the manner of an ordinary veneer, as already
explained ; when the work is again dry, it is scraped and
polished. Exactly the same routine is pursued in combining
holly ground and the ebony honeysuckle, and these con-
stitute the counter or count^r/mrt buhl, in which the pattern is
the same but the colours are reversed.
It is obvious that precisely the same general method would be
pin-sued to make four satin-wood honeysuckles at the respective
angles of a rosewood box ; the veneers for which would be then
selected of the full size, and glued together with paper inter-
posed. To ensure the exact similitude of the several honey-
suckles, one of them having been cut out would be printed from,
by sticking it slightly to the table, dabbing it with printing-ink,
and then taking impressions, to be glued on the other angles of
the box at their exact places. The counter would have, in this
case, a satin-wood ground, with the honeysuckles in rosewood.
To advance another stage, three thicknesses of wood may be
glued together, as rosewood, mahogany, and satin-wood, and a
center ornament added to the group of four honeysuckles. The
three thicknesses, when cut through, split asunder, and re-com-
bined, would produce three pieces of buhl-work, the grounds of
which would be of rosewood, mahogany, and satin-wood, with
the honeysuckle and center of the two other colours respec-
tively. Such are technically known as works in three woods,
and constitute the general limit of the thicknesses, but the
patterns consist of many more parts than here supposed.
In a series of three woods in the possession of the author, or
three veneers, cut and interchanged as above explained, the
three tablets each present forty-eight different pieces, and by
the introduction of a broad arabesque band, the ground con-
sists of a central panel of one colour, and a margin of another.
It is the general aim so to arrange the design as to have about
nn equal quantity of each colour, to make every combination
effective, or without the predominance of any one colour.
Before glueing such works together, it is sometimes required
to take off a printed impression for future use; in such cases
one thickness is entirely stripped off, and those pieces of this
thickness which best display the character of the pattern, are
slightly glued on their corresponding places on the two thick-
nesses, and project therefrom in the manner of type ; so that
736
BUHL-WORKS IN BRASS AND PEARL SHELL.
they alone receive the printing-ink, and return it to the paper
pressed upon them with the hand, or with a tool handle used as
a burnisher.
Brass borders, technically known as Vandykes, are worked in
narrow slips, and in other respects as above, except that unless
a small hole is drilled through the brass and wood for the saw,
it is allowed to cut its own path from the outside edge of the
materials, and which is more usual. The true buhl, or the wood
ground with brass scrolls, is laid down in four or more pieces
around one box or panel ; and the counter, or the brass ground
with wood scrolls, upon another.
When the material is small and costly, as pearl-shell, it
becomes necessary to use two or several pieces, accurately placed
edge to edge, to cover the entire surface to be ornamented ; and
the joints are placed where least observable in the pattern.
The paper knife, from part of which fig. 718 was drawn, required
eight pieces of pearl shell; in using this material, a hole is
made in the wood close against the pearl, and the saw is sent in
from the edge of the same. The counter, when glued on another
veneer, is not inlaid of the irregular angular form of the rough
pieces of pearl, but it is cut around the general margin of the
pattern, as at the one part of fig. 719, which represents the
counter to fig. 718.
Fig. 718, the buhl or true buhl.
Fig. 719, the counter or counterpart buhl.
Inlaid by ordinary cutting.
Inlaid by internal cutting.
Sometimes, to give additional elaboration and minuteness, the
saw is made to follow all the device of the counter, and leave a
MAIMJI 1 IH\ UOKKK. 737
narrow line of pearl both within and without : this is called
internal cutting, and is represented in figure 719; but in
general, the counter fails to present the same good effect as
that of the true buhl, in which the drawing of the ornament
is more eHVctually preserved ; und in the internal cutting the
pattern presents a thready or liny appearance.
Before concluding this part of the subject, it deserves to be
noticed that in the more minute buhl works, the parts are not
cut exactly square, but slightly bevilled, so that the pearl may
be left a trifle larger than the interstices in the wood, to com-
pensate for the saw-kerf, and make the fitting close as regards
the true buhl. But this bevilling is prejudicial to the counter,
as the line of junction in it becomes wider than usual ; this
defect is, however, considered to be less observable in the coun-
ter, and which is also the less valuable piece. The stringing* t
or the straight and circular lines combined with pearl buhl work,
are mostly of white metal, such as tin or pewter, and are inlaid
with the routing gage.*
In buhl works no part of the material is wasted, and the
whole of the work is cut at once. The circumstances are
entirely different with the marquetry works now to be de-
scribed, of which a slight specimen is represented in fig. 720,
Fig. 720.
The frouBd BUck Ebony. Hit pen Iram. arc of Bolljr lUinrd (TM». Botrhi-d. tod rnjnurd.
llnllV Whll*.
MiM. Uolly.
I. ..-
• Buhl works of brass and wood, are sometimes made by itamping instead of
tawing. As however the action of stamps and punches will be considered in a
subsequent chapter, it need only be here observed, that the brass inlay, whether a
honeysuckle or other ornament, is stamped out of sheet brass, and the wood veneer
is stamped with the name tools; the brass honeysuckle is then inserted into the
cavity in the wood as before. This method produces, so far as the nature of the
materials will allow, an absolute identity of form, but it must be obvious the mode
is not applicable to small patterns, as the punches then inflict too much injury on
the wood ; neither does the stamping admit of the unbounded choice of design
attainable with the saw, as the punches are necessarily expensive and limited to
their particular forms.
3 B
738 MARQUETRY WORKS.
wherein the ground is ebony, and the flowers or other orna-
ments are made of coloured woods, as denoted by the annexed
names. The dyewoods are used so far as they are available,
and the greens, blues, and some other tints, are of holly stained
to those colours. Each different leaf or coloured piece is pro-
duced one at a time, and mostly requires two cuttings, which
may be accomplished in three several ways.
In the first mode, an engraving of the design is carefully
pasted on the ground or counter, and cut out entirely; after
which the several leaves are sawn out from different veneers, by
aid of another impression of the engraving cut into pieces, and
the leaves are inserted in their respective places ; this mode
requires extreme exactness, but admits of complete success.
In the second mode, the design is also pasted on the counter,
which is then left entire : the leaves are cut out from woods of
appropriate colours, and are then glued on the respective parts
of the paper pattern on the counter. The projecting leaves are
cut in, either singly or in groups, with the saw, which is just
allowed to graze their external margins. The leaves are then
all parted from the ground, and inserted in their respective
apertures in the counter. By this, or the counterpart method,
the fitting becomes more easy, and the cuts may be slightly
bevilled, to improve the closeness of the joints.
In the third mode, the separate leaves to constitute the inlay,
are cut out from the different coloured veneers, and glued in
their appropriate positions on a sheet of paper. A sheet of
white paper is also glued or pasted on the veneer to be used for
the counter or ground ; and further, a sheet of the blackened
or camp paper, such as that used in the manifold writers, is also
required.
The three are assembled together — at the bottom, the veneer
with the paper upwards, then the camp paper, and at the top
the leaves, the backs of which are then struck at every part, with
several blows of a light mallet, so as to print their own impres-
sions on the white paper. The printed apertures are then cut
in the counter one at a time, so that the outer edge of the saw-
kerf falls exactly on the margin of every aperture.
In this, or the third mode, the fitting of the parts may bo
made unexceptionably good, as the operation is not prejudiced
by the unequal stretching of the paper, which is liable to occur
< III IM.VR, OR l<: \ll\0, 8AW MACHINES. 739
\\ l.rn t\vu copies of the engraved design arc employed, as in the
tii-t and second modes.*
Tin- ribs and markings of the leaves in marquetry work, are
made by cuts of the saw, or scratches of the graver, which
-.(• tilled \\ith the fine wood dust and glue.
Occasional assistance is derived from the judicious disposition
of the grain of the wood ; and the shading of the leaves, to give
them roundness, is obtained by scorching their edges by holding
them near a heated iron before they are laid down. In this
manner white roses and other flowers with many leaves are most
successfully imitated in holly; the several leaves being cut out,
scorched on the edge, and grouped together to form the flower,
before incision. Ivory is used for very white flowers ; and ivory,
either white or stained, and also pearl shell, and other materials,
are used for insects, and parts requiring additional brilliancy of
effect.
SECT. IV. RECTILINEAR, OR RECIPROCATING, SAW MACHINES.
Rectilinear sawing machines are for the most part derived
from, saws used by hand for similar purposes ; and under these
circumstances it appears desirable that the machines to be
noticed should, so far as practicable, be introduced in the order
adopted in the last section ; namely, machines derived from the
felling, cross-cutting, and pit saws, and those from the frame,
bow, and buhl saws.
Few sawing machines have been made for felling timber,
because the labour of removing the machines from tree to tree,
in general outweighs any mechanical advantage to be derived
from their use. In the most simple machine of this kind, the
saw is formed as the arc of a circle, attached to a wooden sector
moving on its center, and worked with reciprocating motion by
a horizontal lever.f
• Aa a more expeditious mode of transferring the pattern than with the mallet,
the three parts above described, havo been squeezed in a fiat screw press, this fails
to bring up the impression, from the unequal thicknesses of the Tcneers ; the hydro-
static press does not produce the required effect, and is liable to crush the wood
from its enormous force ; but tho rolling press, such as that for copper-plate
printing, was tried by Holtzapffel and Co., and found to succeed in all respects in
transferring the pattern.
t Another construction for A felling and cross-cutting saw, which is more
elaborate, is described in the Mechanics' Mag. vol. ii. p. 49-50 ; and at vol. iii. p. 1
of the same Journal, is a proposition for a pit-aaw, which, as well aa the above, it
I -2
740
CROSS-CUTTING SAW MACHINES.
In cross -cutting .taw-machines erected in the Portsmouth Dock-
yard and Woolwich Arsenal, the timber is laid as through a
doorway, the posts of which are double, so as to form two nar-
row grooves for the guidance of the saw; this resembles the
ordinary cross-cut saw, except that it has two guide-boards
riveted to it, in continuation of its length, and the boards work
freely through the grooves in the posts. The saw is actuated by
a vertical lever, or inverted pendulum, moved by the steam en-
gine, and the workman bears down the opposite end of the saw
with any required degree of force ; the saw is guided in its first
entry by a board with a saw-kerf, which then rests upon the
timber, and when not in use the saw is turned up on its joint,
leaving the doorway free for the reception of other timber.*
A cross-cutting saw machine of a more exact kind is erected
at the City Saw Mills : the saw-blade is strained in a rectangular
frame, which both reciprocates and descends in a vertical plane.
The machine has a large double cross ; the two horizontal arms
have grooves that receive the rails of the saw frame, and which
is reciprocated by a crank and connecting rod ; the vertical arms
of the cross fit in a groove formed by double vertical beams.
The cross and saw frame are
almost counterpoised, so that a
moderate psessure alone, and not
their whole weight, falls on the
saw teeth, and the timber is
clamped on a railway or slide,
which is at right angles to the
plane of the saw's motion.
A cross-cutting saw machine
worked by hand, that is much used
on the Continent and in America,
for cutting firewood, is repre-
sented in fig. 721. The wood is
laid in an X form sawing horse,
and fixed by a chain and wooden
lever, which latter is brought
under a peg. The frame saw is suspended by its lower angle in
is proposed to work by means of the oft-repeated scheme, of a heavy pendulum
put in motion by manual power.
» See Roes's Cyclopaedia, Art. Machinery for Manufacturing Ships' Blocks,
Vol. xxii. ; also Encycl. Metrop. Part Manufactures, Art, 532.
Fig. 721.
VKRTK M. -\\\ M\( MINIS HIU\I.\ 11^ POf 741
the elrft of a lever that swings as a pendulum when the saw
frame is moved. Tl. iipports and guides the saw frame,
the action of which is assisted l>y the momentum of an adjust-
able weight, built out at right angles to the suspending lever.
The saw always rests on the timber, and cuts both ways; and
being guided in its required position, a person but little experi-
enced in the use of the ordinary frame saw, can exert his whole
strength in the act of cutting, and accomplish the work expcdi-
tiously, especially as the saw is longer than that shown on page
726, and employed in the ordinary manner for the same purpose.
Upright or reciprocating saw machines, are largely employed
to perform that kind of sawing which is usually done at the
saw-pit ; the larger upright or frame saws are used for cutting
large round or square timber into thick planks and scantling,
the smaller for cutting deals into boards. The earlier of these
machines appear to have been those for round timber: they
were mostly built of wood and driven by water power, these
have been repeatedly described.*
The vertical saw mills now used in England are made almost
entirely in iron, and driven by steam power, and as the several
constructions differ but little either in respect to principle or
general arrangement, the modern frame-saw for deals, fig. 722,
• The reader interested in the practical details of the earlier saw-milk, is
directed to Gregory's Mechanics, 1807, vol. ii., p. 321 ; and, in addition to tho
authorities there quoted, he will find useful matter on the subject in Hassenfratz'a
Traitf de FArt du Charptntier, Paris, 1804, in Evan's Young Millwright, and
Miller's Quide, Philadelphia, 1821, and more particularly in the reprint of Belidor's
work, Architecture I/ydrauliqve, avec Notct, par M. Navier, Paris, 1819.
In Season's lAttrumcntarum, published in 1578, at Plates 13 and 14, are two
very curious and graphic drawings of saw -machines driven by manual power; tho
one by a crank and winch-handle ; tho other by a pendulum pulled as a church
bell, and acting through the medium of a right and left-handed screw, and a system
of diagonal links, as in the so-called " lazytongs." One of the saws has curvilinear
teeth, of which 1, 3, 5, 7, cut during the descent, and 2, 4, 6, 8, during the ascent
of the blade.
In the saw invented by Lieutenant J. W. Hood, for cutting through ice, the
blade is suspended from the end of a lever, like that of an ordinary hand-pump,
and has a heavy weight beneath the ice. The axis of the lever is in a wooden
frame, or sledge, the progression of which is caused by the end of a rod or paul-
that sticks into the ice ; the rod being jointed to the lever a little in advance of its
pivots, thrust* the frame and saw some three or four inches forward during the act
of cutting. This ice-saw is worked by two to four men, whereas the previous
methods used in the Greenland fisheries, with a triangle and pulley blocks, required
from twenty to thirty men.— Trans. Soc. of Arts, 1827, voL xlv., p. 96.
742
VERTICAL SAW MACHINES, DRIVEN BY POWER.
will be principally spoken of. In this drawing the whole of the
mechanism has been brought into view, by supposing the floor
to have been removed, and some unimportant alterations to
have been made; in reality the pedestals F F rest upon the
floor, and the machine occupies considerable length.
The stationary frame work in fig. 722 consists of two standards
or vertical beams, in front of which are fixed two accurate square
bars, by means of six loops. The sliding saw frame shown
geometrically in fig. 723, has four vertical and two horizontal
bars and is cast in one piece, or as a rectangular frame, which is
attached to the stationary square bars b b, by appropriate bear-
VEKi IMS l>K I'oWER.
ings at the tour angles. One central crank is in general used,
hut for greater di-tim -tur-«>, t lie drawing is inailr from a machine
having two exterior cranks, although one only is represeir
the crank rods are not attached uuvetly to the saw-frame, hut
to a floating lever, which is jointed at its center to the saw-
frame; so that even supposing the two cranks to be a little
: nnlar in length or angular position, they nevertheless move
the platform equally, without straining or racking it.
\Vhen only one crank placed beneath the floor is emp!
it is needful, both to avoid excessive height in the machine, and
the disadvantage attending the action of a short connecting rod,
that the latter should pass freely through an oval loop in the
lower cross rail of the saw-frame, and be united to the upper
rail ; sometimes the crank shaft is fixed to the ceiling of the
Imilding, but this construction is the least in estimation. The
crank shaft, in addition to the driving pulley, has always a heavy
fly-wheel to equalise the action of the machine, but which is not
shown in the drawing.
Two deals are usually sawn at once ; the parts now to be
described are therefore in duplicate, although in the figure, one
deal is supposed to be removed for the purpose of showing the
mechanism more distinctly. Generally each deal has to be cut
into three boards, and two saws are then employed on each side
of the frame ; but sometimes as many as eleven thin saws or webs
are used, then producing twelve thin boards or leaves from each
deal. The saws, of which one is shown at * #, have buckles
riveted to them, and these pass through mortises in the top and
bottom rails of the sliding frame ; the buckles at the bottom are
solid and shaped like an inverted T, those at the top have mortises
and thin steel wedges ; the T pieces and wedges bear on the
outsides of the frame.
The distances between the blades are adjusted by interposing
pieces of wood, and pressing the whole together by the side
us, after which the saws are separately tightened by the steel
wedges : these details are sufficiently manifest in the gcomctrieal
\ie\v, l'i£. 7~-'i. It is to be further ob-rm-d that the edges of the
saws are not quite perpendicular, hut have a little lead, or then-
upper ends overhang the lower about J or J inch, to extend the
cut throughout the descent of the blade, and to carry the *a\\s a
little distance from the cuts, in mling or back stroke.
744 VERTICAL SAW MACHINES, DRIVEN BY POWER.
The two deals lie on a series of rollers built on pedestals, of
which two only are shown at F F; the rollers also support a
long rack, which, at the left of the figure, has dogs or nippers,
that grasp the end of the deal by means of a side screw. The
weight to the left of the figure, pulls the longer end of a
horizontal lever, the shorter end of which (not seen), has a
roller that presses the part of the deal contiguous to the saw,
against a fixed vertical plate or fence, so that the cuts become
exactly parallel with the side of the deal, whether it be straight
or crooked.
The deal is advanced by means of the rack and pinion, which
are actuated by a ratchet movement as follows : an eccentric on
the main shaft alternates the shorter end of the lever I, and to
the longer end of the same is fixed the ratchet or paul, which
according to its distance from the center, slips over two or three
teeth in its descent, and in rising thrusts the ratchet-wheel round
the same distance, and by its connexion with the pinion for
the rack, advances the rack and wood a proportionate quantity.
The retaining pauls or detents on the top of the wheel pre-
vent its retrogression ; when they are turned back, the wood
ceases to advance, and the slide may be run quickly back by
a winch.
The plank frame by the late Mr. Benjamin Hick, of Bolton,
(of which a model is deposited in the Museum of the Inst. Civil
Engineers) has no long rack. Each deal is grasped between
two grooved feeding rollers ; the one fixed to the framing
of the machine, the other pressed up by a loaded lever, and
moved a small step at a time, by a ratchet as usual.
The single saw frames above described make about 100 to 120
strokes, of 18 or 20 inches long, in the minute, and cut two
12 -foot deals in from five to ten minutes ; the saws require to be
sharpened about every tenth round, or journey, for hard deals, and
every twentieth for pine. Similar frame saws are made double,
so as to operate on four deals at a time ; the crank is then
double, and so contrived that the saws in one frame descend,
whilst those of the other ascend. By this arrangement the
vibrations of the machine are somewhat lessened, so that the
velocity may be increased to about 160 or 200 strokes in the
minute ; but the time occupied in fixing and adjusting is also
greater, so that but little if any real advantage is obtained.
\IKII. VI. ^V\\ MV(IIIM>, I»KIV|\ IIV TIIK FOOT.
Sawing mat-nines for round timber, an larger, stronger and
somewhat dillrivnt from the deal fi-aim-.. The timber-slide moves
on tillcts or V. V.'s, which are fixed to tbe floor, and panel
between the standards of tbc saw frame; the timber slide has
strong vertical end plates, through mortises in which stout iron
spikes or dogs are driven like nails, into the ends of the required
nlauks. The dogs are then secured by side screws or wedges in
the dog plates, from which they project sufficiently, to allow t la-
saw blades to stand between the end of the timber and the dog
plate, at the commencement of the sawing.
The sliding frames carrying the saws for timber frames are
longer than for deal frames, and those in the Government saw
mills at Woolwich rest in contact with rectangular fillets on the
standards, against which they arc pressed by powerful springs, so
that the square bars bb, fig. 723, are dispensed with. In these
machines the blades are strained one at a time by a loaded lever,
like a Roman steelyard, which gives to each the tension of about
one ton, and whilst under this tension, the wedges are driven
just home, but without violence ; each blade becomes therefore
tense alike. Various contrivances are added to vertical saw
machines driven by power, so that, when the saws have arrived
at the end of the timber, the motion of the wood or that of the
entire machine may be arrested automatically.
Rectilinear sawing machines are not much used for those
kinds of work that arc performed with the ordinary hand saws,
back saws, and frame saws, used in carpentry; but two useful
sties mecaniques suited to works of this scale are described in the
Manuel du Tourneur, and fig. 724 is reduced from one of these.
The saw frame has a central wooden rod, and a blade on each
e.lure, which are stretched by clamps, screws and nuts, much as
usual. The saw is guided perpendicularly by fixed wires ; these
pass through holes in the cross heads of the saw frame, which
are sometimes fitted with rollers to relieve the friction. The saw
frame is suspended from a bow spring attached to the column
erected on the bench ; and the lower end conimnnieates by a
double-ended hook with a light treadle. The spring, when left
to itself, raises the saw frame and treadle some 8 or 10 inches,
and the pressure of the foot gives the cutting motion.
746 SCIE MECANIQUE FROM THE MANUEL 1>E TOURNEUR.
For straight pieces a wide saw is used, and the work is guided
agaiust a square fence, which overlaps the front edge of the
bench, and is fixed by a binding screw passing through a mortise.
For bevilled pieces a chamfered bar c, is fixed to the right hand
side of the bench, and carries a square sliding block, surmounted
by an angular fence, with graduations and a clamping screw ;
the work is laid against the angular fence, and moved upon the
chamfer slide past the saw. For circular works a narrow blade
is employed, and the popit head or center point connected with
the stationary frame work, serves as the axis of motion for the
piece of wood to be cut.
In order to leave the bench unobstructed, so that large pieces
may be sawn, the guide rods upon which the saw frame works
are discontinuous ; the lower parts terminate beneath the bench,
the upper are fixed to cross pieces, connected with a dovetail bar,
itself attached in front of the column, so that the group of pieces
carrying the upper wires may be fixed at a greater elevation to
MA« 'I UK HAW MM II
admit of thicker work. The back edges of the blades run in
•aw-ki riV in tin- lower rail of the guide frame.*
Tlnvr .small reciprocating saw machines, fitted upas adjmn-t-
to the latin-, \\ill now be described; their constructions
rntuvly ilitlViviii, and they were planned by their respe<
inventors quite independently of each other. The one first de-
scribed was especially contrived for buhl cutting ; this appears
however, to be far the least valuable application of these machines,
as they may be much more efficiently used for various works
similar to those done by the slender bow or sweep saw. The
i \trcme delicacy of buhl work, is incompatible alike with tin
encumbrance arising from the mechanism, and the friction of tin-
work upon the supporting platform.
In Mr. Mac Duffs buhl cutting machine, the saw is stretched
in a frame about 1 to f> inches high and 10 to 14 inches wide ;
t IK- frame reciprocates vertically upon small fixed
wires, by the modification of the crank shown in
fig. 725. The pulley e, beneath the lathe bearers b,
receives continuous motion from the foot- wheel, the
lower end of a cord r, is fixed to a pin about an
inch from the center of e, passed around the fixed
pulley />, then between the bearers to the saw
frame, which is raised by a spiral spring j by this
arrangement, the parallelism of the cord is obtained.
The work is supported upon a table or platform,
midway between the path of the saw frame. f
* A machine on a somewhat larger scale was erected by Mr. Brunei, at the
Woolwich dockyard, and worked by the peculiar but expensive parallel movement
of the interior epicycloid. There is a fixed wheel, aay of 16 inches diameter, with
internal teeth, and a corresponding pinion of 8 inches diameter, carried round by,
and revolving upon the end of a crank of 4 inches radius ; the pinion carries
a stud by which it is connected with the saw frame. The velocities of the crank
and pinion are as 2 to 1, and in the tame direction ; the stud, if attached to the
center of the pinion, would move in a circle of 8 inches, but when attached to the
edge or pitch line of the pinion, it reciprocates in a right line, 16 inches long ; the
.:* placed in any intermediate position, would travel in an ellipsis,
A reciprocating saw machine for sawing, boring, and manufacturing bavilled and
curvilinear works in wood, was patented in 1833, by Mr. Samuel Hamilton, and
is briefly noticed in the foot note following the application of the circular saw to
curvilinear works.
t Mac Duff's buhl saw received the prize of 102. awarded by Dr. Fellowes :
and is fully described in the Mech. Mag. 1830, voL ziii. p. 129 ; at page 285 of the
same volume Mr. Mac Duff has described a larger and more simple machine of
the same kind.
748 LUND'S VERTICAL SAW MACHINE.
In the two following machines the saw is unprovided with the
frame, by which, under ordinary circumstances, it is stretched
and guided, these functions being fulfilled by the motive parts of
the respective apparatus.
Mr. Lund's vertical saw machine, which is represented from the
back in fig. 726, consists of a bench with foot wheel and treadle,
surmounted by a rectangular frame, the lower rail of which is
rebated to fit the bearers ; the center rail is extended into a plat-
form about three feet square, which, for the sake of portability,
consists of two wide flaps with hinges and brackets, somewhat
as in an ordinary pembroke table. To the extremities of the
upper rail are fixed two long and narrow springs, made of ham-
mered steel, that spring downwards when left to themselves.
The ends of the saw are grasped in screw clamps, formed at the
ends of square wires, working rather freely in the two outer rails,
within holes fitted with metal. The lower saw clamp is connected
by a cat-gut with an eccentric and guide pulley, as in Mac Duff's,
but the eccentric shown detached in fig. 727 has more range, the
traverse being sometimes 4 or 5 inches.
The upper saw clamp is connected with the straight springs
by means of a catgut line, reeved in the manner shown more at
large in fig. 728 (one of the side frames being removed), the
catgut proceeds from the springs, over the two fixed pulleys, and
under the pulley on the top wire or clamp ; this arrangement
equalises the actions of the springs, and gives a parallel motion
to the blade, the back edge of which lies towards the operator,
and works in a notch on the edge of a hardened steel disk, inlaid
in the platform. One end of the catgut has a small circular
button, which is passed through a round hole in the spring, and
then sideways into a notch, so as to be readily detached for the
removal of the saw.
Mr. Lund's machine is simple and effective for inlaid and fret
works, and a variety of thin curvilinear pieces, which occur in
cabinet work and pattern making. For cutting parallel and
bevilled pieces, appropriate guides are added to the platform,
similar to those elsewhere described. For circles, a brad-awl is
passed through the center of the work into the platform, or rather
into a subsidiary and common platform then added. And to
shorten the length of stroke during the working of the machine
as required in sawing around small curves and rounded angles,
a sliding bolt beneath the platform, is thrust across the path
LUND'S AM) MUM. \\ II 1 IS*S VBftTICAL SAW MAC1IINK8. 749
•lie saw, 80 th:it the HMVIU »>f the saw to the full height
i- thru i>iv\eutnl b\ the temporary increase of thickness in
Fig*. 726.
the platform, as the saw clamp strikes against the sliding-bolt
or slide.*
Fig. 729 is copied from Professor Willis's sketch of a vertical
saw for curvilinear works, constructed by himself in 1837. The
frame of the machine is elevated above its true position to
show the details, and is clamped on the bed of a lathe or
* Mr. Land makes an ingenious use of this machine for inlaying the instrument*
in drawing-cases lined with velvet. The bottom of the trays are glued up in three
thicknesses, the grain of the inner piece being crossways, of the outer lengthways,
a piece of white paper is added to receive the outlines of the instrument*, the spaces
for which are then cut in the saw machine, with a saw thinned away at the back,
and very much set to cut a wide path.
The inner pieces having been removed, are split through the joint and glued flat
down on a piece of velvet; each inner piece is then cut round with a penknife,
leaving the face alone covered. The principal piece, or skeleton, is then glued and
laid on another piece of velvet, which covers the holes as in a drum ; the velvet
is cut through at various parts of each aperture, and folded round the edges of the
hole*, and lastly, every removed and covered inner piece, is pushed into its place,
•i stretches and smooths the edges of the velvet, and completes the work.
As the central pieces are in three layers, the cells may be either of one-third or
two-thirds the entire depth, at pleasure.
Mr. Lund's saw machine was constructed and used in 1828.
750
PROF. WILLIS'S VERTICAL SAW MACHINE.
grinding frame, and the saw derives its motion from an eccen-
tric carried by one of the ordinary grindstone spindles. This
eccentric is a pulley of hardwood cut in half and screwed against
the face of the mahogany pulley. A loop of wire embraces it,
and connects it with the lower spring, so that when the spindle
revolves the spring is thrown into rapid vibration ; the springs
are of wood, 21 inches long and 2|- inches broad.
The saw is clamped at each end in a small iron clamp ; the
lower clamp is joined to the lower spring by the same steel pin
that carries the loop of wire. The upper clamp has several
hooks filed in its edge, any one of which can be hooked on a
steel pin fixed to the upper spring. Thus the saw is carried
and stretched at the same time by the two springs, and can be
readily disengaged, either by unhooking the upper clamp or by
uuclamping either end. The lower spring is fixed to the frame,
the upper is fixed to a separate piece of wood that can be ad-
justed to different heights, and the platform is 12 inches above
the bearers.
The only point that requires further consideration is the
adjustment of the saw in the springs, so that it may traverse as
nearly as possible through one and the same point of the platform,
notwithstanding that the ends of the springs nearly describe arcs
of circles, and therefore carry the extremities of the saw slightly
to and fro during its move-
729. vS,, ments.
The vertical distances
between the springs at their
roots, where they are fixed
to the framing, and at their
pins where they carry the
saw, must be so adjusted,
that when the saw is at the
top of its stroke, the lower
spring is horizontal; and
when at the bottom of its
stroke the upper spring
must be horizontal, and the
platform midway between
the two horizontal lines.
In this condition, \\ith a range of two or even three inches, the
one curvature will neutralise the other at the platfozm, as in
MM MINES FOR SMALL WOlu
some of tin- p:ir:illel motions, which may be proved by ;i diagram
carefully drawn on paper.
Professor Willis has used this machine extensively for cutting
<>ut in thin wood, models of (Jothir ti so mathcm.v
runes in illustration of the teeth of wheels and other elements
of mechanism. To adapt the machine to take cither short or
long strokes as required in buhl cutting, without discontinuing
the motion of the foot- wheel, Prof. Willis proposes to apply a
contrivance to the eccentric, analogous to that explained in hU
Treatise on the Principles of Mechanism, p. 1 1."».
A very curious sawing machine, the connecting link between
ilincar and circular saws, was patented by Mr. Newbury in
1808, and is thus described . — " Nr. Newbury's engine is formed
by a long and very flexible blade of a similar nature to a clock-
spring, which passes over two rollers of considerable diameter,
placed in the same plane, and whose extremities are united so]as
to form a band round the two rollers. When this blade is intended
to act as a saw, one of its edges is cut into teeth of the usual
shape, and the substance to be sawed is placed on a stage,
through which the blade passes, and is pressed against the blade
with the necessary force, and in the direction proper to produce
the shape required for it."* Guides for cutting rectilinear,
curvilinear, and circular pieces are alluded to, the description
does not however state the most difficult point of the construction,
namely, the mode adopted in joining the ends of this elastic
blade, or ribbon saw.
SECT \. COMMON APPLICATIONS OP CIRCULAR SAWS TO
SMALL WORKS.
The remainder of the present chapter will be devoted to the
consideration of machinery for circular saws ; and in treating
• See Retrospect of Philosophical Discoveries, 1*06, vol. IV., p. 222. Tho
following paragraph respecting Newbury's flexible saw, appears on page 527 of tho
last edition of Belidors Architecture I/ytlraulIque, arec A'ote*, par M. Navier,
Pant, 1819.-—
it a lame jlex'Me el tant Jin." — " Ctttt intention a M propotte en AngUterre,
MOW it paratt qn'on y dontait de *OH lucre*. EUe a itt employee arte arantaye en
Fraud par M. Tonrondt pour refendn let lUemue q*i competent let tuyatuc det
vittfArckimUt. (BuUetindeloSocUtc'd'EnvnragemeHt.JuilUtUlS.) Lt modMt
de ta machine at dtpott an Oontenattirt det Artt et Mftiert."
752 ARRANGEMENT; SAWS FIXED ON LATHE CHUCKS.
this extensive subject, it is proposed to present the matter in
the following sections.
V. Common applications of circular saws to small works.
VI. Common applications of circular saws to large works.
VII. Less common, or specific applications of circular saws.
VIII. Circular saws and machinery for cutting veneers.
It is further to be observed that in the present or fifth section,
in speaking of the construction and application of small sawing
machinery, or that which may be conveniently used by the
amateur, the matter will be arranged under the following sub-
divisions.
•
1. Lathe chucks for very small saws.
2. Spindles for saws of medium size.
3. Platforms, or tables and benches, for saws of medium size.
4. Stops to prevent the vibration of flexible saws.
5. Parallel guides.
6. Sawing the sides of rectangular pieces.
7. Sawing grooves, rebates and tenons.
8. Sawing or cross cutting, the ends of pieces, either square
or bevilled ; or those works in which the angular variations are
in the horizontal plane.
9. Sawing bevilled edges, and prismatic pieces ; or those
works in which the angular variations are in the vertical plane.
10. Sawing geometrical solids and irregular pieces; or those
works in which the angular variations are in both the horizontal
and vertical planes.
The sub-divisions 1 to ] 0, when a little modified, denote also
the arrangement followed in Sections VI. and VII.
1. Lathe chucks for very small saws. — Circular saws not
exceeding one or two inches diameter, are occasionally mounted
on lathe chucks, similar to that represented in fig. 730, which is
not only the most simple, but probably one of the earliest modes
in which the circular saw was used. The chuck should be of
moderate length, with a tenon to fit the hole in the saw, and a
central screw or nut to fix the same, as represented.
Opticians use this mode for the small thin saws with which
they cut the notches in the tubes serving as springs in pocket
SAWS FIXED DN I V I II I. 01
-copes. Carvers in ivory and similar materials employ .small
In if thick saws, the edges of which are of round, angular, or
other sections. In each art tin- objects are mostly applied l»y
the hands alone.
rutting the notches in the heads of screws for mcch
tmetion, thirk saws are similarly employed. The screw is
held in a socket, fig. 731, the end of which is tapped ti-
the thread of the. screw, and in cutting the notch, the socki
supported an inch or more from its extremity, upon the edge of
the rot for the turning tool. The socket in wriggled up and
down as a lever, to make the bottom of the notch tolerably
straight, instead of concave, and the precautions to make the
cut diametrical will be found at the beginning of page 723.
The gas-burners designated as bat's iriny burners have a narrow
slit through which the gas issues : these are cut in a similar
manner by thin circular saws; and Mr. Milne, gas-fitter of
Edinburgh, serrates such saws with a screw-cutter or tap, as in
making the teeth of a worm-wheel (see pages 591-2), but the
cutter should for the present case have one side of the tin
perpendicular, to produce saw teeth of the customary form.
733-
V
In cutting the knuckles and tenons for joints, fig. 732, the
work is usually supported on a small iron platform, fig. 733, the
surface of which is horizontal, with a notch to receive the saw,
and a cylindrical stem to adapt the platform to the bed piece of
the common rest. The platform is fixed a little below the axis,
to place the knuckles exactly central to the saw, so as to make
the notches equally deep on both sides; and if the surface of
the platform is parallel with the axis of the spindle, the notch is
sure to be perpendicular or square to the side of the work.
Sometimes two saws are used upon the same chuck or spindle,
3 c
754
SAW SPINDLE.
to ensure parallelism in the sides of the middle piece or tenon ;
and similar methods are commonly used in sawing, notching,
and drilling the small wooden mechanism of piano-fortes. For
some of these works, especially those in metal, the saws are not
always mounted on lathe chucks, but occasionally on small spin-
dles similar to that drawn in the next figure.
2. Spindles for circular saws of medium size. — For sawing
ordinary works in wood, the above arrangements are mostly
insufficient; as the saw should be further removed from the
pulley or lathe head, to enable pieces of moderate width to be cut
off, and also larger in diameter to serve for thicker pieces. The
saw is then mounted on a spindle such as that shown in section
in fig. 734 : the saw plate fits upon the cylindrical neck of the
spindle, and is grasped between the two flat surfaces of the flange
and loose collar, (which latter is shaded) and pressed forward
by the nut. A steady pin, or a small wire (represented black)
is inserted obliquely in the spindle, and passes through a cor-
responding notch in the saw. The steady pin constrains the saw
always to travel with the spindle, without depending on the
grasp of the nut alone.
Fig. 734.
The saw spindle, fig. 734, is frequently squared at one end,
and has a center at the other, to admit of being supported in the
lathe at its extremities, by the square hole chuck and popit head
respectively, so as to revolve together with the mandrel. When
the saw spindle is used independently of the lathe, it has a
center at each end for the center screws then employed, and also
a pulley to receive the band from the foot wheel or other motive
apparatus. In regard to the proportions of circular saws and
some other particulars concerning them, the reader is referred
to the table on page 784, near the commencement of the follow-
ing or sixth section of this chapter.
WOODEN PLATFORM FOR SAWS.
8. Platform* or tablet, and benches. — "Wooden platforms em-
ployed for supporting the work have sometimes iron stems, and
are in ; itsions of fig. 733, except that they are placed
abovr tl , so th:it one-third the saw-plate protrudes per-
pendicularly through the center of the platform. But a large
platform thus constructed is very weak, from being attached
only at one point; and every time the platform is fixed, there
is the trouble of placing the sa\v-kcrf exactly parallel with the
saw, otherwise great friction ensues.
The saw platform and apparatus in fig. 735, arc made almost
entirely in wood; they are applicable to the ordinary turning
lathe, and to saws not exceeding about 8 to 10 inches in
diameter. The wooden platform is supported at the front and
back, nearly throughout its width, upon the edges of the
wooden box, the position of which is defined by a tenon fitting
between the lathe bed, and secured by a bolt passing through
the same. The platform is hinged to the back of the box,
thus constituting as it were, a large and overhanging cover.
The lost process in the construction of the apparatus, is to fix
it upon the lathe bearers, and to allow its own circular saw
to cut the saw-kerf or slit in the platform, which thence
becomes exactly parallel with the saw.
Fig. 735.
In refixing the apparatus ready for work, the wood frame is
first placed loosely on the bearers, and the platform is turned up ;
the saw spindle is then adjusted between the centers, and lastly,
the platform is shifted sideways until the saw enters the kerf, the
entire wood frame is then secured by its bolt and nut ; but on in-
to the tenon beneath, there is no risk of the groove being other-
than parallel with the saw. Occasionally that part of the
3c 2
756
SMALL SAW MACHINE OF 1ROX.
platform which is contiguous to the saw, is covered with a thin
plate of brass to increase its durability.
The sawing apparatus, fig. 735, although made principally in
wood, will be found a very convenient appendage to the turning
lathe ; or the same parts may be used independently of the lathe,
upon a wooden bench or frame with a wheel and treadle, much
the same as that partly represented in the succeeding figure,
except that the wooden standards are then required to extend
above the bearers, so as to carry the center screws for the saw
spindle. The back board for receiving any parts of the work
under progress, and the drawer for the saws, are convenient for
their respective purposes, but by no means important.
The sawing machinery represented in fig. 736, although
generally similar to the last, is made entirely in metal, except
the wooden frame. The principal piece in fig. 736, or the bed
piece, is planed flat on its underside, and has a fillet to adapt it
to the lathe bearers or other frame ; the ends of the casting are
formed as popit heads, and are tapped for the reception of the
center screws, which support the saw spindle. The middle of
the bed piece is formed as the box or trough, to which the plat-
form is hinged by two center screws, tapped into projections on
the underside of the platform, the front part of which rests
upon the supporting screw, fitted into the bed piece.
Fig. 736.
In general construction the iron machine fig. 736 is a great
improvement on that in wood, fig. 735, in respect to strength
STOP! POR FLEXIBLE SAW!.
and permanent accuracy ; ami an the supports for the spindle
and platform, are all unhid in «>m- iron ca-tin-, the inechaiiiMn
is not subject to derangenx nt, and is quite independent of the
frame or bench, which may br i-ithcr that partly represented in
tin- li.u'inv, or the frame of an ordinary loot lathe after the removal
iie headstocks; or on any bench w hat>or\er, pro\ided nn
power from any source can be conveniently applied to the saw
spindle. And in the course of the following descriptions it will
be seen, that the latter machine, with certain additional mechan-
ism, is capable of performing, within the limitation of its size,
almost any kind of work to which the circular saw is applied.
4. Slops to prevent the vibration of flexible saws. — When the
diameter of the circular saw is considerable, compared with the
diameter of the flange on the spindle, the blade becomes very
flexible, and may be easily diverted sideways from the true
plane; the prevention of this is accomplished in many ways.
The saws used for slitting the thin wood of wbich cedar pencils
are made, are from about 4 to 6 inches diameter, and very thin,
so as to act rapidly and with little waste ; such saws have fre-
quently supplementary collars, or thick flat plates of brass, fitted
to the cylindrical neck of the spindle, and extending to within
\ or \ of an inch of the edge of the saw, which thereby nearly
acquires the stiffness of the collars themselves. But as saws are
in general required for thicker wood, such large flanges are
mostly inadmissible, and other methods must be employed.
For small saw machines having wood platforms, it is generally
considered sufficient, that the saw should work in a narrow cut or
groove made by the revolving blade in the platform, and which
allows the saw but very little lateral play ; as the teeth can no
.rcr cut when the smooth part of the blade rubs against the
slit. The friction will in time wear away the wood until the
slit becomes inconveniently wide, but a fresh piece of wood can
IK- thru inlaid, and another notch made by the saw as at fii>t.
Metal platforms are sometimes made in two parts for the
convenience of forming the slit for the saw, but friction again-t
the metal would blunt the t« th, and should be avoided. In
such cases, the inner edges of metal platforms made in two
pieces are usually tapped for small screws, which are adjusted
nearly to grasp the smooth part of tin thin the
PARALLEL GUIDES FOR SMALL CIRCULAR SAWS.
line of its teeth. The platform fig. 736, is made in only one
piece, with a wide shallow groove in its upper surface, which is
again filled up flush with a bar of iron, in the end of which is a
deep notch to admit the saw, and at right angles thereto the
stop screws are inserted laterally in the bar. The latter can be
adjusted in the groove, to place the stop screws just within the
line of the teeth, after which they are twisted by their capstan
heads until they nearly touch the saw plates.
But stop screws, howsoever constructed, give rise to noise,
and are somewhat liable to wear the saw into grooves. A
preferable mode for small saws, is to inlay a piece of ivory or
hard wood in the groove on the top of the platform, and allow
the saw to cut its own slit ; or else to fit two pieces of ivory
into dovetail grooves, made transversely in the under sides of
the platform, and to advance them to the saw by adjusting
screws, but which, although a more costly method, is no better,
as in every case the stops should be as nearly as possible flush
with the platform; various other stops will be described in
speaking of large sawing machinery.
5. Parallel guides for small circular saws. — Saw machines of
every kind, depend very materially for their usefulness on the
various guide principles introduced into their several constructions,
and upon the advantage of which principles, as applied to cutting
tools generally, some preliminary observations were offered in
pages 463 to 471 of the volume now in the reader's hands.
In circular sawing machinery, the table or platform being a
flat surface, and the saw-blade at right angles thereto, all pieces
that lie tolerably flat on the saw-bench are sure to be so guided
as to be cut out of winding, and square with the face on which
they lie. But to guide them across in a right line, it is requisite
to have some kind of rectilinear guide parallel with the saw ;
the width of the piece sawn oft' then becomes equal to the dis-
tance between the saw and guide, and any number of succeed-
ing pieces may be produced exactly of the same width.
The guides for parallelism are constructed in many ways,
three of which, available for small sawing machines, will be
noticed at this place ; the jointed parallel rules are also used,
and will be described in subdivision 5 of the next section.
The most simple parallel guide, is a straight bar of wood fixed
SAWING RECTANGULAR PIECES. 759
to the platform by a screw clamp at each end, or by two screws
passing through transverse mortises iu the cuds of the bar; but
two sets of guaduations are then required on the platform, to
place the straight fence or bar exactly parallel with the saw.
Sometimes A shallow groove, inclined 30 to 40 degrees with
the saw, is made in the top of the platform, and fitted with a
slide, the overhanging edge of which is also inclined 80 to 40
degrees, so as to be always parallel with the saw; the variation
of width arises from placing the guide in different parts of the
groove. ThU may be considered a modification of the principle
employed in the Manjuois scales and parallel rule, but as a
saw-guide the range is rather too limited.
A more convenient guide was suggested by Professor "Willis
of Cambridge, and is shown iu figs. 735 and 736. The first is
simply a square, the two bars of which are not in the same
plane, as the one bar lies upon the platform, the other is flush
with it, and fitted to the back edge of the platform by a groove
and tongue joint : a screw-clamp is there situated, to fix the
one bar of the square to the platform, after the position of the
other bar has been adjusted to the width required in the works.
This parallel guide may be allowed to extend altogether beyond
the sides of the platform, so as to have fully twice the range
of the jointed parallel rules, to be described hereafter, and is
besides steady ali£e in every position, provided the surfaces
by which the two bars are united are sufficiently large, and
firmly joined. The parallel guide in fig. 736, is made iu iron,
and also after Professor Willis's plan; but the back bar, then
lies in a rebate in the platform, and is secured by a small clamp
and screw, partly seen.
6. Sau-iny the fides ofrectumjular pieces. — Before commencing
to saw a piece of wood with the circular saw, it is desirable, in
order to ensure accuracy in the result, that two neighbouring
of the work should be moderately straight, to serve as the
basis from which to commence; otherwise as the work is thrust
past the saw with the hand, it may assume different positions
in its course, and thereby give rise to enormous friction against
the saw, and may also present, when finished, curved instead of
flat surfaces.
Round wood is in general too large to be cut up with the
760 SAWING RECTANGULAR PIECES.
small saw-machines here referred to, but particulars of the mode
adopted iu large machines, are given iu the corresponding sub-
division of the next section. It may however be observed, that
when the first cut is diametrical, small round wood may be held
with tolerable facility to the saw, and it is sometimes sawn at
twice, or with two radial cuts, from opposite sides, but which
cannot be expected exactly to meet. When the first cut is
required to be on one side the center, it is much the best plan
to flatten some part of the wood with the hand-saw or plane, to
serve as the bed on which the work may rest upon the platform.
In sawing up pieces of plank-wood, the broad surfaces left by
the pit-saw will in general be found sufficiently accurate for
their guidance in that plane, so that the edges alone then require
examination, and one of these is sometimes corrected with a
jack-plane, for greater exactness.
When the saw has been put in rapid revolution, and so that
the teeth near the operator descend, the work is laid flat on the
platform and against the parallel guide, and is then gradually
advanced towards the saw. If the work be thrust forward too
quickly, the saw may be altogether stopped from the excessive
work thrown upon it, and if it be not advanced at an uniform
rate, the markings left by the saw will present corresponding
irregularities.
In dividing a piece of wood that is long* compared with its
width, it occasionally springs open as a fork when sawn, so that the
outside or guiding edge of the work, from having been originally
straight becomes a little concave. This is sometimes allowed
for by making the face of the parallel guide to consist of two
straight lines, a little distant one from the other, instead of one
continuous line, by fixing a thin plate to the principal piece by
countersunk screws. The set-off in the guide usually occurs a
little behind the cutting edge, and allows the work to escape the
saw, so as not to be scored by the ascending teeth at the back
part of the plate, and which are otherwise apt to catch up the
work, if small, and throw the pieces in the face of the operator.
It usually happens that many similar pieces are cut in imme-
diate succession; in such cases, the succeeding piece is frequently
made to push forward that which is nearly sawn through, by
which mode the risk of hurting the fingers with the saw is
avoided ; otherwise the piece is thrust towards the conclusion
with a stick of wood, having a rectangular notch at the end.
BAWINQ GROOVES, REBATKS, AND TENONS; CROSS-CUTTING. 7CI
The jointed platforms arc very convenient, aa they can be
turned up to shoot off an\ ae. •mnuliitiun of work or sawdust,
niul also for the removal of any little pieces of wood, which may
occasionally In-come wedded in the cleft beside the saw.
7. Satring grooves, rebates, and tenons. — When the platform of
;i circular saw machine docs not admit of any change of elevation,
as in that shown on page 765 and many others, the quantity the
taw projects through the table can only be varied by select
saws of different diameters, or by placing supplementary beds of
different thicknesses upon the platform ; the latter method
generally interferes with the action of the parallel rule. But
in the machine, fig. 736, constructed in iron, the hinged plat-
form may be adjusted by the regulating screw in front, so that
the projection of the saw through the table may, if required,
barely exceed the thickness of the wood to be operated upon, or
the saw may be only allowed to cut to a limited depth, and to
form a groove either in the side or edge of the work.
By making two incisions on the contiguous faces of the wood,
the solid angle may be removed, as in the formation of a rebate,
fig. 787, the same cuts again repeated would form the tenon,
fig. 788; but this process requires that the end of the wood
should have been previously cross-cut exactly square, in the
mode explained in the following subdivision of this chapter.
8. Saicing or cross-cutting the ends of pieces, either square or
devilled ; or those in which the angular variations are in the hori-
zontal plane. The most general guide for cutting the ends of
work either square or oblique, is shown in fig. 7ol>, and also iu
plan in figs. 7H', 111, and 712; it is applicable to every angle.
An undercut L'PM.U is made iu the platform parallel with the saw,
for the reception of a slide that carries a semicircular protractor,
is graduated, and may he fixed at any angle by the
thumb-screw parsing through its semicircular mortise into the
slide beneath. The slide has sometimes V grooves made in its
two sides, and the platform is then in two parts with bevilled
edges, corresponding with the V grooves. The work to be sa\\n
i> held hy the fingers in contact with the straight fence of the
guide, and the t\u> thus grasped are slid together past the saw.
762
SAWING PIECES INCLINED HORIZONTALLY.
The guide for angles is represented in fig. 740, in the position
for cutting rectangular pieces from the end of a long bar, and the
edge p p of the parallel guide, then serves as a stop for the width
of the blocks thus removed. By the similar employment of an
oblique position, such as that shown in fig. 741 ; rhomboidal
pieces of any angle and magnitude, may be as readily produced.
Figs. 737.
739.
IAAAA71*
740.
741.
742.
When the pieces are not cut from the end of a long rod, but
are small, and only require to be reduced to any exact size, it is
more convenient, to affix the stop for width upon the fence or the
semicircular protractor, as in fig. 741, and in this manner small
pieces can be easily sawn into regular or irregular polygons of
any particular angles and numbers of sides.
In cutting mitres, as for picture-frames, the once piece would
be cut by placing the semicircular fence in the position, fig. 741,
but for the other piece of the mitre, it is necessary to place the
semicircle as in fig. 742, so that the guide may precede the work
that is to be sawn ; consequently, unless the slide will admit of
being withdrawn from the groove, and replaced the other end
foremost, there should be two holes for the thumb-screw, and
two indexes for the graduations.
Although the oblique fence may be placed at the smallest
angle, and even parallel with the saw, yet when the pieces are
required to be thin and acute, it is more generally convenient to
prepare with the apparatus, fig. 740, a wooden guide of the parti-
cular angle, and of the form shown in fig. 739; p, being the
v \\SIM, iMl.il.v IMCUMU VERTICALLY. ~ ">
llcl rule-; g, the guide or bevilled block, and w, the work.
A separate wooden block is necessarily required for every angle,
and the parallel guide is still available in determining the general
width or thickness of the works.
\\lirn pieces arc parallel in one direction and bevilled in the
other, they nmy be cut out without any waste beyond tha;
from the passage of the saw. In such cases the work is prepared
M a parallel piece equal in thickness to the parallel measure of
the objects, and the work is turned over between every cut so a*
to saw the pieces " heads and tails/' or the wide end of the one
from the narrow end of the other, as shown by the dotted lines
in fig. 739. This mode is employed for ivory knife-handles, and
for the thin slips for covering the keys of pianofortes, which are
made thicker in front, where the principal wear occurs.
Triangles may be sawn out of parallel slips in a similar
manner; thus, by using guides at the angle of forty-five degrees,
and turning the work over each time, right-angled triangles, r,
are produced exactly of one size; with sixty degrees, equilateral
triangles, e, and so on for all others having two equal sides, a
half triangle at each end being the only waste. In manufactories
where large quantities of bevilled works are sawn, it is usual to
employ a wooden bevil guide for every different angle required;
both from motives of economy, and also to prevent the acci-
dental misadjustmeut of variable guides; and sometimes the
unchangeable guides are made in metal.
9. Sauriny bevilled edges and oblique prisms ; or those in which
the aiiyulur variations art in tlit vertical plane. — In cutting pieces
with bevilled edges, a supplementary bed of metal, the hinge of
which is quite close upon the saw-platform and against the saw,
is occasionally employed ; this may be set at all angles by a stay
and binding-screw. But the more simple and usual plan is to
employ supplementary wooden beds planed to the definite angles
m-d, and through which beds, the saw is allowed to cut a
thin kerf as usual.
A i in pie of the use of inclined saw-beds is seen in
the so-called mosaic works, consisting of groups either of
nglcs, rhombuses, or of squares, cut in different coloured
woods, and arranged so as to constitute various patterns, which
it is proposed to distinguish as triangular mosaics and square
764- MOSAIC WORKS IN WOOD.
mosaics. Mr. James Burrowes, of Tonbridge Wells, informs the
author that nearly every sort of wood is used, both English and
foreign, and also many sap-woods, but principally holly and ebony
for white and black ; and bar-wood, barberry, beech, cam-wood,
cherry, deal, fustic, green ebony, king-wood, laurel, laburnum,
lilac, mulberry, nutmeg, orange, partridge, plum, purple, ye\v,
and walnut, for various colours. Mr. Burrowes adds, that he
was the first to introduce this work in Tonbridge-ware turnery,
boxes, and toys, although striped, feathered, and tesselated works
somewhat of the same kind, were used long prior, in the band-
ings and stringings of ornamental cabinet-work.
For the triangular mosaics, beds of the angles of 45 and 22^-
degrees are principally used, but others of 15, 30, 60, and 75
degrees are also occasionally employed; they require guides for
parallelism, either to be applied to the inclined beds themselves,
or to be added to the parallel rule, with the power of adjustment
vertically as well as horizontally ; very thin saws are used, and
they project but little through the beds.
Figs. 743. a 6 c 744.
o <] <
The wood is cut in pieces six or seven inches long, first into
veneers of appropriate thickness, the formation of which into
slender squares requires no explanation. Figure 743 shows
that a bed of 45 degrees, will at one cut for each piece, convert
the veneer into rhombuses figured separately at a, the acute
angles of which measure 45, the obtuse 135 degrees each; and
when the wood is turned over between each cut, right-angled
triangles b, are produced, with the same bed. When, as in the
dotted line fig. 743, the bed measures 22£ degrees, and the work
is also turned over, triangles are produced such as c, and from
which three figures, a, b, c, almost all the work is compounded.
Such of the pieces as are required to form the pattern, are
selected and carefully arranged in groups on the bench: one
MOSAIC WORKS IN WOOD.
768
man picks up a small group, brushes them over quickly with
thin glue, and ha n to another workman, who dexterously
arranges them in their required positions ; ami further quantities
of the pieces are handed up by the first workman, until all that
constitute the first glueing are arranged. The stick, or faggot,
is then tightly bound with string, and before the last coils are
-trained around the mass, any pieces which stand out beyond
their true positions, arc rapped with the hammer along the side
of the faggot.
Genenilly, eight rhombuses, a, constitute the central group, as
in fig. 7-H-, and the eii;ht angles are then filled up by ri_ht-
angled triangles, b, thus producing an octagon, which is allowed
to dry. At other times, the eight rhombuses, a, are combined
for the central star, the hollow angles of which are filled in by
eight squares, which themselves produce eight new angles, A B,
fig. 745, each measuring 135 degrees. Sometimes each angle
Fig«. 745.
746.
A B, is filled by the obtuse angle of one rhombus, a, and this
also produces an octagon. At other times, each angle, A' B', is
filled by the three acute angles of three rhombuses, a, which
together measure 135 degrees also (one group being striped, the
others only dotted), and afterwards 16 right-angled triangles, b,
complete a nearly eirenlar figure. The whole of the latter group
would be combined at one glueing by dexterous workmen ;
except when the squares or other pieces are themselves com-
pounded of little bits, which is a preparatory process.
The central octagon, fig. 744, when dry, is often surrounded
by other sectional groups, as in fig. 746, either eight compounded
766 MOSAIC \VORKS IN WOOD.
triangles, such as c, with the new spaces filled by eight right-
angles, b, to reconstitute the octagon, or else eight wedge-form
pieces, d, are alone used. The edges of the sections are glued,
and quickly placed around the octagonal nucleus, after which the
whole is sometimes fixed between powerful clamps, or wedged
within external rings ; at other times, string is again used to
bring the parts together.
The blocks, when finished, are allowed to dry for some weeks,
and are ultimately cut into thin veneers, and glued upon round
boxes. Octagons of different patterns are united side by side,
and the spaces filled in with right-angled triangles, so as to con-
stitute straight patterns for the centers and borders of rectangular
boxes. Small round sticks are occasionally turned into little
ornaments, and the curvilinear surfaces so obtained, present
various pretty effects when the intersections are accurate.
The compounded sections of the wooden mosaics are generally
prepared beforehandof small triangles, as adistinctprocess, andare
frequently screwed fast in cauls of their appropriate angles, or they
are built up as laminated sheets, and cut into form with the saw.
The chequered squares are prepared from slips of veneer one
inch or more wide, so as to avoid handling the little squares,
which could scarcely be tied up in true rectangular arrangement.
The pieces of veneer are glued together, either white and black
alternately, or in any arrangement that the pattern may require ;
strips cut off the edges of the laminated pieces and reversed as
at a, fig. 747, produce the chequered squares, cut obliquely and
alternated they produce rhombuses b; and striped rhombuses c,
triangles d, and squares, can be also readily obtained, and the
author suggests that b, c, d, and similar pieces, should as in the
diagrams, figs. 745 and 746, be mingled with the present patterns,
a Fig. 747. f> c d
many of which are much elaborated, principally from small
triangles alone, without a sufficient regard to the general design
or drawing of the figure. The author possesses however, a very
good specimen of mosaic work composed almost entirely of
triangles, which in a diameter of 3£ inches, contains no less thnn
808 separate pieces of wood, combined with very good effect.
MOSAIC WORKS IN W- 7 ''7
The square wood mosaics, called also Hrrlin mosaic*, from
thoir assimilation to worsted works, arc more recent than the
triangular. Figures of vases, animals, and running patterns, are
composed entirely of little squares of various coloured woods,
which are glued up like the chequered works. Supposing the
iv pattern to constitute a rectangle composed of 20 squares
in \\itiih, ami -'50 in length, 30 slips of veneers of appropriate
colours and an i:i< li \vi.ie, are first glued together, and this is
repeated 19 times, making one laminated block A, for every line
of the figure. A veneer B, is then cut off from each of the 20
blocks A ; and these striped veneers B, are glued side by side to
constitute the group c, of 600 slender squares ; the thin leaves cut
off from the end of this last constitute the mosaic pattern D.
The accuracy of the work greatly depends on the exact simi-
litude of the veneers as to thickness ; and as the blocks A, will
each produce some 15 or 20 repetitions of B and c, the perse-
vering care required in the formation of a single specimen, will
also effect a vast extent of repetition of the same pattern or D.
The small square mosaics for borders and other works are
usually inlaid in slips of holly as running patterns, by aid of the
buhl saw. Very large mosaics are usually made in 6, 9, or 12
sections, glued up separately into squares, and then combined.
One example, thus formed by Mr. Burrowes, represents the
Prince of Wales's feathers, arms, and motto ; it measures 3£ by
2^ inches, and consists of between 8000 and 9000 squares ; the
block was prepared in 12 sections, that were afterwards united.*
• From the researches of Winkclmann, Wilkinson, and others, there appears to
be no doubt but that, 3300 years ngo, the ancient Egyptians were wonderfully
successful in making mosaics of minute cylinders, squares, and filaments of glass,
united by partial fusion ami pressure ; and that from the end of the mam, slices,
about one-sixth of an inch thick, were cut off and polished, much the same as
above described.
Various specimens are referred to, in which the pictures are said to be very
perfect sod exactly alike on opposite sides, showing them to run through ; the
modo of construction is apparent, from the joinings being just visible in a strong
light, and from the colours having in some places run into one another, from the
partial excess of the brat employed in uniting them.
The Egyptian* also appear to have made other mosaics, by cementing pieces of
glass, stone, and gems on backgrounds, just the same sa nince practised by the
ancient Romans, and by the artists of Italy and other countries in our own times.
— See Wilkinson's Manners and Customs of the Ancient Egyptians, 1885, Vol. iii.
pages 94—97, ftc.
76S
SAWiN'G PRISMATIC PIECES.
Iii sawing the regular prisms of from 3 to 12 sides, it is neces-
sary the inclined beds should meet the saw-plate, at the same
angle as that at which the sides of the polygon meet, or their
exterior angles. It is therefore proposed as an example for all
prisms, to trace in fig. 748 the formation of the hexagon, or
6-sided prism, from a round or irregular piece of wood, upon
which, as a preparatory step, one plane surface has been cut in
any manner, either by the saw or plane. The following table
contains the several angles required.
In regular prisms of . 3
4
5 6
7
8
9
10 11
12 sides.
Their external angles 1 „ ,
measure . . . . J
90
108 120
128J
135
140
144 147&
i
150 deg.
The supplements to 1
the external angles,
or what they fall ) 120
90
72 60
51?
45 40
36 32£
30 deg.
short of 180 de-
grees, are . . . J
Referring to the above table it is seen the external angle
of the hexagon is 120 degrees (represented by the dotted arc A),
Figs. 748.
O CO
A
d e f 9
and that the supplement to the latter is 60 degrees, therefore
the inclined bed should also meet the saw at an angle of 60
degrees (represented by the dotted arc, B,) by means of this bed
alone, the second side of the prism would be cut on the piece
of wood. But in cutting the remaining four sides, it would be
required to introduce some guide, to ensure the parallelism and
equality in width of the sides ; and this is done by laying a second
angle upon the first, also equal to the supplementary angle of
60 degrees (represented by the dotted arc, C,). Then B, and C,
which are of the same angle, together constitute a trough, and
the width of the side of the trough near the saw, must be equal
to the side of the required hexagon ; but the second piece C, is
not adjusted to its position, until after the first two sides of the
prism have been sawn. The angle of the inclined beds must be
very exact ; as any error that may exist, becomes accumulated,
or is six times multipled in producing a hexagon.
SAU NTALLI \M) VERT1CAI.1 ^ . ?'•'»
.iihir poly^o'.. :n <|iiently the angles alike, hut tin:
sides dissimilar; thus it may be consult n d that in a, fig. 749, a
parallel piece is added between the halves of the regular hexagon,
whereas in bt a piece is abstract i -d, and in r, two of the sides dis-
appear. These and the entire group, a to yt fig. 749, may be
sawn with the bed B, fig. 748, of 60 degrees.
It is most convenient, especially when many pieces are wanted,
to prepare fora, a rectangular prism, and then to cut off the four
dotted triangles at four cuts, leaving the stop *, in the same
position throughout ; b may he treated in the same manner
as fl, or else as in r, the two exterior cuts may be made on the
edge of a wide piece of board, and then two interior cuts remove
the rhombus c, and leave a hollow angle of 120 degrees, as
explained by the dotted In
The several inverted angles of the piece ff, may be also pro-
duced in tliis manner by two cuts each; two of the cuts in ff,
are however made on the horizontal table, and not the inclined
bed, B. The inverted angles are convenient as troughs, to support
prismatic pieces on their angles, instead of their surfaces.
Pieces analogous to those, a to ff, may be cut on beds of any
other angles; but when the prismatic pieces have dissimilar
angles, unless they are complementary one to the other, separate
inclined beds are generally required for every angle.*
10. Sawinff geometrical solids and irregular pieces, or those in
which the angular variations, are in both the horizontal and vertical
planes. — It is proposed to illustrate this part of the subject, by
some remarks on the formation of various solids illustrative of
geometry, and crystallography ; such as erect and oblique prisms,
pyramids, double pyramids, the five regular solids or platonic
bodies, (namely, 1st, the tetrahedron, 2nd, the hexahedron, 3rd,
the octahedron, 1th, the dodecahedron, 5th, the icosahedron,)
and some other polyhedra. And, although in the formation of
tin- models of these solids, various modes are employed, those
methods will be selected, in which all, or nearly all the work,
• It will to shown in the succeeding section that, in some cases, prismatic worka
are mounted upon an axis, placed at various angles by a dividing plate, and
then applied to the saw. And in the subsequent volumes, it will to likewise
explained that most lathes for ornamental turning, possess very ready means'of
producing, both iu wood and metal, an infinite variety of polygonal and polyhedral
works, with great precision and smoothness.
3 D
770 SAWING PYRAMIDS.
may be performed by the saw machine alone, independently of
the various other means.
The models above referred to, are generally made in sycamore,
maple, or horse chesnut, and in the majority of cases, the wood
is prepared as prisms, the sawing of which has been fully
described. Sometimes, before the subsequent processes, the
prisms are very carefully planed in angular beds, mostly so
arranged, that the surface to be planed is horizontal.
A long prismatic rod, carried to the saw at right angles, is
readily cut into short erect prisms of various heights j and the
same prisms, carried obliquely to the saw, become oblique prisms.
For pyramids of 3 to 12 sides, long prisms should be first pre-
pared also of 3 to 12 sides, the sections of which are exactly equal
to the bases of the required pyramids.
The prisms are usually cut into short pieces equal to the
vertical height of the pyramids, and one guide-block suffices for
making all pyramids the sides of which meet at the same angle.
The ordinary guide or gage-block, is simply a piece of wood
having at the end a rectangular and perpendicular notch BCD,
fig. 755, which may be made at the saw machine by aid of
the protractor. For pyramids, the sides of which meet at 60
degrees, as in fig. 750, the side B C, of the notch in fig. 755,
measures 30 degrees with the principal edge A B, of the guide;
for pyramids of 40, 50, or 70, the angle of the guide is respec-
tively 20, 25, and 35 degrees, or half the angles at which the
sides meet.
The side A B, of the guide is placed in contact with the
parallel rule, and the short prism is placed in the nook, so that
in every case the base of the prism rests against the face C D,
and one of its sides, whatsoever their number, touches the vertical
face B C; the parallel rule is then adjusted to direct the saw s s,
through the dotted line proceeding from the apex to the base of
the pyramid. One cut having been made, the guide and work
are quickly withdrawn, the waste piece removed by the saw, is
thrown away, and the block is shifted round until the succeeding
face of the prism, (or so much of it as remains,) touches the face
B C, and so on to the last face of the pyramid.
Sometimes, as in fig. 751, a pyramid is cut at each end of a
prism, the method is almost the same ; but the wood and guides
are each longer, as in fig. 756. The square end of the prism is
«- \ U 1 M.
l'\ H \MI1»S.
771
placed against the stop, and the fir>t pyramid having been cut,
piece is changed end fur end, and the process is repeated ;
in cuttiiiu'tlic M-rond pyramid, tlie point of the first touches the
stop, or a notch \n-.\\ be made in the stop to prevent the extreme
point of tin- priMii from being bruised.
\Vhen tin- pyramids meet base to base, as in fig. 752,
other mi tiioiU are pursued, dependent on the parallelism of the
opposite sides or angles of equal pyramids. Sometimes the
prism is cut off to the exact length of the double pyramid ; and
the first pyramid having been cut as shown in fig. 756, the
second pyramid is produced as is fig. 753, by laying the sides of
the first pyramid against the parallel rule, and placing a wedge
beneath the point of the first pyramid, to support the axis of
the piece horizontally.
Fig. 750.
A 755.
7SU. C
758.
A much ea>ier and more accurate way of cutting the second
pyramid, is suggested by the author in figs. 757 and 758. The
prism is in all cases to be left longer than the two pyramids,
the first of which is cut as in fig. 756. Then leaving all matters
as before, for pyramids of 4, 6, or 8 sides, simply to remove the
parallel guide sideways, so as to change the position of 756
into 757, in order that the saw may enter the opposite side of
the prism, at the base of the first pyramid, and proceed into the
solid prism as far as its center. In a 4, 6, or 8-sided prism, the
4, 6, or 8 cuts release the double pyramid in 757, from its hollow
bed, or inverted pyramid, or that which is sometimes termed, by
8 D 2
77- SAWING MACLED OR TWISTED PYRAMIDS.
mineralogists, its pseudo-morphous crystal. It is needful the
saw should penetrate slightly beyond the apex, and the crystal
will jump out of its bed when the last side is nearly cut through,
leaving a, trifling excess on the last side, just at the point; but
if the inverted cuts are extended much beyond the apex, the
model will be released before the last side is completed.
For double pyramids of 3, 5, or 7 sides, meeting base to base,
as in fig. 752, the position of the saw in fig. 757, cannot be
employed in cutting the second pyramid ; because in a pyramid
with uneven sides, the saw then would enter at one of the angles
instead of at one of the faces of the first pyramid. Conse-
quently the angular guide, fig. 756, is changed end for end, as
in fig. 758, and all the sawing is done on the same side of the
axis of the prism. The position fig. 758, might be used for all
second pyramids, whether of odd or even sides, but for the latter
the guide fig. 757, is more conveniently placed.
Sometimes, however, it is required that the face of one pyra-
mid should meet the edge of the opposite, as in fig. 754, thus
producing what is termed in mineralogy, a macled or twisted
crystal. Macled double pyramids with 3, 5, or 7-sides, are cut
by pursuing throughout the method prescribed for ordinary
double pyramids with 4, 6, or 8 sides; namely, using the one
guide, after the mode fig. 756 for the first, and after the mode
fig. 757 for the second pyramid, and then with pyramids of
uneven sides the required displacement is obtained.
Macled double pyramids, with 4, 6, or 8 sides, require the face
B C, of the first guide, fig. 757, to be perpendicular as in the
reduced figure a 758, and the face B C, 757, for the second
pyramid, to be inclined 22^, 30, or 45 degrees respectively, as
at b, or half the supplement to the external angle of the respec-
tive polygons. For macled hexagonal pyramids, the side B C,
may continue perpendicular, provided that in sawing the second
pyramid, the edges, and not the faces, of the 6-sided prism are
placed against B C, fig. 757.
Irregular prisms may be sawn into irregular pyramids, but
certain corrections are sometimes required. Thus, the prism
beneath fig. 759, which is more, and fig. 760, which is less than
a regular hexagon, produce the irregular pyramids respectively
annexed ; the sides of each of which meet on one base line. In
the first pyramid, fig. 759, the plain ridge is equal to the central
«• \ui\-. IRREGULAR PYRAMIDS.
M added to the hexagon : in the second pyramid, li^'. '.
ral face that corresponds to the narrow side of the* hexa-
gon, terminates below the extreme point. The six faces mi^ht
iu cither case be made to converge exactly to unr \> <\\\\, by
employment of a second guide adapted to the irregular aide.
Fig«. 759. 780. 761. 703.
A
O o
Irregular pyramids, having as in fig. 7G3, equal sides, but ////-
equal angles, produce pyramids, that converge exactly to a point.
Thus fig. 761 shows the result when the rhombic prism is cut
into a pyramid, the bases of the sides also meet on one plane,
and when the piece is released by cutting the inverted pyramid by
the method shown in fig. 757, the solid that results is an irregular
octahedron, the section of which is rhombic in both planes.
To produce an irregular octagonal pyramid from a regular
octagonal prism, a wedge is placed beneath the prism, as in
fig. ? 62, which now represents the guide; the point of the wedge
is to the left, in cutting the sides 1, 3, 5, 7, of the octagon, and
the point of the wedge is to the right, in cutting the sides 2, I .
6, 8. By thi> twisting of the axis, the regular prism yields an
irregular pyramid of the section shown at fig. 763, and the
departure of the latter from the true polygon, is shown by the
angular space, between the true polygon, and the vertical face in
fig. 702, which space represents the piece removed in vii
of the subjacent wedge, the angle of the two being alike.
\Vhen the inverted irregular pyramid is similarly cut, the line
of junction of the two is in one plane when the more obtuse
edges of both pyramids meet; but the line of junction becomes
zig-zag or macled, \\hen the more obtuse angles of the one octa-
gon meet the less obtuse of the other.
thud pursued with the 1 or ii-sidcd prisms pro-
duces similar results, subject, however, to certain displacements
of the edges and point «., the modes of correcting which will
ly manifest to those «ho take up these matters
practically.
774 SA\VIXG THE TETRAHEDRON, HEXAHEDRON AND RHOMBOID.
It is now proposed to show how, by pursuing the methods of
cutting various pyramids, the five regular solids, and many
others, can be obtained with the saw-machine.
The tetrahedron, with 4 planes each an equilateral triangle, is
cut from a regular triangular prism, inclined 19| degrees,* and
it is best to cut it at the end of a long piece, as in fig. 756, and
then to remove it by one cut of the saw at 90 degrees, which at
any distance between the apex and base, produces the true
tetrahedron.
The hexahedron or cube, with 6 planes each a square, is cut
off from a square prism held at 90 degrees; the length of the
piece removed, must necessarily be the same as that of the
sides of the prism.
The regular hexahedron or cube, may be also viewed as two
triangular pyramids, the faces of which are interposed or macled,
or so placed, that the face of the one pyramid meets the angle
of the opposite, as before explained in fig. 754. And pursuing
this method, the cube may be sawn from a triangular prism by
the positions figs. 756 and 757, provided the prism is inclined
exactly 35£ degrees to the saw.f The cube, when produced in
this manner from the triangular prism, is however very small, as
viewed diagonally, (and in which direction it is cut,) the cube
appears as a hexagon, three angles of which touch the centers of
the triangular prism. It is better to use the hexagonal prism,
and to place its alternate sides, 1, 3, 5, successively upon the plat-
form, both for the first and second processes, figs. 756 and 757;
in which case the hexagonal outline of the cube, may be as large
as the section of the hexagonal prism from which it is sawn.
Any other inclination than 35£ degrees produces an oblique
hexahedron, or rhomboid, with six equal rhombic faces. For
instance, the very dissimilar figures 764, 765, and 766, were
cut from hexagonal prisms of the same size, and respectively as
large as the prisms would permit. In fig. 764, which is an acute
or elongated rhomboid, the angle at which the prism met the
saw was 10 degrees; and in fig. 766, an obtuse or compressed
rhomboid, the angle was 80 degrees. Viewed along the dotted
line or through tlieir common axis, the three figures all appear
as equal hexagons, and show the three pyramidal planes of each
solid as equal rhombuses, as in the figure 767 ; but the axis of
• Mathematically, 19°. 28'. 17". t Mathematically, 35°. 15'. 52".
•AWIXO THE OCTAHEDRON
about four time* as long as that of the cube, 705, the
axis of 766 is only about one eighth as long as the cube, and its
edge is acute like a knife.
Figa. 7«4. W. 7«7.
The octahedron, with 8 planes, each an equilateral triangle,
may be viewed as a double square pyramid, cut off at an angle of
35 J .* and is produced in that manner with very little
clilliculty from a square prism. When the prism meets the saw
at a smaller angle than 85J degrees, the octahedron is said to be
acute or elongated ; and when the angle is greater, the octa-
hedron is obtuse or compressed, as recently explained in regard
to the rhomboids figs. 764 and 766.
It has been considered unnecessary to represent the regular
tetrahedron, hexahedron, and octahedron, which are simple, and
fr.miliarly known; and the subsequent figures 76S to 771, of
the dodecahedron, the icosahedron, and trapezohedron, are to be
viewed as explanatory diagrams, and not as faithful representa-
tions of these respective polyhedra.
The dodecahedron, fig. 768, with 12 planes each an equilateral
pentagon, may be viewed as frusta of two pentagonal pyramids,
the sides of which are interposed or raacled, and the pyramids
being truncated form the two remaining pentagons. The double
5-sidrd pyramids, are first cut at the angle of 26| degrees,t and
discontinuous!}', by means of the positions shown in figs. 756 and
757, the sides of the pyramids will then be found to meet at 36°,
the angle made by the first and third sides of a pentagon. The
outer plane is obtained by cutting off the point of the pyramid
at right angles to the prism, and extending it by trial, until the
terminal pentagon itself, and the 5 pentagons near it, become
equilateral. The second pyramid, not having been cut so far as
the c. -liter, the solid is now remove, 1 from its matrix or prism, by
one cut at right angles to the prism, and so far removed from
• Mathematically 35*. 15'. 52"., or half the »upplem«nt to 109*. 28'. 16"., the
angle at which the pyramidal plinea of the octahedron meet Soo Brooke'*
illograpby, page 118.
f Mathematically 26V 83'. 54".
776 SAWING THE RHOMBIC DODECAHEDRON AND ICOSAHEDRON.
the angles of the zig-zag line oil which the pyramids join, as the
corresponding pentagon, at the outer end of the solid.
The above, or the pentagonal dodecahedron, is also called the
Platonic dodecahedron ; but there is another kind named the
rhombic dodecahedron, which is more referred to by minera-
logists. The rhombic dodecahedron, fig. 769, has 12 faces, each
an equilateral rhombus, and may be viewed as a hexagonal prism
with a shallow triangular pyramid at each end.
The rhombic dodecahedron may be therefore sawn from the
hexagonal prism, provided, that first three pyramidical planes are
cut at the angle of 54f degrees,* and that the solid is then
released from the prism, by three similar but inverted cuts on the
intermediate angles of the hexagon, so much of the central prism
being left, as will make six rhombuses equal to those terminating
the original prism.
Figs. 7
V\ "./>'
V
The rhombic dodecahedron may be also viewed as a square
prism terminating in two square pyramids cut off at an angle of
45°; but as these planes run on to the angles of the prism, it is
needful the bed should be inclined 45° horizontally, for the
pyramids, and also 45° vertically, for their displacement.
The icosahedron, fig. 770, with 20 planes each an equilateral
triangle, may be viewed as two obtuse pentagonal pyramids,
united by frusta of two other pentagonal pyramids a to b, the
sides of which are very acute and interposed. The icosahedron
may be sawn from the pentagonal prism nearly in the manner of
• Mathematically, 54°. 44'. 8".
THE ICOs \lll Pllox \M. IKAPEZOHKDl:
the 1 -irst guide is the au_'lo of 10} degrees,* and suitable
itting the two central frusta. This guide is first employed as
in tig. 750, antl then shifted as in fig. l'>7, the 1U cuts produce
tin- 10 angles, each of 00°, constituting the central zone of the
figure. The extreme end of the piece is then sawn at five cuts
on a bed of 52$ degrees,t so that the five planes of the outer
pyramids constitute equilateral triangles exactly terminating on
the line a, or on the sides of one series of five triangles, and the
points of the other series, constituting the central zone of the
solid. The icosaliedroii is removed from the prism by placing
the guide block as in ~i->l , and cutting the second pentagonal
pyramid, which similarly to the first, falls on the line b, and just
meets both the sides and angles of the 10 central triangular
faces ; when the work is accurately performed, every point is the
center of a group of five equilateral triangles.
The solid fig. 771, with 24- equal trapezoidal planes, may be
viewed as two frusta of octagonal pyramids, joined base to base
with continuous edges, and surmounted by two obtuse four-sided
pyramids. This solid belongs rather to mineralogy than geometry,
and occurs with various angles; its usual name is an icositessera-
hedron ; but it has been sometimes termed a trapvzuhedron, from
the shape of its faces : three of its varieties will be noticed. 1 u
the first, the three quadrantal sections, namely, through A o E,
through C o G, and through A B C D E F G H, are all regular
octagons, and the angles of the solid are throughout alike; this
variety may be therefore called the regular trapezohedron. In
others the three sections are irregular octagons, and the alternate
angles dissimilar ; these may be called irregular trapezohe<lra,
and two of these varieties that occur in mineralogy are referred
to in the annexed table.
The reynlar Impezohedron may be sawn from the regular
octangular prism, by means of two beds, one of them inclined in
two directions. The first bed for the frusta of the two central
pyramids, is inclined 21 degrees horizontally, or on the line B C,
ii_'. 756. The second bed for the two exterior four-sided pyra-
mids, is inclined .V.» 1 decrees horizontally on the line B C, fig. ',
and '2~2 ;eally, as at b, in the same group, in onh r
to twist the prism on its axis, because the four terminal planes
run on to the angle of the octagon.
• Mathwiuiittlly, 10*. 48'. 44". t lUthematioiJly, W. 37'. 21".
773
SAWING THE MIXERALOGICAL TRAPEZOHEDRA.
The four planes of the terminal pyramid produce trapeziums,
and which are increased, by trial, until they just equal the eight
trapeziums formed by the partial obliteration of the central
pyramidal faces. The second four-sided pyramid, which com-
pletes and releases the solid, is merely an inversion of the first.
The irregular or mineralogical trapezohedra, may be produced
from the regular octangular prism, nearly in the manner just
explained, by the employment of different angles, that are stated
exactly in the annexed table, which shows the comparison of the
three varieties of this solid selected for illustration.*
Alternate angles of
the solids.
Beds for the central
parts.
Beds for the ter-
minal parts.
A. C. E. G.
B. D. F. H.
Hor.aiigles.
Wedge.
Hor. angles
Vert,
angles.
Reg. Trapezohedron
135°. 0'.
126°. 52'.
143°. 8'.
135°. 0'
143°. 8'.
126°. 52'.
20°. 5V.
24°. 6'.
17°. 33'.
none
8°. 8'.
8°. 8'.
59°. 38'.
54°. 44'.
64°. 46'.
22°. 30'.
22°. 30'.
22°. 30'.
The table supposes the regular octangular prism to be in every
case used, but to produce the irregular pyramid from the regular
prism, requires the use of a wedge, as explained in page 773, and
the angle of the wedge is half the difference between the two
external angles of the prisms, which are simply the reverse one of
the other. The wedge becomes unnecessary, if prisms are pre-
pared, having the same irregular section that occurs in the second
and third solids, and which is the preferable mode. If the lathe
with revolving cutters and dividing plate is used for preparing
the prisms, as hereafter recommended, instead of stopping the
lathe at eight equal spaces, or taking 45° each time, the angles
taken alternately, are the supplements to the two external angles
of the prism, common to the second and third solids, namely
53°. 8'. and 30°. 52'., which together are equal to 90°. t When
* The irregular trapezohedron, in another of its sections is a regular hexagon, as
Fig. 772. illu>ti-ated by the figure 772; six of the trapeziums then con-
stitute parts of tlie original prism, three trapeziums at an
obtuse angle form the summit of the crystal, nnd three jmirs
«>f trapeziums are situated more acutely and intermediately,
The trapezohedron might be therefore also worked from the
hexagonal prism, by aid of two beds of the particular angles,
one of them having a double inclination,
t The angles for the dividing plate are consecutively as follows :
1—53% 8'. 3—143°, 8'. 5—233°. 8'. 7—323°. 8'.
2— 90°. 4—180°. 6—270°. 8—360°.
Unless the lathe has an index with an adjusting screw, the 8' must in each case be
neglected, but it is an admissible error.
vl. REMARKS ON THE MODELS OF SOLIDS. ",',.>
the wedge is thus dispensed with, the vertical angle 22°. 30'., suit-
able to the regular prism, becomes 18°. 20'. for the second, and
26°. 3V. for the third solid in the tnhlc, or half the supplements.
The order of procecdm- -ivc -\\, in reference to producing the
various solids with the circular saw.namely, first tosaw the central
parts of the solids, and then the terminal planes or pyramids, is
in all cases advisable when only one or two solids of a kind are
made, as the equality of the faces is then arrived at by two
adjustments in place of four. The two central portions arc
simply inversions one of the other, and necessarily agree without
trial ; the central part thus produced, serves as the base from
which to determine the two adjustments for the terminal parts.
As however, every step of this process depends on the primary
accuracy of the prism, which serves as the means both of guiding
and holding the pieces whilst under formation, it is desirable, as
regards the more complicated polyhedra, that those who possess
the lathe with revolving cutters, for ornamental turning, should
make, or at any rate finish the prisms therewith, which will
thence acquire an unexceptionable degree of accuracy. The
trouble of preparing the wooden prisms, may be entirely saved,
if metal prisms of the several sections, each with a conical hole
to serve as a driving chuck, are prepared. The pieces of wood
for the solids are then roughly turned, as cylinders with conical
stems, which arc driven into the prisms for their attachment.
The metal prisms may be used for an indefinite number of pieces ;
they save much trouble and uncertainty, and are especially
desirable in the more complex polyhedra.
There are other and very different ways of making the
geometrical and crystallographical solids. Sometimes the wood
is prepared with the plane alone, into prisms of unequal sides and
angles, so arranged, that two or four of the sides of the solid,
may be parts of the surfaces of the original prism, and that some
of the edges of the solids may fall on the remaining faces of the
prism. The plane is then used subsequently to the saw machine,
in perfeetinir and smoothing all the fan
The- Jo not admit ui'thesa: ili-ation or facility
of method as that described, which the author believes to be
mal, and that may be called the method of double pyramids ;
and which he was led to work out practically to the extent set
780 SAWING VARIOUS CRYSTALS AND SOLIDS THAT ARE
forth, in order to show how much may be done by the saw-machine
and various simple adjuncts.
The author has now the pleasing duty to acknowledge the
kindness of Professor Willis, who has examined the several
details mathematically, and furnished the corrected angles that
are given in the notes and table.
Many crystals that occur in mineralogy are considered to be
derived from the primary solids, especially from the tetrahedron,
cube, octahedron, and the rhombic dodecahedron, by the oblitera-
tion of some of their edges and angles in various ways ; or as it
is said in mineralogy, the edges are bevilled or replaced, the points
or angles are truncated. By way of general illustration of .the
method of producing these secondary crystals from their prima-
ries, a few of those derived from the cube are demonstrated by
figs. 773 to 778, but numerous other crystals, from this and other
primary solids, might be advanced.
The cubes are first prepared as described on page 774, and
their faces are rubbed smooth ; in cutting their edges and
angles, beds similar to fig. 779 are required. The latter may be
made entirely with the saw ; for example, the rectangular block
is supported on the face A, and two incisions a b, each at
45 degrees, are made by means of the saw and protractor ; then
the piece being placed with B downwards, and with the face A,
against the parallel rule, the perpendicular notch c, is sawn ; the
three cuts release a piece of wood, leaving a cubical matrix.
Figs. 773. 774. 775. 77<3. 777. 778.
Fig. 773, the cube with bevilled edges, requires that the edges
of the cube should be parallel with the saw, and the guide is then
placed, as in fig. 781 ; that is, before the protractor, which is set at
zero, and * is the stop for the quantity each of the 12 edges is
bevilled or truncated. Cubes with two bevils or planes on each
edge, may be bevilled with the position 781, provided the guide
is tilted up some 20 degrees, by fixing a wedge of 20 degrees
DERIVED FROM TIIK • I in:. 781
tin- ^uidr, as dottrel in fig. 779; or otherwise by making
n similar bed, fig. 780, with the angles 25 and 65 instead of 45,
which will make a rectangular notch, inclined 20 degrees, as iu
fig. 780, so that the wedge may be dispciiM-d with.
Fig«. 779.^^ c 780.^-
774, the cube with three bevilled planes at each angle of
the cube, (one angle only being shown,) is obtained with the
:ion of fig. 781; but the protractor is then set about 10
degrees from 90, so as to cut off every edge of the cube by
two cuts slightly inclined. The square face of the cube then
becomes an octagon, if the facets meet as represented in dotted
lines, or a dodecagon when the bevils do not meet. The bed,
if also inclined vertically, as by the wedge in fig. 779, will
duplicate the angular chamfers, and it is clear this elaboration
may be carried systematically to any required extent.
Fig. 775, in which the angles of the cube are truncated on
the diagonal, require that the bed, fig. 781, should be placed at
85J degrees,* and then the angles of the cube will be cut off
nearly at 3 \ \ degrees to every plane, or at right angles to the
diagonal, and this little facet, in like manner to the above, may
be converted into three planes, somewhat after the manner of
fig. 774, if so required.
When, as in fig. 776, the angles of the cube are so far oblite-
rated, that the eight little triangular planes exactly meet, the
rube is converted into the cubo-octahedron, a solid having six
square faces and eight triangular faces, the whole of which are
equilateral ; one only of each is represented, to avoid confusion.
By pursuing the last method a little further, so that the trian-
gular faces encroach upon each other, they first produce a little
ridge intermediate to the neighbouring facets, and carried to the
proper extent, convert each of the triangular faces, in fig. 776
• Mathematically, 85*. 15'. 52*. the wine angle as that employed to produce the
cube from the regular prism with 8 or 6 sides, by six pyramidal cuts ; and also
the regular octahedron from the square prism.
7S2 CONCLUDING REMARKS ON THE MODELS OF SOLIDS.
into equilateral hexagons, in fig. 777 ; the six little square faces
are all that remain of the original cube, and these squares are
united by eight hexagons, all equilateral. The name of fig. 777
when perfected, is the ex-octahedron, and which implies that this
solid may be also obtained from the regular octahedron, by
obliterating its six points, which develope the six squares, and
the hexagons are then consequently parts of the octahedron.
If, as in fig. 778, all the angles of the cube could be truncated
by planes extending from angle to angle, the cube would descend '
to the octahedron. With the circular saw this is impracticable
to the full extent, although some of the planes may be deve-
loped ; but the mineralogist produces the octahedron from cubes
of fluor spar, which splits diagonally from every point of the
cube with great facility.
"When the octahedron is produced by the cleavage of fluor,
further reduction only makes a smaller octahedron, which form
is thence described as the primary crystal of this mineral. In
other minerals, the cube is the primary to the octahedron.
It is expected that enough has been said to show that, with a
little contrivance in the carrying out of the methods advanced,
a vast number of even the most complex models of geometrical
and crystallographical solids, with plane surfaces, may be pro-
duced with comparative facility and great exactness, by the
saw-machine; and the mechanical amateur will find it a some-
what fascinating study, especially if he be likewise interested
in geometry or crystallography.
The circular saw should be rather stiff, and have fine teeth,
as then the planes developed by the instrument will be tolerably
smooth, and merely require to be rubbed slightly on a sheet
of fine glass-paper, laid on a flat board or metallic surface; they
are sometimes cleaned off on a wooden face wheel, on which
powdered glass or flint is glued after the manner of glass-paper.
In concluding this section, the author begs to add that the
whole of the various works described, subsequently to page 766,
may be executed by the amateur with the machine represented
on that page, aided by the simple additions described. The
remainder of the chapter refers to larger sawing machinery,
principally used by manufacturers.
CIRCULAR SAWS FOR LARGE WORKS. 733
SECT. VI. — COMMON APPM- \Ilu\s Of CIRCULAR SAWS
TO LARGE WORKS.
Iii the present section, it is proposed to devribp the principal
,-s of con i in large circular nwing-benchet, such ns
in general driven by steam power, and used for various
manufacturing purposes. Sonic remarks are first offered on the
conditions and proportions of the circular saws themselves and
the subsequent matter is arranged under the sub-divisions
employed in the last section and enumerated on page 7
1. Conditions and proportions of circular saws. — It appears to
be uncalled tor to enter into particulars on the manufacture of
circular saws, especially after the remarks already offered (pages
683 — 698 of this Volume,) on the modes of constructing, sharpen-
ing, and setting rectilinear saws, as the methods are nearly
similar for both kinds; and some remarks on the circular saw in
particular, are given on the first and last of the pages quoted.
As regards the methods of hammering and blocking circular
saws, to give them the right degree of flatness and tension, a
point of considerable importance, the reader is referred to the
section, " On the principles and practice of flattening thin plates
of metal with the hammer/' (vol. i., p. 414 — 422,) and particularly
to the remark, (p. 419 — 20,) on the propriety of keeping the edge
of the saw " rather tight or small " prior to its being set to work.
So that the heat communicated to the edge in the course of
work may, by stretching the edge, render the blade tense alike
throughout ; whereas had the saw been at first rather large or
loose on the edge, the expansion at that part would render it
so loose or flaccid on the edge, as to cause it to vibrate when
at work, which is a great di>advantage.
The teeth of both circular and rectilinear saws have been
considered at some length, both as regards their outlines, (pages
683 — 6K7,) and in respect to the modes of sharpening and setting
them (pages 688 — 698), but on the whole it may be said that the
teeth of circular saws are more distant, more inclined, and more
let, than those of rectilinear sa\\s.
The teeth of circular saws are more distant than those of straight
•<, because their jri iocity causes the teeth to follow in
such rapid succession, that their elleet is almost continuous; the
distance is carried to the extreme in Mr. R. Eastman's circular saw,
784
TABLE OF THE DIMENSIONS OF CIRCULAR SAWS.
Tlit columns, " Gage of Plate," refer to the Birmingham sheet-iron gage : for the
comparison of which, tcith ordinary linear measure, see Appendix, page 1013.
The columns, " Form of Tooth," refer to the diagrams on page 684.
The columns, " Revolutions per Minute" and "Horses' Power," required for the
maximum of effect, are from the expedience of Mr. Ovid Topham, Engineer.
(1.) SINGLE PLATES OF EQUAL THICKNESS THROUGHOUT.
Generally called Bench Saws, and used either for'tbick or thin Wood.
Intermediate sizes used, and also thick Saws for cutting Grooves.
Diameter.
Gage of Plate.
Form of Tooth.
Space of Tooth.
Revolutions Horses'
per Minute. Power.
2 inch
3 —
4 —
6 —
9 —
12 —
15 —
18 —
24 —
36 —
48 —
60 —
23 to 28
21 — 27
20 — 26
19 — 24
17 — 22
15 — 21
14 — 20
13 — 18
12 — 16
10 — 14
8 — 12
6—9
644 to 646
644 to 653
^ to ^fein.
5¥
IB S
A - i -
i - f-
s i
i — a —
4 4
» ~ 1' ~
I5 — 22 —
H - 3 -
2 — 4 —
2000
1800
1600
1400
1200
1100 1
1000 1J
900 2
750 2£
500 3
393 3J
330 4
(2.) SINGLE PLATES BEVILLED ON THE EDGE.
Generally called Bevilled Saws, and used for Veneers.
The largest, medium, and smallest of the ordinary sizes alone are given.
Diameter.
Width of Gage of Gage of
BeviK Plate. Edge.
Form of Space of Revs, per Horses'
Tooth. Tooth. Minute. Power.
8 inches
22 —
36 —
2 to 3 in. 12 to 15 22 to 28
3 - 5 - 10 - 13 20 - 25
4 - 6 . 8 - 11 18 - 22
644 or 645 | to J in. 1300
— — j • 5 - 800 1
- - i - f - 550 2
(3.) SEGMENTS FIXED TO A DISK, AND BEVILLED ON THE EDGES.
Generally called Segment or Veneer Saws, and used for Veneers and thin Wood.
The largest, medium, and smallest of the ordinary sizes alone are given.
Dia- ^- of Width of
meter- mente. **gmeut*.
Width of Gage of
Bevil. Plate.
Gage of Form of
Edge. Tooth.
Space of R^f Horses'
*°°tb- EL Power-
5ft 10tol5 5 to Sin.
12- 15-2054- 9-
18- 20-306 -10-
2 to34in. Iltol2
24-44- 10-11
3 -5 - 9-10
24to28 644or645
22-26 — —
20-24 — —
'. t . > .| in. 320 3
130 5
I - f - 85 6
Bench saws, below about oiie foot diameter, are usually mounted on spindles
running on conical steel centers, and driven by catgut bands ; those above one
foot on spindles running in cylindrical brass bearings, and driven by leather straps.
Compared with the diameter of the saw, and speaking generally, the hole or eye
may be considered to measure from J to T^ part of the diameter ; that of the flange
of the spindle, from J to J part of the diameter ; of the pulley for leather straps,
about | ; and for the catgut, } the diameter of the saw.
The velocity of the edge of the saw varies from about 4500 feet to 5000 feet per
minute; and the greatest thickness of work done can scarcely exceed | the diameter
of the saw, and is generally below J the diameter.
CIRCULAR SAWS FOR LARGE WORKS. 7S5
!i only eight sectional teeth (see fig. 791, p. 797). The
ular saws are more inclined, because such teeth cut
more keenly, and the additional power they require is readily
applied, by the great velocity and momentum that may be
• n to circular saws. The teeth of circular saws are more set,
to make a wider kerf, which is required, because the large
circular plate can neither he made nor retained, so true as the
narrow straight blade. The general proportions of circular saws
are given in the annexed table.
It is generally politic, to use for any given work, a saw of as
small diameter as circumstances will fairly allow, as the resist-
ance, the surface-friction, and also the waste from the thickness,
rapidly increase with the diameter of the saw. But on the other
hand, if the saw is so small as to be nearly or quite buried in the
work, the saw-plate becomes heated, the free escape of the dust
is prevented, and the rapidity of the sawing is diminished.
Hassenfratz, Emy, and other French writers on carpentry,
have described the mode of cutting thick logs of timber, as in
fig. 782, by means of two comparatively small saws, each extend-
ing alone to the center of the log. The saws are in the same plane,
but one above and the other below the log, and a little removed
Lto avoid the contact of their teeth ; but from the reasons above
stated, and some others, the plan is but rarely if at all adopted.
Fig* 782. 78S.
:
I'nder iiH»t cimim-tanee.s, it is \)e&t to employ that part of
the saw which is nearest to the center, and it may be stated
generally that, as in fig. 783, the diameter of saw *, should
be about four times the average thickness of the wood w, and
that the flange on the spindle, should be as nearly as prac-
ticable flush with the saw table or platform p p.
1 dit ion to various other particulars in the table on circular
saws, an attempt has been made to tabulate the velocities proper
for different Haws, and the amount of power severally required,
but • , iibei. s must be received with some latitude, because
3 E
786 CIRCULAR SAWS FOR LARGE WORKS.
they are very much influenced by accidental circumstances.
Amongst these are the particular quality of the wood or other
material, as to its hardness and grain, its greater or less freedom
from moisture, or from gummy or resinous matters, also its
magnitude, and the degree of smoothness desired in the surfaces
left by the saw; all these circumstances demand certain variations
in the porportions and conditions of the saws used. A few words
will be therefore added respecting each of these conditions.
The harder the wood, the smaller and more upright should be
the teeth, and the less the velocity of the saw ; hence it follows
that the rate of sawing is proportionally slow.
In cutting with the grain, or lengthways through the fibres,
the teeth should be coarse and inclined, and the speed moderate,
so as rather to cut the removed wood into shreds than to grind
it into powder ; as the more minute the sawdust, the greater
the power that must be expended in its production.
In cutting across the grain, the teeth should be finer and
more upright, and the velocity should be greater than in the
last case ; so that each fibre of the wood may be cut by the
passage of some few of the consecutive teeth, rather than be
torn asunder by one tooth only.
Wet wood is softer than dry, and is therefore more easily cut,
but the saw is required to be keener and more coarsely set ; the
waste is consequently greater.
For gummy or resinous materials, and for ivory, the saw teeth
are required to be very keen, and the velocity comparatively
slow, to avoid the dust becoming softened and rendered adhesive,
as it will then stick to the blade. This disposition is lessened
by lubricating the saw either with a tallow candle, solid tallow,
lard, or oil applied with a brush.
When the object is to get through as much work as possible,
the rapidity with which the wood is then advanced, will prevent
regularity in its progress, and consequently likewise in the saw
marks on the wood. The saw is then liable to be overloaded;
if so, it vibrates rapidly sideways with great noise, requires
greater force, but nevertheless proceeds through the wood
.slowly and leaves it full of coarse ripple marks.
Smooth sawing requires the work to be regularly advanced
towards the saw, and the latter must be keen and very uniformly
set; as one tooth projecting beyond the general line, is sufficient
IP1NOLM i'>R LARGE CIRCt'LAR BAWi.
787
to score or scratch the work. It is a proof that the saw wns in
most excellent onlt-r ami well applied, when the portion cut in
every revolution of the saw, cannot be detected by the c«
marks left on the wood or other material.
taws exceedm;/ nlxmt one foul diameter.
— Saws of this magnitude are seldom used on spindles mounted
In 'tween pointed centers, as represented on page 754, but on
those resembling the sections figs. 784 and 785. These spindles
revolve in hearings or brasses b b, made in halves, and secun ly
united to the stationary framework of the saw bench. The end-
play, or end-long motion of the spindle, is usually prevented
alone by the two collars or projections c c, which embrace the
one bearing; sometimes, however, the one collar c', fig. 7t>5, is
screwed on the spindle to admit of adjustment, and has a side-
screw to retain its position ; or else the collar c', is in the solid,
as usual, and a fixed screw *, exterior to the pulley, is made to
bear on the end of the spindle.
Each spindle has a wooden or iron pulley of about one-third
the diameter of the saw, for the driving strap, but in mills driven
by power, a fast and a loose pulley of equal diameter are placed
on each spindle, as in fig. 786, so that the spindle may be dis-
connected with the engine by throwing the strap on the host,
free, or lire pull.
Saws below about 20 inches diameter, are commonly held like
those previously described, between the fiat surfaces of the collar
or projection r, that is forged in the solid with the spindle, and
the surface of the loose collar or washer u>, as in fig. 7S4 ; one
3 E 2
788 BENCHES, PLATFORMS AND STOPS, FOR
steady pin then suffices, and which is fixed near the periphery
of the flange. Large saws require flanges, say from 5 to 10
inches diameter, and which are then added to the spindle, as in
fig. 785; the one is fixed by a feather or parallel key, and car-
ries three steady pins ; all the steady pins are represented black
in the figures.
The loose flange is sometimes pressed up by only one screwed
nut n, but it is preferable to have two, of different threads, that
the second may prevent the first from being accidentally loosened;
as the two then unwind at different rates, and check each other's
motion. Either the one nut is right and the other left-handed,
as in Collinge's patent axletrees, or else both nuts have right-
handed threads, which differ in pitch as well as diameter.
3. Benches and platforms for large circular saws. — These are
in general framed together very strongly in wood, in the ordi-
nary manner of carpentry; they measure from about 4 to 12
feet long, 2^ to 4 feet wide, and 2^ to 3 feet high. The bear-
ings for the saw are placed close beneath the platform, and at
about the middle of its length ; the central part of the bench is
represented in plan in fig. 786.
To arrive at the saw spindle for the purpose of changing the
saw, there is frequently inlaid in the platform a rectangular
frame of cast iron with a rebate on the inner edge, fitted with a
loose iron panel in two pieces to form the cleft for the saw. The
panel is supposed to be removed to show the nuts and stops for
the saw, and before the saw can be changed, it is also needful
to lift out the wooden bar, which lies across the end of the
spindle and against the saw; the bar is added for the purpose
of carrying the stops * *, to be explained.
Sometimes the bench is nearly covered with plates of iron to
lessen the friction of the timber upon it ; and in benches for
heavy work, the half of the platform in front of the saw is occa-
sionally made as a slide, with a rack, pinion and winch handle,
by which it is moved endlong. The work is in such cases placed
against a ledge or cross piece on the slide, and is carried to the
saw with great facility. A few saw benches, for some specific
kinds of work, are constructed entirely in iron.
4. Stops to prevent the vibration of large saws. — These are in
I.AIUJK CIIUII.MI
MM MINES.
781
many cases inl-iid in the wooden bed of the machine, beneath
tin- nun plate l>y which access is obtained to the saw, as shown
in tig. 786. The two grooves * «, nearest the periphery of the
saw, are in some instances each entirely Tilled with a block of
hard wood, kept in position by the top plate, and set forward
from time to time by pieces of card or veneer placed behind
them, to compensate for the portion worn away by the saw. At
other times, the grooves are fitted with blocks of wood or metal,
which have mortises for fixing screws, as shown on a larger
scale at *' *' ; these admit of adjustment and fixation. Screwed
holes are also used, especially in the iron framings, cylindrical
wooden plugs from f to f inch diameter are then screwed into
the holes and set forward to meet the saw.
Large saw machines have sometimes wedge-form pockets
beside the saw plate, which are filled with greasy hemp ; the
downward motion of the saw carries the hemp into the narrow
part of the pocket, and pressing it against the saw, checks the
vibration. This method, although it causes more friction, is
nevertheless much approved of, as the elasticity of the packing
enables the saw to be at all times closely gripped ; which on
account of its small irregularities, cannot be the case when rigid
metallic or wood stops are used; but hemp is less suitable than
wood for small saws. Frequently the stops are applied to both
the front and back edges of large saws, as shown in the figure.
790 PARALLEL GUIDES FOR LARGE CIRCULAR SAWS.
5. Parallel Guides for circular saws. — The parallel guide
mostly added to large saw benches, closely resembles the ordi-
nary parallel rule used for drawing, as will be seen on the
inspection of fig. 786. The principle requires that the four
centers of the parallel rule should constitute the four angles of a
parallelogram, or that the four sides should be exactly two pairs,
with which view the two radius bars are clamped together and
drilled as a solid bar, and so likewise are the long bars. Unless
the centers or pins fit accurately, it will be found that when
the bars lie very obliquely, that the front bar or fence will
have a rolling motion, as on a center, instead of being firm and
parallel.
In some few cases the long metal bars are dispensed with ;
iron ears or plates, for two of the centers are then fixed to the
wooden fence or rail, and the back centers are similarly attached
to the platform itself, through which a circular mortise, parallel
with the paths of the radius bars, is sometimes made for the
clamping screw that fixes the rule. It is, however, better the
rule should be constructed as in the figure 786, and quite inde-
pendently of the platform, to admit of ready detachment. The
long back rod is then essential, and also a fixing bar, placed as
a chord to the arc described by the radius bars, and retained by
a screw and nut passing through a mortise in the bar.
In the above construction, the long fence moves in an arc,
like those described by the radius bars, and shown by the dotted
lines, but the three-bar parallel rule is sometimes employed,
because it may be opened in a right line, and therefore moves
simply sideways to the saw ; its path is directed by a pin in the
long bar or fence, which enters a straight groove made trans-
versely in the platform. The construction of the three-bar
parallel rule is nearly a duplication of the former, and as it is
equally important that the centers of the similar parts should
be equidistant, the four radius bars are drilled together, to
ensure their similitude, and so are also the three long bars.
In the two and three-bar parallel rules, two slit clamping bars
are occasionally used, which entirely restrain any wriggle, as
they secure both ends of the fence ; the perpendicular height
of which varies from two to ten inches, according to the nature
of the work to be sawn.
RAWING THE 8IDK8 Of RECTANOUI \K MICE*.
6. Sairiny the tides qf rectanffular pifCff. — In both small and
«• sawing machines, the work. i < applied much in the snme
manner ; hut in saw-mills two individuals are commonly em-
ployed, one to hand np and thrust forward the work, and another
to assist by dragging and afterwards removing the work from tin;
bench. \Yhen the pieces are short, the person who pulls com-
monly uses a tomahawk, \\ hich is like the half of a small pickaxe,
tin* point of which is struck into the wood to serve as a handle.
When a log or round piece of wood is applied by the hands
alone to the circular saw, it is difficult to get the first cut exactly
true, ns the wood is apt to roll on the two or three points at
which it may touch the platform ; but when the saw has pene-
trated a little way, the blade itself materially assists the holding
of the work. One cut having been made, the flat side is placed
downwards, and a second cut is made from either of the ed_
and provided the first side is moderately true, the second will
become at right angles to the first; the third and fourth sides
will he found to present no difficulty.
As a ready means of adapting the parallel guide to works of
different widths, a parallel piece of wood is often placed along-
side the object to be sawn. Thus in cutting the blocks for
wood-paving, the round larch timber is first cut into pieces
about 3 feet 6 inches long, and these are, for the most part,
sawn into pieces six inches square; but should any of them fail
to hold that size, a parallel board half an inch thick, is placed
alongside the work, which is then reduced to the next following
size, or 5£ inches square. And in the same manner, pieces of
two dimensions, as of 2 by 1 inch in section, are in some cases
cut by setting the parallel rule to 2 inches, and packing the
work the thin way, with a piece 1 inch thick.*
• In reality, the standard size of the squared timber for the blocks of the
Metropolitan Wood-Paving Company, is 54 by 6 inches ; but the round logs are
cut as large as they will respectively hold, the one measure being always half an
inch more than the other. The wood is used very soon after it is felled, and is
so wet, that the men find it needful to suspend a board over the saw and at right
angles to it ; this arrests the saw-dust, which if allowed to drive against the
attendant, soon wets him to the skin.
In some wood-cutting proems*, a screen of wire-game is placed between the
work and the workman, that he may be enabled closely to watch the operation
without risk of the shavings entering his eyes.
702 LARGE CIRCULAR SAAV MACHINES FOR SPECIFIC WORKS.
SECT. VII. LESS COMMON OR SPECIFIC APPLICATIONS OF
CIRCULAR SAWS TO LARGE WORKS.
It may be considered that in the last section, the remarks on
the structure and use of the circular saw-bench, were concluded,
so far as concerns its ordinary application to the conversion of
timber into scantling, or squared pieces of various sizes. But
it still remains to notice, in continuation, some of the miscella-
neous and large applications of circular saws, which so far as
admissible, will be introduced in the order formerly adopted, as
the subdivisions 7, 8, 9, and 10, will be repeated, to which will
be added the sawing of curvilinear works, and some other less
classifiable matters.
Part of the contrivances for these works, are merely additions
to the ordinary saw-bench, others are machines expressly con-
structed for their respective purposes ; but to save unnecessary
subdivision, they will be collectively and briefly noticed ; as the
principles rather than the mechanical details will be advanced,
together with references to such published descriptions of them
as have come under the author's notice. Two contrivances for
obtaining an accurate base to work from, in pieces not originally
straight, will be first referred to.
The late Mr. Smart, in obtaining the first true side in irregular
pieces three or four feet long, intended for the staves of casks,
attached the pieces to an external fence or guide. The wood
was grasped by its extremities, somewhat as between the centers
of a lathe, in a kind of trough made of two boards united at
right angles ; one end of the trough had a solid block of wood,
that could be fixed at variable distances ; the other end had an
iron bar, roughened at its extremity, and brought up by a rack
and pinion, so as to stick into the ends of the wood, the grasp
being secured by a ratchet.
The trough was considerably longer than the length of the
wood to be sawn, and two studs projected from its extremities
beyond the side of the work. These projections were made
to rub against the face of the parallel rule, and avoiding the
saw, to direct the cut exactly in a right line, and produce,
on the irregular wood, one flat surface that might serve as
the base for the subsequent operations.* The same end is
* See Trans. Soc. of Arts, Vol. 47, plate 8.
CIRi I I
iliflPmmawi
CIRCULAR SAW M \ in s KS FOR GROOVES, RKBATKS AND TENONS. 793
differently obtained, and on larger pieces of timber, in the
following method.
In the Ravensbourne wood-cutting mills at Deptford, battens
10 or 12 feet long, and intended to be sawn and plain
flooring-boards, are grasped by their upper and lower edges, and
without strain, by screw-teeth or dogs built out from a carriage
which runs in V bearings; tbe slide is carried by a self-acting
rack and pinion movement, past a circular saw revolving in a
vertical plane, which skims the side of the batten, and leaves it
as straight as the V slide itself. The traversing carriage or drag
of this machine, is closely analogous to that of the veneer saw
to be hereafter noticed.
7. Sawing grooves, rebate*, and tenon*. — These works may be
accomplished in the large way, in the modes already described
on page 761. The flooring boards of the warehouses in the St.
Katherine's Docks, London, were grooved on each edge upon
an ordinary saw-bench, for the reception of strips of hoop-iron
used as tongues to prevent dust falling through the joints; and
the frames for doors are occasionally grooved for the panels in the
same manner, but with thick saws. The still wider rectangular
grooves in the blocks for wood pavement, are cut out with
two ordinary saws on the same spindle, having two or more
intermediate chisels, to cut the bulk of the removed wood into
chips.
The mortises in the shells of ships' blocks, for the reception
of the sheaves, are cut by small double circular saws ; a hole is
first bored through the shell at each end of the mortise, and the
saws are then made to penetrate from each side, and nearly
complete the mortise, in a less expensive manner than with the
mortising engines in Portsmouth Dockyard.
The squares or tenons of the steel pins for harps, by which the
strings are tuned are also cut by means of two thick saws, sepa-
rated to the extent of the side of the square; the pin is presented
twice to the saws, the second position being at right angles to
the first. The equality in size of the squares is also ensured by
this method, so that they all fit the same tuning key.
Rebates may of course be cut upon the ordinary saw bench
at two processes, as before explained, but they are also made by
two saws mounted on separate spindles, and placed in the exact
794 SAWING TENONS AND COMBS; COMB MACHINE.
directions of the two cuts required ; one saw spindle is a little
before the other, to avoid the contact of the teeth. The angular
grooves or rebates in the blocks for wood pavement, are thus
made at one operation, in a machine with two saws at right
angles to each other.
The combination of two saw spindles was first employed by
the late Mr. Smart, in cutting the tenons for the construction
of his patent hollow mast. The small pieces of wood were first
squared on all sides to the proper measures, each small block
was then rebated, first on the one angle, it was then turned
over, and the formation of the second rebate completed the tenon.
Another part of the same machine carried a mandrel and center
bit, so that by the aid of a guide, the holes in the tenons could
be also made exactly true and alike.*
Two saws mounted on the same spindle are used in cutting the
teeth of combs, which may be considered a species of grooving
process. One saw is in this case larger in diameter than the
other, and cuts one tooth to its full depth, whilst the smaller saw,
separated by a washer as thick as the required teeth, cuts the
succeeding tooth part way down, on the same principle as in the
stadda, and rack saws, figs. 703 to 706, page 723.
A few years back, Messrs. Pow and Lyue invented an inge-
nious machine for sawing box wood and ivory combs. The
plate of ivory or box wood, is fixed in a clamp suspended on two
pivots parallel with the saw spindle, which has only one saw. By
the revolution of the handle, a cam first depresses the ivory on
the revolving saw, cuts one notch, and quickly raises it again ;
the handle in completing its circuit, shifts the slide that carries
the suspended clamp to the right, by means of a screw aud
ratchet movement. The teeth are cut with great exactness, and
as quickly as the handle can be turned ; they vary from about
30 to SO teeth in the inch, and such is the delicacy of some of
the saws, that even 100 teeth may be cut in one inch of ivory;
the saw runs through a cleft in a small piece of ivory, fixed ver-
tically and radially to the saw, to act as the ordinary stops, and
prevent its flexure or displacement sideways. Two combs are
usually laid one over the other and cut at once; occasionally the
machine has two saws, and cuts four combs at once.
* See Gregory's Mechanics, 1807, Vol. II, pige 328, plate 2G.
i I \R SAW M \( MINKS FOB CROSS-CUT! 7M
8. Sawing or cro**-cutting the end* of piece*, either *quare or
bevillfd; or those in which the angular variation* are in the hori-
zontal plane. — The saw-bench is not much employed in cross-
cutting tlu- ends of long timber for the general purposes of
lit iy ; but short pieces are sometimes guided to the saw, as
in the small machines, by the intervention of either a wooden
square or bevil, the one edge of which rests against the parallel
rule, the other thrusts forward the work. In cutting the square
scantling for wood pavement into oblique prisms, a wooden
slide is sometimes added to the saw-bench, with a trough exactly
at the required angle, and in this case, as well as the last, the
parallel rule serves as the guide for the length of the blocks.
The Metropolitan Wood- Paving Company employ for this pur-
pose, an iron machine which has a slide running in V bearings
or angular grooves, planed in the bed of the machine and parallel
with the saw : the cast-iron slide is constructed to serve as the
inclined trough to receive the squared wood, and has an adjust-
able stop to determine the length of the blocks.*
The three following diagrams are intended to show the prin-
ciples of different circular saw machines for cross-cutting; the
wood is shaded in each of the examples, and the arrows denote
the movements for following up the cuts of the revolving saws.
In cross-cutting the round logs of lignum vitae for the sheaves
of ship blocks, Messrs. Esdailes use a wooden saw-bench, the
sliding platform of which is inclined, and has at its lower end a
perpendicular rail, as in fig. 787. The log of wood is laid in the
nook, and the entire platform is then thrust by the hands past
the saw, which revolves on a fixed axis as usual, and thus the
log is sliced into pieces, their thickness being determined by a
wooden stop ; but it is necessary, in this machine, that the saw
should have rather more than twice the diameter of the log.
In the block machinery at Portsmouth, a somewhat elaborate
machine is used for the same purpose, which is so constructed
that the saw *, need only be large enough to penetrate to the
* The angle specified in the Count de LiUSt Patent u 6J* 2G' 6% every block is
afterward* chamfered on three edges, grooved on the face, and drilled with four
holes for the dowels, in appropriate machines, nearly the whole of which are con-
structed in iron and driven by two steam-engines, each of twelve hones' power.
The thirteen various machines, are managed by sixteen men and fifteen boys, and
in one week of seventy-two working hours, produce on the average 80,000 blocks,
or 800 square yar.ls of paving.
796
CIRCULAR SAW MACHINES FOR CROSS-CUTTING.
center of the log, as explained in fig. 788. A short log of
lignum vitae is mounted on a kind of lathe mandrel ; the saw
spindle is then traversed sideways until the teeth cut to the center
of the wood, and the mandrel is afterwards rotated once on its
axis by a wheel and pinion, to extend the cut around the log.
One slice having been removed, the saw is withdrawn sideways
to the dotted position s', and the mandrel and wood are set for-
ward through the collars, as much as the thickness of the sheave,
by a screw at the back of the mandrel, preparatory to the next
slice being removed.
Figs. 787. 788. 789.
Another cross-cutting machine, after the manner of fig. 789,
and also contrived with a view of using a saw for work of nearly
its own diameter, is used at Portsmouth, for cross-cutting the
butts of round elm timber, into short pieces used for the wooden
shells of the blocks. In this latter case, the timber is fixed hori-
zontally and immoveably, and the saw is carried in one plane, first
down the one side of the timber and then the other. To accom-
plish this, the saw spindle is mounted at the end of a double
swing frame, near the centers of which are placed guide pulleys,
for the strap that connects the saw with the steam-engine. The
parts of the wooden swing frame, are double and strongly braced
with iron bars, and the angular movements of the frame are
governed by racks and pinions, but the various details are alto-
gether omitted in the diagram.*
9. Sawing devilled edges and prismatic pieces; or those works in
which the angular variations are in the vertical plane. — The most
* The two machines, figs. 788 and 789, were invented by Mr. (now Sir M. I.)
Brunei, and are fully described and figured in Rees's Cyclopaedia, article "Machi-
nery for Manufacturing Ships' Blocks;" and also in Encycl. Metrop., part
Manufacture?, articles 533 and 535.
EASTMAN'S SAW MACHINE FOR WEATHER BOARDS. 797
• Ir niul usual method of accomplishing this class of work, is
by the employment of oblique supplementary beds, as explained
in fig. 748, page 768; the hexagonal blocks for wood paving
have been cut on the common (taw-bench, precisely in the mode
t lie re described for small hexagonal and other prisms: indeed,
the whole of the remarks already given on bevilled or prismatic
works, are applicable alike to the small saw machines and the
full-sized saw-benches.
In the sawing machine invented by Mr. Robert Eastman, of
America, for cutting feather-edged or weather-boards, &c., (as in
fig. 790,) the round log of timber is held horizontally, between
centers inserted in the end of a long rectangular frame or
carriage, which has rollers that run on fixed bars or rails. The
round timber is placed above the revolving saw, which makes a
vertical and radial incision into the timber; the slide then runs
quickly back, and the wood is afterwards shifted on its axis
for a new cut, by means of a dividing plate and appropriate
mechanism. The machine is automatic, or self-acting, so that,
the primary adjustments having been first made, the entire tree
is cut into radial feather-edged boards without further atten-
tion. The rough exterior edges of the board are also cut away
by tappers, or chisels c, screwed near the center of the saw-plate,
which cut away the sap or waste wood, and reduce the tree to
the cylindrical form ; sometimes, if the tree is large, two series
of radial boards are cut.
Up It <.
791.
792.
g
The account further states that ordinary steel saws, toothed
all round as usual, were found to heat and choke when thus em-
ployed, on account of their being so deeply buried in the wood,
the inventor, therefore, contrived what he termed sectional teeth,
798 SAW MACHINES FOR HEXAGONAL PAVEMENT, ARCHITECTURAL
shown in fig. 791. An iron plate of one-eighth of an inch thick
had four dovetail notches, fitted with four pieces of steel, each of
which constituted two teeth in the form of the "hawk's bill/'
the paucity of teeth was compensated for by giving the spindle
a velocity of 1000 to 1100 turns per minute, and the saw is said
to have penetrated with facility eight inches deep into white
Canada oak. The radial boards are described to be, (as explained
in the former volume,) much less liable to split in shrinking than
those cut out in the ordinary way.*
A mode, somewhat resembling the above, for cutting hexago-
nal blocks for wood pavement, has been recently proposed by
Messrs. Randolph, Elliot, & Co., of Glasgow, and is illustrated
by fig. 792. In this case, two saws are employed on the same
horizontal spindle, and the headstocks, which are of iron and just
like those of a lathe, pass exactly between and beneath the saws,
which thus produce two parallel cuts at once. The round timber
being shifted twice, and one-third of the circle each time, becomes
an exact hexagonal prism, three or four feet long, and is after-
wards cross-cut into the proper lengths.f
Professor Willis is in the habit of using the circular saw for
blocking out Gothic and othermould-
ings, for the illustration of architec-
tural science. For example, if in the
moulding, fig. 793, the several cuts
are made that are denoted by the
surrounding lines, the fillet and cham-
fers are definitively produced, and
the margins of the curvilinear parts
are accurately blocked out or defined,
so that the mouldings may be easily
and faithfully finished by moulding
planes.
The wood in such cases, is marked at one end with the sectional
and formation Hues, as in the figure, and then mounted between
centers in a species of lathe, with a dividing plate, so that the
line a, first becomes horizontal. The saw, which is also horizontal,
* The full description of this machine, with figures, is transcribed from Pro-
fessor Silliman's American Journal of Science and Art, into Gill's Technological
Repository, 1822, vol. ii. page 217.
+ Practical Mechanic and Engineer's Magazine. Glasgow, 1843, p f>7.
Fig. 793.
MOULDINGS, AND WORKS OF TWO 1S< I I NATIONS. 799
is attached to :i kind of slide-rest, witli three adjustments ; a
aid a lateral adjust incut, to adapt the saw also to the
I'M- a ; and a longitudinal adjustment, by which the saw is then
ti;i\crscd the entire length of the moulding. The work is then
adjusted on its axis by the dividing plate, until b becomes
/ontal, and the saw having been as before adjusted to b, is
swept tin- 1. ii-th of the moulding, and the two incisions remove
the angle of the square block. The cuts c and d, similarly treated,
remove another portion of the wood that is in excess, and so on
to the end ; all the cuts thus made become strictly parallel, or
in prismatic relation to one another.
When the mouldings run on to a chamfered base or plinth,
which commonly occurs in Gothic architecture, the plinth is
of all removed by a transverse and oblique incision of the
saw, after which the mouldings are made, and finally the removed
plinth is replaced without alteration, and the work is complete.
10. Sawing works, in which the angular variations are in both
the horizontal and vertical planes. — All the observations and
i n >t ructions given in the former and corresponding subdivision,
are in truth applicable to large saw-benches ; but the machine
now to be described is more suitable to large works of this class.
In Mr. Donkin's saw-bench, fig. 7 9i, the half of the platform
in front of the saw is hinged like the flap of a table, and has
quadrants, somewhat after the manner of the sketch, by which
it may be fixed for cutting any bevils within its range. The
parallel rule is available for setting out the widths of the works ;
and the saw is mounted upon a swing-frame of cast-iron, shown
separately in fig. 795. So that the quantity the saw projects
through the table, as for sawing rebates, can be regulated by a
cam '•, upon which the one end of the swing-frame rests.
In cutting small bevilled works, such as those for the wooden
cogs of cast-iron mortise wheels, and various other pieces, Mr.
Doukin employs a supplementary carriage, running upon three
iron rollers, and guided by the hands against the parallel rule.
b« carriage is also conveyed by fig. 71H. It is made
in cast-iron, and rectangular, but deficient of the half of the
lower side ; and carries a center screw, a dog or prong chuek,
and a dividing plate, much as in a lathe; but the axis of these
parts, although sometimes horizontal, is generally vertical.
800
DONKIN'S SAW MACHINE. CURVILINEAR SAWING.
The small pieces of wood are cut out square as usual, but
somewhat too large ; they are then grasped between the dog
and center screw. If the pieces are parallel or prismatic, the
saw-table remains horizontal as usual ; if the pieces are taper or
pyramidal, the table is inclined, and which throws the guiding
carriage to any required obliquity. The parallel rule is next
adjusted to enable the saw to cut the first side; and should the
object have four, six or more sides, the dividing plate is brought
into requisition, for giving the four or more angular positions.
The parallel rule determines the respective distances of each
side from the axis on which the work is shifted.
Fig. 794
795.
In this ingenious manner, by the changing of the horizontal
and vertical angles, by the adjustment of the parallel rule, and
by the projection of the saw through the platform, almost any
piece, having plane surfaces, may be sawn ; and the settings once
adjusted, an unlimited number of similar pieces may be produced,
as it is only necessary to make the first cut, throughout every
piece of the entire number, then the second cut throughout the
whole, the third, and so on. This is accomplished by leaving
every adjustment undisturbed whilst the first cut is repeated
throughout all the pieces, except the removal of the one block
of wood from between the centers and the insertion of the next,
and so on with each of the succeeding cuts. The indentations
made by the center screw and dog, ensure the similitude of
position throughout the entire operation.
11. Sawing Curvilinear Works. — The trephine-saw used in
surgery, and represented nearly full size in fig. 796, appears to
have been by far the earliest of the circular saws of this kind.
It consists of a thin tube of steel, with teeth cut on the edge,
of the peculiar form represented, and at the opposite end of the
tube is fixed, by small side screws, the stem by which it is
attached to the mechanism whereby it is worked.
Mil H riiM \M> OTHER SURGICAL S.vWi. 801
The motive apparatus of the trephine-saw, is usually a cross
"He like that of a corkscrew, or a revolving brace like that
used in carpentry. To guide the first entry of the trephine-
saw, the shaft is drilled and fitted with a drill-point p p, which
is fixed by a side screw *. In the commencement, the point
makes a small central hole, and when the saw has once fairly
penetrat <>mt is loosened and allowed to fall back into
the stem of the saw.
In another modification the center of the trephine-saw is dis-
pensed \\ith, as the " guide principle" is effectually introduced,
saw is fixed at the one extremity of a cylindrical stem,
which ut the other has a winch handle; the stem works freely
in a vertical tube or socket with three legs, constituting a tripod
stand, therefore the axis is kept steady and vertical by the left
hand; and \\hilst the teeth fulfil their office, the saw advances
through its fixed collar by the pressure of the right hand, with
which the winch-handle is turned.*
* The art of surgery baa given rise to an enormous variety of instruments, a
most complete collection of the representation of which, both of the earliest and
latest times, was published by A. W. H. Seerig, in a work entitled Armamentarium
Chirur<jic*m ; oder moylichitc volUtandigt Sammlung row Albildunyen ehiruryitcher
InttrwmenU Ultcrer u*d newrer Zeit. The work contains 145 large and crowded
lithographic plates, and was published at Breslau, in 1835.
It appears from plate 75 of this collection, that the trephine-saw was known in
the time of Hippocrates, and that both the blades and the mecbaui&m for moving
them, have since assumed numerous varieties of form.
The amputating saws set forth in this work as having been contrived or used by
various eminent surgeons, are modifications of the bow, frame, and piercing saws
for metal, and the tenon and dovetail saws for wood ; they vary from about 14 to
4 inches in length. Some of the small saws analogous to the dovetail saw, have
edges more or less curved, and the smallest of these dwindle down to a'nearly
ar plate of steel lew than one inch in diameter, serrated around the edge,
except where a slender wire, terminating in a wooden handle, is rivetted to the
edge of the saw-plate. These last are known as Hey's saws, and are principally
used for the cranium and the metacarpal bones.
A saw intended for dividing deeply-seated bones, is formed like the chain of a
table clock, but with the one edge serrated ; it is worked with two cross handles
by the alternate motion of the two hands. One of the bandies is detached, whilst
the end of the chain-saw is passed beneath the bone, by a kind of semicircular
needle. The chain saw was invented by Dr. Jeffrey of Glasgow.
A nearly similar chain-saw is arranged as an endless band, passing around the
grooved edge of a taper staff like the blade of a poniard, but terminating in a small
semicircle. There ar* guards to cover up portions of the edge, and a prop or
strut to steady the instrument, whilst the endless chain is put in motion by a winch
hau.il* attached to a pin-wheel, around which also the chain circulates. Thin
3 r
802
ANNULAR OR CROWN SAWS FOR LARGE WORKS.
The trephine-saw has given rise to various larger applications
of the same kind of instrument, having teeth of the ordinary
form, and known as crown saws, annular, curvilinear, drum, and
even as washing-tub saws, the respective merits of which names
it would be useless to discuss. Small saws of this kind, when
mounted upon the lathe, are often employed for cutting out
disks of metal and wood ; the material is in general thrust against
the saw, by a block of hardwood fitted to the front center of the
lathe, and frequently, as in making buttons, the cutting out is
combined with the shaping of the two faces of the button.
Fiys. 796.
In the block machinery at Portsmouth the crown-saw is used
for rounding the sheaves, which are cut out of transverse slices
of lignum vitse ; the wood is held at rest by its margin whilst the
singular instrument is ascribed to S. Heine, and is figured on plate 60 of Seerig's
work, which also contains several schemes for using small circular saws, but some
of the mechanical arrangements are not clearly defined in the figures.
A circular saw proposed for cutting deeply-seated bones, and as an occasional
substitute for the trephine-saw, was invented by Mr. Thomas Machell of Durham,
surgeon, and is accurately described in the Trans. Soc. of Arts for 1812, Vol. xxx.,
page 150. In Mr. Mach ell's saw the axis of rotation is constructed within the thick-
net* of the blade, so that two thirds the area of the circular saw may be depressed
in the saw cut. The saw is worked by a phi-wheel, the pins of which enter
notches in the edge of the saw-blade, the pin-wheel has teeth, and is itself moved
by a larger and more distant toothed wheel, having a small winch-handle.
The great difficulty encountered in almost all the surgical saws, arises from the
removed particles of bone becoming mixed with the fluids, and forming a thick
paste which clogs and nearly stops the action of the blades. To remedy this
inconvenience, Mr. Weiss suggested that slits terminating in round holes should
be cut in the edges of such blades as admit of these receptacles being made. — See
Weiss on Surgical Instruments, page 10, plate 18 ; and figure 796 in the text.
Small bones are now more frequently cut by strong nippers than by saws, and
many nippers are drawn on Seerig's plate 134.
TROTTER'S SPHERICAL SAW. H :',
unur mandrel, \\ln.-h carries the crown-saw and also a drill,
is advanced through its collars, and rounds and bores the
sheaves a, at the oue operation, ready for the coaking-eu^
turning-lathe, &C.*
Crown-saws, as large as 5 feet diameter and 15 inches deep,
constructed somewhat after the manner of fig. 797, arc employed
Messrs. Esdailes' saw-mills. The three or four pieces of steel
tii' n constituting the hoop, are rivcttcd to the outride of a strong
ring, and very carefully hammered, so that the plates exactly
constitute one continuous cylinder; although the ends of the
plates are not united, but simply make butt-joints. The ring
is fixed to the surface-chuck of a kind of lathe-mandrel, by
means of hook-bolts A, and the work is grasped in a slide-rest,
which traverses \\itliiu the saw, and parallel with its axis.
The saws of about 2 feet diameter are used for cutting the
round backs of brushes bt and the larger saws are employed for
felloes of wheels d, and similar curved works. If the wood is
applied obliquely, the piece also becomes oblique, in the manner
explained by the diagram c, which represents the sloping and
hollowed back of a chair thus produced. It is, however, much
more usual to saw curvilinear works of the kinds referred to,
with the felloe or pit-turning saw (see page 707), the chair-
maker's and wheelwright's saw (p. 725), aud the turning sweep,
or bow-saw (p. 728), the respective applications of which have
been already noticed at the pages referred to.
Mr. Trotter proposed for curvilinear sawing, the employment
of a saw-plate «, fig. 798, which instead of being a flat plate, as
u-ual, was dished as the segment of a large sphere. The fence/,
which was made as the arc of a circle, had a conductor c, to
receive the work w ; the circular fence was attached to a three-
bar parallel rule, so as always to keep the curvatures of the fence,
conductor, and saw, which were equal, truly parallel with each
other. The construction of the spherical saw-blade is difficult, and
its advantage questionable, especially as the edges of the pieces
when Irtt from the saw, would be curvilinear in width as well as
length, or part of a spherical surface, of the same radius as the
taw. This form is seldom required in the arts, and its conversion
into the simple arch-like form with square edges (proposed to be
Cyclopedia, art. " Machinery for Manufacturing Shipe' Blocks." —
. c. Metropolitan, rol. Mechanic*, art. 870.
3 i
804
SAWING THE CURVILINEAR STAVES OF CASKS.
approached by inclining the work), would fully cancel the intended
economy of the spherical saw, which is however curious, as one
of the links in the chain of contrivances under consideration.*
Much ingenuity has been displayed in cutting the curvilinear
and bevilled edges of the staves of casks by circular saws. The
late Sir John (then Mr.) Robinson, proposed many years back that
the stave should be bent to its true curve against a curved bed,
shown in two views in fig. 799, and that whilst thus restrained
its edges should be cut by two saws s s, placed as radii to the
circle, the true direction of the joint, as shown by the dotted circle
representing the head of the cask. The principle is perfect, but
the method has been found too troublesome for practice.
Figs. 70S.
800.
Mr. Smart cut the edges of thin staves for small casks on the
ordinary saw-bench, by fixing the thin wood by two staples or
hooks to a curved block, fig. 800, the lower face of which was
bevilled to give the proper chamfer to the edges. One edge having
been cut, the stave was released, changed end for end, and refixed
against two pins, which determined the position for cutting the
second edge, and made the staves of one common width. The
curved and bevilled block, was guided by two pins p p, which
entered a straight groove in the bench parallel with the saw.
This mode of bending was from various reasons found inap-
plicable to large staves ; and these were cut, as shown in three
views in fig. 801, whilst attached to a straight bed, the bottom of
which was also bevilled to tilt the stave for chamfering the edge.
To give the curve suitable to the edge, the two pins on the
under side of the block then ran in two curved grooves g g, in the
* Trans. Soc. of Arts, 1805. Vol. xxiv., p. 114.
CIECC
I \H -\\w \ M) M \flll\CK\ roil CtTTINO VENEERS. 805
saw-bench, which caused the staves to sweep past the saw in the
arc of a very large circle, instead of in a ri^rlit line, so that the
ends were cut narrower tli.-m the middle. Mr. Smart observes,
tluit in staves cut whilst straight, the edges become chamfered at
the same angle throughout, which although theoretically wrong,
is sufficiently near for practice ; the error is avoided when the
staves are cut whilst bent to their true curvature.*
SECT. VIII. CIRCULAR SAWS AND MACHINERY FOR CUTTING
VENEERS.
Valuable and beautiful woods are seldom used in the solid
state for decorative furniture, but are cut into veneers or thin
plates, to be glued upon fabrics made of less expensive woods, an
art successfully practised by the Romans, as formerly adverted
to (Vol. i., page 64). Until of late years the cutting of veneers
was generally accomplished, either at the saw-pit with very thin
plates strained in the ordinary pit-saw frame, (see Vol. ii., page
703), or by the cabinet-maker with the smaller frame-saw,
(page 726). In this latter mode, which is still much practised on
the continent, the wood is fixed perpendicularly, and the saw is
also guided by two men. Expert pit-sawyers could cut six
veneers out of each inch of wood, and cabinet-makers seven or
eight from smaller pieces, but the difficulty of these methods
rapidly increases with the size of the veneer-.
Small veneers for the backs of brushes and other works, have
been split or planed from small pieces squared to the respective
sizes. Pine, willow, and other woods, are planed into thick con-
* See the original paper, Trans. Soo. of Arts, Vol. xlvii., pp. 121-7. In the
year 1833, Mr. Samuel Hamilton took out a patent for "certain machinery for
aawing, boring, and manufacturing wood for various purposes, such aa bevilled
timber for ship-building, tenon cheeks, felloes of wheels, the circular rails of
chair backs, choir legs, and other works of the same description, either square on
the face, or bevilled to any required angle, or in any required radius or dim
of a circle."
The specification is Tory complex, but it may be said briefly, that the felloes are
cut by a vertical reciprocating saw worked by a crank, and the edge of the work
is guided either by a fixed circular fence, or by radius ban ; for bevilled works
the table of a similar machine is tilted to any angle. For other classes of work,
the saw-frame is jointed, and may be brought down by a swing-frame in the arc of
a circle, to penetrate to any assigned depth. The work is grasped by numerous
arrangements of parts, that hold any successive number of pieces exactly in the
same position. — Set Newton's London Journal and Repertory, A--:, Vol. viL, p. 1.
806 BRUNEI/S MACHINE 1'OR SPLITTING VENEERS.
tinuous shavings called scale-boards^ for making hat and bonnet
boxes (Vol. ii., p. 504). And of late years oak, when softened by
steaming, lias been split into staves for casks (foot-note, Vol. i.,
page 32). All these processes are accomplished without waste of
the materials, but they are only applicable to pieces of limited
dimensions.
In 1806, Mr. Brunei took out a patent for splitting veneers,
of considerable size, by means of a horizontal knife, the length
of which exceeded the length of the block to be converted.
The knife was composed of several pieces of steel, placed exactly
in a line on their lower surfaces, but with edges faintly rounded
and very keen. The compound knife received a short recipro-
cating or sawing action, and the block of mahogany or other wood
was carried slowly sideways, and beneath the knife by a strong
screw slide, worked with a spoke wheel, like that by which a
ship is steered. After one veneer had been cut off, and the
log brought back again to its first position, it was raised in exact
parallelism, by a system of two right and two left-handed screws
at the four angles of the frame, which were simultaneously moved
with one winch-handle, by aid of appropriate mechanism.*
This machine for cutting or splitting wood into veneers, the
precursor of the segment veneer-saw, is said to have answered
moderately well with straight-grained and pliant woods, such as
Honduras mahogany, but there were serious objections to its
use for woods of irregular, harsh, and brittle grain, such as
rosewood; as the veneer curled up considerably on removal,
and the wood if harsh and brittle had a disposition to split and
become pervious to the glue.f This is to be regretted, as the
splitting-machine converted the whole of the wood into veneer
without waste, whereas the veneer-saw, on the average, cuts
one-third of the wood into saw-dust.
As already explained, the ordinary circular saw will not, in
general, serve for work exceeding in thickness about one-third
the diameter of the saw, and the larger the saw, the thicker it
is required to be, to give a proportionate degree of stability.
These two conditions, joined to the impracticability of obtaining
* See the drawing and description in the Rep. of Arts for 1810, Vol. xvi., p. 257.
t The Russian machine for cutting the entire tree into one spiral veneer, (see
Vol. i., p. 154,) seems open to the same objection in regard to brittle woods, neither
does it expose the most ornamental section of the tre*».
SINGLE-PLATE VENEER-8AW8 POR 1VC WOOD 807
plate* of steel exceeding some 4 or 5 feet diameter, limit the
application of the rin-ular >a\v under ordinary circumstance*.
Hut when this instrument is employed for veneers, advantage is
taken of the pliancy of the thin h at* or veneer, and the saw is con-
sequently made thick and strong towards the center, to give it the
required stability, but towards the edge it is thinned away almost
to a feather edge, as at * *, in the diagram, fig. 802. Therefore
Fig. 802.
the solid block of wood or ivory tc, which is unyielding, can pass
along the parallel guide y, and across the flat face of the saws* 5,
whil>t the thin pliant veneer v, separates so much as to form an
opening that admits the wedge-formed edge of the blade, and the
veneer proceeds along the conical back of the saw without frac-
ture or interruption ; circumstances that would be impracticable
were both parts of the material when sawn, alike unyielding.
In the small application of this principle, as for sawing blocks
of ivory into leaves for miniatures, and small square pieces of
wood into veneers for brushes and small works, the veneer-saw
is made as a single plate of steel, from 6 to 86 inches diameter.
In the large application of the principle, as for cutting logs of
square or round wood into veneers, the saw is composed of many
segments or plates, and commonly varies from about 5 to 1 ^
feet diameter. But as the segment-saws are occasionally made
at small as 20 inches diameter, the two kinds constitute an
unbroken series, and their principal applications will now be
described, beginning with the smallest.
The single-plate veneer-saw (described in section 2 of the
table, on page 781), is thick and parallel at the center for about
one-half its diameter, the edge is ground away, as a cone,
almost to a feather edge; at other times the edge is thin, and
nearly parallel for about an inch, and is then gradually coned,
making the section somewhat concave. The edge is required to
run exceedingly trur, and the teeth must be sharp and very
faintly set.
808 SAWING IVORY VENEERS FOR MINIATURE LEAVKS.
Saws of six to ten inches, are sometimes used in machines such
as that shown on page 756, for very small pieces of ivory veneer
and for slicing up wooden mosaic works, but it is more usual to
employ larger saws for miniature leaves, say those from fifteen
to twenty inches diameter, and consequently larger machines
are also required, which are driven either by a hand fly-wheel
or other motive power. The principal variations between veneer
saw -benches, and those for ordinary and thicker works, is in the
parallel guide, which, for veneers, is made fully as high as the
width of the block to be sawn, by screwing a parallel piece of
wood or metal against the vertical face of the parallel rule, and
cutting it off in a circular arc, exactly to agree with the curvature
of the saw, and without extending at all behind it. In many
cases the parallel guide is constructed \vith a set-screw, that it
may be adjusted for distance very minutely, after which it is fixed
as usual. When, therefore, the block of ivory or wood is placed
against the parallel rule, and pressed towards the saw by hand,
the thin leaf bends away as cut from the block, or yields
sufficiently to pass behind the saw without impediment.
In bevilled or veneer-saws for ivory, the teeth should be finer,
and the rate of motion slower than for wood, say, three-fourths
the speed, as when a considerable velocity is used the saw
becomes heated, and this, from the gelatinous nature of the
material, causes the sawdust to adhere to it; the heat also
tends to split the thin leaves of ivory. These sources of mis-
chief are avoided by giving to the saw-blade a subdued rate of
motion, and keeping it moderately anointed with tallow or lard.
Some idea of the delicacy of veneer-saws for ivory, will be
given by the inspection of the annexed scale, which shows the
average numbers of veneers or leaves cut from each solid inch
of ivory: —
When the width of the ivory is 1 2 3 4 5 6 7 inches,
Each inch of ivory is cut into 30 27 24 22 20 18 16 leaves.
The leaves from 1 to 2 inches wide and 2 to 3 inches long,
are used for memorandum-books, the larger sizes for miniature
leaves, the lengths of which are about one-third more than their
widths. When scraped and prepared ready for the artist, the
30, 27, or 16 leaves, respectively measure about half an inch in
total thickness, showing the waste in sawing and scraping to be
equal to about one-half the original material. The leaves might
LARGE SEGMENT-SAW, OR V KN C tR-SA WM ILL. ^09
be cut still thinner, hut this would be objectionable as regards
r intentleil purposes.
lu-villr.l or vcncer-saws, when used for wood,
greater diameter, coarser teeth, are used without grease, and
at a higher velocity thau for ivory ; hut the single-plate ven
saws are not frequently made of the full-size named in the table,
nor are they used for wood exceeding about six inches wide, or
that has not been previously squared into small pieces.*
In the larger applications of the veneer-saw, it is built up of
segments or separate plates of steel, screwed to the edge of a
metal disk or chuck. Some few of the smallest segment-saws
are even less than two feet diameter, and those not exceeding
about four feet diameter are generally used in the ordinary
saw-benches, with fixed horizontal platforms, the work being
then fed by hand as usual.
But when the segment veneer-saw exceeds about four feet
diameter, the horizontal platform or table is rejected, and the
guidance of the wood is entirely effected by machinery, called
the drag ; the arrangement of this construction, which is known
both as the veneer-mill and the segment-saw, is shown in the
perspective figure 804, page 812. The veneer almost always
proceeds from the edge of the saw, through a curvilinear trough
parallel with the back of the saw; but in the figure the veneer
is represented as if bent almost at right angles, so as to quit the
• A manufacturer, experienced for thirty yean in cutting miniature leave*,
generally employs single-plate saws from sixteen to twenty inches diameter. He
also uses a segment-saw, measuring the larger diameter, when new, and composed
of six segments, attached to a gun-metal chuck, the edge of which is very thin.
and the center enlarged into a boss cut with a hollow screw, for its attachment to
the saw-spindle, which runs in a collar and center, exactly after the manner of a
lathe-mandrel He prefers about eight to ten points per inch, and an average
Telocity of about 000 to 700 revolutions per minute ; in topping the teeth, he use*
a steel turning-tool, and sets the teeth before sharpening them.
He adds, that when the blocks of ivory are cut into lengths, prior to being sawn
into veneers, loss occurs, because the central and wider leaves require to be longer
than those from the same block, which are exterior and narrow. Sometimes the
entire tooth, or a large portion of it, U cut into veneers with the large segment-taws,
Laving the drag (to be describe' 1) ; this is better as regards the cutting of the leaves
into squares ; but the apparent economy ia again lost, a* these saws being intended
for wood, have coarser teeth, and will not leave such smooth surfaces as the saws
exclusively used for ivory, neither will they produce more than about fourteen or
fifteen veneers from each inch of ivory.
810 CONSTRUCTION OF THE SEGMENT-SAW.
saw in front; this construction is far less common, but was
selected for the present illustration, as it affords a more con-
spicuous view of the entire process.
In the veneer-saws furnished with the drag, the axes run in
massive brass bearings, which are fixed on brick or stone piers ;
the edges of the larger saws dip below the ground into a pit
lined with brickwork or masonry.
The axis of the saw is connected or disconnected with the
steam-engine at pleasure, by means of a fast and loose pulley ;
and in bringing the saw to a state of rest, the brake-wheel at
the end of the axis is strongly grasped by a friction-hoop, as in
some cranes. Between the driving pulleys and the cone for the
saw is placed a bevelled pulley, for a catgut band or rope that
is used in feeding the cut, as will be hereafter explained. The
saw, which is the all-important part of the machine, is made of
great strength, and consists of three parts, shown in the section
of the edge, fig. 803, of which the shaded part c to c is of cast-
iron, the white part * to * of soft steel, and the black h to h of
hardened steel.
Fig. 803.
~> Log of wood.
J h shea
The saw is composed, first, of a cast-iron wheel or chuck, with
from six to eighteen arms, which are taper, so as to constitute a
cone, the thickness of which at the center is about one-twelfth
the diameter. The rim of the wheel c c, is flat and turned smooth
on the face to receive a series of 6 to 18 segments of soft steel,
about one-quarter of an inch thick, marked s s, which are fixed
to the cast-iron by strong rivets ; the segments project from 5 to
8 inches beyond the cast-iron, and are chamfered at the edge.
To the soft-steel segments * s, are affixed a second series h h,
consisting of about twice the number ; these are hardened and
serrated, so as to constitute the cutting edge of the saw.
The tempered plates are technically called the hard, and are
attached to the soft segments by numerous countersunk copper
Ml . I NEm-.SAWMIH . 11
screws, tapped into * *. \Vhen ni-\v, the hard segment* pr"
from 4 to 6 inches beyond the soft; so that the angle then
he three parts, h to c, con-iden -ively, is
only alxmt 4 to 0 degrees with the flat face of the saw, and the
i-r will readily yield to more than that extent from the log
without splitting. To prevent the risk of accident from the
exposed spokes of the wheel or chuck, and also the current
of wind caused by their rapid rotation, the spaces intent-inn.;
between them are filled up on the face with wood, and an entire
cone of thin boards is attached to the back of the chuck.
The log to be sawn sometimes requires to be previously adzed
all over, to remove the sand and dirt that would soon blunt the
saw ; it is then partially levelled with the adze or plane, to adapt
it to the vertical face of the drag. The drag has three long bars
of wood, in order that the revolving saw may cut or prepare for
itself the surface against which the log is fixed. The sharp
ends of the iron dogs are driven a little way into the log, and
the dogs arc then drawn down by screw-bolts as represented.
Sometimes the log is only temporarily held by the iron fasten-
ings or dogs, whilst its surface is partially levelled with the saw,
after which it is glued on a wooden frame, that is full of trans-
verse and oblique bars, and has been also levelled with the saw ;
the log and frame are afterwards bolted to the drag. In this case
the entire body of the wood can be cut into veneer without inter-
ruption from the fastenings, and the glue joint is safe so long as
the log does not project more than the width of the glued surface.
The timber requires two motions to be impressed upon it; the
one motion, longitudinal, to carry it across the face of the saw ;
the other motion, lateral, to advance it sideways between each
cut, the exact thickness of the intended veneer.
For the first or cutting motion, a long railway extends across
the face of the saw, and supports the drag, which is carried past
the saw by means of a rack and pinion, actuated by a cord pro-
ceeding from one of the grooves of the cone pulley on the man-
drel, down to the pinion axis, which is beneath the surface of the
ground, and not represented. On the pinion axis there is a
double train of toothed-wheels, and a clutch-box, by the three
positions of which latter, the draj: is left at rest, or it is carried
slowly past the saw in the act of cutting, or quickly back pi •
ratory to the succeeding cut. The gearing lever, by which the
812
CONSTRUCTION OF THE DRAG AND MODE OF
three positions of the clutch-box are given, is perpendicular, and
passes downwards through a trap-door, situated close behind the
little stool on which the attendant is seated.
Fig. 804.
The second motion of the log, or its lateral adjustment, is thus
effected. The slide that runs on the railway has a horizontal
plate, which carries three or more triangular standards, like but-
tresses, to the perpendicular faces of which are fixed the three
wooden bars against which the wood is clamped.
The horizontal plate that carries the triangles, is united at
each end to the lower piece of the drag, by a chamfer slide with
an adjusting screw and nut, one of each alone being seen. The
adjusting screws have worm-wheels at the one end, and are simul-
taneously moved by means of a winch-handle w, at the extremity
of a long rod, having two worms taking into the two worm-
wheels fixed on the adjusting screws. From 50 to 60 turns of the
handle are required to advance the log of wood one inch ; the
attendant can therefore determine with great facility, the number
of veneers cut out of each inch of wood, or he can cut the
veneers to any particular pattern for thickness.
There is no impediment to the passage of the log across the
rectilinear face of the saw ; but for the guidance of the veneer
around the back of the cone, some particular arrangements are
US I SEGMENT VENEER-SAWMILL. 813
required. To enable the veneer to avoid the edge of the soft
steel segments, to winch the s. nated blades an i feather-
edged guide. plate, usually of brass, and extending around about
one-sixth or eighth of the circle, is fixed almott in contact u-ilh the
blade, by screw-bolts and nuts, which, as seen in fig. 804, unite
the stationary framing of the machine; the guide is repre-
sented black in the sectional view, fig. 803. As the vencc:
•awn off, the attendant leads the veneer on to the guide, by
means of a spud, or a thin blunt chisel, the veneer then slides
over the guide, as shown, and proceeds through a curvilinear
wooden trough, usually extending round the back of the cone,
and the veneer is pulled out on the other side by an assistant,
and stacked on the heap. Sometimes the veneer is bent nearly
at right angles, and quits the saw in front, as in the figure : this
arrangement is less usual, but was selected for the illustration,
as it offers a more comprehensive view of the several parts.
Before running back the drag, preparatory to a new cut, the
handle IT, is unwound two or three turns, to remove the log beyond
the reach of the saw, and prevent its being scratched by the saw
teeth, these turns are afterwards moved in addition to those
required for the new thickness : the handle is managed by a boy,
who stands outside the railway.
Whilst the saw is in the act of cutting, the principal attendant
applies a soft deal freeing -stick, on the right and left of the
blade beneath the timber, in order to clear the sawdust out of the
teeth. The speed at which the table is fed is easily adjusted, by
the selection of an appropriate groove of the cone pulley on the
main shaft, which communicates with the driving pinion beneath
the floor ; and this adjustment of the feed is jointly dependent on
the condition of the saw as to sharpness, and the general quality,
hardness, and size of the wood.
The veneer-saw may be used for logs of wood measuring as
much as 24 feet in length and 5£ feet in breadth, but which sizes
are rarely or never met with in the same log. It may be added,
that the number of veneers cut out of each solid inch of wood,
varies with the width and the intended purpose of the veneers ;
but that on the average —
When the width of the wood te 0 12 18 24 30 36 48 «0 inohw,
Each inch of wood i« cut into 15 14 13 12 11 10 9 8 renew* ;
and, as about one-third of the wood is wasted in sawdust, the
814 VENEER-SAWMILL ALSO USED FOR THIN BOARDS.
respective veneers are about two-thirds the 15th, 14th, &c. of
aii inch in thickness.
The veneer-saw is also applied to cutting cedar wood for
making pencils ; bead stuff, or thin wood for making the headings
in cabinet work ; quarter stuff, or wood j inch thick ; and occa-
sionally also to wood nearly ^ inch thick ; and this may be con-
sidered the point of meeting, between the veneer-saw and the
upright frame-saw, page 742, in which ten or a dozen saw-blades
are occasionally used for deals. But the veneer-saw works with
greater accuracy, and is almost always used for such thin boards
of mahogany as are not cut by hand at the saw-pit.
For sawing thin boards, the segments should be nearly new
or very wide, in order that the angle made by the removed board
may be slight. But as the board in riding over the guide, (page
81 0,) near the edge of the saw, is nevertheless somewhat strained
open, it becomes needful to apply a contrivance called a guard,
to prevent the thin board from being at all split off, instead of
being entirely separated by the saw. This is accomplished
by a curvilinear arm, equal in size and form to the feather-
edged guide which lies against the hardened saw-plates, but the
guard is very much thicker and stronger, and is covered with a
thin plate of brass.
It will be further perceived in the perspective figure, page 812,
that the guard is attached to a column, and is represented turned
back, or out of work, which is the case whilst veneers are being
cut ; but in sawing boards, the guard is placed parallel with the
edge of the saw, just external to its teeth, (as dotted,) and is ad-
justed by set-screws to rest in hard contact with the face of the
wood which is sliding past it, the removed board is consequently
held securely unto within half an inch of the saw teeth, or
the line of separation, as shown by the diagram, fig. 803.
In sharpening the veneer-saw, the workman first applies a
lump of grindstone very cautiously upon a proper support,
against the edge of the teeth as the saw revolves, so as to reduce
the few points extending beyond the circle. The saw having
been stopped, he then stands on a stage and rests his left arm,
which is guarded by a wooden board, or leather shield, upon the
teeth of the saw, whilst he manages the triangular saw-file with
both hands. . The saw teeth are afterwards set by a hammer
and a small flat stake held in the left hand. The necessity for the
SO REMARKS ON CIRCULAR SAWS. - 1 .~i
recurrence to sharpening and setting depends much on the bard-
nets of the wood, but it is commonly needed several times each
• hat the saw is in constant work.
\\ hcu the edge becomes too thick and wasteful, it is ground
ans of revolving laps of lead or iron fed with emery, one
lap on the face, another on the back of the saw ; the laps are
placed one below the other, to prevent their faces touching, and
are kept in rapid motion, whilst the saw traverses between them,
as in cutting, so that all parts of the circumference, of this most
stupendous and accurate of saws, may be ground alike.4'
Notwithstanding the very considerable length to which the
chapter on saws has been extended, the subject may be considered
as very far from exhausted. Thus the great majority of the
applications of the saw hitherto noticed have been for manufac-
tures in wood, but toothed saws are also employed for many other
purposes, and different materials, some few of which will be
glanced at by way of conclusion.
Both reciprocating and circular SHWS are occasionally employed
in cutting off piles beneath the surface of water, when to draw
them (by the aid of the hydrostatic press,) would endanger the
safety of the foundations. Two methods of thus using rectilinear
saws have been described, to which the render is referred.f
The circular saw, when used for piles, is commonly placed at
the bottom of a long vertical shaft, the top of which is driven by
a winch, through the medium of a pair of mitre-wheels. The
shaft is attached to a swing-frame, like a gate, or to a traversing
platform, connected with such of the piles as may with safety be
ultimately drawn up ; in every case the erection of machinery
for sawing piles is troublesome, and the process tedious.
In the American steam pile-driving machine, intended princi-
pally for constructing the foundations of railways, two piles are
driven at the same time, in the respective track. After which, they
• The author U greatly indebted to Hewn. Eadaile and Margrave, of the Citj
Saw-Hills, for the free access they permitted him to their establishment, which
contains eleven veneer-sawn, from 17 ft 6" in. to 6 feet diameter, and also nearly
every kind of machine-saw and shaping-engine for wood that is extensively used.
Many of the practical details, on sawing ivory veneers, were derived from the
experience of Mr. Donald Stewart.
t See EncycL Metro. Part Mechanics, article 536 ; also, Civil Eng. and Arch.
Journal, 1843, voL vi , page 439.
816 CONCLUDING REMARKS ON CIRCULAR SAWS.
are sawn off by a circular saw four feet in diameter, tlie spindle of
which is mounted on the end of a strong horizontal frame, moving
on a joint, so as to cut first the one pile and then the other.
Notwithstanding the irregularities of the ground, the piles may
be cut either to a dead level or to any particular inclination.*
Circular saws areusedin cutting sheets of slate into rectangular
pieces, many of which are afterwards planed by machinery (vol. i.
page 165). Slate is also grooved with thick circular saws, for
making a particular kind of roofing, the joints for cisterns, and
other works ; and more frequently two thinner saws are used,
and the intermediate substance is chiselled or tooled out. Recti-
linear toothed-saws, driven both by hand and machinery, are
likewise used for blocks of slate and soft building stone.
A saw machine is used at the Butterley Iron Works, Derby-
shire, in cutting off the ends of railway bars whilst red hot ; in
fact, the moment they leave the rollers. The two saws are exactly
like those for wood, of three feet diameter, with flanges of two
feet, they travel at upwards of 1000 revolutions per minute,
and their lower edges, dip into water. The bar is brought up
to the saws by machinery, and both ends are cut off simul-
taneously, in twelve to fifteen seconds, to the precise length
required, f
If the customary applications of the saw machine to works in
metal had been touched upon in this chapter, they would almost
inevitably have trenched upon the fifth volume; as it would have
been difficult, to avoid proceeding from the circular saw, used
simply for dividing works, to circular cutters with plain edges,
used in cutting grooves, and to cutters with curvilinear or figured
edges, used for the teeth of wheels, and various other analogous
works, subjects that are for the present held in reserve.
By analogy, it might also have been shown, that in some of
the various apparatus employed in ornamental turning, revolving
cutters of all kinds, with plain or figured edges, are likewise
used. But in reference to these, it will be explained in the
fourth volume, that the many teeth of the circular saw, or figured
cutter, dwindle down to a single radial tooth; and that the
solitary cutting edge makes up for its apparent deficiency, by
the extreme rapidity with which it is in general driven.
* Civil Eng. and Arch. Journal, vol. v., page 1.
t Trans. Inst. Civil Engineers, vol. iii., p. 197.
617
U [AFTER XXVIII.— FILES.
SECT. I. — GENERAL AXD DESCRIPTIVE VIEW OF FILES Of
USUAL KINDS.
file is a strip or bar of steel, the surface of which is cut
into fine points or teeth, that act by a species of cutting, closely
allied to abrasion. When the file is rubbed over thr material to
be operated upon, it cuts or abrades little shavings or shreds,
which from thrir iiiimiti-ness arc called file-dust, and in so doing,
the file produces minute and im ^ular furrows of nearly equal
depth, leaving the surface that has been filed more or less smooth
according to the size of the teeth of the file, and more or less
accurately shaped, according to the degree of skill used in the
manipulation of the instrument. In treating this subject, it is
proposed to divide the matter into the following sections : —
I. General and descriptive view of files of usual kinds.
II. General and descriptive view of files of less usual kinds.
III. Preliminary remarks on using files, and on holding works
that are to be filed.
IV. Instructions for filing a fiat surface, under the guidance
of the straight-edge, and of the trial-plate, or planometer.
\ Instructions for originating straight-edges and trial-plates,
or planometers.
VI. Instructions for filing rectilinear works, in which several
or all the superficies have to be wrought.
\ 1 1. Instructions for filing curvilinear works, according to the
three ordinary modes.
Y I II. Comparative sketch of the applicatious of the file, and of
the engineer's planing machine, &c.
The files employed in the mechanical arts are almost endless
in variety, and which is to be accounted for by there being some
four, five, or six features in every file, that admit of choice, in
order to adapt the instrument to the several kinds of work for
which the file is used; and most of the names of files express
818 GENERAL CHARACTERS OF FILES.
these different features, for instance the three following files are
in common use : —
6 inch, blunt, single-cut, Sheffield, saw-file,
9 inch, taper, smooth, Lancashire, half-round-file,
12 inch, parallel, rough, Sheffield, safe-edge, cotter-file.
From the perusal of these compounded names it will be seen,
that six sources of variation have been noticed, and upon which
several characters a few observations will be offered.
1. Length. — The length of files is always measured exclusively
of the tang or spike, by which the file is fixed in its handle, and
the length and general magnitude of the file require to be pro-
portioned to the work to be performed. When the works are
both large and coarse, the file should be long and strong, that
the operator may be able to exert his entire muscular force in
using the instrument; when the works are minute and delicate,
the file should be proportionally short and slender, so that the
individual may the more delicately feel the position of the file
upon the work ; as the vigorous employment of force, and the
careful appreciation of position or contact, are at opposite ex-
tremes of the scale. Thus, it may be said, the watchmaker
frequently uses files not exceeding three quarters of an inch in
length, and seldom those above 4 or 5 inches long ; artisans in
works of medium size, such as mathematical instrument makers
and gunmakers, employ files from about 4 to 14 inches long ; and
machinists and engineers commonly require files from about 8
to 20 inches long, and sometimes use those of 2, 3, feet and
upwards in length.
The lengths of files do not bear any fixed proportion to their
widths ; but, speaking generally, it may be said the lengths of
square, round, and triangular files, are from 20 to 30 times their
widths, measured at the widest parts ; and the lengths of broad
files, such as flat files, half-round files, and many others, are
from 10 to 12 times their greatest widths.
2. Taper, blunt, and parallel files. — Almost all files are required
to be as straight as possible in their central line, and are distin-
guished as taper, blunt, and parallel files ; a very insignificant
number of files are made curvilinear in their central line, as in
the rifflers used by sculptors and carvers, and some other files.
The great majority of files are made considerably taper in
their length, and to terminate nearly in a point, such are called
OEN I it» OF PILES. v 1 l»
taper files; others are mad parallel, and known as "blunt
ly as blunt files; but in each of these kinds tin-
section of the iilr is the largest towards the middle, so that all
sides are somewhat arched or convex, and not absolutely
straight. A very few files are made as nearly parallel as pos-
sible, and have, consequently, nearly straight sides, and an equal
section throughout ; such are designated as parallel files, and by
some, as dead parallel files, just as we say "dead level" for a
strictly level surface, but it is very far more general for the so-
called parallel files to be slightly fuller in the middle.
3. Lancashire and Sheffield files. — In England the principal
seats of the manufacture of files, are Sheffield and Warrington;
th.se made at the latter place being more generally designated
.-hire files. The Sheffield files are manufactured in very
much the larger quantity, and for nearly every description of work,
both large and small. The Lancashire files are less used for large
than for small works, including watch and clock-work, some parts
of mathematical instruments, and the finer parts of machinery.
Formerly all the Lancashire files bore a great pre-eminence
over the Sheffield, in respect to the quality of the steel from
which the files were made, their greater delicacy of form, the
perfection and fineness of their teeth, and the success with which
they \\erchardcned; these circumstances rendered the Lanca-
shire files more expensive, but also much more serviceable than
the Sheffield. Of later years, this superiority is generally con-
sidered more particularly to apply to the smaller Lancashire
files, not exceeding about 8 or 10 inches in length, as from the
steady improvement amongst the best of the Sheffield file manu-
faeturers, in respect both to the quality of the steel, and the
• Ixinanship, it now results, that the larger files made both in
Lancashire and Sheffield, assimilate much more nearly in their
6 qualities than formerly.
1 . Tin- tfttli of files. — Many files that are in all other respects
alike, differ in the forms and sizes of their teeth. Three forms
of teeth are made, those of double-cut files, those of floats, or
tingle-cut files, and those of rasps. The floats and rasps are
scarcely used but for the woods and soft materials ; the double-
files are used for the metals and general purposes; and
when the tile is spoken of, a double-cut tile is always implied,
unless a single-cut tile, or a rasp, is specifically named.
3 G 2
820
TEETH OF FILES.
In a double-cut file, the thousands of points or teeth occur
from two series of straight chisel-cuts crossing each other ; in a
single-cut file or float, the ridges occur from the one series of
chisel-cuts, which are generally square across the float ; and in a
rasp the detached teeth are made by solitary indentations of a
pointed chisel or punch, a subject that will be further noticed
when the cutting of files is adverted to.
Double-cut files are made of several gradations of coarseness,
and which are thus respectively named by the Lancashire and
Sheffield makers : —
LANCASHIRE FILES.
SHEFFIELD FILES.
1. Rough.
2. Bastard.
8. Second-cut.
4. Smooth.
5.* Dead-smooth.
1. Rough.
2.* Middle-cut.
8. Bastard.
4.* Second-cut.
5. Smooth.
6. Superfine.
The sizes marked with asterisks are not commonly made, and
this reduces each scale of variety of cut to four kinds, of which
the Lancashire are somewhat the finer. The above names afford,
however, but an indifferent judgment of the actual degrees of
coarseness, which, for all the denominations of coarseness, differ
with every change of length ; but the numbers in the annexed
table may be considered as pretty near the truth : —
Approximate Numbers of Cuts in the Inch, of Lancashire Files.*
Lengths in Inches.
4
6
8
12
16
20
Rough-out .
56
52
44
40
28
21
Bastard-cut . .
76
64
56
48
44
34
Smooth-cut .
112
88
72
66
64
56
Superfine-cut . .
216
144
112
88
76
64
Of floats and rasps, but two denominations are generally made,
and which are simply distinguished as coarse and fine ; the fine
are also called cabinet floats and rasps ; and as with the files, the
* The numbers in the Table, were counted from the engravings of the teeth of
files in Mr. Stubs' pattern book. These engravings were laid down with great care
from the files themselves, and it is somewhat curious the numbers should so nearly
fall in regular series. The second courses of teeth were in each case counted, and
which are somewhat finer than the first course, as explained on page 829.
One of the smallest and finest Lancashire files, was found by the author to con-
tain from 290 to 300 cuts in the inch, which is confirmatory of the above numbers.
SECTIONS OP PILES.
621
two nominal sizes of the t, < th of floats and rasps, differ for every
variety of length in tin- instrmni i
5. Safe-edge*. — Some files have one or more edges that an l.-l't
uncut and these are known as naft-tdgtu, because such edges are
not liable to act upon those parts of the work againat \\ hieh •
are allowed to rub, for the purpose of guiding the lustrum •
The safe-edge file is principally required in making a set-off, or
shoulder, at any precise spot iu the work, and in filing out r
angular corners; as whilst the one side of the notch is being
filed, the other side can be used to direct the file. Occasionally
the edges alone of files are cut, and the sides are left safe or
smooth, as in some warding files, which nearly resemble saws.
6. The name* qffile*. — These are often derived from their pur-
poses, as iu saw files, slitting, warding, and cotter files ; the names
of others from their sections, as square, round and half round files.
Figs. 805. Sections derived from the Square.
B C D F
G
H
Figs. 808. Sections derived from the Circle.
L M N 0 P
R
Fig*. 807. Sections derived from the Triangle.
S T V \V X Y
Ml
Files of all the sections represented in the groups, figs. 805,
806, and 807, are more or less employed, although many of them
are almost restricted to particular purposes, and more especially
to the art of watchmaking, for which art indeed, very many of
the files have been originated. The sections may be considered
to be derived from the square, the circle, and the equilateral
triangle, as will be detected by the eye without description.
To avoid wearying the reader by attempting to describe all
the various tiles that are made, the eight or nine kinds which are
of most extensive application, will be briefly adverted to, nud
these will be placed in the supposed order of their usefulness
as derived partly from the author's observation, aud partly from
822 FILES COMMONLY USED.
the relative quantities considered to be manufactured of each
kind in two large establishments. After this, a few remarks will
be given on some of the files to which the sections 805 to 807
refer, and this, or the first division of the chapter, will be con-
cluded by a short account of the mode of forming the teeth of
files, and some other particulars of their construction.
It may be considered that in nearly every branch of art in
which the file is used, that the following constitute the basis of
the supply ; namely, taper files, hand files, cotter and pillar files,
half-round, triangular, cross, and round files, square, equalling,
knife and slitting files, and rubbers ; a short explanation will be
given of all of these varieties, in the course of which, reference
will be occasionally made to the sections A to Z just given.
Taper files, or taper flat files, are made of various lengths from
about 4 to 24 inches, and are rectangular in section as in B
fig. 805 ; they are considerably rounded on their edges, and a
little also in their thickness ; their greatest section being towards
the middle of their length or a little nearer to the handle, whence
these files are technically known to be "bellied;" they are cut
both on their faces and edges with teeth of four varieties, namely,
rough, bastard, second-cut, and smooth-cut teeth. Taper flat
files are in extremely general use amongst smiths and mechanics,
for a great variety of ordinary works.
Hand files or flat files resemble the above in length, section, and
teeth, but the hand files are nearly parallel in width, and some-
what less taper in thickness than the foregoing. Some few of
them are called parallel-hand-files, from having a nearer equality
of thickness, and parallelism of sides. Engineers, machinists,
mathematical instrument makers and others, give the preference
to the hand file for flat surfaces and most other works, except in
filing narrow apertures and notches, as then the small end of the
taper file, first described, may be employed in the commence-
ment, gradually the central and wider part, and then the entire
length of the instrument, as the space or notch to be filed becomes
wider; the taper form thus enables a larger and stronger file to
be used in the commencement, but for other and accurate pur-
poses the hand file is esteemed preferable to the taper.
Cotter files are always narrower than hand files of the same
PILES COMMONLY USED.
h ami thickness ; they are nearly flat on the side* and edge*,
so as to present almost the same section at every part of their
.••tli, in which regret they \.iry IV. nn 6 to 22 inches. Co1
files are mostly used in filing grooves, for the cotters, keys or
wedges, used in fixing wheels ou their shafts, whence their n;
The taper cotter files, or as they are also called entering files, are
entirely dillerent from the above, as they arc taper both in width
and thickness, and almost without any swell, or pyramidal, in
which respect alone they differ from ordinary taper files that are
usually much swelled or bellied.
Pillar files, also somewhat resemble the bund files, but they
are much narrower, somewhat thinner, as in C, and are used for
more slender purposes, or for completing works that have been
commenced with the hand files. Pillar files have commonly one
safe edge, and vary from 3 to 10 inches in length.
Half round files, are nearly of the section L, notwithstanding
that the name implies the semicircular section ; in general the
curvature only equals the fourth to the twelfth part of the circle,
the first being called full half round, the \&stflat half round files.
The half round files, vary from about 2 to 18 inches in length,
and are almost always taper. The convex side is essential for a
variety of hollowed works, the flat side is used for general
purposes.
Tringular files, commonly misnamed "three-square" files, are
of the section R, and from 2 to 16 inches long; they are used for
internal angles more acute than the rectangle, and also for clear-
ing out square corners. One of the greatest uses of triangular
files from 3 to 6 inches long, is the sharpening of saws, the
greater number of which have teeth of the angle of 60 degrees;
an aiiL'li- doubtless selected, because it appertains to all the angles
of the equilateral triangular file, the three edges of which are
therefore alike serviceable in sharpening saws. In the southern
parts .. f Knjaud, saw-files with single-cut teeth, are in more
general nse.from the idea that they "cut tweeter;" in the midland
and northern ,. the double-cut files of the same dimensions
are more in vojjue, being esteemed more durable. Small saws
for metal, which are harder than those for wood, are always
K in (1 with double cut files, the Lancashire being preferred.
Cross files, or crossing files, sometimes called double half-
rounds, are of the section M, or circular on both faces, but of
824 FILES COMMONLY USED.
two different curvatures, they are used for concave or hollowed
forms the same as the convex side of the half-round ; but cross-
ing files are on the whole shorter and less common than half-
round files, and are probably named from the files being used
in filing out the crosses of arms or small wheels, as in clock-
work, in which ease the opposite sides present a two-fold choice
of curvature in the same instrument, which is convenient.
Those cross files which are principally known as double half-
rounds, are fuller or more convex on both faces than ordinary
cross-files, and are employed by engineers.
Round files, of the section I, range from the length of 2 to 18
inches ; they are in general taper, and much used for enlarging
round holes. The round file is better adapted than the so-called
half-round file, to works the internal angles of which are filled in
or rounded, as the round file is much stronger than the half-round
of the same curvature. Small taper round files, are often called
rat-tail files, and the small parallel round files, are also called
"oint files, as they are used in filing the hollows in the joints of
snuff-boxes and similar objects, for the reception of the pieces of
joint wire (vol. i. page 429), that are soldered in the hollow
edges of the work for the joint pin or axis.
Square files, are used for small apertures, and those works to
which the ordinary fiat files are from their greater size less
applicable. The square files measure in general from 2 to 18
inches long, and are mostly taper ; they have occasionally the
one side safe or uncut.
Equalling files, are files of the section D ; in width, they are
more frequently parallel than taper, in thickness they are always
parallel. They are in general cut on all faces, sometimes, as in
the warding files for locksmiths, the two broad surfaces are
left uncut or safe, and they range from 2 to 10 inches long.
Knife files, are of the section T, and in general very acute on
the edge, they are made from 2 to 7 inches long, and are as
frequently parallel as taper. The knife files are used in cutting
narrow notches, and in making the entry for saws, and for files
with broader edges ; knife files are also employed in bevilling
or chamfering the sides of narrow grooves.
Slitting files, called also feather-edged files, resemble the last in
construction and purpose, except in having, as in section V, two
thin edges instead of one ; they are almost always parallel.
"illl-R FILES OF DIFFERENT SECT I
, are strong heavy files generally made of an inferior
kind <>:-•(•,!, they measure from 12 to 18 inches long, from f to
uches on every side, and are made very convex or fish-
bellictl ; tlu van- frequently designated by their weight alone.
which varies from about 4 to 151bs. Rubbers are nearly re-
stricted to the square and triangular sections A and R. Some
few rubbers are made nearly square in section, but with one side
roiiiuit -d, as if the sections K ami B were united, these are called
half thick. Rubbers are scarcely ever used by machinists and
engineers, but only for coarse manufacturing purposes, where
the object is rather to brighten the surface of the work, than to
give it any specific form. Rubbers were formerly made only of
bar or common steel, but are now also made of cast-steel, and in
a more careful manner.
Many arti/aus, and more particularly the watchmakers, require
other files than those described, and it is therefore proposed to
add the names of some of the files to which the sections refer,
premising that such names as are printed iu Italics, designate
small files especially used in watchmaking.
Names of some of the Files, corresponding with the Sections
A to Z, (represented on page 821).
A. — Square files, both parallel and taper, some with one safe
side ; also square rubbers.
B. — When large, cotter files ; when small, verge and pivot files.
C. — Hand files, parallel and flat files; when small, pittance
files ; when narrow, pillar files ; to these nearly parallel
files are to be added the taper flat files.
D. — \Vhcu parallel, equalling c/ocAr-/>i/iio« and endless-screw files ;
\vhen taper, slitting, entering, warding, and barrel-hole
til.-.
E. — French pivot and shouldering files which are small, stout, and
have safe-edges; when made of large size and right and
left they are sometimes called parallel V tiles, from their
suitability to the hollow V V's of machinery.
F. — Name and purpose similar to the last.
G. — Flat file with hollow edges, principally used as a nail file
for the dressing case.
H . — Pointing mill-saw file, round-edge equalling file, and round-
edge joint file ; all are made both parallel and taper.
S2l> OTHER FILES OF DIFFERENT SECTIONS.
I. — Round file, gulleting saw file, made both parallel and taper.
K. — Frame saw file, for gullet teeth.
L. — Half round file. Nicking and piercing files, also cabinet
floats and rasps ; all these are usually taper. Files of this
section which are small, parallel, and have the convex
side uncut, and have also a pivot at the end opposite the
tang, are called round-off files, and are used for rounding
or pointing the teeth of wheels, cut originally with square
notches. The pivot enables the file to be readily twisted
in the fingers to allow it to sweep round the curve of
the tooth to be rounded.
M. — Cross, or crossing files, also called double half rounds.
N. — Oval files; oval gulletting files for large saws, called by the
French limes a double dos. Oval- dial file when small.
O. — Balance-wheel or swing-wheel files, the convex side cut, the
angular sides safe.
P. — Swaged files, for finishing brass mouldings ; sometimes the
hollow and fillets are all cut.
Q. — Sir John Robison's curvilinear file, to be hereafter described.
R. — Triangular, three-square, and saw files, also triangular
rubbers, which are cut on all sides. Triangular files
are also made in short pieces, and variously fixed to
long handles, for works that are difficult of access, as
the grooves of some slides and valves, and similar works.
S. — Cant file, probably named from its suitability to filing the
insides of spanners, for hexagonal and octagonal nuts,
or as these are generally called, six or eight canted
bolts and nuts ; the cant files are cut on all sides.
T. — When parallel, flat-dovetail, banking and watch-pinion files ;
when taper, knife-edged files. With the wide edge round
and safe, files of the section T, are known as moulding
files, and clock-pinion files.
V. — Screw-head files, feather-edge files, clock and watch-slitting
files.
W. — Is sometimes used by engineers, in finishing small grooves
and key ways, and is called a valve file, from one of
its applications.
X. — A file compounded of the triangular and half-round file, and
stronger than the latter; similar files with three rounded
faces have also been made for engineers.
MANUFACTURE OF FILES. V.'7
N I> >i,i,|. • ,,i :i£ filet, used by cutlers, gun-makers
and others. The tiles are made separately and r.
together, with the edge of the one before that of the
dtlu-r, iu order to ^i\c the equality of distance and
parallelism of ehecki n •<! works, ju-t as in the double saws
for rutting the teeth of racks and combs, see p. 7~
Z. —Double file, made of two flat files fixed together in a wood
or metal stock; this was invented for filing lead pencils
to a fine conical point, and was patented by Mr. Cooper
under the name of the Styloan/non.
The manufacture of files. — The pieces of steel, or the blanks
intended for files, are forged out of bars of steel, that have been
either tilted or rolled as nearly as possible to the sections
required, so as to leave but little to be done at the forge ; the
blanks are afterwards annealed with great caution, so that in
neither of the processes the temperature known as the blood-red
heat may be exceeded. The surfaces of the blanks are now
rendered accurate in form and quite clean in surface, either by
filing or grinding. In Warrington, where the majority of the
files manufactured are small, the blanks are mostly filed into
shape as the more exact method ; in Sheffield, where the greater
number are large, the blanks are more commonly ground on
large grindstones as the more expeditious method, but the best
of the small files are here also filed into shape : and in some few
eases the blanks are planed in the planing machine, for those
called dead-parallel files, the object being in every case to make
the surface clean and smooth. The blank before being cut is
slightly greased, that the chisel may slip freely over it, as will
be explained.
The file cutter, when at work, is always seated before a
square stake or anvil, and he places the blank straight before
him. witli the tang towards his person, the ends of the blank
are fixed down by two leather straps or loops, one of which is
held fast hv each foot.
The largest and smallest chisels commonly used in cutting
files are represented in two views, and half size in figs. 808 and
809. The first is a chisel for large rough Sheffield files, tin-
length is about -'3 inches, the width :2| inches, and the angle of
8-28
CUTTING THE TEETH OF FILES.
the edge about 50 degrees, the edge is perfectly straight, but
the one bevil is a little more inclined than the other, and the
keenness of the edge is rounded off, the object being to indent,
rather than cut the steel ; this chisel requires a hammer of about
7 or 8 Ibs. weight. Fig. 809 is the chisel used for small super-
fine Lancashire files, its length is £ inches, the width £ inch, it
is very thin and sharpened at about the angle of 35 degrees, the
edge is also rounded, but in a smaller degree; it is used with a
810.
hammer weighing only one to two ounces, as it will be seen the
weight of the blow mainly determines the distance between the
teeth. Other chisels are made of intermediate proportions, but
the width of the edge always exceeds that of the file to be cut.
The first cut is made at the point of the file, the chisel is held
in the left hand, at an horizontal angle of about 55 degrees, with
the central line of the file, as at a a fig. 810, and with a vertical
inclination of about 12 to 4 degrees from the perpendicular, as
represented in the figures 808 and 809, supposing the tang of
the file to be on the left-hand side.* The blow of the hammer
upon the chisel, causes the latter to indent and slightly to drive
forward the steel, thereby throwing up a trifling ridge or burr,
the chisel is immediately replaced on the blank, and slid from
the operator, until it encounters the ridge previously thrown up,
which arrests the chisel or prevents it from slipping further
" A foreman, experienced in the manufacture of Sheffield files, considers the
following to be nearly the usual angles for the vertical inclination of the chisels :
namely, for rough rasps, 15 degrees beyond the perpendicular; rough files, 12
degrees; bastard files, 10 degrees; second-cut files, 7 degrees; smooth-cut files,
5 degrees ; and dead-smooth-cut files, 4 degrees.
Ct 1 KB TEETH OF FILES.
back, and the T. 1»\ «K -ti nuines the succeeding position of the
rhivl. The heavier tin- blow, the greater the ridge, and the
greater the distance from tin- pn -ceding cut, at which the chisel
is arrested. The chisel having been placed in its second posi-
tion, is again struck with the hammer, which is made to give
the blows as nearly as possible of uniform strength, and the pro-
cess is repented with considerable rapidity and regularity, GO to
80 cuts being made in one minute, until the entire length of the
file has been cut with inclined, parallel, and equi-distant ridges,
which are collectively denominated the first course. So far as
this one face is concerned, the file if intended to be single-cut
would be then ready for hardening, and when greatly enlarged
its section would be somewhat as in fig. 81 1.*
Most files, however, are double-cut, or have two series or
courses of chisel-cuts, and for these the surface of the file is now
smoothed by passing a smooth file once or twice along the face
of the teeth, to remove only so much of the roughness as would
obstruct the chisel from sliding along the face in receiving its
successive positions, and the file is again greased.
The second course of teeth is now cut, the chisel being
inclined vertically as before or at about 12 degrees, but horizon-
tally, only a few degrees in the opposite direction, or about 5 to
10 degrees from the rectangle, as at b b, fig. 810 ; the blows are
now given a little less strongly, so as barely to penetrate to the
bottom of the first cuts, and from the blows being lighter they
throw up smaller burrs, consequently the second course of cuts
is somewhat finer than the first. The two series of courses, fill
the surface of the file with teeth which are inclined towards the
point of the file, and that when highly magnified much resemble
in character the points of cutting tools generally, as seen in
fig. 811, for the burrs which are thrown up and constitute the
tops of the teeth, are slightly inclined above the general outline
of the file, minute parts of the original surface of which still
remain nearly in their first positions.
If the file is flat and to be cut on two faces, it is now turned
over, but to protect the teeth from the hard face of the anvil, a
thin plate of pewter is interposed. Triangular and other files
• The teeth of tome »ingle out file* are much lea inclined than 55 degree*, thoee
of float* are in general equare arrow the instrument.
830
CUTTING THE TEETH OF FILES AND RASPS.
require blocks of lead having grooves of the appropriate sections
to support the blanks, so that the surface to be cut may be
placed horizontally. Taper files require the teeth to be some-
what finer towards the point, to avoid the risk of the blank being
weakened or broken in the act of its being cut, which might
occur if as much force were used in cutting, the teeth at the
point of the file, as in those at its central and stronger part.
Eight courses of cuts are required to complete a double-cut
rectangular file that is cut on all faces, but eight, ten, or even
more courses are required, in cutting only the one rounded face
of a half-round file. There are various objections to employing
chisels with concave edges, and therefore in cutting round and
half-round files, the ordinary straight chisel is used and applied
as a tangent to the curve, but as the narrow cuts are less
difficult than the broad ones, half-round and round files are
generally cut by young apprentice boys. It will be found that
in a smooth half-round file one inch in width, that about twenty
courses are required for the convex side, and two courses alone
serve for the flat side. In some of the double-cut gullet-tooth
saw files, of the section K, as many as 23 courses are sometimes
used for the convex face, and but 2 for the flat. The same diffi-
culty occurs in a round file, and the surfaces of curvilinear files
do not therefore present, under ordinary circumstances, the
same uniformity as those of flat files, as the convex files are
from necessity more or less polygonal.
Hollowed files are rarely used in the
arts, and when required it usually becomes
imperative to employ a round-edged chisel,
and to cut the file with a single course of
teeth. Sir John Robison's curvilinear
file will be hereafter noticed, in which the
objections alluded to in both hollowed
and rounded files are nearly or entirely
removed.
The teeth of rasps are cut with a pecu-
liar kind of chisel, or as it is denominated a
punch, which is represented also half size,
and in two views in fig. 812. The punch
for a fine cabinet rasp is about 3£ inches long, and f square at its
widest part. Viewed in front, the two sides of the point meet at
! KTII OF RASPS. 831
mglc of about 60 degrees, viewed edgeways, or in profile, the
edge forms an angle of about 60 degrees, the one- face being
only :i lift!.' inclined to the body of the tool. Different si
rasps necessarily require different sized punches, tin- ends of
h would luiu-li resemble the ordinary point tools for turning
wood or i\ory. hut that they are more obtuse, and that the edge
of the punch is rounded, that the tool may rather indent than cut .
In cutting rasps, the punch is sloped rather more from the
operator than the chisel in cutting files, but the distance between
the teeth of the rasp cannot be determined as in the file, by
placing the punch in contact with the burr of the tooth previously
made. By dint of habit, the workman moves or, technically,
hops the punch the required distance; to facilitate this move-
ment, he places a piece of woollen cloth under his left hand,
which prevents his hand coming immediately in contact with,
and adhering to the anvil.
The teeth of rasps are cut in rather an arbitrary manner, and
to suit the whims rather than the necessities of the workmen
who use them. Thus the lines of teeth in cabinet rasps, wood
rasps, and farriers' rasps, are cut in lines sloping from the left
down to the right-hand side ; the teeth of rasps for boot and
shoe-last makers and some others, are sloped the reverse way;
and rasps for gun-stockers and saddle-tree makers are cut in
circular lines or crescent form. These directions are quite
immaterial; but it is important that every succeeding tooth
should cross its predecessor, or be intermediate to the two before
it ; as if the teeth followed one another in right lines, they would
produce furrows in the work, and not comparatively smooth
surfaces. Considering the nature of the process, it is rather
surprising that so much regularity should be attainable as may
be observed in rasps of the first quality.
In cutting files and rasps, they almost always become more
or less bent, and there would be danger of breaking them if they
were set straight whilst cold, they are consequently straightened
whilst they are at the red heat, immediately prior to their being
l and tempered.
Previously to their being hardened, the files are drawn through
beer grounds, yeast, or other sticky matter, and then through
,mou salt, mixed with cow's hoof prc\ loudly roasted and
pounded, and which serve a* a defence to protect the delicate teeth
832 HARDENING AND STRAIGHTENING FILES.
of the file from the direct action of the fire. The compound
likewise serves as an index of the temperature, as on the fusion
of the salt, the hardening heat is attained; the defence also
lessens the disposition of the files to crack or clink on being
immersed in the water, see vol. i. page 253.
The file after having been smeared over as above, is gradually
heated to a dull red, and is then mostly straightened with a
leaden hammer on two small blocks also of lead ; the tempera-
ture of the file is afterwards increased, until the salt on its
surface just fuses, when the file is immediately dipped in water.
The file is immersed, quickly or slowly, vertically or obliquely,
according to its form ; that mode being adopted for each variety
of file, which is considered best calculated to keep it straight.
It is well known that from the unsymmetrical section of the
half-round file, it is disposed on being immersed, to become
hollow or bowed on the convex side, and this tendency is com-
pensated for, by curving the file whilst soft in a nearly equal
degree in the reverse direction ; by this compensatory method,
the hardening process leaves the half-round files nearly straight.
It nevertheless commonly happens, that with every precaution
the file becomes more or less bent in hardening, and if so, it is
straightened, not by blows, but by pressure, either before it is
quite cold, or else after it has been partially reheated in any
convenient mode ; as over a clear fire, on a heated iron bar, over
a hooded gas flame, as in tempering watch-springs, or in any
other manner. The pressure is variously applied, sometimes by
passing the one end of the file under a hook, supporting the
center on a prop of lead, and bearing down the opposite end of
the file ; at other times by using a support at each end, and
applying pressure in the middle, by means of a lever the end of
which is hooked to the bench, as in a paring-knife. Large files
are always straightened before they are quite cooled after the
hardening, and whilst the central part retains a considerable
degree of heat. When straightened, the file is cooled in oil,
which saves the teeth from becoming rusty.
The tangs are now softened to prevent their fracture ; this is
done either by grasping the tang in a pair of heated tongs, or by
means of a bath of lead contained in an iron vessel with a per-
forated cover, through the holes in which, the tangs are immersed
in the melted lead that is heated to the proper degree ; the tang
MEANS OP GRASPING PILES. « '•'••'>
is afterwards cooled in oil, and when the file has beeii wiped,
ami the teeth brushed clean, it is considered fit for use.
i
The superiority of the file will be found to depend on four
points, — the primary excellence of the steel — the proper forging
and annealing without excess of heat — the correct formation of
the teeth — and the success of the hardening. These several
processes are commonly fulfilled by distinct classes of work-
people, who are again subdivided according to the sizes of the
files, the largest of these being cut by powerful muscular men,
the smallest by women and girls, who thereby severally attain
great excellence in their respective shares of the work.
The manufacture of files, especially the cutting of the teeth,
has been entered into much more largely than was at first
intended, but it is hoped this may not be without its use ; as
notwithstanding the suitability of ordinary files to most purposes,
still occasions may and do occur, in which the general mechanist
or amateur may find some want unsupplied, which these hints
may enable him to provide for, although less perfectly, than if
the file in question had been manufactured in the usual course.
The process of cutting teeth, is also called for in roughing the
jaws of vices and clamping apparatus.*
Means of grasping the file. — In general the end of the file is
forged simply into a taper tang or spike, for the purpose of
fixing it in its wooden handle, but wide files require that the
tang should be reduced in width, either as in fig. 813 or 814.
The former mode, especially in large files, is apt to cripple the
steel and dispose the tang to break off, after which the file is
nearly useless; the curvilinear tang, 814, is far less open to this
objection, and was registered by Messrs. Johnson, Cammell, and
Co., of Sheffield. Some workmen make the tangs of large files
red hot, that they may burn their own recesses in the handles,
but this is objectionable, as the charred wood is apt to crumble
• There is perhaps an equal mixture of philosophy and prejudice in the harden-
ing of file* : some attach very great importance to the coating or defence, other* to
the medication of the water, and all to the mode of immersion bent calculated for
each different file, in order to keep it as straight as possible, question* of opinion
which it is impossible to generalise. Mr. Stube's process of manufacture ]•
pretty much as above described, and although he has experimented with mercury
at 8° F., as the cooling medium, as well as various fluids, he has arrived at the
conclusion, that the salt principally acts ai an antiseptic, and that fresh spring
water at 45* is as effective as any fluid.
3 H
834
VARIOUS MEANS OF GRASPING FILES.
away and release the file : it is more proper to form the cavity
in the handle, with coarse floats made for the purpose.
In driving large files into their handles, it is usual to place the
point of the file in the hollow behind the chaps of the tail vice,
Figs.
813.
814.
81 5.. 1
and to drive on the handle with a mallet or hammer. Smaller
files are fixed obliquely in the jaws of the vice, between clamps
of sheet brass, to prevent the teeth either of the vice or file, from
being injured, and the handle is then driven on. The file, if
small, is sometimes merely fixed in a cork, or in a small piece of
hazle rod, but these are to be viewed as temporary expedients,
and inferior to the usual wooden handles turned in the lathe.
Very small watch files are fixed in handles no larger than drawing
pencils, and some few of them are roughened on the tang, after
the manner of a float, and fixed in by sealing wax or shell lac.
Several of the small files have the handles forged in the solid,
that is, the tang is made longer than usual, and is either parallel,
or spread out, to serve for the handle, as in a razor strop ; many
of the watch files are thus made. In the double-ended rifflers,
or bent files, fig. 815, used by sculptors and carvers, and in
some other files, there is a plain part in the middle, fulfilling
the office of a handle ; and in several of the files and rasps made
for dentists, farriers, and shoemakers, the tool is also double, but
without any intermediate plain part, so that the one end serves
as the handle for the other.
In general the length of the file exceeds that of the object
filed, but in filing large surfaces it becomes occasionally neces-
sary to attach cranked handles to the large files or rubbers, as in
• US MEANS OF ORASPIN'; FILK*.
336
fig. 810, in order to raise the hand alx.\e the plane of the work.
ad of the file is simply inclined, ns in fig. v
or bent at right angles, as in 818, for the attachment of the
wooden handles represented ; hut the last two modes
Mvond >ide of the file from hen until the tang is 1
the reverse way. The necessity for bending the file is :
by employing as a handle, a piece of round iron $ or $ J'»<'h in
diameter, hent into the semicircular form as an arch, the one
extremity (or abutment), of which is filed with a taper groove to
fit the tang of the file, whilst the opposite end is flat, and r»
upon the teeth ; in this manner, both sides of the file may be
used without any preparation.
Pig. 819 represents, in profile, a broad and short rasp with fine
teeth, used by iron-founders in smoothing off loam moulds for
iron castings, this is mostly used on large surfaces, to which the
ordinary handle would be inapplicable, and the same kind of tool
when made with coarser teeth, will be recognised as the baker's
r.-'.-p. For some slight purposes, ordinary files are used upon
large surfaces, without handles of any kind, the edges of the file
itself being then grasped with the fingers.
Cabinet-makers sometimes fix the file to a block of wood to
serve for the grasp, and use it as a plane. Thus mounted, the
file may also be very conveniently used on a shooting board, in
filing the edges of plates to be inlaid.
Fig. 820 represents a very good arrangement of this kind by
Mr. W. Lund, a a is the plan and b the section of the file-stock, c c
Fig. 820.
is the plan oft lie shooting board and r/its section. Two files fl
' (1 hlack), are screwed against the sides of a straight
3 n 2
VARIOUS MEANS OF GRASPING FILES.
bar of wood, which has also a wooden sole or bottom plate, that
projects beyond the files, so that the smooth edge of the sole may
touch the shooting board instead of the file teeth. The shooting
board is made in three pieces, so as to form a groove to receive
the file dust, which would otherwise get under the stock of the
file; the shooting board has also a wooden stop s, faced with
steel, that is wedged and screwed into a groove made across the
top piece, and the stop being exactly at right angles, serves also
to assist in squaring the edges of plates or the ends of long bars,
with accuracy and expedition. Mr. Lund prefers a flat file that
is fully curved on the face, as nearly half the file then comes
into action at every stroke.
Short pieces of files (or tools as nearly allied to saws), are
occasionally fixed in the ends of wooden stocks, in all other
respects like the routing gages of carpenters, as seen in two
views in fig. 821 ; the coopers' croze, page 488, is a tool of this
description.
Files intended for finishing the grooves in the edges of slides,
are sometimes made of short pieces of steel of the proper section,
) 823.
£
a>i ) MB.
"I- a fell )82T.
(see fig. 822,) cut on the surfaces with file teeth, and attached in
various ways to slender rods or wires, serving as the handles, and
extending beyond the ends of the slides. Or the handle is at
right angles to the file, and formed at the end, as a staple, to clip
the ends of the short file, as in reaching the bottom of a cavity.
Files intended to reach to the bottom of shallow cavities are
also constructed as in figs. 823 and 824, or sometimes an inch or
more of the end of an ordinary file is bent some 20 or 30 degrees,
that the remainder may clear the margin of the recess.
To stiffen slender files, they are occasionally made with tin or
brass backs, as in figs. 825 and 826 ; such are called dove-tail
>S USUAL M
ti!i •*, c\idcntly from tln-ir similitude to dove-tail saws; and thin
equalling files, are sometimes grasped in :i brass frame, fig. v
exactly like that used for a metal frame-saw, by which the risk of
breaking tin- instrument in the act of filing is almost annulled.
equivocal analogy, both to the file and saw, is to be
observed in Mime ut the delicate circular cutters, used in cutting
watch u heels and other small works. The teeth of such cutters
are in many instances formed by cuts of a chisel, the same as
the teeth of files, and the axis of the cutter becomes, by corn-
on, the handle of the circular file.
SECT. II. — GENERAL AND DESCRIPTIVE VIEW OF FILES OF
LESS USUAL KINDS.
Notwithstanding the great diversity in the files alluded to in
the foregoing section, it is to be remarked that all those hitherto
noticed are made entirely of steel, and their teeth are all pro-
duced in the ordinary manner by means of the chisel and hand
hammer ; in the present section, a few of the less usual kinds
of rasps, floats, and files, will be noticed, the teeth of which are,
for the most part, produced by means differing from those
already described.
The rifflers, fig. 815, used by sculptors, are required to be of
numerous curvatures, to adapt them to the varying contour of
works in marble. In general the rifflers are made of steel in
the ordinary mode, but they have also been made of vrrought-
iron, and slightly case-hardened, in which case the points of the
teeth become converted into steel, but the general bulk of the
instrument remains in its original state as soft iron; conse-
quently such case-hardened rifflers admit of being bent upon a
block of lead with a leaden mallet, so that the artist is enabled
to modify their curvatures as circumstances may require.
Several kinds of floats are made with coarse, shallow, and
sharp teeth, which are in section like fig. G4G, page 684 ; these
ii could not be cut with the chisel and hammer in the ordinary
manner, but are made with a triangular file. Figs, a to /, 828,
represent the sections of several of these floats, which have teeth
at the parts indicated by the double lines ; for instance, a is the
float, b the yraille, c the found, d the carlet, e the topper, used
by the horn and tortoiseshell comb-makers; parts of the names
of \\hieh floats are corrupted from the French language, indeed
888
FLOATS FOR TORTO1SESHELL, IVORY, ETC.
the art was mainly derived from French artizans. The floats,
/ to i, are used by ivory carvers for the handles of knives, and in
Figs. 828.
829.
f
the preparation of works, the carving of which is to be com-
pleted by scorpers and gravers ; k and I are used in inlaying
tools in their handles; k is made of various widths, and is
generally thin, long, and taper; / is more like a key -hole saw.
When the teeth of these floats have been formed with the
triangular file, and made quite sharp, the tools are first hardened
and very slightly tempered, just sufficiently to avoid fracture in
use ; but, when after a period the tools have become dull, they
are tempered to a deep orange, or a blue, so as to admit of being
sharpened with a triangular file.
The larger of the floats, such as those a to e, used by the
comb -makers, are kept in order principally by the aid of a burn-
isher, represented in two views in fig. 829, the blade is about
2 inches long, 1 inch wide, and -^ inch thick ; the end is mostly
used, and which is forcibly rubbed, first on the front edge of
every tooth, as at a, fig. 830, and then on the back, as at b, by
which means a slight burr is thrown up, on every tooth, somewhat
like that on the joiner's scraper; but in this art the burnisher is
commonly named a turn-file. When the teeth of the floats have
become thickened from repeated burnishing, the triangular file
is again resorted to, and then the burnisher for a further period ;
by these means the floats are made to last a considerable time.
The quannet is a float resembling fig. 819, but having coarse
filed teeth, of the kind just described ; it may be considered as
the ordinary flat file of the horn and tortoiseshell comb-makers,
and in using the quannet, the work is mostly laid upon the knee
as a support. An ingenious artizan in this branch, Mr. Michael
WHITE'S IM i FILE. 8 /.'
y, invented the i|ii:uiuet represented in figs. 830 and 831.
stock consists of a piece of beech- wood, in which, at inter-
vals of about one quarter of an inch, ruts inclined nearly 80
degrees with , arc made with si thin saw; every cut is
tilled with a piece of saw-plate. The edges of the plates and
wood, are originally tiled into the regular float-like form, and
the burnisher is subsequently resorted to as usual. The n
mtage results from the small quantity of steel it is necessary
to operate upon, when the instrument requires to be restored with
the file. From this circumstance, and also from its less weight,
the wooden quannet, fig. 830, is made of nearly twice the width
of the steel instrument, fig. 819, and the face is slightly rounded,
the teeth being sometimes inserted square across, as in a float,
at other times inclined some 30 degrees, as in a single-cut file.
A more elaborate, but less available, instrument was invented
by Mr. White, probably daring his residence in France, about
the time of the Revolution (1793). It consisted of numerous
parallel plates of steel, which were placed vertically and in con-
tact, something like a pack of narrow cards, and were fixed in
that position in an appropriate frame, and as the edges of the
plates were all bevelled, they constituted a single-cut file. The
most curious part of the contrivance was, the ingenious mode of
chamfering the edges, as for this purpose the plates were loosened
and arranged in a sloping direction, so that the chamfers then
lay collectively in one plane, which was ground either on a
grind-stone, or a lead lap fed with emery ; the plates were re-
placed perpendicularly before use. Means were also described
for placing the steel plates square across the instrument as in a
float, or inclined to the right or left as in a file, according to
the material to be wrought; and. a drawing is also given of a
circular float of similar nature for cutting dye-woods into small
fragments. "White's "perpetual" file, with movcable plates, is
however scarcely known, and it is very questionable if it ever
obtained more than the experimental application which led to
its description having been published.*
The cutting of files by machinery is an operation that has
engaged the attention of many persons, and the earliest attempt
• Publiihed in Diicnptimu da Mackina tt Proe^de$ tpccijiit dam let Hrtrtti
<T/uu, i '•'••», Ac. Par M. Chrittian. Parii, 4to, 1824. Tome 8, p. 99. Patent
dated 6 Jan. 1795.
840 THE CUTTING OF FILES BY MACHINERY.
at the process that has come under the author's notice is that
of Thiout aine, which was figured and described in a work by
his son in 1740; and this machine being based on the manual
process, in all probability differs but little in its general features
from most of those of more recent projectors.
According to the drawings referred to, the file is attached to a
screw slide, Avhich is suspended at the ends by pivots, and covered
with a thin plate of tin ; the slide rests upon a stationary anvil,
and is actuated by a guide screw, which is moved at intervals,
the space from tooth to tooth by a pin wheel, for which the
ratchet wheel would be now substituted. The chisel is held by
a jointed arm, beneath which is a spring to throw up the chisel
from off the file, the moment after a drop hammer, which is also
fixed on a joint, has indented the tooth. The movements of the
slide and hammer are each repeated at the proper intervals, in
every revolution of the winch handle, by which Thiout's machine
is represented to be worked.*
The practical introduction of machinery for cutting files
appears to be due to a Frenchman of the name of Raoul, at
about the close of the last century, but the description of the
machine has not been published, and the manufacture is now
carried on by his son, some of whose files are in the possession
of the author. They are certainly beautiful specimens of work-
manship, being more strictly regular, and also less liable to clog
or pin when in use, than files cut by hand, as usual.
His manufacture is principally limited to watch files with flat
sides, and measuring from f of an inch, to 5 or 6 inches long.
When magnified, the teeth of the files, cut either by hand or
machinery, appear as nearly as possible of the same character.f
Machines have been recently constructed in England for
* See Thiout's TraH6 de I 'Horlogerie. Paris, 1740. Vol. 1, page 81, plates 33
and 34.
+ Mr. Raoul was rewarded for his files by the Lyce'e desArts,im institution that
no longer exists, but which was founded soon after the French Revolution, for the
reward of national discoveries and improvements. From the Report of the Lyceum
of Arts it appears, that on the 1 Oth Thermidor, year 8 of the Republic (July, 1800),
an honorary crown was decreed to Citizen Raoul for the perfection of his files.
And on a subsequent page of the report, is given the opinion of a Committee
appointed to examine into the comparative merits of Raoul'a files, from which
report it appears, they were pronounced by tho Committee to be equal, and even
superior, to the best English files.
UY.
.)_' both large and small filet, and half a dozen or more at
>r. I lie details of the machines display great intimity
and skill, especially in the arran-eiiu 'tit for holding the blanks
and the chisels, and also in the intruduetiuu of templets and
other mechanism, by which, in cutting taper files, the hammer
is leas raised in cutting the ends of the file than at the middle,
so as to proportion the force of the blow to the width and depth
of the cut, at different parts of the file. Two machines u
used for double-cut files, the bed of the one inclined to the right,
of the other to the left, to give the different horizontal inclina-
tions proper to these teeth; and a machine with a straight bed
was used for single-cut floats, and for round and half-round files.
Considerable difficulty was at first experienced in the manage*
ment of the chisels, which were then very frequently broken,
but with more dexterous management it is ultimately considered
that the chisels last for a longer time in the machines, than
when used by hand. The machines make about 24-0 strokes
in the minute, or three times as many as the file cutter, with the
advantage of nearly incessant action, as unlike the arm of the
workman, the machines are unconscious of fatigue ; moreover,
to save the delay of adjustment, two beds for the files are
employed, so that the one may be filled whilst the blanks in the
other are being cut, and two frames for the chisels are also
alternately used. Taking all these points into account, each
machine is considered by the proprietors, nearly to accomplish
the work often men, but there are various drawbacks that prevent,
under ordinary circumstances, any great commercial advantage
in the machine over the hand process, from which considerations,
the patent file cutting machines, are not at present used.
In concluding this section, there remain to be introduced, two
propositions for the manufacture of files, suggested by a very
talented and philanthropic member of the scientific world, the
late Sir John Robisou, K.H., F.R.S.E., late President of the
Royal Scottish Society of Arts, &c., namely, his methods of
making curvilinear files, and of cutting flat files with very fine
h. The subjects cannot be better stated than by quoting
Sir John's correspondence with the author; speaking of the
• Captain Lriocton* Patent File Cutting Machines, specified 1836, constructed
by Meters. BraKhwatte* of London, and carried into practical effect by Me
Turton & Sons, of Sheffield.
SIR JOHN ROBISON'S CURVILINEAR FILES, AND
curvilinear files of the Section Q., page 821, lie introduces the
subject as follows : —
" I have just entered on a new project, of which I should be
glad to know what you think. Having always found difficulty
in filing hollow surfaces, from the scratches which the irregular
cutting of even the best half-round, or round files, leave in the
work, in spite of every care, I was lately led to consider whether
half-round, or even round files, might not be made as perfect in
their cutting as flat ones. It has occurred to me, that this object
may be attained by cutting flat strips of rolled steel plate on one
side, and then squeezing them into the desired curve by a screw
press, and a block-tin or type-metal swage, and in the case of the
round file, by pressing the plate round a cylindrical mandrel.
" I do not think that the files made in this way should cost
more than those now made, as the surface would be cut by two
courses of cuts (as flat files are), instead of the numerous courses
required to cover the surface of round files, the saving in this
respect would make up for the time required in bending the
plates." * * * *
A valuable addition to Sir John's proposal occurred inciden-
tally ; Messrs. Johnson and Cammell, to whom the scheme was
communicated, in the haste of putting it to trial, took a thin
equalling file that had been previously cut on both faces. The
equalling file was softened, bent, and re-hardened, and this pro-
duced a file, the convex and also the concave surface of which
were both useful additions to thetools of the general mechanician.
But it was found that with a plate of equal thickness, the
central part bent more easily than the edges, making the curve
irregular. This was successfully obviated by making the blank
thinner and more flexible at the edges, somewhat as a half-round
file, and in which case the bending was quite successful, and the
section became truly circular.*
Sir John Robison's second project in respect to the manufac-
* The Society for the Encouragement of Arta, of London, bestowed its silver
medal on Sir John Robison for his invention of the curved file, which distinction
it is to be regretted arrived as a posthumous honour. (See Trans. Soc. of Arts,
vol. liv., p. 128.) And the Royal Scottish Society of Arts presented, in November,
1843, a silver medal to Messrs. Johnson, Cammell, and Co., for the skilful manner
in which they had carried out and perfected the above scheme, and introduced the
curved files as a regular article of manufacture. (See the official report in the
Edinburgh New Philosophical Journal for January, 1844, p. 86.)
HIS MODE 07 CUTTING PINE PLAT FILE*. s 1 ">
tore of files, refers to a new mode of forming the teeth of
herwisc than by percussion; and without delay
tin render by referring to tin earlier correspondence on the
subject, the author jjives a short extract from a letter recehrd
v days before Sir John's death, and also the contents of the
packet tli 1 to.
" Lest my medical friends should be mistaken, ami this malady
.case so as to prevent my communicating my project for cut-
ting fine files, I shall now make out a memorandum of my ideas
on the subject, and making a scaled packet of it shall enclose it
to you. If I get better and reach London, we can discuss the
matter together, and if I am put hors de combat, you will con-
sider it your own. *
" It appears to me that the graver may be applied with good
cllect in cutting the teeth of the finer classes of flat files, and that
if a number of steel blanks were firmly embedded on a platform
similar to the bed of a planing table, and made to move forward
in their own plane by a micrometer screw, then if an equal num-
ber of gravers were to be fixed in a frame to lie over the plat-
form, so that each graver point should be in a certain relative
tion to one of the blanks, on motion being communicated
to the frame in a proper direction, and to a distance a b'ttle ex-
ceeding the breadth of the blank, a line would be ploughed out
of the surface of each blank. If the frame were then brought
back to its first position, and the platform advanced or receded
by the micrometer screw, a second movement of the cutter frame
would produce a line parallel to the first, and so on in succession.
" If the points of the gravers, instead of being set to cut
equilateral grooves as at A, were inclined so as to cut them as
at 15, then, by a proper proportioning of the depth of the cut,
and the progressive movement of the platform, a regular cutting
tooth of great sharpness may be given to the file.
ic movement to be given to the graver frame may be an
oscillating one round a distant center, so that the short arc of
the teeth may be sensibly a straight b'ne.
" It is evident that the sharpness and smoothness of the
PRELIMINARY REMARKS ON USING TILES.
engraving must depend mainly on the way in Avhich the cutter
is presented to the work, and experience shows that the position
of the tool in the hand of the engraver is the most favourable,
both to the production of clean lines, and the preservation of the
point of the tool ; the graver must be supported endways, and
not alone by fastenings in its middle, like the tool of a planing
machine, or a slide rest cutter.
" The means of regulating the depth of the cut, and the other
arrangements of the parts of such a machine, would of course
require consideration by engravers and practical mechanics.
" (Signed) JOHN ROBISON.
" EDINBURGH, 17th February, 1843."
The author much regrets that the multiplicity of his engage-
ments, and especially those connected with these pages, should
have prevented him putting the above project to experimental
proof, but he would be well pleased to hear that the subject had
been brought to successful issue, by any person more favourably
situated for carrying out the suggestion.*
SECT. III. — PRELIMINARY REMARKS ON USING FILES, AND ON
HOLDING WORKS THAT ARE TO BE FILED.
The use of the file is undoubtedly more difficult than that of
the generality of mechanical tools, and the difficulty arises from
the circumstance of the file possessing, but in a very inferior
degree, the guide principle, the influence of which principle, in
all tools, from the most simple cutting tool used by hand, to the
most complex cutting machine or engine, formed the subject-
matter of the introductory chapter of the present volume. The
comparative facility of the manipulation of turning-tools, was
shown to depend on the perfection in which the guide principle
exists in the turning lathe. It was further stated at page 468 —
" The guide principle is to be traced in most of our tools ; in
the joiner's plane it exists in the form of the stock or sole of the
plane, which commonly possesses the same superficies that it is
desired to produce. For instance, the carpenter's plane used for
• Since writing the above, the author learns that Captain Ericcson tried some
experiments on cutting file teeth as with a graver, but that he was led to con-
aider the modeless practical than that of cutting teeth by percussion. The subject
appears, however, to deserve more extended trial.
PREMMINMIY REMARKS ON' V8INO FILES.
surfaces is itself flat, both in length nnd width, nml therefore
furnishes a double guide. The flat file is somewhat under the
same circumstances, but as it cuts at every part of its surface,
from thousands of points being grouped together, it is more
!n TOMS than the plane, as regards the surface from which
it derives its guidance, and from this nnd other reasons it is far
more difficult to manage than the carpenter's plane."
These points are recalled not to impress the amateur with the
idea that the successful use of the file will be to him unattain-
able, but rather to call forth such a measure of perseverance, as
may enable many to arrive nt a practice which is confessedly
difficult. It is proposed in the present section to notice certain
preliminary and general topics, before attempting, in the next
three sections, to convey the instructions for manipulating the file.
Commencing with the position of the work, it is in all cases
desirable that the surface to be filed should be placed horizontally,
and the general rule for the height of the work above the ground
is, that the surface to be filed should be nearly level with the
elbow joint of the workman, and which may be considered to
range with different individuals from forty to forty-five inches
from the ground. Some latitude is, however, required in respect
to the magnitude of the works, as when they are massive, and
much is to be filed off from them, it is desirable that the
work should be a trifle lower than the elbow ; when the work is
minute and delicate, it should be somewhat higher, so that the
eye may be the better able to add its scrutiny to that of the sense
of feeling of the hand, upon which principally the successful
practice depends. The small change of height is also in agree-
ment with the three different positions of the individual in the
act of filing ; for instance.
Firstly. In filing heavy works, or those which require the
entire muscular effort, the file varies from about 12 to 2t inches
long, and the length of the stroke is from about 10 to 20 inches,
or nearly the full length of the file. The operator stands a
little distant from his work, with the feet separated about 30
inches, which somewhat lowers his stature ; he grasps and thrusts
the handle of the file with his right hand, and bears forcibly near
the end of the file with that part of his left hand which is conti-
guous to his wrist, so as to make the file penetrate the work, or
hamj to it. The general mou'inrnt of the person is then an
846 PRELIMINARY REMARKS OX USING FILES.
alternation of the entire frame upon the knee and ankle joints,
the arms being comparatively fixed to the body, the momentum
of which is applied to the file.
Secondly. In filing works of medium size, the file varies from
about 6 to 12 inches, and the length of stroke is from about 4 to
9 ; the operator then stands nearer to the work and quite erect,
with his feet closer together. The right hand grasps the file
handle as before, but the extremity of the file is now held between
the thumb and the first two fingers of the left hand, and the
general movement is that of the arms, the body being compara-
tively at rest.
Thirdly. In filing the smallest works the file is less than
6 inches long, and the stroke does not exceed 3 or 4, and some-
times is not one-tenth as much. When the work is fixed, the file
is still usually held in both hands as last described, but frequently,
in fact more generally, the file is managed with the right hand
alone, the forefinger being stretched out as in holding a carving
knife, and the work is held upon the support or filing block with
the left hand, as will be explained. The act of filing is then
accomplished by the movement of the elbow, or even of the
fingers alone, but so little is the body moved, that the workman
is usually seated as at an ordinary table.
It is apparent, and also true, that the most direct way of pro-
ducing a flat surface with the file, would be to select a file the
face of which was absolutely flat, and that should be moved in
lines absolutely straight ; but there are certain interferences that
prevent these conditions being carried out. First, although it is
desirable to employ files that are as nearly straight as possible,
and that are also fixed straightly in their handles, yet very few
files possess this exactitude of form, and although in the attempt
to attain this perfection, some files are planed in the engineer's
planing machine before being cut with teeth, still the cutting
and the hardening so far invalidate this practice, that few even of
these planed files can retain their perfect straightness, and either
both sides become in a small degree irregularly tortuous, or the
sides become respectively concave and convex. Therefore, as
for the sake of argument, it may be almost taken for granted
that no files truly possess the intended form, it is better purposely
to adopt that kind of irregularity, which the least interferes
with the general use of the instrument.
PRELIMINARY REMARKS ON USING FILES.
M7
'1 In file, if concave or hollow in respect to its length, in the
manner coarsely exaggerated in fig. VJ2, might be used for
nwily ; but it would be impossible
n flat surface therewith, as the concave file would only
r - .
- !.
touch the surface at its edges, but the convex side of the same
file might, as in fig. 833, be made to touch any and every part
of the surface if moved in a right line. On this account most
files arc made thicker and wider in the middle, or with both
faces convex, and the error of hardening will then rarely make
cither side concave, but will leave both faces convex, although
differently so ; and consequently, both sides, notwithstanding
some irregularity, are useable upon flat works, provided the
operator can move them in a right line across the work.
In reference to the manipulation of the instrument, it is to
be observed that the most natural movements of the hand and
arm are in circular lines, the several joints of the limbs being the
centers of motion ; but, as in filing a flat surface, it is needful
the hands should move very nearly in right lines, a kind of
training becomes necessary.
If, however, the file were carried quite straight across a wide
surface, the central part of the file would be alone used ; but as
the continual effort of the individual is to feel that the file lies in
exact contact with the surface being filed, the hands imperceptibly
depart so much from the exact rectilinear path as to bring all
parts of the file from point to heel into use.
Again, it might be urged that the file, from being itself in the
form of the arc of a large circle, \\nuld reduce the work to the
counterpart form, or make it hollow in the opposite degree; it is
true this is the tendency, and may by dexterity become the
result, even on narrow pieces; but the contrary error is more
PRELIMINARY REMARKS ON USING FILES.
common, so that the surface of the work becomes rounded instead
of concave or plane.
If the surface to be filed is four or five inches or more in
width, the risk of departing from the true figure becomes
reduced, as the file has then a wide base to rest upon, and the
pressure of the hands readily prevents any material departure
from the right position of the file ; but the difficulty becomes
greatly increased when the surface to be filed is narrow.
The file held in the two hands upon the narrow work, may
be then viewed as a double-ended lever, or as a scale beam
supported on a prop ; and the variation in distance of the hands
from the work or prop gives a disposition to rotate the file
upon the work, and which is only counteracted by habit or
experience.
Assuming, for the moment, that in the three diagrams the
vertical pressure of the right hand at r, and the left at /, to
be in all cases alike, in fig. 834, or the beginning of the stroke,
the right hand would, from acting at the longer end of the lever,
become depressed; in fig. 835, or the central position, the
hands would be in equilibrium and the file horizontal ; and in
fig. 836, or the end of the stroke, the left hand would prepon-
derate; the three positions would inevitably make the work
round, in place of leaving it plane or flat.
It is true the diagrams are extravagant, but this rolling action
of the file upon the work is in most cases to be observed in the
beginner ; and those practised in the use of the file have, perhaps
unconsciously, acquired the habit of pressing down only with the
left hand at the commencement, and only with the right hand at
the conclusion of every stroke ; or negatively, that they have
learned to avoid swaying down the file at either extreme, and
which bad practice will necessarily result, if the operator have
not at first a constant Avatch upon himself, to feel that the file
and work are always in true contact, throughout the variable
action of the hands upon the instrument.
When the work is fixed in the bench or table-vice, the file is
almost always managed with both hands, as above described ; but
when the file is held in the one hand only, all the circumstances
are altered, except the continued attempt to keep the work and
file in accurate juxta-position; and to assist in this, the work
when so small as to be filed with the one hand only, is almost
i: I MtllAL ROTATION OP nil I ll.E OR WORK. 840
imariahlyheld on tlir tilinir-block with the h ft hand, occasionally
through the intrr\< nt'ou of a hand-vice, as in fig, 858, page v
In this case the two hands act in concert, the right in moving the
file, tin- h-t't in adjusting the position of the work, until the indi-
vidual is conscious of the agreement in position of the two parts.
Sometimes indeed the partial rotation of the work, in order
to adapt thexwork to the file, is especially provided for, so as
to compensate for the accidental swaying of the file ; such is the
case in the various kinds of swing tools, used by watchmakers in
filing and polishing small flat works. A similar end is more
rarely obtained, on a larger scale, when the file is required to
he held in both hands. For example, filing-boards resembling
fig. 837, and upon which the work is placed, have been made
Figs. 837. 8S8. 839.
to move on two pivots, somewhat as a gun moves on its trunnions ;
consequently the works, when laid upon the swinging bonrd,
assume the same angle as that at which the file may at the
moment be held.
A more common case is to be seen in filing a rectangular mor-
or key-way, through a cylindrical spindle, as in fig. 888;
the hole is commenced by drilling three or four holes, which are
thrown into one by a cross-cut chisel, or small round file; and
the work, when nearly completed, is suspended between the
centers of the lathe, so that it may freely assume the inclination
of the file. At other times, the cylinder is laid in the interval
between the edges of the jaws of the vice, that are opened as
inue.h as two-thirds the diameter of the object, which then simi-
larl uithesupporting edges; this mode is shown in fig. 839.
•i Implications are objectionable in some instances,
as the file is left too much at liberty, and the works are liable to
be filed hollow instead of flat, especially if the file be rounding,
because the unstable position of the work prevents the file from
beinu' constrained to act on any particular spot that may require
to be reduced.
850 ON PREPARING WORKS FOR FILING BY
Some general remarks will be now given on certain practices
in respect to economising the wear of files ; and these will be
followed by other remarks on the modes of holding works that
are to be filed, prior to giving, in the next sections, the practical
instructions upon filing.
The exterior surfaces of iron castings are usually more or less
impregnated with the sand of the foundry moulds, which is very
destructive to the tools; and this is in many cases removed
by pickling them with dilute sulphuric acid, which dissolves a
little of the metal, and undermines and loosens the sand, as
explained in vol. i., p. 375. Iron castings become moreover
superficially hard from coming in contact with the moist sand of
the foundry mould ; so that a thin but hard skin envelopes the
entire object to the depth of the twentieth or thirtieth of an
inch, and as this is very injurious to the files, it is usually
chipped off with a chisel and hammer ; the pickling is then less
required.
The ordinary chipping chisel is about six or eight inches long,
and three-fourths of an inch broad on the edge, which is a little
convex, that the corners may not be liable to dig into the work.
The bevils are ground to meet at an angle of about 80 degrees,
and the hammer used with the chipping chisel varies from about
two to three pounds in weight. Before commencing to chip the
work, it is usual to rub both the face of the hammer and the end
of the chisel upon the bench or floor, to remove any grease and
leave them bright and clean, as were either of them greasy there
would be risk of the hammer glancing off and striking the
knuckles. A blow is first given with the hammer upon the angle
of the work, to make a little facet upon which the first chisel-cut
is made, about the thirtieth of an inch below the general sui'face
of the casting, the chisel being then only raised some 30 degrees
above the horizontal line. In continuing the cuts the chisel is
elevated to about 45 degrees, the blows are given in quick suc-
cession, and the cuts are led gradually over the entire surface,
the advance being always upon a line that is convex to the chisel.
Provided the casting is moderately flat, the edge of the chisel
is kept at one uniform distance below the general surface of the
work, which is occasionally examined with the straight-edge.
Should the surface of the casting present any lumps or irregu-
larities of surface, a thicker chip or two thin chips are removed
CHIPPING, PICKLING, GRINDING, ETC. 851
such high parts, to lessen the suhsi <juent labour of filing,
hut which process is much less destructi\c to the file after tin-
hard sand-coat has been removed by acid from the iron.
In some massive works, and also in cases where large quanti-
ties have to be chipped off certain parts of castings, much larger
chipping chisels are used, which are called flogging chisels ; tin y
commonly exceed one foot in length, and are proportionally stout ;
one man holds the chisel in both hands, sometimes by means of
a chisel-rod for greater security, whilst another strikes with a
lijrht sledge-hammer. Where much has to be removed, it is also
usual to employ cross-cutting chisels ; these are about seven or
eight inches long, a quarter of an inch wide on the edge, and an
inch broad in the other direction; the cross-cut chisel is first
used to cut furrows, half or three-quarters of an inch asunder, to
the full depth of the parts to be removed, and the intervening
ridges are then easily broken off with the ordinary chipping
chisel; but since the general employment of the planing-
machinc, and others of the engineer's tools, the chipping chisels
are scarcely required. When iron castings are so near to their
required dimensions, that chipping would remove too much, they
are either cleaned with a nearly worn-out file, or the outer coat
is removed on the grindstone, means that are much less wasteful
of the material.
\Vrought iron is but seldom pickled previously to being filed,
but is either cleaned with an old file, or is ground on a stone to
remove the outer scale or oxidised surface ; the chipping cl i
is only in general required when the nature of the work pre-
vents it from being forged so nearly of the required form as to
bring it properly within range of the file.
Brass and gun metal are, as already noticed in the first volume,
75, sometimes pickled, but with nitric acid, instead of the
sulphuric acid which is employed for iron; and brass is com-
monly hammered all over to increase its density, unless a minute
quantity of tin is added, say a quarter or half an ounce to tin-
pound, which materially stiffens the alloy, so as to render ham-
mering as unnecessary as it is with good gun-metal.
After a file has been used for wrought iron or steel, it is
leas adapted to filing cast iron or brass, which require k« »-u
files, therefore to economise the wear of the instrument, it is used
3 i 2
852 DRAW-FILING AND CURLING.
for a time on brass or cast-iron, and when partially worn, it is
still available for filing wrought iron or steel ; whereas, had the
file been first used on these harder materials, it would have been
found comparatively ineffective for brass and cast-iron.
As a further measure of economy, the pressure on the file
should be always relieved in the back stroke, which otherwise
only tends to wear down or break off the tops of the teeth, as
their formation shows that they can only cut in the ordinary or
advancing stroke ; the file should, in consequence, be nearly
lifted from the work in drawing it back, but it is not usual
actually to raise the file off the work, as it then becomes needful
to wait an instant before the next stroke, to ensure the true posi-
tion of the file upon the work being resumed : whereas, if it is
brought back with inconsiderable pressure, the file is not injured,
and the hand still retains the consciousness of the true contact
of the file and work, without which the instrument is used with
far less decision and correctness than it otherwise would be.
Some workmen smooth the work by the method called draw-
filincj, or by drawing the file sideways along the work, using it
in fact, as a spoke-shave instead of a file : this certainly has the
effect of smoothing the work, because in that position the file can
only make slight and closely congregated scratches, but the teeth
will not cut in this manner. Another mode sometimes employed
is to curl the work with the file, by describing small circles with
the instrument as in grinding or polishing, but neither of these
practices employs the file teeth in the mode in which they are
legitimately adapted to cut, and no great reliance should be
placed upon them. When smooth surfaces are required, it is a
better and quicker practice, as the work advances towards com-
pletion, to select files that are gradually finer, but always to use
them from point to heel.
When it is desired to make the smooth files cut wrought-iron,
steel, and other fibrous metals very smoothly, the file is used with
R little oil to lubricate the surface, so that it may not penetrate
to the same degree as it would if used dry ; the oil also lessens
the disposition to the scratching and tearing up of the particles,
which, should it happen, mostly produces a furrow or scratch,
especially if the file be pinny, a circumstance now to be explained;
but the oil should not be used on the coarser or preparatory files.
The particles removed from the materials operated upon, are
REMOVING THE FILE-DUST FROM FILES.
always more or less liable toclug the tile, but which particularly
win n the instrument is dry, nre partially removed by giving the
edge of the file a moderately smart blow on the chaps of the vice
or the edge of the bench ; but particles of wrought iron, at
and other tibrous metals, arc apt to pin f fie file, or to stick i
hard as to require to be picked out with a pointed steel u ire,
which is run through the furrow in which the pin is situated.
The marking point, used in setting out works, is commonly
employed for the purpose.
riles are sometimes cleaned witli a scratch-bruxh, which is a
cylindrical bundle of tine steel or brass wire, bound tightly in
its central part, but allowing the ends of the wire to protrude
at both extremities as a stiff brush. Occasionally also, a scr<
is used, or a long strip of sheet brass, about an inch wide, a
small portion of the end of which is turned down at right angles,
and thinned with a hammer; the thin edge is then drawn
forcibly through the oblique furrows of the file, and serves as
a rake to remove any particles of metal that lodge therein.
But the best and most rapid mode of cleaning the file, is to
nail to a piece of wood about two inches wide, a strip of the so-
called cotton card, which is used in combing the cotton-wool
preparatory to spinning; the little wire staples of the card that
are fixed in the leather constitute a most effective brush, and
answer the purpose exceedingly well. Some workmen, to lessen
the disposition of the file to hold the file-dust, or become pinny,
rub it over with chalk ; this absorbs any oil or grease that may be
on the file, and in a considerable degree fulfils the end desired.
To remove wood-dust from files, floats, and rasps, some per-
sons dip them for a few moments into hot water, and then brush
them with a still' brush; the water moistens and swells the wood,
thereby loosening it, and the brush entirely removes the par-
ticles ; the heat given to the file afterwards evaporates the trifling
quantity of moisture that remains, so as to avoid the formation
of rust. This plan, although effective, is neither general nor
import;:.
.il methods of fixing works, in order to subject
them to the action of the file, will be now noticed. .Many of
the in:i»i\e parts of machinery are MI heavy, that gra\ity alone
, p them steady under the action of the file, and
854
TAPER-VICE.
for such as these, it is therefore only needed to prop them up
in any convenient manner, by wedges, trestles, or other supports,
so as to place them conveniently within reach of the operator.
But the great majority of works are held in the well-known
implement, the smith's bench-vice, or tail-vice, the general form
of which is too familiar to require description : but the annexed
figures represent the front and side views of a less-known modi-
fication of the same, called a taper-vice, which presents some
peculiarities, and is occasionally employed by engineers.
The taper-vice, figs. 840 and 841, is made principally of cast-
iron, and to include within itself the base whereon it stands, that
has at the back two small iron trucks or rollers, so that when
the vice is supported upon them alone, it may be easily rolled
from place to place notwithstanding its weight. The front limb
of the vice moves on the joint a, the back on the joint b, so as to
Figs. 840.
grasp either wide or narrow pieces ; but it is by this arrangement
adapted alone to objects that are parallel, which condition, it is
true, is more usually required. But in the present apparatus, if
the jaws are closed upon a taper object, a form that frequently
occurs in steam-engines and similar works, the two parts of the
vice swivel horizontally on a joint, the axis of which is on the
dotted line c, so as to place the jaws at an angle corresponding
uuniN.uiY I \ll-\HK AND VICE-BENCH.
with that of tin- work ; in tact, the lower part or pedestal of the
mted somewhat like the front axlctree of a carriage.
Under ordinary circumstances, however, the screw and nut of
such a vice would bear very imperfectly upon tin- moving j»:
owing to tlirir obliquity ; hut this objection is met by cutting a
spherical recess in the outside of each half of the vice, and
making the collar of the screw, part of a sphere to constitute a
ball-and-socket-joint, and also by making the nut a perforated
sphere, adapted to a spherical cavity or seat, but with a feather
to prevent it from turning round. The two bearings of the
A thus accommodate themselves at the same time, both to
the horizontal and vertical obliquities of the jaws. To constrain
the two parts of the vice to open in an equal degree, there are
two links that are jointed to a collar that slides freely on a
cylinder, which latter is in fact the continuation of the joint pin
c : and to the collar are also attached the two springs that open
the limbs of the vice when the screw is relaxed. This useful
apparatus is well adapted to its particular purpose, such as the
larger pieces of steam engines, and similar machinery.
The ordinary tail-vices, or standing-vices for heavy engineer-
ing and large works, sometimes exceed 100 Ibs. in weight; but
the average weight of tail-vices, for artizaus in general, is from
40 to 60 Ibs., and of those for amateurs, from 25 to 35 Ibs.
The bench for the vice usually extends throughout the length
of the engineer's shop, or vice-loft, and is secured against the
windows. The tail-nee is strongly fixed to the bench at the
required height, and the tail that extends downwards is fixed
in a elect nailed to the floor, or against one of the legs of the
bench, which latter mode is desirable, as the vice is then in
better condition to resist the blows of the chisel and hammer,
which give rise to much more violence than the act of filing.
Amateurs sometimes employ portable vice-benches, having
nests of drawers for containing the files and other tools ; or the
is attached to the right-hand side of the turning-lathe; less
frequently the tail-vice is attached to the plauing-bench, but it i>
then requisite it should admit of ready attachment and detach-
ment, to have the planing-hcnch at liberty fur its ordinary
application.
rq>rescnts a very convenient mode of mounting the
t ail- \ ice upon a tripod stand of cast- irou, which indeed i> in
856
Til I POD VICE-STAND, ETC.
Fig. 842.
many cases preferable to the wooden benches; as although small,
it is sufficiently heavy to ensure firmness, especially as from
having only three points of support, all are sure to touch the
ground. The tripod readily admits of being shifted about to
suit the light, and also of temporary change of height, by lifting-
pieces added to the feet, when
the work is required to be
nearer to the eye of the ope-
rator. The tripod pedestal
serves additionally for the
occasional support of a small
anvil (when not required
for forging), and also for a
paring knife, fig. 8, page
26, Vol. I.), when an appro-
priate wooden cutting-block
is added to the tripod.
The table-vice mostly used
by watch-makers and similar
artizans, resembles that
shown in figs. 843 and 814.
It is attached to the table by
a clamp and screw, which are
armed with teeth to give a secure hold ; but it is usual to glue a
small piece of wood on the table to receive the teeth, and also
to prevent the lodgment of small pieces of the work at that part,
and the work-table has also a ledge around it, to prevent the
work or tools from rolling off. It will be also perceived, that
the clamp is surmounted by a small square projection a, used
as a stake or anvil ; and that the jaws of the vice have center
holes on one or both sides for the employment of small center
drills, that are too delicate for the breast-plate, after the mode
described in page 553 of the present volume.
It is in all cases desirable that the jaws of vices should be
exactly parallel, both with the edge of the bench and with the
ground, in order that the position of the work maybe instinctively
known ; but the tail-vice and bench-vice are liable to various
objections that arise from their opening on a center, or as a
lunge; for although the jaws are almost parallel when closed, or
then nip in preference at the upper edge, when opened widely,
i.\ini:-\JCK FOR SMALL \\oliKs.
ie nuliiil position <>t' the jaws causes the lower edges alone to
grasp tli.- \\urk, and as in addition, the front jaw moves in .1
844.
circular arc, a wide object, on being fixed, is necessarily thrown
out of the horizontal into an inclined position ; each of which
imperfect conditions is shown in fig. 844.
The inclination of the two limbs of the vice, likewise depre-
ciates the contact of the screw and nut; this is sometimes
remedied by a modification of the ball and socket already de-
scribed. A more simple mode is the employment of a washer of
the form represented at w, fig. 842, which is placed beneath the
screw; the fork embraces the lower extremity of the curved jaw
of the vice, and the washer being thickest in the center, rolls, so
that the flat side always touches the entire surface of the shoulder
of the screw, and the central and bulged part of the washer
touches the limb of the vice, and causes the pressure to be nearly
central upon the screw, instead of, as in fig. 844, against the
upper edge of the collar of the screw, which is then liable to be
bent and strained. The box or internal screw, b, fig. 8 1 2, in which
the screw-pin works has also a power of adjustment or hinge-like
rotation, which eiiMires, here likewise, centrality of piv»ure.
This mode is extremely simple, and worthy of general adoption.
The inconveniences common to vices opening radially on a
joint pin, are completely removed in those opening on straight
islides ; these are called parallel rices, because the surfaces of their
jaws or chaps, and also the bearings of their screws and nuts,
alwuvN retain their parallelism; consequently whether the work
be wide or narrow, it is always firmly grasped by the chaps
provided the work be itself parallel. One of these vices is repiv-
ted in fig. 815. The front jaw is forged in continuation of
the body of the vice, the whole being of a rectangular form, and
858
PARALLEL VICES.
receiving at its upper parts the extremities of the pinching
screw, which has a semi-cylindrical cover to protect it from the
file-dust. The back or sliding jaw of the parallel vice fits accu-
rately upon the upper surface of the principal bar at a, and also
upon a square bar b, placed above it.
846.
Parallel vices are sometimes attached to the table or bench,
by clamps that only allow them one fixed position, namely, with
the jaws parallel with the bench, as in the bench-vice, fig. 843 ;
but more generally the clamp of a parallel vice, c c c, fig. 845,
has a vertical socket or hole, and the principal piece of the vice
terminates in a round stem that fits the socket, and has a nut n,
by which means any horizontal inclination may be given to the
jaws ; they are represented inclined, or they may even be placed
at right angles to the bench.
Some parallel vices are attached to the table by ball and
socket joints, as shown detached in fig. 846; and various similar
schemes have been proposed. The screw-clamp is attached to
the table by a thumb-screw «, and the clamp terminates in a
portion of a sphere ; the lower part of the vice has two shallow
spherical cups adapted to the ball, so that by turning the thumb-
screw b} the ball is grasped between the two cups. It is true
this kind of parallel vice may be inclined both horizontally and
vertically, and therefore offers much choice of position ; but it
is too unstable in any to serve for more than very light works,
which require but a small application of force.
The jaws of vices are faced with hardened steel and cut like files,
so as to hold securely; but works that are nearly finished would
s.VJ
he injured hy the indentation of the teeth, and are therefore
•.i-il by various kinds of shields or vice-damp*, aa they are
generally called ; several of these are shown in figs. 847 to 857.
-clamps, such as fig. 847, are often made of two detached
pieces of stout sheet-iron, brass, or copper, of the length of the
chape of the vice, and nearly as wide. The two pieces are
pinched between the jaws, and then bent closely around the
shoulders of the vice to mould them to the required form, and
make them easily retain their positions when the work is removed
from between them.
BUT3
Iff.
849.
Sometimes sheet lead an eighth of an inch thick is used ; but
such clamps answer better when cast in the rectangular form, ns
. 8 18, and then bent as at b; the lead should be hardened
n a,
with a little antimony, to resemble a very soft type metal (Vol. I.,
page 277), and, previously to bending the clamps, they should be
heated to about 300° to 400° Fahr., to avoid fracture. This alloy,
although harder than lead, is still sutliciontly soft to adapt its( -If
to irregularities in the objects IK Id, and the clamps being thick,
last longer, and more readily admit of being restored to form
by the hammer or rasp, than those made of sheet lead
860 VICE-CLAMPS.
Spring or jointed clamps of the several forms, figs. 849 to 857,
are also made. Fig. 849 represents tAvo stout rectangular pieces
of metal, united by two springs which pass on the sides of the
vice-screw ; these open to a considerable distance, and from the
flexibility of the springs, readily adapt themselves either to
thick or thin pieces.
The clamp, fig. 850, is made in two pieces of cast or wrought
iron, jointed like a wide door hinge, and with a spring to separate
the two parts to a small extent ; this clamp has a piece of soft
steel or iron attached to each half, to make a fine close mouth,
suitable to delicate works and thin plates.
Fig. 851, is a narrow spring clamp made of one piece of steel,
to which are attached pieces of wood or brass, that may be
renewed when worn out of shape; the clamp, fig. 852, is made
of one piece of steel, and formed with a crease to hold small
wires horizontally; 853 and 854 are detached clamps, one
plain, the other with an angular notch, that serve for holding
round and other pieces vertically; 852 and 853 are each useful
in holding round bars whilst they are being tapped, and not
unfrequently their inner edges are cut with file teeth, after
which they are hardened and tempered. As shown in fig. 855,
some of the vice-clamps are made with jaws inclined at about 30
degrees to the perpendicular, to serve for holding chamfer bars
for slides, and various bevilled works; these clamps have the
effect of placing the chamfered edge nearly horizontal, which
latter is the most convenient position for the act of filing.
Fig. 856 are the long sloping clamps, consisting of two pieces
of wood bevilled at their extremities, and united by an external
strap of sheet iron or steel, which is riveted to them ; should
they fail to spring open sufficiently, a stick is thrust between the
two parts, as shown by the dotted lines ; fig. 857 are upright
wooden clamps, which are forked so that the tails proceed verti-
cally, one on each side of the screw of the vice. The sloping
wood clamps commonly used by gun-makers, are made long
enough to rest upon the floor, and when the one end of the
^un-barrel is pinched between them, the other end is supported
either by a vertical prop, called a horse, or by a horizontal
wooden horse, fixed to the bench at about the same height as
the jaws of the vice.
Wooden clamps, although of great convenience, are open to a
ll \\li-vicu. sill
tliut is sometimes acutely frit, as when small pieces
briskly tilcil \\liilst lirld in wooden clamps, owing to the slow
inctin^ power of the wood, the works become so hot as to be
inconvenient to be held in the lingers, but which is continually
i. MS it is necessary at short intervals to remove the v
from the vice, for the purpose of testing, by the straight ad
square, or other measuring instruments, the progress made.
Sometimes the work is grasped between slips of leather or card,
that are simply held to the vice by the penetration of its teeth.
Leather and card are, however, partly open to the same objec-
tion as wood clamps, from which the metal clamps, owing to
their superior power of conducting heat, are nearly free.
A great number of small works are more conveniently filed,
whilst they are held with the left hand, the file being then
managed exclusively with the right; this enables the arti/an
more easily to judge of the position of the file. In such cases, a
piece of wood/, fig. 858, called 9.jiHi>y-l>l<>ck, is fixed in the table
or tail-vice, and square, round, and similar pieces, are rested in
one of several notches made in the block with a triangular file.
If the works are rectangular, or have flat surfaces, they are held
quite at rest ; if they are circular, they are continually rotated,
as will be explained, and it' they are wide and flat, they are laid
on the flat surface of the filing-block/, against a ledge or projec-
tion represented on the lower side of the block, which is then
placed upwards.
Pieces that are suHiciently long and bulky, are held upon the
filing- block by the hand unassistedly ; but small and short
works arc more usually fixed in some description of hand-\
and applied in the position shown in fig. 858, and the vice b,
larger than the work, serves as a handle, and affords a better
grasp.
For works of larger size the hand-vices are progressively
larger, as in 859 and 860 ; some of them have wooden handles.
Almost all the hand-\ ices have fly-nuts to be t\\ isted v> ith the
fniL'ers l>nt the most powerful, \\hicli sometimes wei^'h as much
as about three pounds, have square nuts that are fastened by a
or spanner *. Occasionally, to ensure a strong grip, one
ear of the ordinary fly-nut is pinched in the tail-\iee, \\lulst
the hand-vice is twisted bodily round; but unless due caution is
862
HAND-VICES AND PIN-TONG3.
used, either the vice may be strained, or the screw broken, from
the great purchase thus obtained.
Hand-vices are not, however, in all cases employed ; but small
wires and other pieces are also held in a species of pliers,
fig. 861, called pin-tongs or sliding-tongs, which are closed by a
ferule that is drawn down the stem. Fig. 862 shows another
variety of this kind, that has no joint, but springs open by
elasticity alone when the ring r is drawn back.
Figs. 858
061.
The small pin-vice, fig. 858, is used by watchmakers in filing
up small pins and other cylindrical objects ; the jaws are not
united by a joint, but are formed in one piece with the stem of
the vice, the end that constitutes the jaws being divided or forked;
the screw and stem are each perforated throughout, that the
ends of long wires maybe filed; and the stem is octangular
that the pin-vice may be readily twisted to and fro between the
fingers and thumb of the left hand, whilst the file is reciprocated
by the right hand, and in this manner a considerable approach
to the cylindrical form is obtained.
Independently of the rapid movement of the hand-vice to and
fro on its axis, simultaneously with the strokes of the file, the
two hands being moved together, the hand-vice is thrown pro-
gressively forward with the fore-finger about a quarter of a turn
MODES OP HOLDING PLAT WORKS. M ',.'',
at nearly every alternation, so as to bring all parts of the work
alike under the operation of the file. Hut as it is in this case
important that the work should In- pinched exactly central in the
, or so that the axis of the work may pass through the axis
or central line of the vice, a central angular groove is frequently
made in each jaw of the hand-vice, to give the work, without
trial, a nearly axial position. This is more usual in the nan
S fig. 859, known as dog-note or piy-nose hand-vices, than in
those with wide or cross chaps, 858 and 860.
Many circular works that were formerly thus filed, are now,
from motives of expedition and accuracy, more commonly exe-
cuted in the turning-lathe, since the great extension in the use
of this machine, which has become nearly as general as the vice
or the file itself; but frequent occasions still remain in which
the hand-vice and file are thus employed, and it is curious to see
how those accustomed to the rotation of the different kinds of
hand-vice with the wrist, will in this manner reduce a square or
irregular piece to the circular section.
In the pin-tongs, fig. 862, besides the facility of turning the
instrument round with the fingers, from the reverse end having
a center and pulley, the same spring tongs serve conveniently
as forceps for holding small drills to be worked with the drill-
bow, and also for other purposes in watch-work.
Numerous flat works are too large, thin, and irregular in their
superficies to admit of being fixed in the various kinds of bench
and table-vices that have been described, and if so fixed, there
would he risk of bending such thin pieces by the pressure of
the vice applied against the edges of the work, consequently,
di tie rent methods are employed in fixing them.
The largest flat works are simply laid on the naked surface of
the work-bench, and temporarily held by half a dozen or more
pins or nails driven into the bench. The pins should be as close
to the margin as possible, and yet below the surface of the work,
so as not to interfere \\itti the free application of the file; it is
frequently necessary to lift the work out of its temporary bed
for its examination with measuring instruments, /ind advantage
is taken of these opportunities for sweeping away with a
small brush (like a nail-brush for the dressing-table,) any loose
SGI FILING BOARD AND FLATTING VICE.
filings that may have got beneath the work, and prevent it from
lying flat.
For thin flat works of smaller size, the filing-board, fig. 863,
is a convenient appendage; it measures six or eight inches square,
and has a stout rib on the under side, by which it is fixed in the
vice. Such thin works are required to be frequently corrected
with the hammer, and also to be turned over, in order that their
opposite sides may be alternately filed, so as to follow and com-
pensate for, the continual changes they undergo in the act of
being filed. In some instances the work is held down with one
or more screw clamps or hand-vices as represented ; this is need-
ful when pins would bruise the margins of nearly-finished works,
and a card or a few thicknesses of paper are then interposed to
protect the object from the teeth of the vice.
Figs. 863. 864.
In filing thin flat works, such as the thin handles or scales
of penknives and razors, and the thin steel plates used in pocket
knives, the Sheffield cutlers generally resort to the contrivance
represented in fig. 864, and known as a flatting-vice. A hand-
vice is fixed, in the ordinary tail-vice or table-vice, by the one jaw
with the screw uppermost, so that the jaws of the hand-vice are
horizontal. The thin scale to be filed is then placed on a flat
piece of metal not less than a quarter of an inch thick, and the
two are pinched together by the one corner, so that all the remain-
ing surface may be free to the action of the files, and the work
is readily shifted about to allow all parts to be successively ope-
rated upon. The facility of changing the position is particularly
useful in working on pieces of tortoiseshell, buckhorn, and other
materials of irregular form and thickness, to which the filing
boards with pins or clamps would less conveniently apply.
As before observed, the one face of the small filing-block/,
fig. 858, is also used for very small thin works, and which are
INS ..it IIIIM. \ FLAT SURFACE.
prevented slipping from • by the wooden Icd^'e, or by
pins drnen in. In many instances, also, thin works OTC held
upon a piece of cork, such as the bnn- f..r a large cask, beneath
which i.s Allied a square piece of wood, that the cork may be held
in the \ice without being compressed. The elasticity of the
. allows the work to become somewhat embedded by the
pressure of the file, between which and the surface-friction, it is
sufficiently secured for the purpose without pins.
SECT. IV. — INSTRUCTIONS FOR FILING A FLAT SURFACE, UNDER
TIIK GUIDANCE OF THE STRA IUHT-EDGE, AND OF TIIK TRIAL-
PLATE, OR PI. ANoMl I I R
In following out the subject of the instructions for the use of
the file, it is proposed, first to explain that which may be called
the manual process of producing a true or plane surface on
a piece of cast iron of moderate dimensions, say four or five
inches wide and eight or ten inches long; and although the
entire routine is only required for surfaces of the most exact and
finished kind, the same general treatment, when discontinued at
certain stages, is equally suited to various other works in me-
chanism, that only demand by comparison an inferior degree of
precision : the routine is also nearly the same for surfaces larger
or smaller than that referred to.
Before any effective progress can be made in filing Hat works,
the operator must be provided with the means of testing the
\e advance of the work, he should therefore possess a
true strai^ht-ed^c, and a true surface-plate. The straight-edges
used by smiths are generally of steel, and although they have
sometimes a nearly acute edge, it is much more usual to give
them moderate width : thus, in steel straight -edges from one to
four feet in length, the width of the edge is from one-sixteenth to
one-fourth of an inch, and in cast-iron straight-edges from six to
nine feet in length, the width is usually two to three in«
The straight-edge is used for trying the surface that is under
cornet ion, along its four margins, across its two diagonals, and
ii-ions intern. which respective lines, if all exact,
denote the surface to be correct ; but the straight-edge alone is
a tedious and scarcely suflicicnt test, and when great accuracy is
red. it is almost imp > have at least one very exact
866 INSTRUCTIONS FOR FILING A FLAT SURFACE.
plane metallic surface, or surface-plate, (the piano-metre of the
French,) by which the general condition of the surface under
formation may be more quickly and accurately tested at one
operation : and to avoid confusion of terms, it is proposed in all
cases, when speaking of the instrument, to employ the French
appellation piano-metre or rather planometer, which is exact and
distinctive.
The flat piece of cast-iron, intended to be operated upon,
having been chipped all over, as described in page 850, a coarse
hand-file, of as large dimensions as the operator can safely
manage is selected, and in the commencement, the rough edges
or ridges left by the chipping-chisel are levelled, those parts how-
ever being principally filed, that appear from the straight-edge
to be too high.
The strokes of the file are directed sometimes square across as
on a fixed line, or obliquely in both directions alternately ; at
other times the file is traversed a little to the right or left during
the stroke, so as to make it apply to a portion of the work
exceeding the width of the file. These changes in the applica-
tions of the file are almost constantly given, in order that the
various positions may cross each other in all possible directions,
and prevent the formation of partial hollows' The work is tried
at short intervals with the straight-edge ; and the eye directed on
a level with the work to be tested, readily perceives the points
that are most prominent. After the rough errors have been
partially removed, the work is taken from the vice, and struck
edgeways upon the bench to shake off any loose filings, and it is
then inverted on the planometer, which should be fully as large
or larger than the work. As, however, it cannot be told by the
eye which points of the work touch the planometer, this instru-
ment is coated all over with some colouring matter, such as pul-
verised red chalk mixed with a little oil, and then the touching
places become coloured.
In all probability the work will at first assimilate so imper-
fectly with the planometer, that it will only rest thereon at its
two highest points, most likely at the two corners of the one
diagonal, and when pressure is applied at the two other corners
alternately, the work will probably ride or rock on the two points
of temporary support. The work is slightly rubbed on the sur-
face-plate, and then picks up at its highest points some of the
INSTRUCTIONS FOR FILING A PLAT SURFACE. "",
red ID tin- fiee, .MM! the file is principally
used in the \icinity of thr coloured parts, with the occnsi
test of the v dgc, :ni(l nfti i a short period the work is
•gain tried on the planom<
Should the same two points still become reddened, they are
reduced with the file, but it is probable the work may
be found to rest upon larger portions of its surface, or upon
three or four points instead of two only; and if so, nil the
marked places are reduced in a small degree before the suc-
ceeding trial. This process is continually repeated, and if
watchfully performed, it will be found that the points of con-
tact will become gradually increased, say from two to four, to
six or eight, then to a dozen or more, and so on.
In this, or rather an earlier stage of the work, the smith's
plane for metal is often advantageously used in connexion with
the file. The general structure of the plane is shown by the
figure and description on page 483, and it is employed much after
the manner of the joiner's plane, but it may be used at pleasure
lengthways, crossways, or diagonally, without any interference
from grain or fibre as in wood work. The grooved or roughing-
out cutter is employed in the commencement because it more
readily penetrates the work, and a few strokes are given to crop
off the highest points of the surface, the furrows made by the
serrated cutter are then nearly removed with the file, which acts
more expeditiously although less exactly than the plane, and in
this manner the grooved plane iron and the coarse file are alter-
nately used. In the absence of the planometer, the metal plane
assumes a greatly-increased degree of importance.
As the work becomes gradually nearer to truth, the grooved
cutter is exchanged for that with a continuous or smooth edge, a
second-cut, or bastard hand file, is also selected, and the same
alternation of planing and filing is persevered in, the plane s<
ing as it were to direct the file, until it is found that the plane
iron acts too vigorously, as it is scarcely satisfied with merely
scraping over the surface of the cast-iron; but when it acts it
>ves a shaving having a nearly measurable thickness, and
efore, although the hand-plane may not injure the gen
truth of the surface, it will prevent the work 1'roin bring so deli-
cately acted upon, as the continuance of the process now demand - :
3 ic 2
868 INSTRUCTIONS FOR FILING A FLAT SURFACE.
a smoother hand file is consequently alone employed in further-
ing the work.
If the piece of cast-iron should have been turned in the lathe,
or planed in the planing machine, instead of having been
wrought entirely with the chipping chisel, plane and file, the
former instructions would be uncalled for, as the remaining
steps alone would remain to be followed. Unless, indeed, the
work had been so imperfectly fixed as to have been strained, and
thence become distorted on being released from the machine :
on the latter supposition the grosser errors would probably re-
quire correction with the bastard file, before the smooth file
could be judiciously used.
The necessity of the convex form of the file will now be ren-
dered most striking, as were the file absolutely flat on its face,
it would be scarcely possible to reduce with it any small and
isolated spot that might become coated with the red chalk from
off the planometer; but as the file is a little rounded, any pre-
cise spot on the work may be acted upon, as the end of the file
may be pressed with the fingers of the left hand on the exact
spot to be reduced, whilst the remainder of the file is held just
out of contact with the rest of the surface.
When, however, the points of bearing become numerous, the
file cannot even thus be managed with sufficient discrimination,
and notwithstanding the best efforts it will act on too large a
part, and thereby lengthen, or it might be said altogether to
prevent the complete correction of the work, because the file is
not sufficiently under control. Before the file has assumed this
questionable tendency, it is politic and usual as a measure of
economy, to discontinue the use of the file, and to prosecute the
work with a scraper, which having a sharp edge, instead of a broad
and abrading surface, may be made to act with far more decision
on any, even the most minute spot or point. A worn-out triangu-
lar file, ground at the end on all the faces, so as to make thin keen
edges, is generally used as the scraper; this should be keenly
sharpened on an oil-stone, so as to act without requiring much
pressure, which would only fill the work with striae or utters.
The continual reduction of all the points, which are sufficiently
prominent to pick up the colouring matter from the planometer,
is now persevered in with the scraper instead of the file, and pre-
INSTRUCTIONS foil MUM; \ i RPACB.
y in the same manner, except as regards the change of the
tool ; ami if the process have been carefully performed through-
out, it will be found nt the i on. IUMUM that it' the work and piano-
meter are both wiped clean, and ruhhed hard t«>_'i-:ln-r, that the
high points of the work will he .somewhat burnished, giving to
>rk a finely mottled character.
In producing metallic surfaces, the constant effort should bo
n-duee all the high places with as much expedition as circum-
stances will admit, but avoiding, on the other hand, that energetic
UM- di the tool, which may too hastily alter the condition of the
surface, and in expunging the known errors, induce others equal
in degree but differently situated. Throughout the work, attempt
should be made to keep the points of bearing, whether few or
many, as nearly equidistant as may be, instead of allowing them
to become grouped together in large patches.
In respect to the tools, there should be a gradual diminution
in their cutting powers, and also of the vigour with which they
are used, as although energy is wise at the commencement of the
work, it should gradually subside into watchfulness and caution
towards the conclusion. The periods of alternation between the
hand-plane and the file, and also the times when these are suc-
cessively rejected, in favour of the scraper as the finishing tool,
must be in great measure left to the judgment of the operator.
There should be a frequent examination of the work by means
of the straight-edge and planometer, which latter should at all
times be evenly tinted with the colour. At the commencement it
is necessary the coating of red stuff on the planometer should be
moderately abundant, so as to mark even those places which are
minutely distant, but with the continued application of the work,
the colouring matter will be gradually removed from the piano-
meter, and which is desirable, as towards the conclusion tho
quantity of red should be small, so as but faintly to mark tho
summits of each little eminence, the number and equality of
which are dependent on the perfection of the planometer, and
the >teady persevering watchfulness of the operator.
It is not to be supposed that it is in every case needful to
proceed in the careful and progressive mode just described, as.
the parts of different works require widely dill', -rent degrees of.
870 RELATIVE DEGREES OF ACCURACY REQUIRED IN FLAT WORKS.
perfection as to flatness. For instance, in many it is only neces-
sary they should be clean and bright, and have the semblance of
flatness, with such even the straight-edge is little if at all used as
a test. Those surfaces by which the stationary parts of framings
are attached, require a moderate degree of accuracy, such as may
be comparable with the perfection in the hewn stones of a bridge
or other massive edifice, which require to be flat, in order that
they may bear fairly against each other, as without a certain
degree of truth the stone might break from the unequal strain
to which it would be exposed.
The flat parts of metallic works, if similarly imperfect, would
bend, and perhaps distort the remainder ; but although it is of
great importance that bearing surfaces should be out of winding,
or not twisted, it is by no means important that such bearing
surfaces should be continuous, as a few equally scattered bearing
points frequently suffice. Thus it was the common practice before
the general introduction of the engineer's planing-machine, to
make fillets or chipping places around the margins of the bearing
surfaces of castings, which fillets alone were corrected with the
chisel and coarse file, for the juxtaposition of the larger pieces
or frame work of machines, the intermediate spaces being left
depressed and out of contact. This mode sufficed, provided the
pressure of the screw-bolts could not, by collapsing the hollow
places, distort the castings, with which view chipping places
were also generally left around the bolt holes of the work, this
method greatly reduced the labour of getting up such works by
hand ; but fillets and chipping places are now in a great measure
abandoned. Smaller and more delicate works, requiring some-
what greater accuracy than those just described, are left from
smoother files, but in most cases without the necessity of
scraping ; but the rectilinear slides and moving parts of accu-
rate machinery, and the trial or surface-plates of the mecha-
nician, require beyond all other works, the most dexterous use
of the file and other means, from which it is again repeated,
grinding should be entirely excluded.
Until very recently, when the points of bearing had been so
multiplied by the file and scraper, as not to exceed about half
an inch in average distance, and that a still higher degree of
accuracy was desired ; it was the ordinary practice to attempt the
IMPOLICY OF GRINDING i IIPACE8.
obliteration of these miii I, oil of grinding.
Supposing only o e or surface t<» luivc been required, it
then became necessary to grind the work uj>on the planoin
If, but to avoid the necessity of so injurious a practice, it was
usual, when practicable, to make three similar pieces at one
time, in order that, when all three had been separately filed and
scraped to agree pretty nearly with the straight-edge and piano-
meter, the three pieces might then he mutually employed in the
correction of one another, by grinding the faces successively
together with emery-powder and water.
1 lie one piece was laid down horizontally, wetted all over with
water, and then strewed with emery powder, after which, one of
the other surfaces was inverted upon it, and rubbed about in
various ways with longitudinal, lateral, and curling or circular
strokes, on the supposition that as the two pieces came into contact
respectively at their highest points, these highest points became
mutually abraded, with a tendency to reduce them to the general
level. After a short period, the top surface was removed, fresh
emery and water were applied, and the third surface was rubbed
upon the first ; after which, all three were variously interchanged,
by placingeveryone in succession as the lower surface, and rubbing
the two others upon the lower until it was considered from the
uniform but deceptive grey tint thus produced, that the errors
in all were expunged, and that the three surfaces were all true.
It is, however, considered quite unnecessary to enter more into
detail on a process that may be considered to be nearly obso!
as regards the production of plane metallic surfaces, especially
as at a future part of this Volume, the practice of grinding will
be noticed, in reference to surfaces requiring inferior exactness,
and consisting of materials that do not admit of the employment
of the file and scraper.
That two surfaces which are very nearly accurate, if ground
together for a very short time, do in some degree correct each
other, is true, but it has been long and well known, that a con-
tinuance of the grinding is very dangerous, and apt to lead the
one surface to become convex, and the other concave in a nearly
equal dl id on this account, three pieces were usually
operated upon that the third might act as an umpire, as although
two pieces possessing exactly opposite errors may appear quite
872 INSTRUCTIONS FOR ORIGINATING STRAIGHT EDGES,
to agree, the third cannot agree with each of these two, until
they have all been made alike, and quite plane surfaces.
But the entire process of grinding, although apparently good,
is so fraught with uncertainty, that accurate mechanicians have
long agreed that the less grinding that is employed on rectilinear
works the better, and Mr. Whit worth has recently shown in the
most satisfactory manner,* that in such works grinding is
entirely unnecessary, and may with the greatest advantage be
dispensed with, as the further prosecution of the scraping process
is quite sufficient to lead to the limit of attainable accuracy; the
only condition being, that the mode of continually referring the
work to the planometer, and scraping down the points sufficiently
high to be coloured, should be steadily persevered in, until the
completion of the process, and works thus treated assume a much
higher degree of excellence than is attainable by grinding.
Mr. Whitworth stated a further and equally important advan-
tage to result from the discontinuance of grinding, as regards
the slides arid moving parts of machinery. Some of the grinding
powder is always absorbed in the pores of the metal, by which
the metallic surfaces are converted into species of laps, so that
the slides and works carry with them the sources of their depre-
ciation and even destruction. The author's previous experience
had so fully prepared him for admission of the soundness of these
views, that in his own workshop he immediately adopted the
suggestion of accomplishing all accurate rectilinear works by the
continuance of scraping, to the entire exclusion of grinding.
SECT. V. INSTRUCTIONS FOR ORIGINATING STRAIGHT-EDGES AMI
TRIAL-PLATES, OR PLANOMETERS.
The remarks hitherto offered on producing a flat surface were
based upon the supposition that the operator is in possession of
a good straight-edge, and a good surface or planometer, and
•.vhich is usual under ordinary circumstances; but it may be con-
sidered necessary that the more difficult case should be placed
before the reader, of originating the planometer itself, by which
alone can he render himself independent of external assistance ;
the previous observations will greatly abridge the description.
* In a Paper read before the British Association for the Advancement of Science.
Glasgow, 1840.
\M> I ill \l I'LATES, OR PLANOMETBE*. 873
/•*/, to on straight-edge. — In originating a straight-
edge, it is judicious to prepare thr ground, so far as possible,
\\ith the means possessed by every joiner; and accordingly,
throe pieces of hard straight -^niined mahogany should he :
pi mod as straight as possible with the joiner's pi me. Calling the
three pieces, for distinction, A B and C, when they are c<>
pared. A and B may appear to agree everywhere, even when
of them is changed end for end : this shows A and B to be either
both straight, or else the one concave, the other convex ; but C
may he unlike either of them. C is then adjusted also to A, and
will therefore become a duplicate of B ; but when the duplicates
l> and C are compared, it may be found that they touch in the
middle, and admit lijjht between them at the ends, showing each
to be convex. The central parts both of B and C, which are
erroneous in the same direction, are then each reduced in a nearly
equal degree, until in fact, the transmission of light is prevented
throughout their length, even when they are reversed, and by
which the condition of each will be somewhat improved.
Next, to ascertain whether B and C, when thus improved, are
each pretty near to the truth. The third, or A, is fitted to B,
making A and B as nearly as may be, counterparts of one
another; and if A, when thus altered, should also agree with the
third or C, all are true : but this can scarcely yet be strictly the
case. And the routine is therefore continually repeated of
redueini: in an equal degree the two which may show evidence
of being nearly alike, (either both convex or both concave,) and
then by titting the third to one of the corrected two, as a test by
wh ifh to try, if they not alone agree with each other but like-
wise agree with the third, or the test ; as the work can only be
perfect when all three admit of being compared without any
want of contact being observable in any of the three comparisons.
If the trying-plane is carefully manipulated, the three pieces
will, in three or four repetitions of the series of operations,
<>me as nearly accurate as the nature of the tools and of the
method will admit; and then, either the best of the three
wooden straight-edges, or all three of them, may be used as the
preliminary test in making the steel straight -edges.*
• The more common practice of the joiner it to operate upon only two piece*,
each of which U first planed until they agree together when placed edge to edge in
the ordinary manner, or in one plane. The two piece* are now placed tide by tidt,
874 INSTRUCTIONS FOR ORIGINATING STRAIGHT EDGES,
Sometimes the metal straight-edges are wide strips cut off
from a sheet of steel of hard quality ; if forged from a bar of
steel, the hammering should be continued until the metal is
quite cold, to render it hard and elastic ; and in some instances,
the straight-edge, when partly finished, is hardened and tempered
before its edges are completed. In all cases, if the one edge is
to be chamfered, this should be done in an early stage, as it is
very apt to throw the work crooked ; and the sides are always
filed, or otherwise finished, before any great progress is made in
correcting the edges. When three straight-edges are made at
one time, the three are generally united by temporary pins
through their ends, to make one thick bar, and are then corrected
in the mass as the first stage.
The work having been thus far prepared, the wooden straight-
edge is rubbed with a dry lump of red chalk, that it may leave
evidence of the points of contact. A coarse file is first used, and
it may for a time be assisted by the hand-plane ; the size rnd
length of the file are gradually decreased, and after a time, it
will be found that the wooden straight-edge is no longer suffi-
ciently delicate to afford the required test. When all three of
the steel straight-edges have been brought collectively to a state
of approximate truth, they are separated, and wrought the one
from the other, precisely in the same order that was described
in reference to the wooden straight-edges; but as on the steel a
very small and smooth file may be used, the process of correction
may be carried with the file much higher upon steel straight-
edges, than upon metallic surfaces. In addition to the mode of
examining straight-edges by the transmission of light, they are
also compared by laying them two at a time upon a true bench
or surface, and rubbing them together without colouring matter ;
the high places will then mutually rub each other sufficiently to
aud their edges are placed in agreement at the extremities, so that the fingers,
passed transversely across their ends, cannot feel any want of continuity of surface;
in other words, cannot feel the joint. If, whilst thus placed, the joint is also in-
appreciable to the sense of touch at various intermediate parts of the length of
both pieces, the work is correct, and the two are straight.
From the very precise action of the trying-plane, the wooden straight-edge may
perhaps be equally well produced by the methods requiring either two or three to
be made ; but the method of making three at once is given in the text, because it
is always followed in metal works, in consequence of the different nature of the
\\orking tools, and of the abstract superiority of the method
IB, OR I'
875
leave a small degree of brightness, that may be easily observed
on a careful scrutiny ; and as both edges of every straight-edge
are commonly wrought, the investigation becomes amplified and
impt a there bring six comparisons instead of three.
tic ^muling is sometimes resorted to in completing steel
straight-edge* : it is less objectionable with steel, than \\itli cast
iron and other metals which arc softer and also more pomu- than
steel, but the process of grinding being very difficult of control
is not desirable; and as very small files may be used, and with
discrimination, in correcting straight-edges, the scraper
although useful here likewise, does not present the same
importance as in correcting wide surfaces or planometers.
Secondly, to originate a surface-plate or planoraeter. — This
process requires that the operator should be in possession of at
least one very good straight-edge; one of a series of three tnat
have been accurately tested in the manner just described. The
present case also demands, like the last, that three pieces should
be operated upon, in order that the same correctional method
may be brought into effect.
The planometer should be a plate of hard cast-iron, having ribs
at the back to prevent its bending, either from its own weight, or
from taking an unequal bearing on the bench or other support.
Generally a deep rib extends around the four margins of the
planometer, and one, two, or more intermediate and shallower
ribs are added, which divide the back into rectangular compart-
ments, as in fig. 865 ; this plauometer would rest upon the bench
around its edges, or on four prominent points at the corners
represented black. It has been recently proposed by Mr. \Ylut-
Kigs. 865.
867.
worth, that the ribs should be placed obliquely and made to con-
_'<? to three points of bearing, as in fig. 866, which is a much
better plan, as the planometer is then at all times supported on
precisely the same points, notwithstanding the inequality of the
bench, which can scarcely be the case when tour feet are used.
876 INSTRUCTIONS FOR ORIGINATING PLANOMETERS.
The handles are added at the ends, that the planometer may be
readily inverted ; in order that it may be applied upon such
heavy works as it would be inconvenient to lift, and then imme-
diately replaced on its feet when returned to the work-bench.
In the absence of the planing-machine, the three castings for
the planometers would be chipped all over and roughly filed, and
in this case the smith's plane for metal would render most
important service for a considerable period. A good wooden
straight-edge is now convenient, as when rubbed with red chalk
it denotes the high places very effectively, and should be applied
at various parts of the length and width, and also obliquely ; and
indeed a small thick block of beech-wood or mahogany, planed
very flat as a surface and rubbed with chalk, will serve to hasten
the process of obliterating the coarser errors.
In due time, the plane, the coarse file, and the wooden
straight-edge, would all be laid aside, and the work would be
prosecuted with a smoother file, under the direction of a metal
straight-edge, and which if coloured must be also greased to
make the red matter adhere. This part of the work may be
carried to no mean degree of perfection, as a very correct judg-
ment of a plane surface can be obtained from a good straight-
edge applied in all directions, as the eye readily measures the
comparative width of the line of light transmitted, and the
fingers also appreciate, when the straight-edge is slightly rotated
or rubbed sideways, which points of the work are the highest,
and give rise to most friction.
One surface, which may be called A, having been corrected
very carefully with the file and straight-edge, may be now
smeared with red stuff and oil, and employed to hasten the
correction of the second piece, or B, and the third, or C, until
these two are about as near to truth as the first, or A ; the three
are afterwards mutually operated upon under the guidance of
colouring matter. At this stage of the work it will soon become
necessary to discard the file in favour of the scraping-tool, in
using which it will be found very convenient to remove by a
paper screen, the glare of the bright metallic surface, so as to
enable the little patches of colour to be more readily observed.
The screen, fig. 867, consists of a small frame of wood, eight to
ten inches square, covered with writing-paper, and attached to a
small board ; the paper is inclined some ten degrees towards the
INSTRUCTIONS FOK OBIOINA'MM. i 877
itor, and nt night a short piece of candle is placed in tin
center of the I HI: ilcstal as shown.
three plates having been, as before observed, brought into
ly ilit- same preparatory state, it is to be now judged of by
the straight-edge, whether all three are nearly alike, or lean to
the same kind of error. Tims, supposing the pieces A and B
to have a tolerably equal disposition to convexity, or tbnt when
plaeed in contact they n »t in the eenter, but fail to touch around
the margin, then A and B are each a little reduced in the middle
until the tendency to rotate in the center is gone; A and B will
be then each a shade nearer to truth than before. The third
piece, or C, is fitted to A, after which, supposing for a moment
A and B to be each a true, or a plane surface, C would become
also a plane surface, and the task would be then completed.
Perfection is not, however, nearly so easy of attainment, and it
is almost certain that although A and B may be counterparts,
they will not be planes; presuming therefore that C has been
fitted to A, it is almost certain that C will not fit B. (This may
be called routine One.)
Considering, therefore, that now A and C are the two most
nearly alike, or that both are proved to be convex, these are
the two upon which an equal amount of correction is this time
attempted, until they become counterparts, or fit well together;
and the third piece, or B, becomes the arbiter in this stage of
the work. (This may be called routine Two.)
We will lastly assume that B, when altered until it fits C, does
not quite fit to A, but that B and C present an equal departure
from truth, and arc still both convex; then B and C are altered
in an equal degree until they appear to be perfect counterparts,
and this time A, when fitted to one of them, shows whether the
whole three are planes, or that two of the pieces are convex and
one concave. (This may be called routine Three.)
The method of comparison will probably be rendered somewhat
more evident, by the following tabular view of the processes.
Routine Two. -:ne Three.
A. B. Counterpart* A. C. Counterpart*. B. C. Counterpart!*.
C. Arbiter. B. Arbiter. A. Arbit
The inspection of the letters in three routines will farther
show, that every one of the three surfaces admits of comparison
with the two others, and that the abstract method is to fit together
878 INSTRUCTIONS FOR FILING FLAT WORKS.
those two which appear to have the same error, by altering those
two in an equal degree, after which, the third piece, when fitted
to one of the other two pieces, incontestably proves whether all
three are planes ; as this cannot be the case until all three agree
together in every comparison. The attainment of true planes
will be found to require several repetitions of the three routines,
but towards the conclusion increasing care will be continually
required, in order that no degeneration may insidiously occur,
to disappoint the hope of the progress towards perfection being
steadily on the increase.
This correctional process, which is precisely analogous to the
mutual correction of three straight-edges, is somewhat familiar
to mechanicians, but the process is obviously very much more
tedious than the origination of straight-edges, on account of
the great increase of the surface to be operated upon, and the
circumstance that the quantity taken in excess from any part,
must be amended by reducing every other part of that surface
in an equal degree.
For the sake of simplicity it has been supposed throughout the
description that the two convex pieces were in each case selected
for correction ; but this is immaterial, as the result would be the
same if the two concave pieces were wrought, or the one and other
pair alternately, as circumstances may accidentally suggest.
The three planometers having been made as perfect as the
skill and patience of the operator will admit, one of them should
be carefully laid aside, and only used in the most guarded manner
in the reproduction of other planometers, or the correction of
those in general use ; which latter process will be found occasion-
ally requisite, but the less frequently so, if the instrument is
equally worn by rubbing the work to be examined, at all parts
of the planometer, instead of upon the central part alone. And a
true surface or standard having been once obtained, it should be
most scrupulously preserved, as it will be found very considerably
less troublesome to copy a good standard, than to originate the
three standards themselves from which the one is to be reserved.
SECT. VI. — INSTRUCTIONS FOR FILING RECTILINEAR WORKS, IN WHICH
SEVERAL OR ALL OF THE SUPERFICIES HAVE TO BE WROUGHT.
The former instructions have been restricted to the supposition
that only one of the superficies of the work was required to be
Mf-vn
IBC1 Ml NEAR SURFACKH.
e plane or flat ; hut utly happens in rectangular
8, such an the piece A I*. < • ,11 six surfaces,
namely, the top and hottmn A, a, tin- t\u> Miles B, b, and ti
ill require to be corrected and made in rectangular
arrangement (the surfaces a, b, c, heiu.u necessarily concealed
>m view), and therefore some particulars of the ordinary
method of producing these six surfaces will he added; and the
former remarks on pages 500 to 503 on squaring thick and thin
works in wood may be also consulted.
The general rule is first to file up the two largest and principal
faces A and a, and afterwards the smaller faces or edges B b, and
Figs. 868.
869. 870.
r .1 p
C e. The principal faces A a, especially when the pieces are
thin, must be proceeded with for a period simultaneously,
because of the liability of all materials to spring and alter in
their form with the progressive removal of their substance, and
on this account the work, whether thick or thin, is frequently
prepared to a certain stage at every part, before the final correc-
tion is attempted of any one part.
The straight-edge and surface-plate are required, to prove that
each of the faces A and a is a plane surface, and the callipers or
a similar gage is also needful to prove them to be in parallelism.
Callipers, unless provided with set screws, are very liable to be
lentally shifted, and it is needful to use them with caution,
otherwise their elasticity, arising from the length of their legs, is
apt : • •. There are gages, such as fij;. ^I'l'.t, with short
parallel jaws that open as on a slide, and arc fixed by a side
screw ; and a still more simple and very safe plan, is to file two
ilar notches in a piece of sheet-iron or steel, as in fig.
870, the one notch exactly of the finished thickness the work is
required to possess, the other a little larger to serve as the coarse
or preliminary gage.
880 INSTRUCTIONS FOR FILING WORKS.
Sometimes the one face of the work, or A, having been filed
moderately flat, a line is scored around the four sides of the work
with a metal moving-gage, the same in principle as the marking-
gage of the joiner, fig. 342, page 487. At other times the
corrected face A, is laid on a planometer larger than the work,
as represented, (neglecting the inversion,) and the marginal
line is scribed on the four edges, by a scribing-point p, fig. 868,
projecting from the sides of a little metal pedestal that bears
truly on the surface-plate.
Chamfers or bevelled edges are then filed around the four edges
of the face a, exactly to terminate on the scribed lines, the central
part of a can be reduced with but little watchfulness, until the
marginal chamfers are nearly obliterated. This saves much of
the time that would be otherwise required for investigating the
progress made ; but towards the last, the callipers and planometer
must be carefully and continually used, to assist in rendering A
and a, at the same time parallel and plane surfaces.
The two principal edges, B b, are then filed under the
guidance of a square ; the one arm of the square is applied on
A, or a, at pleasure, as in joinery work : or if the square have a
thick back, it maybe placed on the planometer, as at s, fig. 868 ;
if preferred, the work may be supported on its edge B upon the
planometer, and the back square also applied, as at s, in which
case the entire length of the blade of the square comes into
operation, and the irregularities of the plane B, are at the same
time rendered obvious by the planometer.
Another very convenient test has been recommended for this
part of the work — namely, a stout bar, such as r, fig. 8G8, the
two neighbouring sides of which have been made quite flat and
also square with each other. When the work and trial-bar, (or
rectangulometer,) are both laid down, the one side of the bar
presents a truly perpendicular face, which may, by the interven-
tion of colour ing matter, be made to record on the work itself, the
points in which B differs from a rectangular and vertical plane.*
When the edge B has been rendered plane and square, the
opposite edge b, may in its turn be marked either with the
gage or scribing-point at pleasure ; the four edges of b may be
then chamfered, and the entire surface of b is afterwards cor-
rected, (as in producing the second face a,) under the guidance
* See Smith's Panorama of Scieuce, Vol. I., page 30.
HAVING \ \11IOU8 RECTILINEAR SURFACES.
881
of the square, callipers, rectangular bar, and surface-plate, or
some of these tests.
ends C <*, now claim attention, and the marginal line is
scribed around these by the aid of the back squat < hut
the general method so closely resembles that just described as
not to call lor additional particulars.
Should one edge of the work be inclined, or bevelled, as in the
three following figures, in which the works are shaded to distin-
guish them from the tools, the rectangular parts are always first
\\ rouirlit, and then the bevelled edges, the angles being denoted
by a bevel instead of a square : either with a bevel having a
movable blade, as in fig. 871, or by a bevelled templet made of
sheet-metal, as in figs 872, or 873, which latter cannot get
Figt. 871.
872.
873.
874.
r
875.
876.
877.
878.
misadjustcd. The bevelled edge of the work, is also applied if
possible on the planometcr ; in fact the planometer and bevel
are conjointly used as the tests. Bevelled works are either held
in the vice by aid of the chamfer-clamps, fig. 855, page 859, or
they are laid in wooden troughs, with grooves so inclined, that
the edge to be filed is placed horizontally. Triangular bars of
equilateral section arc thus filed in troughs, the sides of which
at an angle of 60 degrees, as in fig. 874.
The succeeding examples of works with many plane surfaces
are objects with rebates and grooves, as represented in figs. 875
to 878. Pieces of the sections 87.">, and 870, supposing them
to be short, would in general he formed in the solid, either
from furgings or castings, as the case inijrht be; the four
;md more accessible faces would lie tiled up s.juare and
true, and aftcr\\ard> the i. \\ ith a due regard to their
3 L
INSTRUCTIONS FOR FILING MORTISES.
parallelism with the neighbouring parts, just after the mode
already set forth. The safe-edge of the file is now indispen-
sable ; as in filing the face b, the safe-edge of the file is allowed
to rub against the face a of the work, and which therefore serves
for its guidance; and in filing the face a, the side b becomes the
guide for the file. The groove in fig. 876 requires a safe-edge
square file.
When however pieces of these sections, but of greater
lengths, have to be produced by means of the file alone, it is more
usual to make them in two or three pieces respectively, as shown
detached in figs. 877 and 878; and which pieces are first ren-
dered parallel on their several edges, and are then united by
screws and steady pins ; or rather, they are united before being
actually finished, in order that any little distortion or displace-
ment occurring in fixing them together may admit of correction.
In works of these kinds, which have rebates, grooves, internal
angles, or cavities, the square, with a sliding blade, shown in
fig. 876, is very useful, as the blade serves as a gage for depth,
besides acting as a square, the one arm of which may be made of
the precise measure of the edge to be tried. This instrument is
often called a turning-square, as it is particularly useful for
measuring the depth of boxes, and other hollowed works turned
in the lathe.
In making straight mortises, as at s s, fig. 879, unless the
groove is roughly formed, at the forge, or in the foundry, it is
usual to drill holes nearly as large as the width of the mortise, and
Figs. 879.
880.
in a straight line; the holes are then thrown into one another by
a round file, or a cross-cutting chisel, and the sides of the mortise
are afterwards filed square and true.
M. inii.f- \ ,tTLY WITH DKIKTS. 888
tilar mortise r r, tin- • -nine, with the
.1 that the holes are made on a circular lino; and that,
instead of a flat file In ing used throughout, a half-round or a
crossiir/ tile is used lor the concave side of the mor
Shcu ular mortises, or those which may be rather con-
sidered to be square holes, as iu tig. 880, would if large
pared by forging or casting the material into the form ; and then
the six exterior faces having been corrected, the aperture would
be filed on all sides under guidance of some of the various tests
before rt tt rrcd to. And in such a case, it is convenient to employ
a small square *, in the form of a right-angled triangle to which is
attached a wire that may serve as a handle, whereby the square
may he applied at any part within the mortise without the sight
of the workman being intercepted by his own fingers. Some-
times also, a cubical block filed truly on four of its faces to the
exact dimensions of the aperture, is used as a measure of the
parallelism and flatness of the four iuterior faces.
These miscellaneous examples of filed works with plane sur-
faces, will be concluded by others of somewhat frequent occur-
rence, and in which different tools are judiciously employed in
conjunction with files. The method first to be described, is one
that is considerably used in thick pieces of metal, for making
holes differing from the circular form, such as square, hexagonal,
triangular, elliptical, and other holes, by first drilling a round
hole, and then enlarging and changing the section of the ehvular
hole by a taper punch, better known as a drift, which tool is
made of steel, and exactly of the same section as that required
in the hole; the drift is hardened and tempered before use.
The drift for a taper square hole is made as in fig. 881, or
simply as a square pyramid, considerably longer than the hole
required : a round hole is first drilled in the work, just large
enough to admit the small end of the drift, which is then drivt u
in, its angles indent and force out the metal, making it first like
the magnified line m, and ultimately exactly square, unless by
ike the hole were drilled too large, when the eircnlar part^
would not be quite obliterated. If admissible, the endlong blows
lie drift are mingled with a few blows on the sides of t
work, as at bb, or parallel with the sides of the drift, which ca\
metal to adapt itself more readily to the tool. The drift
must not however be used too violently, for as it aet> as a
••;
88-t
HOLES MADE WITH DRIFTS AND FILES.
wedge, it may burst open the work, and which latter is therefore
mostly left strong and rough before being drifted ; and generally,
when the angles have been somewhat indented, they are partly
filed out, and completed by the alternate employment of the file
and drift, the marks made by the latter serving continually to
indicate the parts to be removed with the file.
Taper square holes, such as those in the chucks for drills, are
made with some facility. The chuck is first drilled on its own
mandrel, and the drift is put in the four different ways in suc-
cession, that the errors incidental to its form may be scattered
and lost; the chuck is also placed on the mandrel at intervals,
with the drift in its place, that the drift may show as it revolves,
whether or not the hole is concentric. When it is required
that the drifted hole should be parallel instead of taper, the drift
is made as in fig. 882 ; that is, parallel for a short portion in the
middle of its length, and the extremities alone are tapered so as
to make the tool smaller at each end ; the work is therefore first
gradually enlarged to admit the largest part of the drift, and the
parallel part is then driven through the work, and renders the
inner surface of the same a true counterpart of the drift, if proper
care have been taken. In some few cases, the sides of the drifts
Figs. 881. 882.
884.
are notched with a file, so as to act as teeth ; but this is not
general.
"\Micn drifts are used, the process of working is often reversed,
or the interior surfaces are completed before the exterior. The
holes are first drifted whilst the work is larger than its intended
size, and afterwards the exterior part is filed or turned, as the
case may be, from the hole, that is, the hole, (sometimes filled with
the drift,) is made the basis of the measurement of the exterior
MAKING KEY-WAts IN \\liiiis \M» 885
•ions of the work. Frequently, as in a square washer, the
drift it-elf, or else a sqnan arbor of similar form, with a center
lu.l<- at each end, is made to serve us the chuck hy which the
work i> |»l:ieeil u, the turning lathe for completion.
In the concluding example of this section, that of making by
hand the key-ways in the round holes of wheels, it is to he
observed that it is common to turn a cylindrical plug exact
till the hole, and to make a notch in the plug as wide as tin-
intended key-way and parallel with the axis : the plug is shown
at g, fig. 883. A piece of steel /, is then filed parallel, and exact ly
to fit the notch, and its edge is cut as a file, and used as such
within the guide-block, the latter being at the time inserted in
the hole of the wheel. In this case the block becomes the
director of the file, and the notches in any number of wheels are
made both parallel and axial, and the only precaution that re-
mains to be observed is in the depth of the notches, and this is
not always important; the depth may however be readily deter-
mined, by making the grooves at first a little shallower than
their intended depth, and then, the plug having been removed
from the hole, a stop is attached to the side of the file, parallel
with its edge, as at *, to prevent its penetrating beyond the
assigned depth.
The method of cutting key-ways in large wheels, that was
frequently employed prior to the introduction of machinery for
the purpose was as follows. Supposing the wheel to have been
bored with a three-inch hole, and to have required a key-way
half-inch wide and half-inch deep. The guide-block g, fig. 884,
of three inches diameter, would have had a groove say half-inch
wide and one inch deep, and a cross-cut chisel c, exactly to fill
the groove would have been made. The chisel having the same
section as the groove, when driven through would produce no
effect; but if a piece of sheet steel *, VTT thick, were laid at the
bottom of the groove, the chisel would then cut a groove half-
inch wide and TV deep ; and if two, three, four, and ultimately
eight such strips were successively employed together, as in the
section and detached views, fig. 88 1, the hole would be accurately
chiselled out by the repetitions of the process. The hole would
require to be finished with a parallel thick file, called a key-way
or cotter-file, which has already been described on page 822 — 3,
of the present volume.
S8G lil'NKHAL KKMARKS Ul'oX
SECT. VII. INSTRUCTIONS FOR FILING CURVILINEAR WORKS
ACCORDING TO THE THREE ORDINARY MODES.
The curvilinear surfaces of works are commonly of less im-
portance than the plane surfaces, neither do they in general
require the same skilful use of the file, especially as the more
important curved lines and surfaces in machinery are circular,
and are therefore produced in the turning lathe; and of the
remaining curves the majority are introduced either to give a
more pleasing outline to the works than would be obtained by
straight lines, or to obliterate the numerous angles that would
be inconvenient to the hands.
In filing works that are convex, flat files are always used, and
the file is necessarily applied as a tangent to the curve ; and in
filing concave works round and half-round files are used, and in
some cases they are selected, nearly or exactly as counterparts of
the hollows to be wrought.
The manipulation of the file upon curvilinear works is entirely
different from that required to produce a plane surface, in which
latter case the work is held at rest and the hands are moved as
steadily as possible in right lines ; but in filing curved works an
incessant change of direction is important, and so far as practi-
cable, either the file, or the work, is made to rotate about the
axis of the curve to be produced.
A semicircular groove of half-an-inch radius, as in fig. 885,
would be most easily filed with a round file of nearly the same
Fi--. 885. 886. 887.
a b t>
curvature, and the correspondence between the file and work,
and consequently of their axes likewise, would render the matter
very easy ; but the file, from the irregularity of its teeth, would
leave ridges in the work, unless in every stroke it were also
ted to and fro axially by the motion of the wrist, and occa-
sionally in the reverse direction, so that the furrows made by the
teeth might cross each other. If the groove to be filed had a
diameter of three or four inches, although the file might be
selected to correspond in curvature with the groove, as it would
not embrace the entire hollow, the twisting and traversing of the
MIVKAB WORKS.
•vould be imperative in ordi-r to arrive at all parts of '
work.
Under ordinary circumstances it is certainly \>< >t that the
eunature ot tin- tile ami work should agree ; as possi!
but it is obvious that the file it' more eoiiu \ than the work, can
only toueli the latter at one part, as at a, fig 88(5, whereas, if
the file is less convex, or flatter, than the work, it will act at •
places, as at b b, fig. 887. The Sheffield cutlers, in filing out
the bows of scissors, and which they do with great rapidity,
always avail themselves of this circumstance, and until nearly
the conclusion, use files flatter or less convex than the work.
In filing concave works, there is but little choice of po-
as the file is always parallel with the axis of the curve, a* in the
dotted line in fig. 88S, but in convex works such as fig. 889, the
file may be applied either parallel with the axis as at p p, or
transversely thereto as at / /. In general however the work
would be fixed obliquely as in fig. 890, and the iile would be iir>t
Fig*. 888.
used transversely for some one or two strokes, at an inclination
of about 30 degrees with the horizontal line, as at a, so as nearly
to agree with the straight side of the object, the file would be
successively raised to the horizontal, and depressed in the same
degree on the other side, in fact proceeding through the positions
a be, fig. 890, at some eight or ten intenals, and which would
1 to make as many insignificant ridges upon the work. The
ridges would be then melted together by swinging the hands
from the position a to c in every stroke, to be repeated a few
times; but as the entire semicircle could not be embraced at
one stroke, the work would be re-fixed in two or more positions,
so as the operation into about three stages.
A more exact although less energetic method would be to
place the file parallel with the axis as on p p, fig. 889, and to
sweep round the curve principally by t ing motion of the
>t, which joint can be more readily moved, and also with less
888 THE THREE DIFFERENT MODES,
fatigue, than the two hands conjointly. A third mode, frequently
adopted in such small pieces as can be held upon the filing-block
•with the hand-vice, is to swing the work upon its axis, and to
use the file with the right hand, as if on a flat surface, a mode
explained in fig. 858, page 862.
Some works are curvilinear in both directions, such as curved
arms and levers with rounded edges ; many of these kinds are
completed by draw-filing them, or rubbing the file sideways or later-
ally around the curve, instead of longitudinally as usual ; but the
changes consequent thereupon do not require any especial notice.
The success of all the modes of filing curved works, will be
found very much to depend on the freedom with which the several
twisting and excursive motions of the hands are performed, and
the work should be frequently examined, in order that the eye
may judge of the parts in excess and that require to be reduced,
in order to produce a pleasing outline.
Having considered the general manipulation of the file in
respect to curved works, it remains to be noticed that curvilinear
objects are filed up in different modes, dependent on their
respective forms and characters. Thus the great majority of
curved works are moulded and formed prior to the application
of the file, which is then principally used to smooth and brighten
them — other works are shaped almost entirely with the file,
assisted by outlines drawn on the pieces themselves — and again
other works are shaped with the file, under the guidance of tem-
plets or pattern-plates of hardened steel. Some observations
will be offered on all three of these modes.
Firstly, curved works that are moulded or formed prior to the
application of the file. — The methods employed in the prepara-
tion and figuration of materials into curvilinear and other forms,
by founding and forging, have been largely considered in the
first volume, and from which remarks it will have been seen, that
the perfection of cast works greatly depends on the perfection of
the foundry models or patterns, and these latter greatly depend
on the facilities offered in pattern-making by the turning-lathe,
and the joiner's planes ; and although such castings in many
cases do not admit of being finished in the* lathe, the per-
fection of the pattern is a great source of embellishment and
economy, in the configuration of the works made by moulding
and casting.
or rn
tiling up metal works that have been accurately
shaped by founding or forging, little or nothing n > be
added to tin- remarks on the last page, as the only object is to
act < part of curvilinear surfaces in the most expeditious
and commodious manner, with the general aim of reducing any
trilling errors of form that may already exist in them, and av<
ing the introduction of new ones; which circumstances call for
the frequent scrutiny of the eye, and an incessant yet judicious
variation in the position of the hands.
Secondly, curved works that are moulded or formed almost
entirely with the file. — These are blocked out square, and the
outlines of the curves are drawn on the ends and sides of tin-
pieces, to guide the file in a manner analogous to the routine
pursued by carpenters, masons, and other artizans. For instance,
to form a bead, as in fig. 891, the work is prepared of a nearly
rectangular form, and the half-circle having been drawn at each
end, the angles of the works are coarsely removed at about 45
892.
893.
degrees, making the end a semi-octagon ; sometimes the four
angles are farther reduced, giving to the work eight facets, prior
to their being thrown together in making the general curve. If
these sides are made with only a very moderate degree of exact-
ness, they \\ill greatly tend to preserve the uniformity of section
throughout.
Many workmen when they have removed the two principal
angles at 15 degrees, will make a chamfer entirely around the
semicircle at each end, to guide the file in hastily reducing the
principal bulk of the material, until the chamfers are nearly
obliterated, after which the curve is f'mishrd, in exact agreement
with the lines, with a smooth file. It is also desirable that the
straight-edge should be frequently applied along the axis of the
curve, at various parts, during the progress of the work.
Should the entire piece, fig. 892, have to be made from a solid
890 FILING WORKS, BY AID OF
block, two cuts a and b, made with the saw, would remove the
corner, and a little filing would then suffice to complete the
internal angle. The round part of the bead would be made as
before, and previous to filing the hollow, it would be chamfered
on the line c ; a half round file, of less curvature than the hollow
itself, would be first sunk in the middle of the chamfer, and the
hollow would be deepened and extended sideways, always main-
taining an easy curve, until it reached the marginal lines where
the hollow meets the plane surfaces. This mode is better cal-
culated to avoid the accidental obliteration of the angles of the
work, than if the file were sunk at each margin.
"Where hollows run on to right lines as at a, fig. 893, there is
some risk of making a break in the junction, either from the curve
sinking below the right line, as at b, or from the straight line,
as at c, advancing too far and breaking in upon the curve. On
this account a break or fillet is usually made at the part as at d,
or else it is usual primarily to give that form, by filing the flat
first, and then sinking down the hollow just to meet it, and at
the conclusion letting the half-round file run a little way on to
the right line. Some however prefer the opposite course, or that
of sinking the hollow to its full depth, and then filing down the
remainder with the flat file, but which mode is certainly attended
with more risk.
Thirdly, curved works that are shaped with the file under the
guidance of templets or pattern-plates of hardened steel. — This
mode is much followed in works of two principal kinds, namely,
thin works required in great numbers and precisely of one
form, and in a variety of works that require to be exactly
circular, although they may not admit of being so fashioned
in the lathe.
Many thin works of the first kind are stamped or punched out
of the sheet-metals, as for instance the washers for machinery,
the links of jointed chains, steel pens, parts of locks for joinery,
and numerous other thin works; but many objects of larger
kinds, and that are not wanted in such large numbers, are not
stamped, but are either cast, or cut out with the shears, and after-
wards filed between templets. Instances of such works are occa-
sionally met with in the numerous class of machines for spinning
and weaving, cotton, silk and wool, and also in lace and stocking
machinery. The mathematical instrument makers likewise
TBMPLBTS OF HARDENED MTKKI.. ^'.*\
•rut in works th.v
uail-uhecl of a .striking clock, fig. 894, is frequently thus
formed, by menus of a tempi, t : it has an i . n twelve
steps, arranged spirally, the j of wliieli <1. • the
iiuiuber of strokes of the hammer on the bell. In this case,
which will serve as a general example, a piece of shect-sto
cutout, ll:ittruc<l.. -ind smoothed on one side, to receive the drawing
of the snsiil-wheel, and a second piece is also prepared. The two
tirst drilled together with a central hole, and another hole as
iit from the center as admissible. The two plates arc then
united by two pins, and the outline of the work having been
drawn on one of them, they are next filed in steps carefully t<>
the lines, and square across the edges, and they are afterwards
hardened and slightly tempered to lessen their liability to fracture
on beiiii: pinched in the vice. The dozen or more snail-wheels
having been cast, or cut out of sheet-brass, and flattened with the
hammer, two or three at a time are pinched alongside one of the
;ilets, whilst the two pin-holes are made with the breast-drill
or in the lathe, with a drill that exactly fits the holes in the
templets. It only remains to place the dozen plates between the
t- in plets, keeping them in position by two pins extending through
the whole number, and then all the notches are filed in the brass
plates, until the file very nearly touches the steel patterns, as
abolute abrasion on the steel itself would greatly injure the files.
In this mode the several brass plates become very exact copies of
the pattern.*
A different application of templets is sometimes met with in
filing up numerous similar parts in the same object, as the arms
or crosses for the wheels of clocks and other machines. The exact
* Templets are M much used for setting out and producing aeries of holes in
any special arrangement, as in filing works to any particular form : the most
complex example of the kind that occurs at the moment to the author, of templets
being used in this manner, is in drilling the aide-plates of harps intended for the
arbors and link-works, used in temporarily shortening the strings. The rsspeotire
positions of the holes in these side-plates require a most exact arrangement, any
departure from which, would prevent that precise shortening of the string re-
quired to produce the semitones with critical accuracy, and would also cause an
unbearable jar, unless the cranks of the harp were severally in true position, <>r
on the lines of centers, so as firmly to support the tension of the strings under all
circumstances.
892
FILING WORKS, BY AID OF
pattern of one spoke is filed up as a templet, which is shaded in
fig. 895, and serves for the similar configuration of every spoke;
the position of the templet being given by a central pin, aided by
any little contrivance which catches into the 3, 4, 5, or 6 equi-dis-
tant teeth corresponding with the number of arms. Many other
equally available cases of the use of templets might be cited, but
we must now proceed to works of the second kind, or those of
an outline partially circular.
It frequently happens that certain forged, cast and other
works have parts, known as bosses, swells, collars and knuckles,
that are pierced with holes, which require their flat surfaces and
also their margins to be made partially or entirely concentric
with the holes. When such parts occur as bosses, they often
Figs. 894.
895.
896.
project from a flat surface, and after the central hole is drilled,
some of the pin-drills drawn on page 550, or analogous tools
used in drilling machines, are employed in finishing the margins :
thus figs. 482 and 484 serve for facing the extremities of the holes,
483 and 485 for the external faces of cylindrical bosses or collars,
used in the guidance of arms jointed concentrically with the
holes, and figured cutters 485 serve for bosses with mouldings
intended for ornament.
When the circular margins are discontinuous, files and tem-
plets are more or less required : thus the extremity of a forged
arm, such as fig. 896, is drilled, and in the configuration of the
remaining parts, if but one or two such pieces are to be made,
a boss or plug of wood is turned like a, that shall fit the hole ; the
shoulder of the wood is then rubbed with red chalk to mark that
part of the surface which is not at right angles to the hole, and
the circular edge of the boss serves for the guidance of the file in
finishing the exterior margin ; visually rather than obstructively,
as the wooden boss would be reduced instead of the file being
TBUPLBT8, ETC. COMPASS JOINTS.
Led. If then fore many such objects had to be filed, two
bosses or templets would be made of hardened steel, and n-..l
one at each extremity of the hole, and they would be held in
position by grasping the three pieces collectively in the tail
. The same general method is very largely and more
rigorously followed in making joints or hinges, of which three
examples will be quoted in conclusion of this section.
The brass and steel plates fig. 897, used for the joints of car-
penters' rules are filed up to templets in all respects after the
manner described in reference to the snail-wheel, fig. 89 i, and
the joint-plates arc inlaid by means of the file, saw, chisel, and
plane, by modes that do not require to be noticed.
The joints of drawing-compasses are made somewhat differ-
ently, and mostly as follows. The solid knuckle a, fig. 898, i^first
$98.
drilled and made circular by aid of a templet r, and the hollow
side b is filed to correspond exactly with a; the two arc then
pinched together in the vice on the line d d, and the parallel
notches for the steel joint-plates are made in each with the saw
fig. 712, page 729, as deep as the line e e. The parts a and b arc
then separated, the notches in b, are completed with the frame-
saw, and the bottom of the notches in a, are rendered circular
with the joint-saw, fig. 713, as there explained. The middle
plates, when filed a little larger than the templets c, are inserted
in ft, and soldered in their places; the two parts are smoothed
on their various internal surfaces, and united by a temporary
joint-pin, and any little invpilaritie.s in the external or cir-
cular curves, (which are left purposely a trifle too large,) arc
mutually detected by their want of agreement when the joint is
894
CONSTRUCTING HINGES AND JOINTS,
opened to different distances ; any parts in excess are very care-
fully reduced with a small smooth file, principally by draw-filing,
after which the screw-pin with its brass cheeks or bosses is
added.
The pin-drill, fig. 475, p. 547, is commonly used for cutting out
the concave parts that extend to the side of small compass-joints,
such as are represented in fig. 899, and also for inlaying the
heads of small countersunk screws.
Larger joints with wider knuckles, such as fig. 900, are in
many instances cast from patterns closely resembling the finished
works. In such cases the first process is generally to remove
any little external errors with the file, and to clear the angles
with a small chipping chisel ; the faces of the knuckles are then
smoothed and inserted within one another very tightly. The
joint-hole is afterwards drilled throughout all the knuckles, and
which are filed up externally, sometimes under the guidance of
templets put at the ends, but principally by the reduction of
those high parts which get scratched or rubbed by the opposite
parts, and thereby show their excess of height.
But if such joints are required to be made more accurately,
the holes are first drilled in each piece separately, and rather too
close in the corners; the holes are broached with a parallel
broach, so as exactly to admit a steel cylinder, fig. 901, which has
a square end for the brace ; this rod is intended to receive the
cutters, shown on a larger scale in fig. 902, which are cylin-
drical pieces of steel bored to fit the rod, and cut with teeth on
the outer cylindrical part and on one flat surface; a pin is inserted
through both the cutter andbar,sothat thetwo may be united after
they have been placed within the joint to be worked ; sometimes
the back face of the cutter has only a diametrical notch to receive
u M I ilI.f.M. ASSISTED OY OTHER TOOLS.
driving-pin, which pmhes the cutter before it as it revolves.
A recess must first be cleared for the rut NT with a chisel and
hammer, or by A wide-joint saw or cutter, such as fig. 713 ; and
the hollowed parts at a a fig. 900, are then cut throughout
their length with the cutter, that afterwards serves to flatten
the faces of the knuckles in exact parallelism throughout, and at
right angles to the central hole.
The two halves of the joint, having been separately hollowed,
and faced until the knuckles will penetrate some distance into
another, the external parts of the joint are next separately
tiled under the guidance of hard steel rings, or templets, of the
same diameter as the cutter, and placed on the cylindrical rod ;
after which, the two parts of the joint are put together when yet
slightly too large, and the central pin is inserted, in order that
the rubbing of the knuckles against the corresponding hollows
may denote the parts that are still too high or full; and by
cautiously removing all the parts that are abraded, the joints may
be made to fit very closely and accurately, and yet to move with
great smoothness.
Many joints that are at the same time wide and small, as in
hinged snuff-boxes, could not be drilled, as above described, with
safety, and are therefore made quite differently, by means of
small tube, called joint-wire, the mode of drawing which was
explained in vol. i., page 429.
For instance, in making a snuff-box, the rims for the top and
bottom are fitted and jointed together before the top and bottom
plates are soldered in, and the joint is thus constructed. Sup-
poking that five knuckles arc required for the bottom, and four
for the top, the nine pieces of joint-wire are cut off, and filed
square at the ends ; the rims for the top and bottom having been
fitted so as to form the rebate, are placed together, and carefully
filed out with a semicircular recess or groove, by means of a
parallel round file, or a joint-file, exactly of the diameter of the
joint-wire, which therefore leaves a hollow equal to the fourth
part of the circle in each rim.
of the joint-pieces are then strung on a wire, inserted in
the hollow of the rim for the bottom of the box, and tied therein
with tine binding-win tervals between these five knuckles
regulated by inserting the other four between them for the
moment, while the binding-wire is being fastened; after which
896 COMPARISON BETWEEN THE FILE,
this first series of knuckles is soldered in with moderately hard
silver solder, which is usually fused with the blow-pipe. The lid
is then treated in the same manner, and the bottom part of the
box now serves as the gage for regulating the distance between
the knuckles in the top rim. The same plan is also used by
mathematical instrument makers and others, who however more
generally turn the joint-pieces in the lathe, as the draw- bench
forms no part of their ordinary supply of tools ; and the wide
joint-pieces or knuckles in mathematical works are usually larger
than could be produced in that manner.
SECT. VIII. COMPARATIVE SKETCH OF THE APPLICATIONS OF THE
FILE, AND OF THE ENGINEER'S PLANING-MACHINE, ETC.
The general aim of this present section, is to show, by way
of contrast, how several of the pieces advanced as illustrations
of works executed with files, in sections iv. to vn. are produced
by the planing-machine and analogous contrivances.
The comparison of the modes of producing flat and rectilinear
works with the file and with the planing-machine, is greatly
in favour of the latter method, in respect to facility, expedition,
and accuracy ; and the modes are besides entirely different.
For instance, the laborious and tedious mode of filing a flat
surface has been spoken of at some length, and it will be
remembered the work is fixed, and the tool is moved in a variety
of directions upon the surface to be filed.
So far as the action of the smith's hand-plane for metal, (page
483,) and carpenters' planes may be brought into comparison,
they are used in many respects as the files, but are applied
generally parallel with the one side of the superficies that is
being wrought.
But the engineer's mode of planing works in metal is entirely
different from either of the above, and is strictly analogous to the
mode of turning works in the lathe with a slide rest, if we
consider the axial motion of the lathe to be replaced by the
rectilinear motion of the planing-machine, as was briefly explained
in general terras in the introductory chapter to the present
volume, more particularly in reference to the " guide principle,"
see pages 468 and 469.
The work to be planed, is there briefly described as fixed on a
\M> NIK ENGINEER'S PLANING MACHINE.
carriage or sledge, that is made to move to and fro in a true
t line, a* upon a \ery accurate railway; whilst the cutting-
which is i those used in the turning-lathe was
supposed to he affixed to a bridge, standing across and at ri»ht
angles to the railway. Such a fixed tool would plough a furrow
in the work, \\hich furrow would be accurately straight as the
railway or guide from which the work itself received its direct
of motion.
If the reader will only conceive the work to be continually
moved to and fro upon the slide or railway, a distance equal to
its own length ; and that by a subsidiary contrivance, or another
slide placed horizontally, the tool between each reciprocation of
the work were moved a small distance to the right continually, a
series of grooves would be ploughed, all individually right lines;
and these grooves would shave off all the asperities and irregu-
larities of the work, leaving it finely grooved in parallel furrows.
Or provided the end of the tool were flat, and ever so little
broader than the small interval between the successive strokes,
the tool would leave a plane or smooth surface ; and the per-
fection of this surface would mainly depend, on the railway or
the cutting-slide, and the horizontal or position-slide, being
each truly rectilinear.
Supposing now, by means of a third slide placed exactly
perpendicular, the tool were depressed the tenth of an inch, and
the process were entirely repeated, the surface would be reduced
with perfect uniformity, one-tenth of an inch all over, and the
new surface would be mathematically parallel with that existing
immediately previous. Pursuing this idea, let it be further
supposed that the surface just planed is the upper surface of the
carriage or sledge of the plauing-machiue, technically known as
the bed or /<////<-, upon which the work that is to be planed is
fixed by screw-bolts and clamps.
It will now be shown how the piece represented by A, B, C,
in fig. 868, page 879, would be treated in the planiug-machine,
in order to make its sides strictly parallel, in pairs, ami also at
right angles to each other, in short, to convert it into a true
parallelopipedon.
The side A, of the piece, would be first placed uppermost and
correctly planed ; afterwards the side A would be inverted, and
placed on the bed of the machine, care being taken that no
:', M
898 COMPARISON BETWEEN THE FILE
shavings intervened to prevent their coming into absolute con-
tact ; and the second face, or a, would be planed strictly parallel
with A, and that without any especial care on the part of the
operator.
Next, to plane the edge B, it would be necessary the third
slide of the planing-niachine should be placed truly vertical,
and that between each reciprocation of the bed of the planing-
machine on its railway, the tool should be depressed a small
quantity by the vertical slide, so as in the end to make it slowly
descend, by intermittent steps, down a vertical and right line,
exactly equal to the perpendicular height of the side B.
All things now remaining fixed as before, if the tool were
traversed horizontally until it touched the second edge or b, this
edge of the work would, on pursuing the same gradual depres-
sion of the tool, be planed also vertical and in strict parallelism
with its opposite, or B.
Continuing the same order of work as in the hand process,
the ends C, c, would require the work to be released from the
bed of the machine, shifted just 90 degrees, and then refixed,
when the ends C, c, would be treated exactly as B, b, had pre-
viously been, and would thence be made parallel and square.
In some instances, indeed, the analogy to the railway is strictly
maintained for a farther stage of the work, as such a piece as
A, B, C, fig. 868, would sometimes be mounted, as it were, upon
one of the turn-plates by which the railway-carriage is twisted
one quarter round, preparatory to moving it from off the prin-
cipal to an adjoining line. In the planing-machine, the turn-
plate on which the work is fixed, is a supplementary circular
bed having a horizontal or azimuth motion, so that by leaving
the tool unaltered, except in its vertical path, the several edges
of any regular polygon, whether a square plate, or a triangle,
pentagon, hexagon, &c., may be planed with strict accuracy.
The sides of any irregular polygon, may be also planed, by
moving the tool so much on the transverse or horizontal slide,
as the differences in the radial distances of the sides of the
unequal polygon from the center of the turn-plate.
Supposing the piece ABC, fig. 868, to be bevelled or chamfered
on one or all of its edges, the slide which had been previously
fixed in the vertical line, or perpendicularly, would be inclined
tine precise number of degrees required, so as to produce the
TIU: r.N(i INKER'S PLANING M.\< H:
chamfered edge with as much facility as the qqunrc or vertical
more convenient course in small and long works of
sections resembling figs. 871 to 874, is to place upon the bed of
the i l.ming-machine two headstocks or lathe-head*, the one
furnished with a dividing-plate, and so arranged that the axis
of the headstock is strictly parallel with the path of the railway
or main-slide of the planing-machinc. In this case the planing-
tool is almost always made to traverse horizontally, and which
indeed is the most generally convenient. The triangular prism
fig. 874 would be planed with great facility and truth by placing
it in three successive positions, one-third of the circle or 12<)
degrees asunder, by means of the dividing-plate; and if the axis
of the headstocks were inclined vertically, a triangular pyramid
or wedge, instead of a triangular prism, would be produced.
The headstocks, if horizontal and shifted four times, or ninety
degrees each time, would plane square or rectangular prisms, and
of course also the rectangular faces of the pieces, 871, 872, and
873 ; and again if instead of constantly shifting the headstocks
ninety degrees, as for the rectangular parts, the changes were
thirty, forty-five, or sixty degrees, according to the angles respec-
tively required in the objects represented, the bevilled or chain -
d edges would be obtained with great facility and accuracy.
The planing- machine almost entirely prevents the necessity
for building up work in a dissected state, as in the figures 877,
and 878, as such grooves may be sunk, and any fillets may In-
planed, upon the upper surfaces of works, the vertical or lateral
surfaces, and even the lower or inferior surfaces, by bending tin-
tools into appropriate forms, so as to reach into the parts, after
tin- manner of fig. 439, page 534; as such contortions of the
instruments do not in any respect interfere with the paths of
the slides in which the tools are fixed and guided.
And consequently, many parts of machinery that if worked by
hand would be very difficult of access, and also very difficult of
proof in respect to their accuracy, are accompli>hed in the planing-
111:11 l:in< \M-h a degree of facility most satisfactory to the mind,
as regards their abstract truth and the parallelism of their various
pars. h'>\\i-ver strangely situated, and also most satisfactory, as
regards the relative economy of the method ; indeed the plauiug-
machine may be truly considered to have cil\ cted a most enor-
3 M 2
900 COMPARISON BETAVEEX THE FILE
mous and beneficial revolution in the art of metallic construction
generally.
The key-grooves in wheels, for the keys or wedges by which
they are attached to their shafts, when made by machinery, are
cut out by a modification of the planing-machine invented by
Mr. Richard Roberts, of Manchester ; it is designated the key-
groove engine, and may be presumed to have been derived from
the inortising-engines in Brunei's block-machinery (ante, 505-6).
The cutter used in the key-groove engine resembles a strong
mortise-chisel, and is reciprocated in a vertical line by means of
a crank or excentric, whilst the wheel to be grooved is placed
horizontally on a slide, and traversed towards the cutter until it
has entered to the required depth. To make the groove taper
to the same angle as the key or wedge, the slide is tilted some
one or two degrees ; and if two or three key-ways are wanted
instead of one only, then the wheel is mounted on a species of
turn-plate with notches cut on its edge, by means of which the
grooves are placed at exactly equal distances, as in planing
squares, hexagons, &c.
An offspring of the key-groove engine, called the paring or
slotting -machine, is also commonly used to fulfil many of tbe
works hitherto performed with the file. The tool of the slotting-
machine resembles in all respects that used in cutting key-ways,
but the slotting-machine has two horizontal slides at right angles
to each other, and a circular adjustment or turn-plate, all three
used in shifting the position of the work beneath the cutter, and
all three fitted with apparatus for mechanically feeding the cut,
as it is technically called, or for moving the respective slides a
minute quantity between every stroke of the reciprocating cutter,
thus making the machine self-acting.
In such a slotting and paring-machine, the piece, fig. 879, on
page 882, could be produced without the intervention of filing.
The central hole d, and the holes at the one extremity of each
mortise * *, and c c, would be first drilled ; the work would be
guided by a pin in the center of the turn-plate, fitted into the
center hole d. The hole * would be elongated into the straight
mortise by a chisel of the same width, the work being traversed
beneath it by one of the straight slides. The other hole c, would
be elongated into the circular mortise by the gradual adjustment
\M> LINKER'S MI \ri\o MACHINES. '.'"1
of tin- turn-plate, which would awing the work round on it*
'/. The turn- plate moving on //, would also serve for paring
Iges parallel with the circular mortise, and the
slides would enable the exterior straight lines of the
work to be pared.
i the small semicircles around the ends of the circular
mortise, in fig. 879, might be shaped, if before the formation of
tins mortise, the piece were chucked with c, c, successively in
the center of the turn-plate ; or a clever workman, by moving
the two slides by hand, or independently of the self-acting 1<
would follow any such outline with tolerable regularity; remov-
ing the bulk of the metal, and leaving the parts square on the
•, and pretty nearly perfect in form, so that a little filing
would complete them satisfactorily ; and thus, by the manual
adjustment of the slides, many irregular curves are pared out,
to any particular outline previously drawn on the work, by that
method which the mathematician would perhaps call the method
of double ordinates.
Another modification of the planing-machinc, called the
shaping-machine, and which may be considered to have grown
out of the paring-machine last alluded to, is much used in cor-
recting the forms of the circular and other parts of large works
of the character of figures 897 to 900, pages 893, 894. In
such works, the central hole is first bored out ; the object is
then chucked on a spindle, or arbor, which may be almost con-
sidered as the mandrel of a turning-lathe ; the tool is i
traversed above the work, and in a line parallel with the axis
of the mandrel, whilst, at every stroke, the mandrel is slightly
moved on its axis ; so that, in the end, the whole of the circular
arc is accurately shaped.
These shaping-machines have also generally two rectilinear
slides, at right angles both to each other aud to the axis of the
mandrel, either of which, or the revolving arbor, can be set to
feed itself; so that, by a little dexterity of manipulation, all the
edges of a piece, such as fig. 897, could be shaped, even including
the hollow, as the cutting-tool is placed at the end of an arm, or
radius, of some three to six inches, so as to be applicable to the
cutting of inverted arcs.
In this manner, with the preparatory aid of the turning-
902
COMPARISON BETWEEN THE FILE
lathe, every part of the cross head, figs. 903 and 904, may be
wrought mechanically. The work is first chucked in the lathe
between centers on the line a a, whilst the whole of the contour
in the side view, fig. 903, is turned, and also the bearings e e ;
it is then fixed transversely on the face-chuck of the lathe to
bore out the center hole b b for the piston-rod, and to turn the
central flat surface. After this the lines seen in the plan,
fig. 904, may be completed in the shaping or paring-engine ; the
central convex part, by the twisting of the work on the general
Fig. 903. b
center; the concave parts by the twisting of the tool on the
centers c c ; and the straight parts, by the movement of the
horizontal slides ; and these several changes may be so nicely
managed as to render the joinings of the several lines scarcely
distinguishable.
The method followed in making such works is not always as
above described, as in many such pieces, especially in those of
large size, the planing-machine is brought into requisition, and
sometimes also boring machinery, by which likewise the hollows
c c may be shaped out. The artist has altogether omitted the
transverse mortise, for the key which fixes the piston-rod, and
which mortise is made in the key- way or paring-engine, leaving,
ia fact, nothing to be accomplished by hand-labour.
Many of the varieties of machines for planing and shaping
metal works with a single pointed tool, and various other
machines of similar effect, in which circular cutters are used,
might be here noticed, and in which numerous machines, objects
that were formerly always shaped by filing, are now worked by
<MNEER'> o \i\«ni 901
machinery ; Imt it is hoped enough has been shown to sat
reader that almost any solid with plane or circular surfaces, how-
nuruerous or combined, and also many irregular or arbitrary
surfaces arc, in the present day, most effectively produced by
means strictly n 1. Hut it will be borne in mind, that
the detailed investigation of these matters appertains mor<
to the proposed fifth volume, to be devoted to the " Principles and
Practices of Mechanical Engineering," and in which it is pro-
i this trilling sketch should be filled up and elaborated.
The author cannot, however, conclude this chapter on files,
their applications, and certain relative topics, without adverting
to the revolution as regards filing, consequent on the introduc-
tion of the planing-machiue and its descendants : a revolution
more especially felt in regard to the larger classes of machinery.
The obvious effect, of the large and economic accession of
engineers' tools which act by cutting, has been to lessen in a
proportionate degree, the employment of files and of mauual
processes generally, amongst engineers and those occupied in
the construction of large machinery. It necessarily follows as a
result, that amongst such artizaus the practice of filing, from
being less required, is far less generally learned by the present
raee of workmen ; and, consequently, many of the latter, when
deprived of tfye refined machinery of the workshop, and thrown
upon their own handicraft or manual efforts with the simpler and
earlier tools, are certainly less skilful than their predecessors.
The art of filing is, however, still largely employed, and will
probably continue to be fostered as much as ever amongst arti-
zaus who work on smaller objects, and those to which machinery
of the kind referred to, is less applicable than the til> and its
more simple congeuitors, by means of which alone, when em-
ployed with skilful manipulation, highly elaborate and accurate
works have been and may still be produced, although in many
instances, at a greater cost.
In justice to the file it is also right to state, that in many cases
it is indispensable that works produced in the planing and other
machines, should be iini.shed and adjusted by means of smooth
files ; and further, that the machines referred to are unavailable
in many small works, which can only be produced by individuals
who have been long and delicately skilled in the use of the file.
904
CHAPTER XXIX.— SHEARS.
SECT. i. — INTRODUCTION; CUTTING NIPPERS FOR WIRES.
SHEARS are instruments of a character quite different from
any of those hitherto described, as the cutting edges of shearing
tools are always used in pairs, and on opposite sides of the
material to be sheared or severed. In many cases the shears
are constructed after the manner of pincers and pliers, or as two
double-ended levers united at the fulcrum by a pin, but other
modes of uniting the two cutting parts of the instruments are
also employed, as will be shown.
The general form and position of the cutting blades of shears,
was adverted to in the elementary diagram fig. 316, at the begin-
ning of this volume, and the sec-
tions of some varieties of this
instrument are represented by a,
b, c, of the annexed fig. 905, from
Fig. 905.
which it will be seen that the edges
of shears and scissors meet in
lateral contact, and pass close against
one another, severing the material
by two cuts, or indentations, or thrusts, which take place in the
same plane as that in which the blades are situated and are
moved.
Some of the largest shearing tools of the kinds used by engi-
neers, such as c, serve to divide bars of iron, 4, 5, or 6 inches
wide, and 1 to 2 inches thick, then requiring the greatest pos-
sible solidity and freedom from elasticity.
On the other hand some of the finest scissors of the section a,
such as are used by ladies in cutting lace, will cut with the greatest
cleanness and perfection, the most flexible thread or tissue of
threads, or the finest membranes met with in animal or vegetable
structures. But this latter kind of shears, unlike the engineer's
shears, is altogether useless unless possessed of a considerable
slmre of elasticity, to keep their edges in accurate contact at
that point in which the blades at the moment cross each other,
PLIERS. '.HI;,
as will be explained, otherwise such thin materials arc f<>l<lr<l
down between the blades instead of being fairly cut. The tran-
u from tlu . l:i-tic to the inelastic kinds of shears is not, as
may be supposed, by one defined step, but by gradual stages,
making it as difficult in this, as in other classifications, to adopt
any precise line of demarcation.
In addition to the above, or to shears properly so considered,
there are a few tools known as cutting pliers or nippers, in
which the blades meet in direct opposition, but do not pass each
other as in the legitimate kinds of shears; this kind is represented
by the section d, fig. 905, and it is proposed to consider these
several tools as nearly as may be under four heads, namely, —
Sect. I. Cutting nippers for wires.
„ II. Scissors and shears for soft flexible materials.
III. Shears for metal, worked by manual power.
„ IV,, Engineer's shearing tools, generally worked by
steam power.
Cutting pliers, if they admit of being classed with shears, are
certainly the most simple of the group, and are used for cutting
asunder, small wires, nails, and a few other substances. Their
edges are simply opposed wedges, exactly as shown in the above
diagram at d; and as respects the remainder of the instruments
by which their wedges are compressed, the most simple kind
exactly resembles carpenters' ordinary pincers for drawing out
nails, except that the cutting pincers are made with thinner
edges ; and figs. 906 to 909, overleaf, represent different kinds of
cutting pliers and nippers.
When cutting nippers are compressed upon a nail or a piece
of wire, they first indent it on opposite sides, and when from
their penetration, the surfaces of the wedges exert a lateral
pressure against the material, the latter eventually yields, and is
torn asunder at the moment the pressure exerted by the wedges
exceeds the cohesive strength of the central metal yet uncut.
Consequently the divided wire shows two bevilled surfaces,
terminating in a ridge, slightly torn and ragged. The quantity of
the material thus torn instead of being cut, will be the less, the
softer the metal and the keener the pliers, but experience shows
an angle of about 30 to 40 degrees to be the most economical for
the edges of such tools.
906
CUTTING PLIERS.
Little remains to be said on the varieties of cutting pliers ;
most of these used by general artizans and clockmakers, are
smaller than carpenters' pincers, and the extremities of the jaws
are bevilled as in watch-nippers, fig. 906, that they may cut pins
Kg* '•' ";-
907.
006.
909.
lying upon a flat surface. Other cutting pliers called side-nippers
are oblique as in fig. 907 ; those used for the dressing-case, and
known as nail-nippers, are concave on the edge to pare the nails
convex ; and another kind known as nipper-pliers, bell-hangers or
bottler3 s-pliers,h&ve flat points at the end for grasping and twisting
wires, and cutters on the sides for removing the waste ends, as
shown in fig. 908.
Surgeons also employ cutting nippers, for dividing small bones,
such as those of the fingers and toes, and for removing splintered
and dead portions of bone. They assume the forms already
explained, and also some others as will be seen on consulting
the work before quoted in the foot note, pages 801, 2, namely,
Seeriff's Armamentarium.
The edges of cutting nippers are apt to be notched, if used
upon hard wires, or if wriggled whilst the cutting edges are
buried in the wire, and they scarcely admit of being reground or
repaired. This inconvenience led to a modification of the
instrument fig. 909, by the enlargement of the extremities, to
admit of loose cutters fitted in shallow grooves being affixed by
one screw in each, as shown detached at c, so that the cutters
may admit of removal and restoration by grinding, which
end is effectually obtained although somewhat to the prejudice of
the instrument, by increasing its bulk.*
* H. Bursill, a youth ouly 12 years old, was rewarded for this contrivance by the
Society of Art* in 1845.
SCISSORS AND SUE A US. > >7
SECT. II. — SCISSORS AND SHEARS FOR COPT FLEXIBLE
MATERIALS.
scissors and shears to be described in this and the suc-
ceeding section, act on a very ilifl'ereut principle Ircmi the nippers
recently spoken of. The nippers have edges of about 30 to 40
degrees, meeting in direct opposition, but yet leave ragged edges
<>n the work; whereas the shears have edges commonly of 90
degrees, seldom less than 60 degrees, these edges pass each other
and leave the work remarkably keen and exact.
Let the edges of scissors be ever so well sharpened, they act
y imperfectly, if at all, unless the blades arc in close contact
at the time of passing ; and this imperfection is the more sen-
sible the thinner and more flexible the material to be cut, as it
will then fold down between the blades if they do not come
in contact. Whereas when the blades exactly meet, the one
serves to support the material whilst the other severs it ; or
rather this action is reciprocal, and each blade supports the
material for the other, fulfilling the office of a counter-support,
or of the bench, stool or cutting-board, used by the carpenter
with the paring chisel.
On a cursory inspection of a pair of ordinary scissors, it may
be supposed that their blades are made quite flat on their faces, or
with truly plane surfaces like the diagram fig. 910 overleaf, repre-
senting the imaginary longitudinal section of the instrument,
the two blades of which are united by a screw, consisting of
three parts differing in diameter, namely the head, the neck, and
the thread ; the bottom of the countersink that receives the
head of the screw is called the shelf or the twitter-bit. If how-
ever the insides of scissors were made flat, and as carefully as
possible, they could scarcely be made to cut slender fibrous
materials, or if at nil, then for only a short period, and additional
friction would accrue from the rubbing of their surfaces.
The form which is really adopted, more resembles the exag-
gerated diagram fig. 911 ; the blades are each sloped some 2 or 3
degrees from the plane in which they move, so that their edges
alone come into contact ; instead of the blades being straight in
their length they are a little curved so as to overlap ; and close
behind the screw -pin by which they are united, there is a little
triangular elevation, insignificant in size but most important in
(. -licet, which may be considered as a miniature hillock or ridge,
908 PRINCIPLE AND CONSTRUCTION OF SCISSORS.
sloping away to the general surface near the hole for the screw.
This enlargement or bulge is technically called the "riding part,"
and as there is one on each blade, when the scissors are opened
or that the blades are at right angles, the points or extremities
only of the riding parts come into contact, and the joints may
then have lateral shake without any prejudice. But as the
blades are closed, first the bases or points of the riding parts, and
lastly the summits or tops, rub against each other, and tilt the
blades beyond the central line of the instrument ; the effect of
which is, to keep the successive portions of the two edges in con-
tact throughout the length of the cut, as by the time the scissors
are closed, the points of the blades are each sprung back to the
central line of the scissors, which is dotted in the diagram.
Although scissors when in perfect condition for work, may be
loose or shake on the joint when fully opened, (and thereby
placed beyond their range of action,) they will be always found
Figs.
to be tight and free from shake, as soon as the blades can begin
to cut the material near the joint, and so to continue tight until
they meet at the points. That all scissors do exhibit this con-
struction may be easily seen, as when they are closed and held
edgeways, between the eye and the light, they will be found
only to touch at the points and at the riding parts, or those just
behind the joint screw, the remainder being more or less open
and gently curved; and their elastic action will also be expe-
rienced by the touch, as whilst good scissors are being closed,
there is a smoothness of contact which seems to give evidence of
some measure of elasticity.
Fig. 912, represents the section of the one blade of a pair of
scissors registered in July 184-1, by Mr. G. Wilkinson, of Shef-
field, and in which the elastic principle is differently introduced.
These scissors are made without the riding part, but instead
thereof, immediately behind the screw which unites the blade
as usual, the one blade is perforated, for the purpose of admit-
PRINCIPLE AND CON <>N' OP SCISSORS. .">'.'
tin:: lively, a small pin or stud fixed to the end of a short and
powerful spring, so that the -tnd .«, from acting on the opposite
blade throws thr points uf both ton ards each other, SO as to give
thriu a tendency to cross, hut which being resisted by the edges
of the blades touching one another, keeps them very agreeably
in contact throughout their motion, and causes them to cut \
well.
If further evidence is wanted of the clastic principle in scis-
sors, it is distinctly shown in sheep shears, which besides their
usible purpose of shearing off the fleece, are used by leather
dressers and others. It is well known that sheap shears, fig. 919,
page 915, are made as one piece of steel, which is tapered at
. end to constitute the cutting edges, is then for a distance
fluted and straight to form the -semi-cylindrical parts for the
grasp, and that in the center or opposite extremity, the steel is
flattened and formed into a bow by which the blades are united
ami kept distended ; sheep shears consequently require no joint
pin, and the hands have only to compress them as they spring
open for themselves. If sheep shears are examined when fully
opened, or when partially closed by tying round the blades a
loop of string, it will be found that the blades have a tendency
to spring into contact, as after having been pressed sideways
and asunder, the cutting edges immediately return into exact
contact the moment the distending pressure is removed.
The construction of scissors with the riding place as adverted
to in fig. 911, is that which ordinarily obtains in most scissors,
from the finest of those used by ladies, to the heavy ponderous
shears for tailors, which sometimes weigh above six pounds,
and are rented on the cutting board by one of their bows, that
are large enough to admit the whole of the fingers.
The peculiar form of the insides of the blades is in all cases
of paramount importance, and in the manufacture of fine scissors
is attended to by a person called a ' /intler- together,' whose pro-
vince it is to examine the screw-joint, and see to the form of the
riding-placet, and lastly to set the edges of the scissors, which
for general purposes are sharpened on an oilstone at an angle
of about 40 degrees, but for the fine scissors more nearly upright
or at 30 degrees from the perpendicular.
So important indeed is the configuration of the inner face of
scissors, that they should never be ground or meddled with at
910
SCISSORS OF DIFFERENT KINDS.
that part, but by a person fully experienced in their action, and
scissors may with careful usage be kept in order for years, with-
out being ground, if the edges are occasionally set on the oil-
stone at the inclination above referred to. It will frequently
happen that well-made scissors which appear to grate a little
when closed, merely do so from dirt or dust, which if removed
by passing the finger along the edges, will restore the scissors
to their smooth and pleasant action.
It seems quite uncalled for to enter into the separate descrip-
tion of various instruments known as button-hole scissors, cutting-
out, drapers', flower, garden, and grape scissors, horse trim-
ming scissors ; hair, lace, lamp, nail, paper, pocket, stationers',
and tailors' scissors, and many others; nor of the large shears
for the garden such as priming, trimming, and border shears,
the distinctions between which varieties are sufficiently known
to those who use the several kinds, but the author will merely
notice such of them as present any peculiarity of structure.
Button-hole scissors are notched out towards the joint screw
as in fig. 914, so as to enable the instrument to make an incision
Figs. 913.
914.
a little distant from the edge of the material; the joint must
be made stiff, so as to prevent the points catching against each
other.
Flower and grape scissors assume the section of fig. 913, so that
they first cut the stem, and then hold it like a pair of pliers, the
one blade requires to be made in two parts riveted together ;
when entirely closed they present an elliptical section a ; and b
shows how the stem of the flower is grasped, the blades are
rounded at all parts that they may not injure the plants.
Lamp scissors have the one blade very broad, and with a little
rim to prevent the snuff of the lamp falling on the carpet.
Nail scissors for the dressing-case, are made very strong and
I'lir.MNO SCISSORS AND SHEARS. I'll
with short blades. In using scissors formed in the ordinary
mode, the fin. ire rs and thumb of the right hand, have naturally
udeney to press the blades together, in that position in
which they an- intended to cut; but the left hand on the
contrary has a tendency to separate the blades and defeat the
phneiple on which scissors act. Therefore nail scissors are
made in pairs, and formed in opposite ways, or as "rights and
.'' so that they may suit the respective hands.
Pocket scissors have blades which admit of being locked
together in the form represented in fig. 915, as the point of the
one blade catches into a small spring near the bow of the otl
and the instrument cannot be opened until the spring or catch
is released with the nail. When closed for the pocket, the
bows stand on one line as at a b, when opened for use as at a c.
Surgical scissors are of many forms, but have generally short
blades and long straight slender handles, that the hand may not
impede the vision. In some of the surgical scissors the blades
are curved as scimitars, and others are curved sideways, these
kinds are difficult to make, as the elasticity of contact in the
blade is required nevertheless to be maintained.
Many of the shears and scissors used in gardening, only
differ from scissors and shears in general in their size, and the
adaptation of their handles, some of which are of wood, and
placed at an angle of 40 or 50 degrees, as m the letter Y
inverted. Other garden shears used in trimming borders,
have handles a yard long and inclined about 80 degrees to
the blades, which may therefore lie on the ground whilst the
individual stands nearly erect. Some of the border shears
have rollers to facilitate their movement along the ground.
In pruning shears and scissors, two peculiarities of form are
judiciously introduced. In the more simple of the two kinds,
which is shown in fig. 916, the one part of the instrument termi-
nates in a hook, with a broad and sometimes a roughened edge, to
retain the branch from slipping away, the other part of the instrn-
formed as a thin cutting blade, the edge of which is con-
vex. Theoretically it should be part of a logarithmic spiral, in
which case the edge of the cutter would present a constant angle
he work throughout its action, and slide laterally through
the incision made by itself, or make a sliding cut, whereas if
the edge of the blade were radial, it would make a direct cut
912 PRUNING SHEARS.
without any sliding, as in a paring chisel. The spiral blade cuts
more easily, and will therefore remove a larger branch, with an
action precisely analogous to that of the oblique cutters in some
of the planes, although differently produced.
Some of these instruments when a little modified in form, are
mounted on poles from 6 to 10 feet long, and are actuated by a
catgut ; this tool which is known as the Averuncator, is very
efficient for pruning at a considerable distance above the head.
The other pruning shears represented in fig. 917, are denomi-
Figs. 916
nated sliding shears, the pin that unites the two parts, fits in a
round hole in the one blade and a long mortise in the other, and
a link or bridle-rod c e, is attached by a screw to each lever ; in
consequence, when the instrument is fully opened the pin or
fulcrum is at the end a, of the mortise, whereas, on the shears
being gradually closed, the cutting blade slides downwards upon
the pin until the fulcrum is near the opposite end b. In this
modification of shears the sliding action is produced to a much
greater extent than with the spiral blade, but the construction is
a little more expensive ; and as the instrument is not provided
with bows for the fingers, the spring d e, is added to throw it open.
Before dismissing this section, two modifications of shears
will be briefly adverted to ; those used by card makers, and the
revolving shears employed in manufacturing woollen cloth.
Card paper is prepared in large sheets; when dried and pressed
it is cut into square pieces of the required sizes by means
of long shears, the one blade of which is fixed at the end
of a table, and has the joint at the farther extremity, whilst
the cutting blade has a handle in front, and moves through a
loop to keep the blade in its position, as in some chaff-cutting
machines ; there is also a stop fixed parallel with the blades,
and as distant as the width of the slips into which the card is
first divided, and these slips are then cut again the lengthway
of the cards. The shears are moved so rapidly, that the action
• [.VINO SHEARS FOR WOOLLEN CLoill. '.' ; i
Rounds like that of knocking at a door, and still the cards agree
most rigidly in si.
Revolving shear* or "perpetual she art " are used for shearing
off the loose fibres from the face of woollen cloths. For narrow
cloths the cylinders are 30 inches long and 2 in diameter, eight
thin knives are twisted around the cylinders, making 2£ turns
of a coarse screw, and are secured hy screws and nuts which
pass through flanges at the ends of the axis : formerly the
cylinders were grooved and fitted with several thin narrow plates
of steel 6 or 8 inches long. The edges of the eight blades are
ground so ns to constitute parts of a cylinder, by a grinder or
strickle fed with emery, passed to and fro on a slide parallel with
the axis of the cylinder, which is driven at about J200 turns in
the minute.
In use, the cylinder revolves about as quickly, and in contact
v it h the edge of a long thin plate of steel, called the ledger
blade, which has a very keen rectilinear edge, measuring 40 to 50
degrees, the blade is fixed as a tangent to the cylinder, and the
two are mounted on a swing carriage with two handles, so as to
be brought down by the hands to a fixed stop. The edge of the
ledger blade is sharpened, by 'grinding it against the cylinder
itself with flour emery and oil, by which the two are sure to
agree throughout their length.
The cloth, before it goes through the process of cutting, is
brushed so as to raise the fibres, it then passes from a roller
over a round bar, and comes in contact with the spring bed,
which is a long elastic plate of steel, fixed to the framing of the
machine, and nearly as a tangent to the cylinder, this brings
tlu- fibres of the cloth within the range of the cutting edges,
which reduce them very exactly to one level. The machine has
several adjustments, for determining with great nicety, the
relative positions of the cylinder, ledger-blade and spring-bar,
but which could not be conveyed without elaborate drawing*.
:uerly the cloth was passed over a fixed bed having a nearly
sharp angular ridge, but which mode was far more liable to cut
holes in the cloth than the spring-bed.
Broad cloths require cylinders 65 inches long, and machinery
of proportionally greater strength. In Lewis's patent cross-
cutting machine, the cloth is cut from Us! to list, or transver>cly,
in which case the cloth is stretched by hooks nt the two edges,
914 HAND SHEARS FOR METAL.
and there are two spring beds ; the cylinder in this machine is
40 inches long, and the cloth is shifted that quantity between
every trip until the whole piece is sheared. The perpetual
shears are also successfully applied to coarse fabrics including
carpets.*
A modification of the above revolving shears, made in a much
less exact manner for mowing grass lawns, is fitted up somewhat
as a wheel-barrow, or hand truck, so that the rotation of the
wheels upon which the machine is rolled along, gives motion to
the shears, which crop the grass to a level surface.
SECT. III. SHEARS FOR METAL WORKED BY MANUAL POWER.
When metals are very thin such as the latten brass used for
plating and other purposes, they may be readily cut with stout
scissors ; and accordingly we find the weakest of the shears for
metal, are merely some few removes in strength, beyond the
strong scissors for softer substances.
It is however to be observed, that as common scissors are
sharpened to an angle varying from about 50 to 60 degrees, they
may fairly be considered to cut the materials submitted to their
action ; but shears for metal have in general rectangular edges,
as they are seldom more acute than 80 degrees, and therefore
instead of cutting into the material, they rather force the two
parts asunder, by the pressure of the two blades being exerted
on opposite sides of the line of division.
It was recently stated to be of the utmost importance, that
the blades of the weaker or elastic kind of shears should be
absolutely in contact, or else thin flexible materials would be
folded down between their blades without being cut.
And it may now be urged as of equal importance, that the
blades of the shears for metal should be also exactly in contact,
not that rigid plates or bars of metal could be bent or folded down
between their blades, even if these were a little distant ; but the
resistance to the operation of cutting would be then enormously
increased, because the force exerted to compress the shears, would
not be then exerted in the line of their greatest resistance,
which is strictly the case when the edges truly meet in one plane.
* Messrs. Sugden and Son, of Leeds, makers of machinery for the manufacture
of cloth, kindly furnished the author with the information from which the above
remarks were gathered.
II AM) SIIK VHS KiiH MKTAI-.
918
It' the blades were distant as iu fig. 924, from the want of
• in ret support, the bar or plate would be tilted up, and become
jammed, this would tend further to separate the blades, and the
shears would be strained or perhaps broken without dividing
the bar, whereas all these evils are avoided if the shears close
accurately in one and the same plane, as if the lower blade were
shifted to the dotted line, and in which case they require the
least expenditure of power and act with the best effect.
Having now in accordance with the general method of this
work, noticed the principles on which the shears for metal act,
the author will proceed to describe some of the ordinary forms
of the instrument.
Hand shears which are the smallest of these tools, are made of
the form represented in fig. 920, and vary from about four to nine
inches in total length, they are much used by tinmen, copper-
smiths, silversmiths and others who work in sheet metals, and are
often called snips, to distinguish them from bench shears ; some-
times however they are fixed by the one limb in the table or tail
vice, and then become essentially bench shears, and this enables
them to be used with somewhat increased power.
Bench shears of the ordinary form are represented in fig. 921,
the square tang t, is inserted in a hole in the bench, or in a large
block of wood, or else in the chaps of the bench vice itself; a
less usual modification is seen in fig. 9~~, with the joint at the
far end, and the cutting part between the joint and the handle.
Bench shears vary in total length from about one foot and a
half to four feet, and the blades occupy about one-fifth of the
It-n^th, sometimes to increase the power of these shears, the
handle is forged thicker at the end to add weight, so that when
3 N 2
916
HAND PURCHASE SHEARS.
the instrument is closed with a jerk, it may by its momentum
cut thicker metal than could be acted upon by a simple thrust,
but when considerable power is required, it is better to resort
to the shears next described.
Purchase shears which are represented in fig. 925, are in every
respect more powerful than those previously noticed, the framing
is much more massive, and the cutters are rectangular bars of
steel inserted in grooves, to admit of their being readily sharp-
Fig. 925. b
ened or renewed. Instead of the hand being applied on the
first lever or a, b, a second lever c, d, e, is added, and united to
the first by. the link b, d, and but for the limit of the paper
the hand lever c, d, e, would have been represented of twice its
present length.
As the length of the part a, b, is three to four times the
length of c, d, the hand has to move through three to four times
the space it would if applied directly to the shear lever, and
consequently the purchase shears have three to four times the
force of common shears, supposing the manual lever to be of
equal length in each kind. There is usually at the back of the
moving blade, a very powerful spring or back stay, to keep the
two edges in contact, and still further behind a stop to determine
the lengths or widths of the pieces sheared off.
Before using shears, in those cases where the stop is not
employed to determine the width, it is usual to mark on the
work the lines upon which it is intended to be sheared, the
ACTION UP SHEARS FOR METAL. PRINTERS* SHEARS. 917
shears arc then opened to the full, and the extremity of the line
is placed in the angle formed by the jaws ; if the work is short,
it is also observed whether the opposite end of the line lies
exactly on the edge of the lower blade, but if the work is long,
the guidance is less easy. When the blades arc closed the work
will probably slip endlong, notwithstanding the resistance of the
hand, until the angle at which the blades meet is so far reduced
that they begin to grasp the work, when the extreme edge will
be first cut through, and then the incision will be extended to
the full length of the blades.
As however each successive portion is severed, the two parts
are bent asunder to the angle formed by the blades, and both
pieces become somewhat curved or curled up ; provided the cut
is through the middle of the sheet so that both are equally
strong, the two parts become curved in the same degree, but
when a narrow and consequently weaker piece, is removed from
the edge of a wide sheet, the curling up occurs almost exclu-
sively in the narrow strip on account of its feebleness. In long
pieces it is sometimes necessary to increase the curvature in
order that as the work is sheared off, the one part may pass
above, and the other below the rivet or screw by which the
halves of the shears are united.
When from use or accident the joint becomes loose, so as not
to retain the two parts in contact, in order to make the shears
cut, the moving half must be pressed against that which is fixed
to the pedestal or tail vice. Sometimes the sway of the blades
of jointed shears is prevented, by allowing the moving arm to
pass through a loop or guide which may retain it in position.
Such a guide is mostly used in the light shears with which
printers cut their space line leads, or those thin slips of metal
inserted between the lines of type, to separate them and make
the printing more open. The leads are cast in strips about a
foot long, and are cut into pieces of the exact width of a page,
by laying them in a trough having at the end a pair of shears,
and bryond these a stop to determine the precise length, so that
any nuinhc-r of the leads may be cut exactly to the length
required. Before adverting to the powerful shears used by
engineers, two modifications of those already described will be
noticed.
Fig. 923, page 915, represents the section through the blades
918 SHEARS FOR TIN TAGS AND STATIONERS' RULING PENS.
of a pair of shears invented by Mr. Collett, by which the tags or
tin ferrules at the end of silk laces are cut and bent at one process,
the general aspect of the tool being that of fig. 921, page 915.
The shearing blades are shaded obliquely in fig. 923, and to
the lower, which is fluted on the edge, is attached a stop that
determines the width of the piece removed from the strip s,
to make the tag. The upper shear blade, which is ground more
acutely than usual, carries a ridge piece, (shaded vertically,)
which compresses the strip as it is cut off, into the fluted edge
of the lower blade, and thereby throws it into a channelled
form ; and by the employment of a pair of hollow pliers, or
else a light hammer and a hollow crease, the bending is readily
completed, and the tag attached to the cord.*
A nearly similar machine, but constructed more in accordance
with the printers' space line shears, is used for cutting slips of
thin latten brass, into the channelled pens used in stationers'
machines for ruling the blue and red lines on paper for account
books, &c. The one side of a slip of brass l£ inch wide, is thus
cut and channelled at intervals suited to every line ; the sides of
every channel are closed to form a narrow groove, and the inter-
vening pieces are removed with hand-shears. The compound
pen is fixed on a hinged board, and a strip of thick flannel laid
at the top of the pen, is saturated with ink which flows steadily
down all the channels, whilst the paper is moved horizontally
under the pens, by two or three rollers and tapes, somewhat as
in the feeding apparatus of printing machines, and thus the
whole page is ruled one way and very quickly.
Shears of the above kinds with rectilinear blades, are not
suited to cutting out curvilinear objects, such for example as the
sides of callipers a fig. 950, page 933. The outline of such
callipers is first of all marked on the sheet of steel from a
templet, and with a brass wire which leaves a sufficient trace ;
the outline is followed with a hammer and chisel upon an anvil,
the chisel having a rounded or convex edge. Detached cuts
running into one another are made around the curve, and the
work is finally separated by pinching it in the tail vice succes-
sively at all parts of the curve, and wriggling the other edge of
the sheet with the hand until it breaks/
The vice is often also used for cutting off straight pieces, which
* See Transactions of the Society of Arts, London, 182tf, vol. xliv., page 76-
ENGINEERS' SHEARING TOOL*.
910
are then fixed with the line of division cxnctly Hush with the
chaps, and an ordinary straight chisel ia so applied, that the
chamfer of the tool rests on the chaps of the vice, and the edge
;xt a small angle to the work, and after every successive blow,
tin- chisel is moved a little to the left without losing its general
position.
SECT. iv. — ENGINEERS' SHEARING TOOLS; GENERALLY WORKED
BY STEAM POWER.
The earliest machines of this class were scarcely more than a
magnified copy of the bench shears shown on page 915, but made
• rv much stronger, thus fig. 926, represents a shearing and
squeezing tool used in some iron works and smithies. It has
one massive piece that is fixed to the ground, and jointed to it is
the lever, which carries at a, a pair of shearing cutters situated
exactly on two radii struck from the center of motion; this
927.
928.
929.
Figs. 926.
machine has also two squeezers b, for moulding pieces of iron
when red-hot to the particular forms of the dies. The longer
end of the lever is united by a connecting rod to an excentric
stud in the disk d, which is made to revolve by the steam engine.
The late Mr. Penn of Greenwich, moved his shears by means
of an axis carrying two rollers, placed at the extremities of a
diametrical arm, as in fig. 927. The one roller acts on the radial
part of the shear lever in the act of cutting, and the curved part
thru allows the lever to descend by its own weight rapidly,
without a jerk, by the time the other roller comes into
action for the succeeding stroke of the machine, which by this
double excentric makes two reciprocations for every revolution
of the shaft.
It is however more usual to employ cams, as in fig. 928, and
in this case the part of the cam which lifts the shear lever is
ally spiral, so as to raise it with equal velocity ; the curve of
BARTON'S SHEARS. ROBERTS' SHEARING
the back is immaterial, provided it forms a continuous line so as
to prevent the lever descending with a jerk.
Fig. 929 represents the double shears contrived by the late
Sir John Barton for the Royal Mint, the one part, shown also
detached, presents two horizontal but discontinuous edges with
the axis in the center, this piece is fixed to a firm support ; the
other or the moving part somewhat resembles the letter T or a
pendulum, to the lower end of which, and beneath the floor
is joined a connecting rod, that unites the pendulum with an
excentric or crank driven by the engine. The machine is
double, or cuts on either side, and has two pairs of rectangular
cutters of hardened steel, which may be shifted to bring the
four edges of all of them successively into action.
Boiler makers have great use for powerful shears for cutting
plate iron from £ to £, and sometimes f inch thick ; and the next
stage of their work is to punch the rivet holes by which the plates
are attached. The two processes of shearing and punching are
so far analogous in their requirements, .that it is usual to unite
Fig. 930.
the two processes in one machine; and as it sometimes happens
the boiler maker's yard is at a distance from the general factory,
it then becomes necessary to work the shears by hand with a
winch handle, and which is effected in the manner shown in
fig. 930, by the introduction of only one wheel and pinion. The
wheel is fixed on the cam shaft, the pinion on the same axis
that carries the heavy fly-wheel employed to give the required
momentum ; this mode of working the shearing and punching
\M» M N< HIM. M U II1NES.
engine is perfectly successful, hut of course less economical than
steam or water power, the agency of which the machine is also
adapted to receive.
\\luii >hrar* tliatmove on a joint and have radial cutters as
in tig. 926, are employed for thick bars, owing to the distance
to which their jaws are opened, they meet at a considerable
angle, and therefore from their obliquity they do not grasp the
thick bar, but allow it to slide gradually from between them,
to prevent which a rigid stop is added at the part c, fig. 926,
when, as the bar can no longer slide away it becomes severed.
The shears with radial cutters, are also liable from their very
oblique action to curve the plates, neither do they serve for
making long cuts, as the joint then prevents the free passage of
long work.
All these inconveniences however are obviated in the shearing
machines with slides, in which the edges approach in a right line
instead of radially, and are also nearly obviated in the very
massive and powerful shearing and punching tool with jointed
lever, designed by Mr. Roberts of Manchester, and represented
in fig. 930, which occupies an entire length of eleven feet, and
serves for cutting plates not exceeding f inch thick, cutting 12
inches in length at a time, and punching holes of 1} inch
diameter in J inch iron. The shearing cutters are in this
machine 15 inches long and raised above the center of motion, as
they lie on a chord instead of a radius, the longest pieces may
therefore be cut without interference from the joint, and the
cutters have the further advantage of meeting at a much smaller
angle than if fitted radially.
The portable punching and shearing machine shown in front
and side elevation in figs. 931, and 932, was also designed by
M r. Richard Roberts, it will serve for a general example of such
machines, as the differences in the several constructions are only
those of form and arrangement, and not of principle.
This machine stands upon a base of a triangular form, and has
in front a strong chamfer slide, which is reciprocated in a ver-
tical line, by an exceutric that is concealed from view, it being
immediately behind the slide, and upon the same axis as the
ntric is the toothed wheel. The pinion that takes into this
\vhcel, is on the shaft that carries the fly wheel, and one of the
arms of the latter, receives the handle by which the machine is
922
ROBERTS SHEARING AND PUNCHING MACHINES.
usually worked ; or if it is driven by power, fast and loose
pulleys are then fixed on the same axis as the fly wheel.
The upper part of the slide carries a shearing cutter, which is
about 7 inches wide, and meets a similar cutter that is fixed to
the upper and overhanging part of the casting. The cutters
although ground with nearly rectangular edges, are bevilled to
the extent of about three-fourths of an inch in the direction of
their length, that they may commence their work on the one
edge, and therefore more gradually than if the entire width of the
cutter penetrated at the same instant ; this degree of obliquity
does not cause the work to slide from the shears, neither does it
materially curl up the work j and as the blades are quite clear of
the framing, a cut may be extended throughout the longest works,
provided the cut is not more than five inches from the edge of
the plate, the distance of the cutters from the framing of the
machine.
The above machine which measures in total height about five
feet, makes 12 or 15 strokes per minute, shears £ inch iron
plates, and punches f holes in iron £ inch thick. A larger
machine makes 10 or 12 strokes per minute, shears £ inch plate,
and punches l£ inch holes in iron f inch thick ; and a still
heavier machine working at 8 or 10 strokes in the minute, shears
THORNBYCROFT'S SHEARS; NASMYTII'S CUTIIM. \ ICE. 928
1 inch plates, and punches 2 inch holes in iron 1 inch thick.
Some of these are provided with railways by which the work is
carried to the shears or punches as will he described ; and
Mr. Roberts' bar-cutting machine, having only shearing cutters
at the bottom, and the exccntric at the top of the slide, is used
for cutting bars not exceeding 6j} inches wide by If thick, or
bars 2 or 2^ square, but he thinks these dimensions of the
works performed might if required be greatly exceeded in
heavier machines.
A patent has been recently granted to Mr. G. B. Thorney-
croft, for a shearing machine for cutting wide plates of sheet iron.
This machine which is used in the manufacture of wrought iron,
has two wide cutters of steel fixed to the edges of thick plates of
cast iron ; the lower cutter is at rest and quite horizontal, the
upper cutter bar is fitted in grooves at the end of the frame, so
as to be carried up and down vertically, by a shaft or spindle im-
mediately above the cutter and parallel with it, this shaft has an
excentric at each end, and one in the center, and three connect-
ing links, which attach the cutter frame to the excentrics, and
give it a small reciprocating motion. The upper cutter is a little
oblique so as to begin to act at the one end, and in removing the
strips curls them but very little.*
Nasmyth, Gaskell and Co.'s vice for cutting wide pieces of
boiler plate, is based on the mode of cutting thin slips of sheet
metal over the chaps of the ordinary tail vice as described on
page 918-9. The jaws of the machine are about six feet long,
faced with steel, and powerfully closed by two perpendicular
screws and nuts, one at each end, which also secure the machine
to the ground.
The plate of iron is therefore fixed horizontally and with the
line of division level with the jaws. A strong rod chisel struck
with sledge hammers, is applied successively along the angle
formed between the work and the vice, and after the iron has
been indented the whole length, the blows of the sledges directed
on the overhanging piece of iron complete the separation.f
Fig. 933, represents the plan, and fig. 934, the partial vertical
section, of a " hydraulic machine for cutting off copper bolts,"
• Thorneycroffa Patent, sealed Slat January, 1843, ia described in the Repertory
of Patent Invention*. Vol. ii., Enlarged Series, page 129.
t Xannyth, Oaskell and Co.'s cutting vice ia figured in plate 49 of Buchanan'*
Mill Work, edited by Sir O. Rennie, F.K.S., 1841.
924 HYDRAULIC MACHINE FOR CUTTING OFF COPPER BOLTS.
devised by Mr. A. M. Renton, and constructed for the Govern-
ment Dock Yards, by Messrs. Charles Robinson & Son. This
machine is actuated by the hydro-mechanical principle discovered
by the celebrated predecessor of the firm, Mr. Timothy Bramah.
The circle in fig. 933, represents the cylinder of a hydrostatic
press, which is flattened to the width of the rectangular bar that
is fixed alongside the cylinder, the two being enveloped in the
external casting which is shaded in the section fig. 934, and
resembles a stunted pillar three or four feet high. The whole of
the parts are traversed by nine sets of holes suitable to bars from
£ to 2£ inches diameter, the holes where they meet on the lines
b b, are furnished with annular steel cutters, and are enlarged
outwards each way to admit the work more easily.
The rod r r, to be sheared, is introduced whilst the holes are
directly opposite or continuous, and the men then pump in the
injection water through the pipe w, it acts upon the annulus or
shoulder intermediate between the two diameters of the cylinder,
Figs. 933.
934.
935. 936.
937.
causes the descent of the latter with a pressure of about 100 tons
and forces the bar asunder very quietly, and from the annular
form of the cutters without bruising it. When the bar has been
cut off, the injection water is allowed to flow out from beneath
the cylinder, and the latter is raised by a loaded lever beneath
the floor ready for the next stroke. The machine is far more
economical in its action, than the old mode of cutting off the
copper bolts, with a frame saw used by hand, and the storekeeper
in charge of the bolts, can if needful perform the entire operation
unassistedly, although usually four men work the pair of one inch
injection pumps, by a double-ended lever as in a fire engine.
In concluding this chapter it is proposed to speak of the rotary
shears for metal, which have continuous action like rollers and
are pretty generally used. In the best form of the instrument,
(IIKII.AR OR ROTARY M NO ROI.I.M. 025
t\\t> spindles connected together by toothed wheels of equal .-
have rat-h two thin disks of ditlVrrnt diameters, which are
opposed to each other, that is, a large and a small in the same
plane, as in the diagram fig. P35, the larger disks overlap each
other and travel in lateral contact, and therefore act just like
shears, and the two disks in each plane meet, or rather nearly
meet, so as just to grasp between them, after the manner of flat-
ting rollers, the two parts of the strip of metal which have b<
severed, and by carrying these forward they continually lead the
•mdiviiled part of the metal to the edges of the larger disks,
whieh in tins manner quickly separate the entire strip of metal
into two parts.
The machine requires that the spindle carrying the disks
should have an adjustment for lateral distance, as in flatting
rollers, to adapt their degree of separation to the thickness of the
metal to be sheared. One of the spindles should also have an
endlong adjustment to bring the disks into exact lateral contact,
and the machine requires in addition a fence or guide, fixed
alongside the revolving shears to determine the width of the
strips cut off. Sometimes the two smaller disks are omitted,
and the larger alone used, as in fig. 936, the circular shears are
then somewhat less exact in their action, but perform neverthe-
less sufficiently well for most purposes.
Circular or rotary shears, are very useful for shearing plates
not exceeding one-eighth of an inch thick, and one of the advan-
tages which the rotary possess over the common shears, is the
facility with which curved lines may be followed, on account of
the small portion of the disks that are in contact, whereas the
length of rectilinear shear blades prevent their ready application to
curves. Of course the speed at which the machines may be driven
depends on the nature of the work, and if the cuts arc straight and
the plates light, the velocity of the shears may be considerable.
As remarked on page 188 of the first volume, the circular
shears, or splitting rolls used in the works where wrought iron is
manufactured, are composed of steel disks of equal thickness,
but of two diameters, arranged alternately upon two spindles as
in fig. 937, so as at one action to split thin plates of iron of about
6 inches in width, into MTV narrow pieces known as nail rods,
and into strips from half to one inch wide designated as bundle
or split iron. Of course different pairs of rolls are required for
every different width of the strips thus manufactured.
926
CHAPTER XXX.— PUNCHES.
SECT. I. — INTRODUCTION : PUNCHES USED WITHOUT GUIDES.
THE title of the present chapter, may at the first glance, only
appear to possess a very scanty relation to the tools used in
mechanical manipulation, as the ostensible purpose of a punch
may be considered to be only that of making a round or square
hole in any thin substance. But it frequently happens that the
small piece or disk so removed by the punch, is the particular
object sought, and some of the very numerous objects thus made
with punches, assume a very great importance in the manufac-
turing and commercial world, as will perhaps be admitted when a
few of these are referred to in the course of the present chapter.
The general character of a punch, is that of a steel instru-
ment the end of which is of precisely the form of the substance
to be removed by the punch, and which instrument is forcibly
driven through the material by the blow of a hammer. When the
subject is entertained in a moderately extended sense, it will be
seen that much variety exists in the forms of the punches them-
selves, and also in the modes by which the power whereby they
are actuated is applied.
So far as relates to the actual edges of the punches by which
the materials are severed, they may be classed under two princi-
pal divisions, namely duplex punches, and single punches. The
duplex punches have rectangular edges and are used in pairs,
often just the same as in shears for metal. The single punches
have sometimes rectangular but generally more acute edges,
the one side being mostly perpendicular.
The single punches require a firm support of wood, lead, tin,
copper, or some yielding material, into which the edge of the
punch may penetrate without injury, when it has passed through
the material to be punched. Consequently many of the tools
the author has ventured to consider as single punches, might be
classed with chisels, and many of the duplex punches might be
classed with shears, analogies which it is not worth while either
to pursue or refute.
PUNCHES PUR CARD PAPER, WAFERS, LOZENGES, i
following classification has been attempted, as that best
calculated to throw into something like order, the miscellaneous
instruments that will be more or less fully described in this
chapter, namely,
Section I. Punches used without guides.
,, II. 1'mirlies used \\ith simple guides.
„ 111. Punches used in fly presses, and miscellaneous
examples of their products.
., IV. Punching machinery used by engineers.
It is proposed in all the sections to commence with those
punches having the thinnest edges, and which are used for the
softest materials.
It would be hardly admitted, that a carpenter's chisel driven
by a mallet through a piece of card could be considered as a
punch, still the circular punch used with a mallet on a block of
lead, for cutting out circular disks of cards for gun-wadding, is
indisputably a punch, and yet scarcely more than a chisel bent
round into a hoop. The gun-punch is formed as in fig. 938, over-
leaf, and isturned conical without and cylindrical within, or rather
a little larger at the top that the waddings may freely ascend,
and make their way out at the top through the aperture; when
however annular punches exceed about 2 inches in diameter, it
is found a stronger and better method, to make them as steel
rings, attached to iron stems or centers spread out at the ends
to fill the rings, as in fig. 939, but holes are then required to
push out the disks that stick into the punch, as shown by the
section beneath the figure 939.
The punch used in cutting out wafers for letters is nearly
similar, it being formed as a thin cylindrical tube of steel, fitted
to the end of a perforated brass cone having at the top two
branches for the cross handle, by which it is pressed through
several of the farinaceous sheets, and as the wafers accumulate in
the punch they escape at the top. Confectioners use similar cut-
ters in making lozenges, and frequently the thin steel cutter is
fixed to a straight perforated handle of wood. The lozenges are
cut out singly and with a twist of the hand.
When the disk is the object required, the punch is always
chamfered exteriorly, as then the edge of the disk is left square
and the external or wasted part is bruised or bent ; but the
928 PUNCHES FOR ARTIFICIAL FLOWERS, ENVELOPES, ETC.
punch is made cylindrical without, and conical within, when the
annulus or external substance is required to have a keen edge.
And when pieces such as washers, or those having central holes,
are required in card or leather, the punches are sometimes con-
structed in two parts as shown separated in fig. 940, the inner
being made to fit the buter punch, and their edges to fall on one
plane ; so that one blow effects the two incisions, and the punches
may then be separated for the removal of the work should it
stick fast between the two parts of the instrument.
Punches of irregular and arbitrary forms, used for cutting out
paper, the leaves for artificial flowers, the figured pieces of cloth
for uniforms and similar things, are made precisely after the man-
ner of fig. 938, and also of fig. 939, except that they are forged
Figs. 938.
9JO.
Q
942.
©
in the solid, or without the loose ring. These irregular punches
are however much more tedious to make, than the circular, which
admit of being fashioned in the lathe.
Figured punches of much larger dimensions, have been of
late used for cutting out the variously formed papers used in
making envelopes for letters. The punch or cutter is sometimes
made in one piece, as a ring an inch to an inch and a half deep,
or else in several pieces screwed around a central plate of iron,
and when the punch is sharp it is readily forced through three to
five hundred thicknesses of paper, by the slow descent of the
screw press in which it is worked. Army clothiers use similar
instruments for cutting out the leather for shoes and various
other parts of military clothing, and several of these punching or
cutting tools are often grouped together.
Proceeding to the punches used for metal, those having the
thinnest edges are known as hollow punches ; they are turned
s FOR REI>-IK>T IRON.
mous diameters from about ^ to 2 inches, and of the section
fig. '.Ml, they are always used on a block of lead, and sometimes
two or three thicknesses at a time of tinned iron, copper, or
rine. Punches IM2, smaller than £ inch, are generally solid,
quite flat at the end, and are also used on a block of lead, which
although it gives a momentary support, yields and receives into
its surface the little piece of metal punched out by the tool.
Fig. 914, represents the punch used by smiths for red-hot
iron, the tool is solid and quite flat at the end, and whether it is
round, square, or oblong in its section, as for producing the
holes represented, it is parallel for a short distance, then gra-
dually enlarged, and afterwards hollowed for the hazle rod by
which it is surrounded to constitute the handle (see foot note,
page 202, vol. i.). Various practical remarks on the application
of the smith's punches are given on pages 215 — 217 of vol. i., it
will be thence seen that the smith's punch is frequently used
along with a bottom or bed tool known in this case as a bolster,
and which has a hole exactly of the same area as the section of
the punch itself.
Punches when used in combination with bolsters, are clearly
similar in their action to the shears with rectangular edges, as
will be seen on comparing figs. 043 and 014, the only difference
Fig* 943. 944.
945.
V
bring that the straight blade of the shears, is to be considered
as bent round into a solid circle for a circular punch, or converted
into a square, rectangle, or other figure as the case may be ; but
every part of the punch should meet its counterpart or the
bolster in lateral contact, the same as formerly explained in refer-
ence to shears. This supposes the tools to be accurately made
and correctly held by the smith, but which is somewhat difficult,
3 o
930 PUNCH USED BY HARP-MAKERS FOR MORTISES.
because, the bolster, the work, and the punch, are all three
simply built up loosely upon the anvil, and the eye can render
but little judgment of their relative positions, the punch is con-
sequently apt to be misdirected so as to catch against the bolster
and damage both tools. The mode sometimes used to avoid this
inconvenience is represented in fig. 915, in which a guide is
introduced to direct the punch, but agreeably to the proposed
arrangement, this figure will be more fully explained in the next
section, when some other tools of a lighter description have been
spoken of.
Previously however to concluding this present section, atten-
tion is requested to fig. 94-6, which shows a punch used by harp-
makers and others, in cutting long mortises in sheet metal. The
punch is parallel in thickness, and has in the center a square
point from which proceed several steps, this punch is used with a
bolster having a narrow slit, as long as the width of the punch.
A small hole is first drilled in the center of the intended mortise,
the first blow on the punch converts this into a square, the next
cuts out two little pieces extending the hole into a short mortise,
and each successive blow cuts out a little piece from each end,
thereby extending the mortise if needful to the full width of the
punch. From the graduated action, the method entails but little
risk of breaking the punch or bulging the metal, even if it
should have but little width. Sometimes, to make the punch act
less energetically at the commencement of its work, the steps at
the point are made smaller both in height and width; the serrated
edge then becomes curved instead of angular, as shown.
SECT. II. — PUNCHES USED WITH SIMPLE GUIDES.
Beginning this section with the tools having the most acute
edges, we have to refer to the punch pliers, fig. 947, fitted with
round hollow punches for making holes in leather straps and thin
materials j some pliers of this kind have a small oval punch ter-
minating in a chisel edge, for cutting those holes that have to be
passed over buttons ; and pliers have been made with circular,
square, and triangular punches, for the cruel practice of marking
sheep in the ear. In all these tools the punch is made to close
upon a small block of ivory or copper, so as to ensure the mate-
rial being cut through without injuring the punch.
PUNCH PLIERS; PEN-MAKINU INSTKCMENT. 931
Another example of v ,i>i 1-like punches, is to be seen
in Mr. Roger's machine for cutting ti, teeth of horn and tor-
toiseshell combs (*ee page 130, vol. i.). The punch or chisel is
in two parts, slightly im lined and curved at the ends to agree in
form with the outline of one tooth of the comb, the cut
attached to the end of a jointed arm, moved up and down by a
crank, so as to penetrate almost through the material, and the
uncut portion is so very thin that it splits through at each stroke,
and leaves the two combs detached.
The little in>t rument called a pen-making machine, is another
ingenious example of punches moving on a joint, it is repre-
sented of half its true size, and ready to receive the pen, in fig.
948, and in fig. 949, the two cutters are shown of full size and
F.,T. »47.
O— D n <] 94S
L-O^eO g
^
c 949.
laid back in a right line ; although in reality it only opens to a
right angle. The lower half has a small steel cutter b, pointed
to the angle of the nibs of the pen, and fluted to the curve of
the quill as at a, the upper cutter d, is made as an inverted angle
with nearly vertical edges as seen at e, which exactly correspond
with the lower cutter, so as between them to cut the shoulders
of the pen. The upper tool also carries a thin blade or chisel,
which penetrates nearly through the quill and forms the slit.
The quill having been pared down to its central line, is
inserted through the hollow joint, on the line /, and the cutters
being very near the joint, the lever on being closed gives abund-
ant power for the penetration of the punches. The pen requires
to be afterwards nibbed, and for which purpose another cutter is
attached to the instrument which has likewise an ordinary pen-
blade, so as to be entirely complete in itself.
Tin> method of producing a pen was introduced in a some-
what different form, in the late Mr. Timothy Bramah's patent
machinery for making portable quill pens, the barrel of the quill
3 o 2
932 PUNCHES WITH BOLSTERS AND GUIDES.
was in that case cut into two lengths, and each length being split
longitudinally into three parts, and shaped at each end in a small
fly-press with cutters of the above character, converted every
quill into six double-ended pens, many thousand boxes of which
were made ; they may be considered to have opened the path to
the present truly enormous manufacture of steel pens, which
consumes many tons of steel annually.
Passing from the punches with guides obtained by means of
joints, and actuated by the pressure of the fingers, we will return
to fig. 945, on page 929, which with its simple guide becomes a
very effective tool sometimes known as the hammer press, in con-
tradistinction to the screw or fly press to be hereafter spoken of.
The guide in the contrivance fig. 945, is a strong piece of iron
attached to the bottom tool, and sufficiently above it to admit the
work between the two. Each part is pierced with a hole of
exactly the same size, and accurately formed as if they were
interrupted portions of the same hole. The punch is made
exactly to fit either hole, so that from the upper it receives a
correct guidance, and it therefore cuts through the material, and
penetrates the lower piece, with a degree of precision and truth
scarcely attainable when the tools are unattached, and are used
simply upon the anvil as before described.
As however the punch mostly sticks tight in the work, it is
needful to turn the instrument over, and drive out the punch
with a drift a little smaller than the punch, and on which account
punching tools of this kind are often made of two parallel plates
of steel firmly united by screws or steady pins, yet separated
enough for the reception of the work, and frequently contriv-
ances are added to guide the works to one fixed position, in
order that any number of pieces may be punched exactly alike.
Thus in punching circular mortises, as in the half of a pair of
inside and outside callipers a, fig. 950, the punch c, is first used
to produce the central hole, and this punch is then left in the
bed b, to retain the work during the action of the second punch
m, by which the mortise is cut. The punch m, is very short to
avoid the chance of its being broken, and it is also narrow so
as to embrace only a short portion of the mortise, which is then
completed, with little risk to the tool, at three or four strokes,
whilst the punch c serves as a central guide.
Occasionally also punches of this simple kind, but on a larger
PORTABLE n M HIM; M \« II INK POft BOILER PLATE. 933
have been placed under drop hammers, falling from a con-
siderable height through guide rods, somewhat as in a pile-
.: machine. This mode of obtaining power is not suited
to the action of punches used in cutting out metals, amongst
other reasons, because the punch sticks very hard in the perfo-
ration it has made, and requires some contrivance for pulling it
out, which is not so easily obtained in this apparatus as in fly-
presses, that are suited alike to large and small works.
The drop hammer, or as it is more commonly called a force,
is, however, very much used at Birmingham in the manufacture
of stamped work, or such as are figured between dies, of which
an example is described at length in pages 409 & 410 of vol. i.
Compared with a fly-press of equal power, the force is less
expensive in its first construction, but it is also less accurate in
its performance.
Fig. 951 is a very simple yet effective tool which may be
viewed as a simplification of the fly-press, it consists of one
very strong piece of wrought iron, about one inch thick and
four or five inches wide, thickened at the ends and bent into the
form represented, the one extremity is tapped to receive a coarse
screw, the end of which is formed as a cylindrical pin, or punch,
that is sometimes made in the solid with the screw, but more
usually as a hardened steel plug inserted in a hole in the screw.
Immediately opposite to the punch is another hole in the press,
the extremity of which is fitted with a hardened steel ring or
bed punch. When the screw is turned round by a lever about
three feet long, it will make holes as large as J inch diameter
in plates \ inch thick, and is therefore occasionally useful
to boiler-makers for repairs, and also for fitting works in con-
fined situations about the holds of ships, and other purposes.
When this screw is turned backwards the punch is drawn out
984 SCREW PUNCH FOR LEATHER STRAPS. FLY-PRESS.
and relieved from the work, but the screwing motion is apt to
wear out the end and side of the punch, and therefore to alter
its dimensions.
A very convenient instrument of exactly the same kind is
used in punching the holes in leather straps, by which they are
laced together with leather thongs, or united by screws and nuts,
to constitute the endless bauds or belts used in driving machinery.
In this case the frame of the tool is made of gun-metal, and weighs
only a few ounces, the end of the screw is formed as a cutting
punch, and it is perforated throughout, that the little cylinders
of leather may work out through the screw, which only requires
a cross handle to adapt it to the thumb and fingers.
In this case the screwing motion is desirable, as the punch in
revolving acts partly as a knife, and therefore cuts with great
facility, as the leather is supported by the gun-metal which con-
stitutes the clamp or body of the tool.
SECT. III. PUNCHES USED IN FLY-PRESSES, AND MISCELLANEOUS
EXAMPLES OF THEIR PRODUCTS.
The punches used in fly-presses do not differ materially
from those already described, but it appears needful to com-
mence this section, with some explanation of the principal modi-
fications of the press itself. The fly-press is a most useful
machine, which, independently of the punch or dies wherewith
it is used, may be considered as a means of giving a hard,
unerring, perpendicular blow, as if with a powerful well-directed
hammer. The precision of the blow is attained by the slide
whereby the punch is guided, the force of the blow by the heavy
revolving fly attached to the screw of the press. When the
machine is used, the fly is put in rapid motion, and then sud-
denly arrested by the dies or cutters coming in contact with the
substance submitted to their action. The entire momentum of
the fly, directed by the agency of the screw, is therefore iustan-
taneou^ly expended on the work to be punched or stamped, and
the reaction is frequently such as to make the screw recoil to
nearly its first position.
The bare enumeration of the multitude of articles that are
partially or wholly produced in fly-presses, would extend to con-
siderable length, as this powerful and rapid auxiliary is not only
OKIMSAHV ' 'INSTRUCTION OH I II I. FLY-PRESS.
988
employed in punching holes, and cutting out numerous article*
from sheets of metal and other materials, but also in moulding,
stamping, bending or raising thin metals into n >: shapes,
and likewise in im[>iv»>iiig others with device* as in medals aud
Fig. 952 represents a fly-press of the ordinary construction,
that is used for cutting out works, and is thence called a cutting
piv-s in contradistinction to the stamping or coining presses. It
will be seen the body of the press, which is very strong, is fixed
upon a bed or base that is at right angles to the screw, the
latter is very coarse in its
pitch, and has a double or
triple square thread, the
rise of which is from about
one to six inches in every
revolution. The nut of
the screw is mostly of gun-
metal, and fixed in the
upper part or head of the
press. The top of the
screw is square or hexa-
gonal, and carries a lever
of wrought iron, terminat-
ing in two solid cast iron
balls, that constitute the
fly, and from the lever the
additional piece h, descends to the level of the dies to serve as
the handle, so that the left hand may be used in applying the
material to be punched, whilst the right hand of the operator is
employed in working the press.
The screw is generally attached to a square bar called thc/o/-
lower, which fits accurately in a corresponding aperture, and is
strictly in a line with the screw; and to the follower is attached
the punch shown detached at a. The punch is sometimes fitted
into a nearly cylindrical hole, and retained by a transverse jnn
or a side screw, but more generally the die is screwed into the
follower, like the chucks of some turning lathes ; the bed or bot-
tom die c, which is made strictly parallel, rests on the base of the
press, and is retained in position by the four screws, that pass
through the four blocks called dogs; these screws, which pomt
936 VARIOUS MODES OF CONSTRUCTING AND WORKING FLY-PRESSES,
a little downwards, allow the die to be accurately adjusted, so
that the punch may descend into it without catching at any
part, and thereby inflicting an injury to the tools.
The piece b, which rests nearly in contact with the die, is
called the puller off ; it is perforated, to allow free passage to the
punch ; when the latter rises, it carries up with it for a short
distance the perforated sheet of metal that has been punched
through, but which is held back by the puller off, whilst the
punch continuing its ascent rises above the puller off, and leaves
behind the sheet of metal so released ; the sheet is again placed in
position whilst another piece is punched out, and so on continually.
Before proceeding to speak of some of the works produced in
stamping presses, it is proposed to describe some of the points
of difference met with in fly-presses.
The body of a cutting press is in general made with one arm,
as represented in fig. 952, because the sheet of metal can be more
freely applied to the die, but stamping and coining presses,
which are used for pieces that have been previously cut out,
require greater strength, and have two arms, or are made some-
what as a strong lofty bridge with the screw in the center.
The fly of the press is frequently made as a heavy wheel, which
may be more massive and is less dangerous to bystanders than
the lever and balls, and in large presses there are two, three, or
four handles fixed to the rim, as many men then run round with
the fly, and let go when the blow is struck.
Fly-presses are variously worked by steam power ; thus in the
Royal Mint the twelve presses for cutting out the blanks or disks
for coin, are arranged in a circle around a heavy fly-wheel, which
revolves horizontally by means of the steam-engine. The wheel
has one projecting tooth or cam, which catches successively the
twelve radial levers fixed in the screws of the presses, to cut the
blanks, and twelve springs immediately return the several levers
to their first positions, ready for the next passage of the cam oil
the wheel.
The fly and screw are also worked by power, in some cases
by an eccentric or crank movement fixed at a distance, a long
connecting rod then unites the crank to an arm of the wheel, or
to a straight lever, and gives it a reciprocating movement.
At other times, in place of the crank motion are ingeniously
COINING-PRESSES, TOOOLt- J t >I M , AM) olHER PRESSES. 937
substituted a pi>ton aud cylinder worked after the manner of an
oscillating steam-engine, if we imagine tin- built r to be supcrst-di d
by a large chamber, exhan-tr.l by the steam-engine nearly to a
\;irmi m, thus t-on.stitutin^nu air engine, the one side of the piston
bring opened for a period to the exhausted chamber, whilst tbc
otlu •; > tlu full pressure of the atmosphere. This mode is
adopted in M M ral Mints, constructed by Mr. Hague, of London,
for foreign countries, aud the author believes it is ulso employ. <l
for the stamping or coining presses of our national Mint.*
Ill the manufacture of steel pens, (see page 942-3,) it is
important to have au exact control over the punches which cut
the slits, and those which mark the inscriptions, as by descending
too far they might disfigure the steel, or even cut it through.
Accordingly Mr. Mordan introduced between the head of the
press and the lever, au adjustable ring which acts as a stop,
and only allows the punches to descend to one definite distance ;
until in fact the ring is pinched between the press and lever.
The screw of the fly-press, is sometimes superseded by a con-
trivance known both as the toggle-joint, and as the knee-joint.
The two parts a, b, and b, c, fig. 953, are jointed to each other at b,
Figs. 953.
954.
the extremity a, is jointed to the upper part of the press, and
c, to the top of the follower, \\lw\\ the parts a, b, and b, c, are
im-lim il at a small angle the extremities a, and c, are brought
closer together, and raise the follower, but when the two levers
are straightened, a and c separate with a minute degree of
motion, but almost im>Mible power, especially towards the
• Sc« Encyclopedia Metropolitan*, part Manufactures, article Coining.
938 EXAMPLES OF PUNCHED WORKS; COIN,
completion of the stroke. The bending and straightening of the
toggle-joint, is effected by the revolution of a small crank, united
to the point b, fig. 953, by a connecting rod b,f.
Presses with the toggle-joint are perfectly suited to cutting
out works with punches and bolsters, provided the relative thick-
ness of the woik and tools are such, as to bring to bear the
strongest point of the mechanical action, at the moment the
greatest resistance occurs in the work ; but as the fly-press with a
screw is in all cases powerful alike, irrespective of such propor-
tions, provided alone that there is sufficient movement to create
the required momentum, the fly-press is more generally useful.
The cut 954 refers to a lever press worked by an excentric,
and used in cutting brads and nails, which will be again alluded
to when this manufacture is briefly noticed.
It is now intended to describe a few examples of works exe-
cuted in fly-presses, giving the preference to those appertaining
to mechanism.
The round disks of metal for coin are always cut out with the
fly-press, and are then called blanks, the punch being a solid
cylinder, the bed or bolster a hollow cylinder that exactly fits it.
In the gold currency, more especially, great care is taken to make
these punches as nearly as it is possible mathematically alike in
diameter, and the sheets of gold also mathematically alike in
thickness, by aidof the drawing rollers or rather drawing cylinders
referred to in vol. i., page 428 ; but notwithstanding every pre-
caution the pieces or blanks \vhen thus prepared do not always
weigh strictly alike. This minute difference is most ingeniously
remedied, by using the one error as a compensation for the
other. Trial is made at each end of every strip of gold, and
by cutting the thicker gold with the smaller punches, the adjust-
ment is effected with the needful degree of accuracy, so that
every piece is made critically true in weight, without the tedious
necessity for weighing and scraping, otherwise needful.
Buttons are made in enormous quantities by means of the fly-
press. That metal buttons should be thus cut out with tools and
stamped with dies, will be immediately obvious to all, but the fly-
press has been also more or less employed in making buttons
of horn, shell, wood, papier-mdche and some other materials.
Amongst others maybe noticed the silk buttons called, Florentine
BUTTON*, WASHERS, CHAINS. !'."/>>
l>nt tons, each of which consists of several pieces that are cutout
in presses, then enveloped hy the silk covering, and clasped
together at the back, (in the press,) by a perforated iron disk,
the ii iir-in of which is formed into 6 or H points that clutch and
hold the silk, whilst the cloth hy which the button is sewed on, is
at the same time protruded through the center hole in the back
plate of the silk button ; details that may be easily inspected by
pulling one of them to pieces. Indeed great ingenuity has been
diMilayed, and many patents have been granted, for making this
necessary article of dress, a button.
Round washers that arc placed under bolts and nuts in
machinery, are punched out just like the blanks for coin ;
although in punching the larger washers, that measure 5 and
6 inches in diameter and J inch thick, with the ordinary fly-
-QS, the iron requires to be made red hot.
The round or square holes in the washers arc made at a second
process with other tools, and to ensure the centrality of the holes,
some kind of stop is temporarily affixed to the lower tool. The
more complete stop is a thin plate of iron hollowed out at an
angle of from 90 to 120 degrees and screwed on the top of the
bed, as this may be set forward to suit various diameters. But the
more usual plan, is to drill two holes in the bed, to drive in two
wires, and to bend their ends flat down towards the central hole
as also shown in fig. 955 overleaf, the ends of the wires are Bled
away until, after a few trials, it is found the blank when held
in contact with the stops by the left hand, is truly pierced; the
whole quantity may be then proceeded with as rapidly as the
hands can be used, with confidence in the centrality of all the
holes thus produced.
Chains with flat links that are used in machinery are made in
the fly- press. The links are cut out of the form shown at a, fig.
956, the holes arc afterwards punched just as in washers and one
at a time, every blank being so held that its circular extremity
touches the stops on the bed or die, and thereby the two holes
become equidistant in all the links, which are afterwards strung
together hy inserting wire rivets through the holes.
The pins or rivets for the links, are cut off from the length of
wire in tho fly-press, by a pair of cutters like wide chisels with
square edges, assisted by a stop to keep the pins of one length ;
or by one straight cutter and an angular cutter hollowed to about
940
PUNCHING LARGE CHAINS FOR MACHINERY.
60 degrees ; or by two cutters each hollowed to 90 degrees. lu
the three cases, the wire is respectively cut from two, three, or
four equidistant parts of its circumference; semicircular cutters
are also used. The straight cutters first named, are moreover
very usefully employed in the fly-press for many of the smaller
works, that would otherwise be done with shears.
Sometimes the succession of the links for the chain, is one and
two links alternately as at b, fig. 956 ; at other times 3 and 2, or
4 and 3 links, as at c, and so forth up to about 9 and 8 links
1 1 ,' 1 ' i 956.
alternately, which are sometimes used, and the wires when inserted
are slightly riveted at the ends.
The pin is generally the weakest part of the chain and gives
way first, but in the chains with 8 and 9 links, the pin must be cut
through at 16 places simultaneously, before the chain will yield.
Chains are sometimes intended to catch on pins or projections,
around a wheel of the kind shown in fig. 958, to fulfil the office
of leather bands, without the possibility of the slipping, which
is apt to occur with bands when subjected to unusual strains.
Such chains are made after the manner shown in fig. 957,
to constitute the square openings that fit over the pins of the
wheel, the central links are made shorter, by which means the
apertures are brought closer together than if the longer links
were used throughout. Fig. 959, shows a different kind of chain,
that has been used for catching in the teeth of an ordinary spur
wheel with epicycloidal teeth, the author believes this chain
to have been invented by the late Mr. John Oldham, Engineer
to the Bank of England.
Chains for watches, time-pieces, and small machinery, are
too minute to be made as above described, therefore the slip
of steel is first punched through with the rivet holes required
for a number of links, by means of a punch in which two steel
PUNCHING SMALL CHAINS FOR WATCHES AND JEWELLERY. I'll
wires are inserted; tin distance between the intended links is
ohuinrd, (somewhat as in file-cutting,) by resting the burrs of
the two previous holes, against the sharp edge of the bed or
bolster. The links are afterwards cut out by a punch and bolster
of the kind already noticed, but very minute, and the punch has
two pins inserted at the distance of the rivet holes, the slip of
steel being every time fitted by two of the holes to these pins,
all the links are thereby cut centrally around the rivet holes.
The tools are carried in a thick block having a perpendicular
square hole, fitted with a stout square bar, the latter is driven
with a hammer, which is supported on pivots, raised by a spring,
and worked by a pedal ; but when the links measure from ^ to ^
nn inch in length, such tools are worked by a screw.
The punches are fitted to the side of the square bar, in a pro*
jecting loop or mortise, and secured by a wedge. They are
drilled with holes for the pins, and across each punch there is a
deep notch to expose the reverse ends of the pins, in order
that when broken they may be driven out and replaced. The
pins are taper-pointed, that they may raise burrs, instead of
cutting the metal clean out, and being taper, no puller-off is
required, and the bed tools are fitted in chamfer grooves in the
base of this old yet very efficient instrument.
A large chain for a pocket chronometer now before the author,
measures nearly 14 inches in length, and contains in every inch
of its length 92 rivets and also 33 links, (in three rows) ; the
total number of pieces in the chain is therefore 770, and its
weight is 9} grains. A chain for a small pocket watch, measures
6 inches in length, and has 42 rivets and 63 links in every inch, in
all »530 pieces, and yet the entire chain only weighs one grain and
three quarters.
The square links of chains for jewellery are often cut out with
punches, the exterior and interior being each rectangular ; after
which each alternate link is slit with a fine saw for the introduc-
tion of the two contiguous links, and then soldered together so
that the gaps become filled up. Other chains are drawn as
square tubes, and cut off in short lengths with a saw, these after
living been strung together are often drawn through a draw-
plate uitli round holes, to constitute chains which present an
almost continuous cylindrical surface like round wire; a very
neat manufacture invented in France.
942 PUNCHING TEETH OF SAWS, COPPER CAPS, AND STEEL PENS.
The teeth of saws are for the most part cut in the fly
press. Teeth of the forms figs. 643 to 647, page 684, whether
large or small require but one punch, the sides of which meet at
60 degrees. Two studs are used to direct the edge of the blade
for the saw to the punch, at the required angle depending on the
pitch or inclination of the teeth, and an adjustable stop deter-
mines the space or interval from tooth to tooth, by catching
against the side of the last tooth previously made. Gullet
teeth, figs. 650 to 653, and the various other kinds shown,
require punches of their several compounded figures, and of
different dimensions of each size of tooth.
The teeth of circular saws are similarly punched out by
mounting the perforated circular disk on a pin or axis, but in
cutting the last six or eight teeth, it is needful to be watchful so
as to divide the remaining space into moderately equal parts.
In cutting the teeth of circular saws not exceeding 12 inches
diameter, Holtzapffel and Co. have been in the habit of mount-
ing the steel plates on a spindle in a lathe with a dividing plate,
and iising a punch and bed fitted to a square socket, fixed
horizontally in the ordinary rest or support for the turning
tool, the punch being driven through the plate by one revolution
of a snail or cam, by means of a winch handle, and thrown back
by a spring. In this arrangement the dividing plate ensures the
exact dimensions and equality of the teeth, which are rapidly and
accurately cut.
The copper caps for percussion guns are punched out in the
form of a cross with short equal arms, or sometimes in a similar
shape with only three arms, and the blanks, after having been
annealed, are thrown into form by means of dies, which fold up
the arms and unite them to constitute the tabular part, whilst the
central part of the metal forms the top of the cap that receives
the composition, and sustains the blow of the hammer.
Steel pens are another most prolific example of the result of
the fly-press, they pass through the hands many times, and require
to be submitted to the action of numerous dies, to five of which
alone we shall advert. The blanks are cut by dies of the usual
kind so as in general to produce a flat piece of the exterior
form of fig. 960, page 944, the square mortise at the bottom of
the slit is then punched through, the next process is usually
to strike on the blanks the maker's name.
LARIVIERE'S PERFORATED SHEET METALS. 94$
The slit is now cut by a thin chisel-like cutter, which makes
an angular gap nearly through the steel, from that side of the
metal intended to form the inner or concave part of the pen, and
the net of curling up the pen into the channelled form, hrings
the angular sides of the groove into contact, rendering the slit
almost invisible. The slit which is as yet only part way thron_-li
the pen, is in general completed in the process of hardening,
(see vol. i. page 249,) as the sudden transition into the cool
liquid, generally causes the little portion yet solid to crack
through, or else the slit remains unfinished, until the moment
the pen is pressed on the nail to open and examine its nibs.
Lariviere's perforated plates for strainers, lanterns, meat safes,
colanders and numerous other articles, exhibit great delicacy and
accuracy in the mode in which they are punched out ; the tools
are illustrated by the enlarged sections, fig. 961 overleaf. The
punch consists of a plate of steel called the punch plate, which
is in some cases pierced with only one single line of equi-
distant holes, that are countersunk on their upper extremities.
Every hole is filled with a small cylindrical punch made of steel
wire, the end of which is bumped up, or upset to form a head
that fills the chamfer in the punch plate, so that the punch
cannot be drawn out by the work in the ascent of the press.
The bed punch or matrix has a number of equidistant holes
corresponding most exactly with the punches. In this case the
holes in the work are punched out one line at a time, and
between each descent of the punches, the sheet of metal is
shifted laterally by a screw slide, until it is in proper position
to receive the adjoining line of holes.
At other times the tool instead of having only one line of
punches, is wide and entirely covered with several lines, so as to
punch some hundreds or even thousands of holes at one time.
For circular plates the punches are sometimes arranged in one
radial line, but more usually, the whole of the punches required
for the fourth, sixth or eighth part of the circular disk are placed
in the form of a sector, and the central hole having been first
punched, is made to serve as the guide for the four, six, or eight
positions, at which these beautiful tools are applied.
Many of the thin plates thus punched require to be strained
like the head of a drum to keep the metal flat, in which case the
metal is grasped between little clamps or vices around its four
944
LARIVIERE'S AND JEFFERY'S PATENTS.
edges, and then stretched by appropriate screws and slides with
which the apparatus is furnished, and the same mechanism pre-
vents the metal from rising, and therefore fulfils the office of
the puller-off commonly used with punches.
The construction of the tools above described, calls for the
greatest degree of precision, the drill employed to pierce the
punch and matrix is of the kind fig. 474, page 547, and of
exceedingly small size in the finest perforated works, as it is
Figs. 960.
961.
962.
said so many as six or seven hundred holes have been inserted
in the length of six inches, which, considering the intervening
spaces to be half as wide as the diameter of the holes, would
make the latter of the minute size of only six thousandths of an
inch diameter. Such finely perforated metal appears to offer
nearly the transparency of muslin, and is a manifest proof of
the great skill displayed in the construction of the instruments
and in conducting the entire process.*
Mr. Julius Jeffery's Patent Respirator, or breath-warming
apparatus, for persons having delicate lungs, presents another
very neat example of punched works. Most persons will have
had an opportunity of seeing, that the apparatus consists of
about a dozen very thin plates of metal, punched out with several
rows of large rectangular holes, leaving the metal like a delicate
lattice. These lattices are severally wound round with fine wire
and then assembled together between perforated covers. The
exhalation of the breath amidst the interstices of the wires,
warms the instrument, and the instrument in return, warms
the air that is inhaled by the wearer.
To return to the operation of punching the lattices, it is to
* M. Marc Lariviere's patent was granted 28th Nov. 1825, and is described in
the Repertory of Patent Inventions, vol. iii. 3rd Series, page 182. Some other
particulars are to be found in Gill's Technical Repository, vol. ix., 1826, page 375,
translated from the Bibl. Univ., for Dec. 1824.
PU.XCHINO JEFFREYS PATK.VT RKSPI R ATOHi.
be observed these in can u re from center to center, half an inch in
length and one fifth of an inch in breadth, the bed punch which
;>ivM-nted in fig. 962, is a piece of steel about f inch thick,
banni; a central aperture, :'• \ incites long, and 18 hundredths of
an incli wide, as the long bars of the lattices are two hundredths
wide. Six transverse notches, one eighth of an inch deep and
half an inch asunder, are then made across the bed with a cir-
cular saw three hundredths of an inch thick, the grooves are
fitted with slips of hardened steel, after which, the whole is
ground to a level surface. The punch is a plate of steel 8$
inches wide and '18 thick, across which six notches about I inch
deep, are also made with the circular saw at intervals of 4 inch.
The press has a puller-off or stop much as usual, and at the
back it has a long screw of five threads in the inch, the nut of
which has two square pins exactly like the two exterior portions
of the punch. The copper, which measures about one hun-
dredth of an inch thick, is cut in long wide strips, and one row
of holes having been punched, the piece is hooked on the two
pins of the nut, and when the screw has moved once round
under the governance of a spring catch, a second row of holes
is punched exactly one fifth of an inch from the former, and so
on. When five rows have been punched, the screw is moved
two turns to leave a wide rib, and another series of five rows
is punched, and so on alternately, and afterwards the lattices
are separated through the wide ribs with a pair of shears. Some
of the lattices of small respirators have only six rows in the
long and four in the narrow direction, and others five rows by
three, thus making three distinct sizes with the same tools, and
all present a most beautiful regularity and slcndcrness.*
All the foregoing examples of punched works, suppose the
punch to have been fixed to the follower of the press, and the
matrix to the base of the same, in which case the bed punch
requires to be very exactly adjusted by the set screws or dogs of
the press. But it remains in concluding this section, to advert
to a different arrangement in which the cutting tools are quite
detached, and are far less liable to accident or fracture, even
* Patent granted to Mr. Julius Jefferym, for his improvement* in curing or
relieving di-ordera in the lung*. Sealed, 23rd January, 1836. Published in
Repertory of Patent Invention!, Vol. vi., 4th Series, page 211. The patent
respirator u very fully described, but not so the machinery.
3 i-
946 PUNCHES MADE IN DETACHED PIECES AND
when the punches are of very large area and complicated figure,
than when constructed in the ordinary manner with a shank
by which they are united to the follower of the press. In this
present case, the press has merely two flat surfaces six or eight
inches in diameter, or square and of similar size, thereby more
nearly resembling a hammer and anvil, of a very powerful and
exact kind, to which the fly press was first compared.
Punches to be used in this manner, for works with various
detached apertures requiring any especial arrangement, and for
various straggling and complicated objects, are constructed as
shown in figs. 963 to 965. There are two steel plates some-
what larger than the work, and from 37 to f thick, the plates
are hinged together like the leaves of a book, but are placed
sufficiently distant, to admit between them the work to be
stamped out, and which is pinched between them by a thumb
screw a. The two plates whilst folded together, are perforated
with all the apertures required in the work, which perforations
may be either detached, continuous, or arranged in any orna-
mental design that may be required. To all the apertures are
fitted punches, which in length or vertical height, are about one
eighth of an inch longer than the thickness of the upper plate,
so as to stand up one eighth when resting on the material to be
punched, as seen in the partial section 965, in which the work
is shaded obliquely and the punch vertically.
As it would be difficult to fit the punches in one single piece
to the ornamental or straggling parts of some devices, and as
moreover such large and complicated punches, would be almost
sure to become distorted in the hardening, or broken when in
use, the difficulty is boldly met, by making the punch of as
many small pieces as circumstances may render desirable, but
which pieces, must collectively fill up all the interstices of the
plate.
In using these punching tools, it is only necessary first to fix
between the plates the metal to be pierced, then to insert all the
punches into their respective apertures, and lastly to give the
whole one blow between the flat disks of a powerful fly press,
this drives all the punches through the work, and leaves them
flush with the upper surface. The whole is then removed from
the press, and placed over an aperture in the work bench, and
with a small drift and hammer the punches are driven out of the
TtlEIR API \ TO BUHL WORK. CUT BRADS.
phi: )>eneath, awl on tin- plates being separated,
the \\..ik \\ill In- found to he exactly perforated to the -v>
design as that of the tool itself ; or with any part of the design
intern! of tl»e whole, if part only of the punches were inserted in
tli< ;. luces. The punches are selected from amidst
the corresponding pieces of brass, which latter are laid on one
side, and the routine is recommenced.
It i> by this ingenious application of punches that buhl works
are stamped, as referred to in the foot note page 737 of this
volume. If a honeysuckle should be the device, the piece of
brass is first placed between the plate and punched out, and
provided the punches are of the same length, the honeysuckle
F. - :• "\
is removed in one piece although the punch may be in several;
the wood is afterwards inserted, and is punched to exactly the
same form, so that the brass honeysuckle will be found to fit in
the most perfect manner as it is an exact counterpart of the
removed wood.
The process is very economical and exact, but is only suited
to large designs, because of the injury it would otherwise inflict
on the wood, and on account of the expense of the tools, the
•mode is only proper for those patterns of which very large num-
bers are wanted ; whereas the buhl saw is not liable to these
limitations, but is of universal, although less rapid application.
Cut brads and nails or those which instead of being forged, are
cut out of sheet iron by machinery, constitute the last example it
is proposed to advance in this section.
Brads of the most simple kind as in fig. 966, have no heads,
but are simply wedge form, and are cut out of strips of sheet
iron, equal in width to the length of the brads, these strips are
slit with circular shears, transversely from the ends of the sheets
3 P 2
948 THE MANUFACTURE OF CUT BRADS AND NAILS
of iron so that the fibre of the iron may run lengthways through
the nails.
When such brads are cut in the fly press, the bed has a
rectangular mortise shown by the strong black line in fig. 966, the
punch is made rather long and rectangular so as exactly to fill
the bed, but the last portion of the punch, say for half an inch of
its length, is nicked in, or filed back exactly to the size and angle
of the brad, as shown in the inverted plan, in which the shaded
portion shows the reduced part or tail of the punch. The punch
is never raised entirely out of the bed, in order that the strip
of metal may be put so far over the hole in the bed, as the tail
of the punch will allow it, and also in contact with a stop or pin
fixed to the bed, and in the descent of the punch its outer or
rectangular edge removes the brad.
The strip of metal is turned over between every descent of the
press, so as to cut the head of the one brad from the point of that
previously made, and the double guides afforded by the tail and
stop, enable this to be very quickly and truly done. The upper
surface of the bed is not quite horizontal but a little inclined, so
that the cutting may commence at the point of the brad, and
thereby curl it less than if the tools met in absolute parallelism.
In cutting brads that have heads, the general arrangements are
somewhat different as explained in the diagram fig. 967, in which
as before, the rectangular aperture in the bottom tool is bounded
by the strong black line, the tail of the punch is shaded, the stop
*, is situated as far beyond the aperture iu the bed, as the vertical
height of the head, and it is so made that the small part which
extends to the right, overhangs the slip of iron that is being cut,
after the manner of a puller-off ; but the overhanging part only
comes into action when the slip is tilted up, either by accident, or
from being so short as to give an insufficient purchase for the
hand. It is also to be observed that the width of the point of
the brad, is just equal to the projection of its head.
On the end of the strip of iron being first applied, a wedge-
farm piece is cut off, exactly equal to the difference between the
tail of the punch and the bed, and a little projection is left near 8,
and which projection, after the iron is turned over, rests against
the tail of the punch, as shown in the figure, so that the succeed-
ing cut removes the one brad and forms the head of the follow-
ing : the tail of the punch being inclined to the precise angle
li V riNCHINO AND SHEARING TOOLS. '.< L'J
iir:i\Mi Jr.. in the point to the head of the brad, as denoted in
tin- digram.
\N lim, 'as it is more usual, brads are cut out by steam power,
tin- cutters are not worked iu a fly press, but the moving cutter
i> commonly fixed at the end of a long arm which is moved rapidly
up and down by a crank ; the strip of metal is held in a spring
clamp, tt •riniuatiiiir in an iron rod, which rests in a Y or fork,
so that the boy who attends the machine, can turn the metal over
very rapidly between every alternation of the machine; these
particulars are shown in fig. 954-, page 937.
The machine fig. 954, may be used for brads either with or
without heads, it is, however, always necessary to turn the iron
over between every cut ; but in the toggle press fig. 953 on the
same page, and which acts much more quickly, it is not requisite
to reverse the metal, as the entire press is moved on its pivots
e et by the rod g, so as to incline the press alternately to the
right and left, to the angle of sucli nails as are simply wedge-
form, or have no heads, as iu fig. 966, page 947.
In some machines resembling fig. 954, the nail as soon as cut
off is grasped in a pair of forceps or dies, whilst a hammer, also
moved by the machine, strikes a blow that upsets the metal, and
constitutes the flat head in the kinds known as cut nails, and tacks.41
* The first patent for making nail* that the author baa met with, was granted
to John Clifford, 17th July, 1790 (see Repertory of Patent Inventions, 1st Series,
Vol. vii., p. 217). The mode preferred by the patentee, was to employ two roller*
of iron faced with steel, in which were sunk impressions of the nails, half in each
roller. The indentations were arranged circumferentiully with the heads and tails
in contact, so as to extend the grooves around the roller, and roll the whole rod of
iron into a string of nails, which required to be separated from each other with
shears, nippers, or other usual means. Sometimes many grooves were cut around
the rollers, and a sheet of iron was then converted into several strings of nails
that required to be separated nearly as before.
The same inventor took out a second patent, about six months later, for a method
of making nails by punching. The plates of metal were forged or rolled taper to
the angle of the naiU, and were then cut up by a punch and bed, each made taper
and also to the angle of the nail. Nails that required heads were afterwards put
into a heading tool or bed, having a taper hole of corresponding form, that k-ft
a small piece of the thick end projecting ; and the head was upset with a punch or
die, just after the manner now practised in making solid headed pins. This second
patent was sealed on the 4th of Deo., 1790. and is described in the 377th page of
the volume before referred to.
Subsequently to this period not less than thirty to forty patents have been
granted for making brads and nails, and some three or four of them have been
very successfully worked.
950 PUNCHING MACHINERY USED BY ENGINEERS.
SECT. IV. PUNCHING MACHINERY USED BY ENGINEERS.
After the remarks offered on pages 919 to 923, on shearing tools,
little remains to be said in this place on the punching machinery
used by engineers, as it was there stated that the cutters for
shearing and the punches, were most usually combined in the
same machine; the punch being placed either at the outer extre-
mity of the jointed lever, or at the bottom of the slide in those
machines having rectilinear action. The punch is fixed to the
slide or moving piece, the die is secured to the framing by
means of four holding and adjusting screws just as in fly-presses,
and the puller-off or stop is likewise added, all which details are
represented in the woodcuts on pages 920 and 922.
The principal application of the engineer's punching engine,
is for making the rivet-holes around the edges of the plates of
which steam-boilers, tanks and iron ships are composed. Another
important use, and in which the punches trench upon the office of
the shears, is in cutting out curvilinear parts and apertures
or panels in boiler work, to which straight-bladed shears cannot
be applied. In this case the round punch is used in making
a series of holes running into one another, along the particular
line to be sheared through, or in other words the punch is used as
a gouge, by which the hole that has been first formed, is extended
by cutting away crescent-form pieces, thus leading the incision in
any required direction.
This employment of the punch to shearing curved lines, is also
much used in cutting out the side plates of the framings of loco-
motive engines, which consists of two pieces of stout boiler plate,
(the technical name for iron in sheets from ^ to f inch thick,)
riveted alongside a central piece of wood, that is sometimes
also covered above and below with iron, all the parts being united
by rivets. The punching engine serves admirably for cutting out
all the curved lines in these side plates, also the spaces where
the bearings for the wheels are situated, and various apertures.
Messrs. Maudslay Sons & Field introduced, many years back,
a very great improvement in the punching engine, as applied to
making boilers and tanks, in which the rivet-holes are usually
required to be made in straight lines, and at exactly equal dis-
tances, so that holes in two pieces punched separately may exactly
correspond.
MAUDSLAY'S PUNCHING MACHINERY. EXPERIMENTS, ETC. 951
'I'll.- plate was fixed down upon a long rectilinear slide or
carriage, and during every ascent of the punch, was advanced
by tin- machine itself, the interval from hole to hole, the moment
after the punch was disengaged from the work. Subsequently,
2, 3, or 4 punches were fixed at equal distances in the vertical
slide, but the punches were made of unequal lengths, to that
they came successively into action, thereby dividing the strain,
and the horizontal slide was consequently shifted every time a
distance equal to 2, 8, or 4 intervals. This machine, which dis-
played much ingenuity of invention, served as the foundation of
the more simple punching engines that are now met with.*
This volume will be concluded by the account of two sets of
experiments in punching. The first "An account of some experi-
ments to determine the force necessary to punch holes through
plates of wrought iron and copper by Joseph Colthurst." f
"These experiments were performed with a cast iron lever, 11
feet long, multiplying the strain ten times, with a screw adjust-
ment at the head, and a counterpoise." — "The sheets of iron
and copper which were experimented upon, were placed between
two perforated steel plates, and the punch, the nipple of which
was perfectly flat on the face, being inserted into a hole in the
upper plate was driven through by the pressure of the lever."
" The average results of the several experiments (which are
given in a detailed tabular form), show that the power required
to force a punch half au inch diameter through copper and iron
plates is as follows :
• Messrs. Maudslay contrived their machine, in order to manufacture in a abort
•pace of time, a very considerable number of water tank* for the Royal Nary ; the
machine is carefully engraved in plate* 51 and 52 of Buchanan's Treatise on Mill
Work, edited by O. Rennie, Esq., F.R.S.
Other punching engines, some of them with shears, are also engraved on pages
48, 50, and 52* of the same valuable work.
The plate 52* contains the section and elevation of a steam punching machine
by Mr. Cave*, of Paris ; it is in effect a combination of the punching machine with
the high pressure steam engine. This machine may carry either punches or
•hearing cutters at pleasure, but although apparently more costly than those
actuated as usual by a simple crank movement, it does not appear to be so con-
venient, neither would it be politic to construct every machine in a factory, so as
to include a steam engine for its own especial use.
t Extracted from the Minutes of Proceedings of the Institution of Civil
Engineers for 1841, pages 60-1.
952 COULTHURST'S AND HICK'S EXPERIMENTS IN PUNCHING.
Iron plate 0-08 thick, required a pressure of 6,025 Pounds.
-0-17- -11,950—
-0-24- —17,100-
Copper plate 0'08 - 3,983—
-0-17- - 7,883—
" Hence it is evident, that the force necessary to punch holes
of different diameters through metal of various thicknesses, is
directly as the diameter of the holes and the thickness of the
metal. A simple rule for determining the force required for
punching may be thus deduced. Taking one inch diameter and
one inch in thickness as the units of calculation, it is shown that
150-00 is the constant number for wrought-iron plates, and 96*000
for copper plates. Multiply the constant number by the diameter
in inches, and by the thickness in inches ; the product is the
pressure in pounds, that will be required to punch a hole of a
given diameter through a plate of a given thickness."
" It was observed that the duration of pressure lessened con-
siderably the ultimate force necessary to punch through metal,
and that the use of oil on the punch reduced the pressure about
8 per cent." A drawing of the experimental lever and apparatus
accompanied the communication.
The second experiments were by Mr. Hick, of Bolton, who by
means of a hydrostatic press having four cylinders in combina-
tion, punched through various pieces of iron ; the thickest of
them measured 3£ inches thick, and from which was punched
out a disk of 8 inches diameter, with a pressure of 2000 tons.
The removed piece was rather thinner than the remainder and
a little taper, which arose from the circumstance of the bolster
having been purposely made with a flat bottom, and a little
larger in diameter than the punch, so that the disk when
removed was a little spread or flattened out.
It is curious that experiments so distant from one another in
their scale of proportion, should yet agree so nearly ; by Mr.
Colthurst's formula
The computed force is . . 150-000 x 8 x 3^=4-200-000 Ibs.
The actual force was . . 2000 x 20 x 112 = 4-480-000 Ibs.
END OF THE SECOND VOLUME.
APPENDIX.
D*ri*g At period in which the Second Volume of Ait Work hat been
through tke prttt, variout new and additional matttrt laving relation both to Ike
firtt and teeond volume* have earn* under the author1 1 notice ; Ae more important
of Aete additions art ken given. By interting in At body of Aejtrtt edition of
At work reference! at follow:— Me Appendix note H. — note I, dx., at Ae paget
respectively designated, Ae notet will come under observation at their appropriate
placet in At tea*.
Note H, Pag* 22— To follow the Foot Note.
( Payne' t Patent for preferring timber, by the double decomposition, of sulphate of iron
and muriate of lime, wUhin Ae poret of Ae wood.)
IN this process, which in now more resorted to than others for this purpose,
several pieces of timber are arranged side by side on a sledge, bound together by
hoops and chains, and thus introduced upon a railway into a long cylindrical iron
Tessel, the cover or end of which ia then screwed on air-tight Steam is now
admitted, first to drive out the air, through a valve opened for the purpose, and then
to form a vacuum, which partially occurs when a little of the cold solution of
tulphate of iron is pumped into the vessel, by means of the steam engine, to condense
the steam ; the vacuum is then completed by an air pump, the liquid flows in as the
air is exhausted, and is ultimately subject to pressure by force pumps also worked
by the steam engine : this fills all the pores of the wood with sulphate of iron. After
a few minute* the sulphate is allowed to flow out of the tank by the re-admission of
air, the vessel is again heated with steam, and is similarly filled with muriate of lime.
A double decomposition instantly occurs within Ae port* of the wood, as the muriatic
acid goes over to the iron, forming muriate of iron, and the sulphuric acid
proceeds to the lime, forming solid sulphate of lime or gypsum, the Utter
remains principally in the pores, whilst the muriate of iron pervades the wood
generally. The entire process of preparing the timber, including the filling and
emptying of the tank requires from one to three hours, according to the sue of
the cylinder. The wood becomes much heavier, iudisposed to decay, less combus-
tible, darker in colour, and also proof against rot and the ravages of insects.
By certain variations of the process, and the employment of some other salts, the
light coloured English wood* may be stained in a variegated manner throughout
their substance, so an to be available for making ornamental furniture, but the prin-
cipal application hitherto made of the process, (for which the patent was specified
in January 1842,) ia for preparing timber for railway purposes, and for building,
especially the wood used in piles and wet foundations.
Mr. Payne has a new patent, which will be shortly specified, designed for a dif-
ferent preparation of timber for the sheathing of ships and sea walls.
Note I, Page 25— To follow the Foot Note.
(Tke BauKUk or Indian Adit.)
" By far the handiest instrument, (said the late Sir John Robison,) for blocking
either hard or soft wood for the lathe, is the BaeaoflHh or Indian adte, with a head
934 APPENDIX NOTES I, J AND K.
of from 1 J to 2 pounds weight The eye is conical and made widest at the upper
end, so that the handle may be knocked out to allow of the adze being ground."
The Bassoolah is represented at d fig. 318, page 473, of this present volume.
Notes J, K, L, Page 46— To conclude the Page.
Note J.—Afr. Irring's Carving Machine.
Since the period at which Messrs. Braithwaite's patent for carving wood by burning
was granted in Nov. 1840 (see Note A, Appendix vol. i.) two other important patents
have been taken out for carving wood by revolving cutters, and on each of which
patents a few words will be now offered.
Mr. Irving's Patent, sealed November, 1843, although it maybe used for figures
in low or high relief, is principally applicable to works in one plane, such as the
mouldings of Gothic tracery, whether straight, curved, or undercut, and of all
sections ; the work is generally executed from templets or pattern plates.
The revolvingdrill, or cutter, which is made globular, elliptical, or of the particular
section of the moulding, is mounted on a vertical axis at the end of a swinging arm
or lever, which is jointed to the solid framing of the machine. The wood or
other material to be carved, is fixed towards the edge of a circular table that is
free to move on a vertical and central post. The arm with the drill is capable
of being adjusted vertically by means of a treadle, to make the tool penetrate
more or less deeply into the work.
As therefore the drill may be moved in one arc, say nearly from east to west by
swinging the arm upon its axis, and as the work may also be moved in another arc,
nearly as from north to south, by swinging the table round upon its axis, and as
these two motions may be accomplished simultaneously and in any relative degrees
by the two hands, any outline that has been drawn on the work may be readily
followed with the drill or cutter. But more usually a perforated templet is affixed
upon the work, and the end of the cylindrical spindle or drill socket is allowed to
rub against the templet, in order that the drill may cut away all the material
between the interstices of the templet, and which latter mode is much the more
rapid and exact, especially when many copies of the same work are required.
Many of the mouldings both in wood and soft stone, that are used in the new
Houses of Parliament, are in the course of manufacture by this machine, which is
now the property of Mr. Pratt, of London.
Note K, to follow Note J, on Page 46.
Mr. Jordan's Patent Carving Machine.
Mr. Thomas Brown Jordan's Carving Machine, patented Feb. 17, 1845, is more
employed for figures and ornaments than for mouldings, and two copies are
generally carved at once, the pattern being placed midway between them.
The model and the wood for the copies are fixed, say exactly 8 or 10 inches
asunder, upon a rectilinear slide free to move from north to south, and which
elide moves upon a second rectilinear slide free to move from east to west, these
two slides run upon anti-friction rollers, and together support what is called " the
floating table" upon which the work is fixed. The two movements of the table are
under the guidance of the two hands of the workman, while he controls a third slide
with his foot. The third slide, which is vertical to the other two, carries in the
center a tracer of globular form, and also at 8 or 10 inches on the right and left of
: KNDIX— KOTBI K ANl» L '.«").">
the tracer, cutters of the Mroe globular fora, which Utter are both net to make
about 0000 or 7000 revolution* in the minute. The third »li«le, which together with
tracer and two cutters foroM one entire mww, when left to itaelf descends with
a moderate prwwure that sends the two cutter* into the two block* of wood, until
the central tracer reete in contact with the model, the cutting then ceases, and the
•li.Ie is raieed from the work by the treadle.
In thU manner by a multitude of Tcrtical incisions at different part*, the whole of
the material might be cut away until the copie* were reduced to the exact form of
the model. But it is a more expeditious mode, together with the vertical motion of
the drilla and tracer, to moTe the work about horizontally by meane of the two tilde*,
as in every each rambling motion, the cutting will cease when the tracer oomee in
contact with the model. The only conditions are, that the cutter and tracer be
exactly alike in form and size, and that the distance between them, and also the
distance between the model and copies, whether 8 or 10 inches or other measure,
be fixedly preserved throughout the one process.
The above case, in which the work lies always horizontally, is that most usually
required ; but when the work has to be carved on all three sides, as for example in
brackets or consoles projecting from a wall, although the arrangement of the cen-
tral tracer and the cutters parallel therewith partaking of a vertical motion in
common, remains unaltered, the model and copies are all three adjusted so as at one
time all to lie on their backs, at other times all on their right or left sides with the
progress of the work. Sometimes this change ia effected simultaneously by mount-
ing them on platforms, that are situated on fixed, parallel, and equidistant axes, and
shifting all three at one movement, by a simple arrangement derived from the ordi-
nary parallel rule with radius ban.
In the case of figures carved in the round, or on every side, the central model
and two copies are built above one wide bar, upon three circulating pedestals or
turn-plates with graduations and detents, by which the three objects may be alike
twUted round to face any point of the compass ; and as the wide bar upon which
the three circulating pedestals are built, has a tilting motion by which the three
pedestals may be all alike placed either horizontally, or inclined, to the right or left
in any required degree, until nearly vertical, it ia clear that these two directions of
motion constitute universal joints, and enable any and every similar part, of all
three objects, to be presented to the tracer and cutters respectively.
Messrs. Taylor, Williams, and Jordan, of London, employ these carving machines
for all the woods, and occasionally for soft stones, marble, and alabaster, and these
machines as well as Mr. Pratt's are also contributing largely to the embellishment
of the New House* of Parliament and other buildings now in course of being
erected.
Note L. — To follow Notes J and K on page 46.
(Mr. Toauft Patent Dentifaetor, for making artificial Gunu, Teeth, mid Palate*.)
Another variety of carving machine, bearing some analogy to that last described,
was invented at about the same time as Mr. Jordan's, we allude to Mr. Tomes's
Dentifaetor, a machine for carving the artificial teeth, gums, and palates used in
dental surgery : patented March 3rd, 1845.
This machine, like the hut, is intended to make an exact copy from a solid model,
but which in Mr. Tomes's case is a true counterpart of the mouth of the individual,
produced by moulding. Thus an impression of the mouth is taken as usual in soft-
ened bees'- wax, from this a plaster cast is obtained, and from the plaster a model or
956 APPENDIX NOTE L.
impression is made in a fusible though hard composition, principally gum lac com-
bined with a softer gum, which produces an exact reverse or counterpart of the
gums ; one that when carefully made fits so exactly to the surface of the mouth as
even to exclude the air from between the model and gums, and is therefore capable
of being retained in position without springs, simply by atmospheric pressure. The
object of the machine is to carve an exact fac-simile of the composition model, in
hippopotamus or walrus ivory, to constitute the artificial palate to which the teeth
are fastened.
As some analogy necessarily exists between Mr. Toines's machine and that last
described, this account will be facilitated by briefly noticing some of the principal
points of difference, resulting from the circumstance that Mr. Tomes moves the
work about in a vertical plane, and moves the drill in a horizontal plane, and usually
cuts the material away by parallel cuts, extended laterally over the surface ;
whereas in the wood carving machine, it will be remembered the work is horizontal
the drill vertical, and the motion rambling in all directions.
Mr. Tomes's tracer and drill are fixed four inches asunder on one slide, that is
moved horizontally towards the work by a weight, and pulled back by a lever ; and
the cement model and the ivory to constitute the copy, are clamped on circular
plates or disks, also four inches asunder, and which disks are fitted upon the slide
plate of a long horizontal slide, moved by a coarse screw with a winch handle, by
the traversing of which the series of lines is usually cut. This horizontal slide is
mounted upon a vertical slide, having a screw and ratchet movement, so arranged
that when one irregular undulating line of the work has been cut, and the drilling
slide withdrawn to its full extent, the work is shifted by the ratchet movement, more
or less either upwards or downwards, according to the particular nature of the work,
and thus, by a succession of parallel cuts, the entire surface is eventually produced,
the weight all along supplying one constant pressure to the slide carrying the drill
and tracer, to keep them up to their work with the right degree of force ; and
from the graduated path of this machine, and its perfection of action, the tool-marks
are not discoverable in the finished work, as they become completely merged one
into the other.
To enable the few undercut parts, that occur in artificial palates, to be carved by
the dentifactor, Mr. Tomes now makes the slide that carries the disks not with one
flat surface, but to have two inclined and parallel planes, that serve as the founda-
tions for the circular disks, and which latter are connected by one long tangent
screw that moves the two upon their axes, similarly and equably ; so as by the
angular change of the disks which carry the work and model, to place the few
undercut parts successively at the lowest sides of the inclines, or at the bottoms of
the hills, when such undercut parts (unless they exceed in inclination 20 degrees,
and which never occurs in this branch of art), slope the reverse way, so as to be
conveniently accessible to the revolving cutter.
The dentifactor was constructed in the author's manufactory, and he therefore
feels increased pleasure in announcing the complete efficacy of Mr. Tomes's project,
which was favourably noticed in the Minutes of Conversation of the Institute of Civil
Engineers, page 250 ; in the Medical Gazette, p. 161, and numerous other publications,
and for which invention Mr. Tomes received the Gold his Medal of the Society of
Arts,— all in 1845.
APPENDIX — NOTES M, v \ Mi n. '.'.') 7
NoU M, Page 121.— To precede the Uut two lines.
(Smigfaniny Hag-kom mud bwdckon.)
Stag and buck-horn admit of being partially straightened, when in thin piece*
or scales, to adapt them to the forma of the handle* of pen and pocket knives. To
effect thia, a dozen piecea of the atag or buck-horn, when reduced nearly aa thin
aa required, are thrown into a vessel of water almoat boiling, and on removal one
at a time, aro flattened or untwisted, by grasping their ends between pliers, and
straining them into form, after which they are allowed to cool in the air, or are some-
times dipped in cold water. The under aides of the scales are then filed or raaped
upou a strip of iron held in tliejtattiny vice, represented in fig. 864, page 864.
Stag-horn and buck-horn are considered to become more brittle from the immer-
sion, which is therefore made aa abort aa possible. Stag-horn, buck-horn, ivory
and pearl-shell, especially the first, are somewhat liable to cause nut on the steel
works of knivea, not so however tortoiseshell, or buffalo and similar horn.
Note N, Page 155.— To follow the first paragraph.
(ItinglaM glue.)
"If it be wished to dissolve good isinglaaa in spirits of wine, it should first be
allowed to soak for some time in cold water, when swelled it is to be put into the
spirit, and the bottle containing it being set in a pan of cold water may be brought
to the boiling point, when the isinglass will melt into a uniform jelly, without
lumps or strings, which it is apt to have if not swelled in cold water previously to
being put in spirits ; a small addition of any essential oil diminishes its tendency
to become mouldy."
"If gelatine which has been swelled in cold water, be immersed in linseed oil
and heated, it dissolves and forms a glue of remarkable tenacity, which when
once dry perfectly resists damp, and two piecea of wood joined by it will separate
anywhere else rather than at the joint Ordinary glue may be thus dissolved and
sometimes a small quantity of red lead in powder is added." Sir J. /Zooixm.
Note 0, Page 160—161.
(Proud* t patent procettfor wort* made of dry efojr.)
The first line of the article on clay, which ran as follows: "This material is only
worked in the soft and plastic state," is unintentionally erroneous, as the author
since learns that Mr. Mencke obtained in 1828 a patent for manufacturing bricks
and tiles from dry pulverized clay, containing a quantity of moisture not exceed-
ing one per cent, the clay was pressed forcibly into moulds and immediately
baked, without the necessity for its being dried, and from the dense condition of
the compressed mass, without the risk of cracking in the fire.
Mr. Rowland Prosser's patent, 1840, is for a similar but superior employment
of dry clay, sometimes mixed with colouring matters, for making buttons, rings,
knobs, the tessera) for pavement, and other things. The dry powder is put into
a deep mould, that holds just the right quantity, and terminates at foot in the
bottom die, the top die is attached to the fly-press, descends within the tube, and
moulds the object, making the four holea in the button at the same moment
The pieces are released from the mould by% piston or rammer pressed upwards
as usual by a treadle or otherwise. This patent is successfully worked by Messrs.
Minter of Stoke-upon Trent.
958 APPENDIX — NOTES P AND Q.
Note P, page 191, to precede Section IV.
(Clay's patent process for manufacturing wrought iron.)
The author transcribes from the Minutes of Conversation of the Institution of
Civil Engineers for 1843, page 82, a part of the account of this process.
" By the ordinary system of iron-making, the ores are reduced into the state of
carburet of iron, and then, by refining and puddling, the metal is de-carburetted,
thus making it into malleable iron by a number of processes which are recapi-
tulated :— "
" 1st. Calcining the ore.
" 2nd. Smelting in a furnace, by the aid of blast, either cold or heated, with
raw coal, or coke, for fuel, and limestone as a flux.
" 3rd. Refining the ' pig ' into ' plate ' iron.
"4th. Puddling, shingling, and rolling, to produce 'merchant' or No. 2. bars.
" 6th. A repetition of the same process to make ' best ' or No 3. bars."
'• Seeking to diminish the number of manipulations by the new process a mixture
of dry Ulverstone, or other rich ore (Haematite,) is ground with about four-tenths
of its weight of small coal, so as to pass through a screen of one-eighth of an inch
mesh. This mixture is placed in a hopper, fixed over a preparatory bed, or oven,
attached to a puddling furnace of the ordinary form. While one charge is being
worked and balled, another gradually falls from the hopper, through the crown
upon the preparatory bed, and becomes thoroughly and uniformly heated ; the
carburetted hydrogen and carbon of the coal, combining with the oxygen of the
ore, advances the decomposition of the mineral, while by the combustion of these
gases, the puddling furnace is prevented from being injuriously cooled. One
charge being withdrawn another is brought forward, and in about an hour and a
half the iron is balled, and ready for shingling and rolling."
" The cinder produced is superior in quality to that which results from the
common system ; it contains from 50 to 55 per cent, of iron, and is free from phos-
phoric acid, which frequently exists, and is so injurious in all the ordinary slags :
when re-smelted the cinder produces as much as No. 1 and No. 2 cast-iron, and is
of as good quality, as the ordinary ' black band ' ore of Scotland."
The process was highly commended by the meeting as being simple and scientific,
and evidence was advanced to show the iron produced in this mode, to be equal
to the best cable iron.
Note Q, Page 196 of VoL L— To follow the Foot Note.
(NatmytlSt Patent Direct-action Steam Hammer.)
Since the foregoing pages were printed, a valued friend of the author, Mr. James
Nasinyth, of Patricroft near Manchester, has brought into successful operation
two very important machines, the one the Direct-action Steam Hammer employed
in the place of the old helves or lift hammers, the other a legitimate descendant
of the above hammer, a machine invented for driving the piles required for the
foundations of buildings and coffer dams. The author is enabled to present to his
readers some particulars of these machines, which their inventor haa been kind
enough to write for these pages.
" Fig. 968 represents a general view of the steam hammer, B. is the cylinder in
which the piston works, and to the piston-rod which comes out at the bottom of
M ri M)i\
the cylinder i* attached UM hammer A, high-pressure steam u let in under the
piatou, which HUM* it together with the hammer A, to any required height within
iu vertical range of motion, and in which it u guided by two planed guidee KE.
Uu the eecape of the steam when the valve of the cylinder U opened, the hammer
falls on the work that liee on the anvil with the full force due to gravity, and
without any loae worth naming from friction ; the instant the hammer has given
it* blow the steam ia again let in under the piston, and the same action is
repeated with ease and rapidity."
" When it ia deaired to lessen the force of the blow, the steam ia let in under the
piston, tn the fall w complete, so that a cushion of steam is then preeented to receive
the force, and modify it to any required extent ; such U the precision with which
this can be done, that the hammer may be arrested in the moat soft and silent
manner even when within one-tenth of an inch of the anvil. The hammer can be
thus set to give any de6nite blows, by the due adjustment of the lever which eloeea
the valve, for which purpose its position U regulated by two long screws seen in
the figure ; the re-opening of the valve is effected by a small cylinder and piston
(at B), on the top of which piston steam is made to act as a most perfect spring."
•• When, on the other hand, it is deaired to increase the energy of the hammer,
by making it give blows even more powerful than those due to the highest fall of
the hammer by gravity alone, the following simple but effective arrangement ia
Fig. 968
Fig. 969.
brought into action. This contrivance consists in m>^{ng the top of the cylinder
quite steam and air tight, so that when the piston passes beyond the holes o oo o
fig. 969, the old steam or air which is then pent up in the chamber Z Z above the
960 APPENDIX NOTE Q.
piston, may obtain a reviving energy by the compression it receives from the
upward motion of the piston, and this compression is wholly returned in the con-
dition of elastic recoil of the most perfect kind, which recoil added to the simple
gravity of the hammer vastly augments the rapidity and intensity of the blows.
As soon as the piston re-passes the holes o o o o the old steam or air re-enters with
perfect freedom, so as to offer no resistance to the fall of the hammer."
" It may be well to notice in conclusion, the peculiar, elastic, yet firm manner
in which the connection between the piston rod and hammer block is made ; this
being one of the most important details in the whole arrangement, and without
which this invention would have possessed but little practical utility. It will be
seen in the enlarged section, fig. 969, that the piston rod has a large end F, forged
to it, this goes down into a well inside the hammer block, and rests on several
pieces of hard wood placed at W, one or two rings of the same material being
placed above the part F, the whole being keyed hard down by two taper keys XX,
which are driven in over the wood rings through the body of the hammer ; these
cross keys retain all the parts firmly together."
" This attachment while it effectually unites the piston rod and hammer, at the
same time presents such an elastic or yielding medium, as to remove all risk of
destructive action, which would be otherwise certain to occur, if any hard unyield-
ing substance were placed between the anvil and hammer, or that these two parts
were allowed accidentally to come in violent contact ; no such concussion can now
injuriously affect the piston and hammer. A close resemblance will be observed
in this arrangement to that of the cartilage in the joints of animals between bone
and bone."
The author of this volume has to add, that several of these steam hammers have
been erected in our Government Dock Yards, and at che works of various engineers ;
sometimes they have flat-faced hammers and anvils for general purposes ; at other
times semicircular tools for swaging round shafts, and in this case peculiar advan-
tages arises from the steam cushion, which prevents the approach of the tools beyond
one precise distance, so that the shaft is made of uniform diameter throughout.
The steam hammer has also been employed in manufacturing large copper
pans, into the central parts of which the convex hammer then dips with unerring
precision, and any particular measure of force.
The largest of the steam hammers as yet made, has been erected in the works
of Sir John Quest, Bart., Dowlais, South Wales, for the manufacture of wrought
iron, and in this machine the hammer weighs 6 tons, it can be raised 7 feet, and
its face measures 4 feet by 2 feet, so as to consolidate at one action, the entire
mass of the blooms or uses for making railway bars, as the hammer face includes
the whole surface of the bloom at every blow ; the bed or anvil, perhaps the
largest iron casting in the world, weighs 36 tons, and was cast in one mass from
the united contents of four great furnaces.
In a former account of the steam hammer, written by Mr. Nasmyth for the Civil
Engineer's and Architect's Journal, Vol. VI. page 40, be first describes the circuitous
mode in which the power was conveyed from the steam engine through intermediate
gear and shifting, to the old helves or lift hammers, alluded to in the first volume,
some of which lift hammers although weighing upwards of 6 or 7 tons, give by
comparison ineffective blows on large masses, because from moving on a joint the
rise and fall of the hammer is limited ; and in forging thick works when the
strongest blows are required, the hammer has the less space to fall. Mr.
Nasy mth then contrasts the above circuitous mode, with his own simple and " direct "
APPENDIX — NOTES Q AND R.
961
Fig. S>70
Fig. 971.
meana applied to the same end, under an arrangement in which the large*
worka may with more conaistency be made to receive the ttronyett blows.
Another eomparison there alao inatituUd is greatly favourable to the patentee,
as he adda that although from various practical reasons, the dimensions of the old
helves cannot be materially exceeded; the cylinders and appendages required in
the new hammer admit of an almost unlimited increase in their magnitude, in
order to meet the continual aggrandisements of engineering requirement*.
Note R— To follow Note Q on page 190.
(Mr. Xiumyth't Steam Pile Driving Engine.)
On thia machine Mr. Naamyth write* — "There are two grand or important
features of novelty in this pile-driving engine, compared with all former con-
trivances for the like purpose. In the first place by the employment of the steam
hammer action, the steam
ia made to act direct in
raiting up and letting fall
the hammer, or monkey,
without the intervention
of any rotative motion,
while in the second place*
another grand feature of
novelty consists in the
employment of the pile
which we are about to
drive, aa the foundation
or sole support of the
apparatus A, B, C, fig.
971, so that by ita resting
on the shoulders of the
pile, we have not only the
effect produced by the
blows of the hammer, (30
cwt. at 80 to 100 three
feet falls per minute,) but
we have also the entire
weight of the apparatus
A, B, C, equal to 3 tons
assisting in a most im-
portant degree to force
the pile down into the
ground."
" The pile to be driven
is raised up and planted
in ita situation by the
machine by means of a
windlass worked by a
small detached steam Fig. 972.
engine at H, the appa-
ratus A, B, C, k at the
same time raised up and
3 Q
962 APPENDIX NOTES R AND S.
placed on the shoulders of the pile, like an extinguisher on a candle, the chain
D, D, is then let free, BO that the entire weight of A, B, C, shall rest on the pile ;
the steam is now let in from the boiler to the cylinder, by the jointed wrought iron
pipe E, E, the hammer then sets to work with great energy, showering down its
ponderous blows on the head of the pile at the rate of 80 to 100 per minute, at
each blow the pile sinks and the machinery A, B, C, follows down with it, guided
in its descent by clamps which loosely grasp a guide rail fixed on the side of the
great upright, and which upright also retains the pile in true position all the way
down."
" Some idea of the rapidity with which piles are driven by this machine may be
formed when we state that a pile of 60 feet in length and 14 inches square, can be
driven 45 feet into stiff soil down to the rock below in 4 minutes, and such is the
good effect resulting from the blows being given by a yreat mass, of 30 cwt. striking
quickly but with small velocity of actual impact, that the pile head requires no
hoop, and presents after being driven a neater appearance than it had when it was
first placed under the hammer."
" This is a very important result, and the natural consequence arising from the
employment of mechanical force in the right conditions for the purpose required,
namely, in this case, striking a quick succession of blows with a large mass or
hammer, but with small velocity of impact, by reason of the small height from which
the hammer falls ; the action of the ordinary pile driver-being quite the reverse of
all these conditions. By inspecting the figure it will be seen that the entire machine
is possessed of locomotive powers, inasmuch as it is mounted on wheels and moves
along rails so as to pass onwards as the piles are driven in succession, it may be as
well to observe that the apparatus A, B, C, is only raised up by the small fixed steam
engine once per pile instead of once per blow, as in the case of the ordinary machine."
The author has not had the advantage of seeing Mr. Nasmyth's pile-driving
machine, but he understands from eye-witnesses " that its rapidity is such as to
excite a smile, from the almost marvellous manner in which this 'jack in the box, '
(the hammer being concealed from view by the frame or casing,) performs its
work, as it fulfils in 4 minutes, that which frequently required, by the old machine,
a period of 36 hours, presenting a ratio in the time saved as 540 to 1, a ratio
most egregious but true withal."
" A pile said to have been driven home, or as far as possible by the old pile
driving engine (as the old ram then rebounded as from a solid rock), was driven a
further quantity of 10 feet by the steam pile driver, until it had indeed met the
solid rock beneath."
" The action of the machine is adduced as a most perfect evidence of the high
importance of knowing under what modification we should use force in the accom-
plishment of certain duties ; thus — if you want to split and shatter a pile into
lucifer matches, then let fall cannon balls upon it from a great height, but if you
want to drive the pile, then let the cannon itself fall on it, and that from a small
height, and as rapidly as it can be effected, say 100 times in a minute, so that it may
never give the pile a moment's time to set fatt in the soil."
Note S, page 202. — To follow the third paragraph.
(The Oliver, or small lift hammer.)
Fig. 973 represents a species of lift hammer worked by the foot. The hammer head
is about 24 inches square and 10 long, with a swage tool having a conical crease
attached to it, and a corresponding swage is fixed in a square cast-iron anvil block,
APPENDIX— NOTES 8 AND T.
968
about 12 inchM square, and 6 deep, with on* or two round hole* for punching, Ac,
The hammer handle it about 2 to 24 feet long, and mounted in a cross spindle nearly
M long, supported in a wooden frame between end screw*, to adj uit the groove in the
hammer face to that in the anvil block, A short arm 6 or 0 inches long, is attached
to the right end of the hammer axis, and from this arm proceeds a cord to » spring
pole over head, and also a chain to a treadle a little above the floor of the smithy.
When left to Ueelf the hammer handle is raised to nearly a vertical position by
IfettS,
the spring, and it is brought down very readily with the foot, so as to give good
hard blows at the commencement of moulding the objects, and then light blows
for finishing them. The machine was used when the author first saw it, in
making long stout nails, intended for fixing the tires of wheels, secured within the
felloes by washers and ri vetting ; the nails were made very nicely round and taper,
and were forged expeditioiuly.
•
Note T, page 226.— To follow the fifth line.
(The Manufacture of Wrought Iron Tubes.)
The author's attention has been drawn to the contents of pages 225 and 226 of
his first Tolume, referring to the manufacture of wrought iron tubes, associated
with a regret, that he had not set forth more fully and historically the progressive
steps through which this interesting and important manufacture has arrived at
Its present state of perfection.
Upon this hint the author requested Mr. Prosser, with whom the suggestion
originated, to point out the errors of mode and date that ho had committed, and
which correction Mr. Prosser has mott kindly rendered in the accompanying
synoptical table here inserted without alteration.
3 q 2
SYNOPTICAL TABLE
or THK
MANUFACTURE OF IRON TUBES.
Draicn up for this Work by Rowland Prosser, Esq., C.E., of Birmingham.
Drawbench introduced into England 1565.
Rolls invented for rolling iron by Cort 17S3.
Drawbench and Rolls used for making lead pipes
by Wilkinson 1790.
Combination of 2, 3 or more pairs of rolls by
Hayledine 1798.
Dates of Patents
!
James and Jones.
Henry Osborn.
Henry Osborn.
James Russell.
i
1
a
George Royl.
Harvey and Brown.
I
a
ri
Richard Prosser.
Job Cutler.
Russell and Whitehouse.
1808
1812
1812
1817
1824
1825
1831
1836
1836 1840
1841
1S42
1
'£$-
i
<-
12
j
(
f==
1=
U-«
4
^-J
=•
**—
as
^
WELDING BY
Hand hammers
-" Power hammers
Many holes in two rolls .
-*• Many holes in two rolls )
alternating . . )
j Segment moving on a bed
i_
_A Three or four rolls mak- )
1808
1812
1812
1812
1812
1817
1824
1831
1812
1846
i841
1S42|
•o —
I
— . .
— . Drawhig through holes )
— . or tongs . . . )
1825
"Hr
^S
0
>— Drawing through rolls .
••
1836
1841
••
FINISHING BY
t
(o)_
O 0
2§:
C 1
>
Drawbench and holes .
%=* Drawbench and rolls
1808
1808
1831
1836
1836
1841
1824
<L>
-
: Drawing over a mandril .
1841
"
FORM OF MANDRIL.
No mandril .
Parallel and in motion .
Taper and in motion
Enlarged end, and at rest
1808
1812
1812
1812
••
1824
1825
1831
1836
IS42
o
1817
..
..
1836
184d
1841
-
FORM OF JOINT.
cz:
-----
Butt (or jump)
1824
USB
is; i
1836
1836
1840
1841
c=
^J
Scarf (or lap) .
1808 1812
1812
1817
••
1836
1840
1S41
1842
APPENDIX — NOTE i '.'•',">
In the firat column on the left of the Synoptical Table, are represented little
•kotcboe of the principal means employed in the manufacture of welded tube*;
next follow the verbal explanation* of the sketches ; and the group of column*
on the right are headed with the names of patentees and the dates of their patents.
The dates inserted in these columns, in the same horisontal lines as the •ketches,
ere intended to show that such means were emplojed under the several patents
designated by the dates.
For example, running the eye down the first date column, it is to be understood
that Benjamin Cook's, the first patent for the manufacture of iron tubes, was dated
1808 — that by him the tube was welded by the hand hammer — finished by the
draw-bench and drawing rolls — that the mandril employed was parallel, and lastly
that the tube had a scarf or lap joint — and so with all the others.
This tabular view, although most fascinating for a cursory inspection, could
not be made to convey various matters of detail, and point* of important yet
minute difference, which have existed in the several modes of practice, and which
have given rise to many and expensive lawsuits. And therefore, as a brief sum-
mary of the entire manufacture, the author subjoins, from the pen of a friend
who is professionally and intimately acquainted with the subject, a condensed
account, showing the dates, titles, and the main features and processes of the
entire series of patents for making wrought iron tubes.
" BENJAMIN COOK, of Birmingham. Patent dated 28th March 1808 for a
method of making barrels for fowling pieces, muskets, pistols and other similar
fire-arms and ramrods for the same."
" The Patentee proposed three plans of making barrels, in one only of which
was there any welding."
" The first plan consisted of forging or otherwise producing a round bar of iron
or other proper metal of a short length as compared with the intended barrel, and
then a hole was drilled in the same, and it was proposed to elongate the barrel by
draw plates similar to wire drawing but having a mandril in the barrel, or the
elongation was to be effected by grooved rollers using a mandril inside the barrel."
" The second plan was to turn a short plate of iron or steel over a mandril or
beak iron, and to weld it by hand, then to elongate the barrel so produced by
drawing through holes in dies or by grooved rollers as before, using a mandril
inside the barrel when elongating it."
" The third plan consisted of taking a circular plate of metal, and then by sue-
sessively forcing it through a series of holes in a die it was proposed to raise it
into the shape of a cup, and then having done so the cup was to be elongated by
drawing it through holes in a die or by means of a pair of grooved rollers, using a
mandril on the inside of the barrel when elongating it ; none of these plans suc-
ceeded, and they never came into public use."
m:\KY JAMES AND JOHN JONES, of Birmingham. Patent granted
26th July 1811, for an improvement in the manufacture of barrels of all descrip-
tion* of fire-arms and artillery."
" There are two methods of welding barrels described in this invention. Firat
the plate of iron WM to be turned over into the shape of a barrel, so that the edges
should be brought into a position for welding, a part of the barrel being heated to a
welding heat, was to be placed on a hollow anvil having several grooves to corre-
spond with the barrel, and then by a series of hammers, worked by machinery, the
966 APPENDIX — NOTE T.
heated part of the barrel was to be welded ; a stamp or mandril being inserted in
the barrel when welding. And secondly, the Patentee proposed to use grooved
rollers, the grooves being of the figures of the barrel, and a mandril was to be
used. This appears to be the first invention of the use of grooved rollers to weld
barrels of fire-arms."
" HENRY OSBORN, of Bordesly, near Birmingham, Sword and Gun Barrel
Maker. Patent granted 1st of March 1817, for a new method or principle of
producing cylinders of various descriptions."
" The Patentee had a previous patent for turning the plates of iron ready to be
welded into barrels or cylinders, and this was done by grooved rollers, the present
patent was for using grooved rollers as a means of welding cylinders or gun barrels
and it consisted in using similar grooved rollers to those described by James and
Jones ; but in this patent a mode of using a mandril was described very different
to that suggested by James and Jones, and it is by means of these inventions that
by far the largest proportion of gun barrels have ever since been welded in
Birmingham."
" The novelty in using the mandril consisted in this, there was to be a shield fixed
on the mandril so as to prevent the mandril being drawn through between the grooved
rollers when welding a cylinder or barrel thereon. In using the mandril it was
inserted into an unwelded barrel (the barrel being at a welding heat) and conveyed
thereon to the rollers, the mandril being retained by stops which prevent the shield
pissing; thus the barrel, as it was welded by the rollers, was drawn off the mandril,
the mandril keeping the bore open and preventing the iron from being rolled into
A solid mass. In this manner was the weld made, and then by repeatedly heating
the barrel or cylinder, and passing it between grooved rollers with a succession of
mandrils, the barrel or cylinder was drawn out to the desired length."
" JAMES RUSSELL, of Wednesbury, Gas Tube Manufacturer. Patent granted
19th January 1824, for an Improvement in the manufacture of Tubes for Gas and
other purposes."
" This Patentee proposed to weld iron tubes or barrels by means of a hollow
hammer and tool, and it was intended that the tube to be welded should be held hi
the hollow tool and receive blows by the hollow hammer, and this welding was to
be done either with or without the aid of a mandril. And then having welded
the tube or barrel it was to be shaped interiorly and exteriorly by means of a
pair of grooved rollers and a mandril with a large head, over which the grooved
rollers were to move the welded tube or barrel. This Patent failed of success. It was
found that thehollowhammer and correspondinghollowtool would, if they embraced
the barrel, have no effect on it, and if the barrel was too large in diameter for the
hollow, it would only be crushed by the sides of the hammer and the hollow tool."
"CORNELIUS WHITEHOUSE/ of Wednesbury, Stafford, Whitesmith.
Patent dated 26th February, 1825, for certain Improvements in Manufacturing
Tubes for Gas and other purposes."
" This Invention was the first to suggest that a tube might be formed and welded
by simply applying external pressure without internal support, and the inventor
described the means of accomplishing the welding and shaping of iron tubes for gas
and other purposes, to consist of, first, turning up the plates of iron so that the
edges would come together or nearly so, and then about half the length was to be
heated to a welding heat, and by means of a draw bench such heated part of the
APPENDIX — NOTE T. '"'-7
prepared tube was to b« drawn through a bell-mouthed die, which might be formed
in the shape of a pair of tonga with handles to open or oloee the two halrea of the
die, or the two halrea might be opened or oloaed by a aorew. The inventor did
not confine himaelf to the particular conatruction of the dies, and it waa held by a
Court of Law that grooved rollcra capable of giving complete circumferential pres-
sure when no internal support of a mandril waa resorted to, waa within the claim
of the I*atontee."
"Such was the great simplicity and utility of this Invention, that notwith-
standing the assignee of the Patent, Mr. Russell, bad made a very considerable
•urn of money by the Patent, the Privy Council advised the Crown to extend the
period for which the Patent was granted from 14 to 20 years."
" GEORGE ROYL, Walsall, Stafford, Whitesmith. Patent granted 21st March,
1831, for an Improved method of making Iron Pipes, Tubes, or Cylinders."
'• This Patentee proposed to use two grooved rollers placed in front of the
furnace, so that the prepared tube when it was heated to a proper welding heat
abould bo drawn out and welded by the rollers ; and to facilitate the working,
the upper roller was capable of being separated from the under one by which the
tube could be moved between the roller", and when the upper roller was brought
to the lower roller and motion communicated to them, the tube waa run out of
the furnace and welded. The tubes being thus welded, were to bo passed through
dies, to give them a better shape : this invention was put into use by Messrs.
Dizon & Co. of \Volverhatnpton. This mode of manufacture was declared to be
an infringement of Whitehouse's Patent because the welding was by circumferential
pressure without any mandril or internal support being employed."
"FREDERICK EDWARD HARVEY, of Tipton, Staffordshire, and JERE-
MIAH BROWN, of the same place. Patent granted 3rd February, 1836, for oar-
tain Improvements in the process and machinery for manufacturing Metallic Tubes,
and also in the process or machinery for forging or rolling metal for other purpose*."
" In this invention grooved rollers were employed, and the principal novelty
consisted in tho mode of supporting the mandril, which waa a short instrument
placed and fixed in front of the rollers, and in such manner that the enlarged
head came just in the pinch of the rollers, and in working, the heated tube was
to be forced over the short cranked stem of the mandril, the unclosed seam of
the tube being sufficiently open to allow it to pass the fin by which the stem of
the mandril was carried."
"THOMAS HKNRY RUSSELL, of Handsworth, Warwick, Tube-maker.
Patent granted 3rd May, 1836, for improvements in making or manufacturing
welded Iron Tubes."
" This Patentee proposed to make welded iron tubes without first turning up the
Iron plate from end to end, and the invention consisted of only turning up a few
inches of the length and then by apparatus placed in front of tho furnace, to cause
the plate of iron when in a welding state to be first turned into the shape of a
tube, and the welding was simultaneously to go on by means of dies or by rollers
in the manner of Wbitehouse's Invention before mentioned."
- K!< H ARD PROSSER, of Birmingham, Civil Engineer. Patent dated 27th
March, 1840, for improvements in machinery or apparatus for manufacturing
Pipes.**
9G8 APPENDIX — NOTE T.
" This Patentee proposed to use a combination of three or four rollers. When
four rollers are employed they are formed with grooves all exactly equal to the
quadrant of a circle, and with edget* bevelled at 45 degrees, so as collectively to
make up the entire circle. The four rollers are connected with equal wheels, in
order that they may travel with the same velocity. The end of the thin strip of
iron is bent to the circle, and when at the proper heat the rollers carry it forward,
and depose the welded tube upon a long mandril smaller than the bore of the
tube, and placed immediately opposite the rollers : the mandril serves to support
the tube whilst in its heated and soft state. Large numbers of tubes have been
made hi this manner by the four rollers, and when three only are employed they
embrace one-third of the circle instead of the fourth."
" THOMAS HENRY RUSSELL, of Wednesbury, Staffordshire, and CORNE-
LIUS WHITEHOUSE, of the same place. Patent granted March 7th, 1842, for
improvements in the manufacture of welded Iron Tubes."
" This Invention has for its object a mode of welding very thin iron tubes when
making lap joints, and the tubes were particularly intended for steam boilers. The
invention consisted in using a mandril of small diameter, when compared with the
intended diameter of the tube, and the tube was welded by passing the tube with
the mandril in it between grooved rollers or through bell-
mouthed dies, the hole being of an oval shape : so that when
1 making the weld the mandril was set fast in the tube throughout
its length, but on passing the welded tube through dies with a
circular opening, the tube was made cylindrical, thus allowing the mandril to be
readily withdrawn in consequence of the smallness of its diameter, when compared
with that of the tube. The pressure of the roller or dies was made to act first
on the outer edge of the lap joint, then on the inner, and lastly on the central
part ; the three processes being accomplished at one heat, and the diametrical
line upon which the pressure was applied, became for the time the shorter
diameter of the oval."
"JAMES ROOSE, of Wednesbury, Stafford. Patent granted 9th May, 1843,
for an Improvement or Improvements in the mode or method of manufacturing
welded Iron Tubes."
" This Invention consisted of a mode of using dies, and also rollers with grooves
and mandrils, in a peculiar manner which does not appear to have come into use."
" JOHN JAMES RUSSELL, and THOMAS HENRY RUSSELL, of Wednes-
bury, Staffordshire, Tube Manufacturers. Patent granted July 24, 1844."
" This Invention was for the welding of the larger class of tubes for boiler and
such like purposes, and consisted of a moving hollow bed on which the prepared
tube in an uu welded state was placed ; and the bed with the tube passed under
a grooved roller. A fixed mandril beiug used on the inside of the pipe over which
the pipe moved, so as to give support and resistance where the weld was taking
place. The end of the tube being fixed to the hollow bed, the movement of the
bed necessarily carried with it the tube, and caused it to pass over the mandril
and under the pressing or welding roller."
" THOMAS HENRY RUSSELL, of Wednesbury, Stafford, Tube Manufacturer.
Patent granted 14th August, 1845, for improvements hi the manufacture of welded
Iron Tubes."
APPENDIX — NOTE T.
" This Patent describes an (oration for welding iron tube* for steam boilers
and other purposes, and it consist* of uaing a long fixed bar or beak iron, supported
at one end, on to which a prepared iron tube at the welding heat is placed, the
edge* of the metal overlapping in order to produce a hip joint, and then the weld
is produced by external mechanical pressure, which ia shown to be produced by a
grooved roller, situated above the end of the beak iron by drawing it off the beak
iron and beneath the roller; the beak iron must not be lees than half u long ae
the tube, and the Utter i» welded at two processes. This invention has come into
extensive use in making tubes of large diameter of thin plate iron with lap joints."
In concluding thu notice of the manufacture of wrought iron tubes, the author
has to observe that the great feature of modern times in the manufacture of tubes,
is the being able to dispense with all internal support, and to complete the tube
by external pressure alone, such pressure acting on all points of the circumference.
The mandril was quite indispensable, when gun-barrels were forged by means
of the lateral blows of band-hammers upon anvils or swages, and the idea of the
necessity for the mandril has been long retained under various modifications
greatly to the prejudice of the entire manufacture of wrought iron tubes, as when
the mandril fits tightly it hinders the progress of the tube over it and spoils the
work. The mandril when now used is only employed as a supporting instrument,
one that does not fit the tube but only serves as a holder or bracket to carry the
tube in its heated and flexible state, and not in any respect as a means of forming
or perfecting the bore of the tube.
On this point the strongest yet clearest judgment was pronounced by Baron
Parke, in the trial on Whitehouse's patent, namely, " that the great novelty it the
complete circumferential pretture, with motion, leaving out the mandril or any internal
tupport."
Another point of great nicety in the manufacture is the rcverbcratory furnace,
which, notwithstanding its length, requires to be heated most intensely yet uni-
formly throughout ; sometimes a blast is used, but the description of Mr. Proeser's
furnace will serve as a general explanation.
The furnace requires of course to be of the full length of the longest tube, and it
has a door at each end for the entry and removal of the skelp; on the one side are
several stoke holes for the introduction of the fuel, which is mostly coal, sometimes
coke, and in the opposite wall, beyond the bridge of the furnace, are corresponding
apertures leading into a longitudinal chamber parallel with the fire, and thence into
the lofty flue ; the dimensions of the apertures must be determined in some measure
experimentally, until the furnace burns with equal intensity throughout its length.
The time the iron is exposed to the intense heat of the furnace likewise require*
careful attention, as if accidentally exceeded, the iron is entirely spoiled.
The manufacture of thin tubes has recently obtained a great impulse, from the
very general adoption of the tubular system in marine boilers. These tubes are
usually about one-tenth of an inch thick, and as large as three inches diameter,
to adapt them to the combustion of coal, the fuel of marine engines ; whereas the
tubes of locomotives in which coke is always burned are of only about half the
bore of those for marine boilers ; the tubes for locomotives, although more gene-
rally of brass, are also made of wrought iron.
The tubular constructions of boilers present a very great fire surface, and effect
a proportionate saving in the dimensions of the boiler, and consequently iu the
weight both of the boiler and the water contained therein. Thick tubes, from their
weight, would be altogether inapplicable either to marine or locomotive boilers.
970 APPENDIX NOTES U, V, AND W.
Note U, page 256.— To follow the Foot Note.
(Additional remarks on the late Sir John Robisoris Worlcahop Blowpipe.)
" Articles heated in the flame of the workshop or gas furnace blowpipe (said its
inventor), preserve their polish in the same way as by Mr. T. Oldham's process, if
they have been Icept in tfie flame. As the whole of the oxygen is taken up by the
hydrogen of the gas, none is left free to act on the surface of the steel, and as there
appears to be a tendency to a deposition of carbon on glass rods when submitted
to this flame, it may be, that this may not only have an influence in saving the
steel from oxidation, but may produce some chemical effect on its composition,
as workmen suppose that gravers or turning tools hardened from this heat, are
more enduring than those heated in the muffle or on a bar of hot iron."
As already noticed on page 440 the workshop blowpipe is figured and described
in the Mech. Mag. for 1842, page 258.
Note V, page 283. — In continuation of the article on SILVER.
(Amalgams used by Dentists for stopping teeth.)
Dentists employ an amalgam containing silver for stopping carious teeth, it is
prepared by rubbing together in a mortar, or even in the hollow of the hand,
finely divided silver and mercury, and then squeezing out all the uncombined
mercury, leaving a plastic mass, which feels to grate and crepitate under the
fingers. When all the unsound parts of the tooth have been carefully cut away,
the amalgam is thrust into the dry cavity, that the tooth may be hermetically
sealed from the air, and in the course of a few hours the amalgam appears to
crystallize, and become considerably harder than lead.
The usual mode of preparation is to dissolve the silver in muriatic acid, and
precipitate it as a fine metallic powder, by stirring the solution with a rod of zinc
or iron. Some dentists file part of a shilling into dust, under the impression that
the copper then also employed makes the amalgam harder, others rub in with the
silver a little gold leaf or platinum leaf with the same intention. Precipitated
palladium forms with mercury a similar amalgam to that with silver, but with
the evolution of heat at the time of combination. These alloys, which have
received various high sounding names, are seldom remelted, but then resume for
some hours their plastic condition.
Note W, page 323.— To follow the seventh line.
(Bobbed Patent Anti-friction Metal.)
Babbet's anti-friction metal, to be used somewhat after the manner of tin, for
the bearings of machinery, is thus described : —
" An excellent compound or alloy for this purpose may be prepared by taking
about fifty parts of tin, five of antimony, and one of copper, but other compounds
analogous in character may be used."
Tin or compounds like the above used alone, owing to their softness, spread and
escape under the superincumbent weight of locomotive engines, and other heavy
machinery ; and therefore brasses or bearings are employed under this patent to
support the softer metal, but the brasses are made larger in diameter, and with
internal fillets that almost touch the axles, so as to prevent the thin lining of the
anti-friction metal from spreading and being pressed out.
APPENDIX — NOTES W AND X. 971
The brasses are first cleaned and tinned, and an exact iron model of the axle
baring been turned, the part* are heated, put together in their relative positions,
luted with plaatio clay, and the fluid anti-friction metal in poured in, which then
become* of the required form, and effectually soldered to the bras*. The anti-
>o metal scarcely appears to suffer from wear, and owing to it* unctuous
greasy nature, requires much leas oil than other tneUli and alloys used for bearing*.
See Letter* Patent granted to Wm. Newton, 15th May, 1843, for "Certain im-
provements in the construction of boxes or axletrecs of locomotive engines and
carriages, and for the bearings or journals of machinery in general, and also im-
provements in oiling or lubricating the same. Being a communication, Ac."
Note X, page 285, at foot, and 802.— Before " The Palladiumizing proMM."
(Craufunfi Patent for Oalvanued Iron.)
At the time the author inserted in bis former volume the account of Mallett's
process for coating iron with zinc and palladium, he accidentally overlooked a
previous patent granted to Mr. Henry William Craufurd, April, 1887 (and described
in the " Repertory of Patent Inventions," Vol. ix, New Series, page 289), he will now
proceed to supply the deficiency ; and also to give some particulars of another
method by which iron that has been previously tinned is also coated with zinc.
In Mr. Craufurd's patent, sheet iron, iron castings, and various other objects in
iron, are cleaned and scoured by immersion in a bath of water, acidulated with
sulphuric acid, heated in a leaden vessel, or used cold in one of wood, just to
remove the oxide. They are then thrown into cold water, and taken out one at a
time to be scoured with sand and water with a piece of cork, or more usually a
piece of the husk of the cocoa nut, the ends of the fibres of which serve as a brush,
and the plates are afterwards thrown into cold water.
Pure sine covered with a thick layer of sal-ammoniac is then melted in a bath,
and the iron, if in sheets, is dipped several sheets at a time in a cradle or grating.
The sheets are slowly raised to allow the superfluous zinc to drain off, and are
thrown whilst hot into cold water, on removal from which they only require to be
wiped dry.
Thick pieces are heated before immersion in a reverberatory furnace, to avoid
cooling the zinc. Chains are similarly treated and on removal from the rinc
require to be shaken until cold to avoid the links being soldered together. Nails
and small articles are dipped in muriatic acid, and dried in a reverberatory fur-
nace, and then thrown altogether in the zinc covered with the sal-ammoniac, left
for one minute, and taken out slowly with an iron skimmer; they come out in a
mass soldered together, and fur their separation are afterwards placed in a crucible
and surrounded with charcoal powder, then heated to redness and shakeu about
until cold, for their separation. Wire is reeled through* the zinc, into which it is
compelled to dip by a fork or other contrivance.
It is to be observed that the zinc is melted in a bath or crucible just a little
beyond the point of fusion, and is always covered with a thick coat of sal-ammo-
niac, both to prevent the waste of the zinc, and further to prepare the metal that is
to be zinced. Cast-iron baths or vessels, such as are used for melting tin or pewter,
wen first employed, but zinc acts very rapidly upon the cast-iron, unites with it,
and falls in a granular state to the bottom of the vessel ; therefore an earthen
lining of fire brick, luted with clay, was, with some difficulty and loss of heat, main-
tained in the cast-iron vessel, to defend the same from the action of the zinc.
972 APPENDIX — NOTES X AND Y.
(Craufurd's patent, 1837.) Now, however, wrought-iron baths welded at the angles
are used without the clay lining (Morewood & Rogers's patent, 1841), as the dete-
rioration both of the zinc and of the vessel are then less rapid, and the process
succeeds better than when cast-iron baths are employed. The spoiled granulated
metal, which is only considered to contain about five per cent, of iron, is ladled
out and returned to the zinc manufacturers for purification or re-manufacture.
Note Y, page 285, at foot, and 302.— Before " The Palladiumizing process"
(Morewood and Rogers's Galvanised Tinned-iron.)
Mr. Edmund Morewood's process is different, and is declared in his patent
dated 1841 — "to consist in tinning the metals to be preserved from oxidation as
aforesaid, in the ordinary manner of what is called tinning, and then, in what I
call zincing the said tin, so that the external surface may be zinc, placed in such
relation with the tin, and the metal to be preserved from oxidation, as that both
the said tin and zinc should have a united or combined influence in preserving the
said metaL" See "Repertory of Patent Inventions," New Series, Vol. xviii. page 170.
The present practice is, however, different from the above, as the iron is covered
with tin by a galvanic deposition, as in the electrotype process, and is afterwards
zinced in a bath of the fluid metal. The following is the practice, which is secured
by subsequent patents, enumerated further on.
The sheets of iron are pickled, scoured, and cleaned just the same as for ordinary
tinning. A large wooden bath is then half filled with a dilute solution of muriate
of tin, prepared by dissolving metallic tin in concentrated muriatic acid, which
requires a period of about two or three days, and two quarts of the saturated solu-
tion are added to 300 or 400 gallons of the water contained in the bath. Over the
bottom of the bath is first spread a thin layer of finely granulated zinc, then a
cleaned iron plate, and so on, a layer of finely granulated zinc and a cleaned iron
plate alternately, until the bath is full ; the zinc and iron together with the fluid,
constitute a weak galvanic battery, and the tin is deposited from the solution, so
as to coat the iron with a dull, uniform layer of metallic tin in about two hours.
Whilst the above process is in operation a wrought-iron bath containing fluid
zinc is prepared, the melted metal is covered with sal-ammoniac mixed with
earthy matter, to lessen the volatilization of the sal-ammoniac, which becomes
about as fluid as treacle. Two iron rollers immersed below the surface of the
zinc are fixed to the bath, and are driven by machinery to cany the plates through
the fluid metal at any velocity previously determined. The plates are now re-
ceived one by one from the tinning bath, drained for a short time, and passed at
once, whilst still wet, through tho melted zinc by means of rollers ; the plates
thus take up a very regular and smooth layer of zinc, which owing to the presence
of the tin beneath, assumes its natural crystalline character, giving the plates an
appearance resembling that known as the moirfe metallique.
When the sheet of metal is dipped vertically into the zinc, 'the lower edge is
much longer in contact with the zinc, than the upper, and from the violent action of
melted zinc or iron, this makes the bottom edges of the sheets sensibly more brittle
than the upper ; whereas the rollers cause every part of the sheet to bo acted upon
in the same degree, and which degree may be exactly determined by the velocity
given to the rollers. Consequently by the roller process thinner iron may be zinced
than by dipping edgeways and vertically, as no part of the iron need to be immersed
APPENDIX — NOTCH Y AND Z.
longer in the metallic bath than is absolutely necessary for iU properly taking the
coating of line.
In addition to Mr. More wood's patent dated 1841 for the general process by
ordinary tinning and zincing, Messrs. Morewood and Roger* have patent* dated
respectively 1843 for the rollers, and the electro mode of tinning, in fact for the
mode of covering metal* by the conjoined processes, first of rolUic deposition,
and subsequently of immersion in another fluid metal. 1844 for new fluxes
an.l details of management; and 1845 for the manufacture of the galvanised
tinned-iron plate into tiles and ridge pieces for roofing and other works, by various
processes of stamping.
Craufurd's Patent (worked by the Galvanized Iron Company), and Morewood
and Rogers'* combined patents, have obtained very extensive employment for a
great variety of purposes, and both methods are well supported by testimonials.
But so for as the author can learn, the galvanized iron covered with pure rinc,
is much more suitable to the sheathing of ships, for which it is highly economical,
as it is proved to be much cheaper, and is expected to prove more durable than
copper; — the galvanized tinned-iron plate is more malleable and may be used for
thinner iron, and is therefore more suitable to being wrought, as by the tin-smith,
with the hammer, and it U also found to answer thoroughly for roofing ; as it can
be bent and soldered with facility. Galvanized iron is now largely used by Govern-
ment and by public companies for this purpose.
The author is informed that both kinds are open to two curious facts, the first
that the chains of tillers and cranes, and objects exposed to much friction, do not
lose their coating of zinc ; this is accounted for by the smooth un-oxidized zinc
surfaces of the chain moving freely on one another, whereas unprotected iron,
when covered with rust (the peroxide used in polishing), is subject to continued
wear; and it has also been imagined the cine becomes as it were burnished into
the surface of the iron. But it may happen, that when moisture is occasionally
present, that the worn parts are then continually re-zinced from the neighbouring
parts, as explained by the curious fact now to be noticed, and which on its dis-
covery excited great surprise.
The edges of some galvanized iron plates cut with shears so as to expose the
central iron, when attached to the piles of the Bell Rock Light House, for the
purpose of experiment, became zinced around the cut edges, and at the holes
where the nails were driven, and it was also observed that even the nails and
fastenings made of urn-galvanized iron became zinced from their proximity to the
galvanized sheets. By the same action, the holes perforated through the sheathing
for nailing it to the ship's sides become coated ; and the zinced wires of the
Electric Telegraph, where cut through, become coated by the action of the rain
water on the galvanised portion of the surface.
Note Z, page 308. — To precede SECTION II.
(Portable bnut furnace.)
Since the foregoing pages were printed, Holtzapflel ft Co. have constructed
portable brass furnaces, made of the hexagonal form in sheet iron, lined with
Stourbridge clay, and fitted with cast-iron pedestals, tiles, and stout sheet iron
pipes complete, so as to be erected on any level spot of ground, and if near a dead
wall so much the better.
The mnaller-sized of these air furnaces serve for about 10 pounds weight of brass
or copper, and a large furnace on the same model will melt 20 pounds ; when
974 APPENDIX — NOTES Z, AA, AB, AND AC.
favourably managed they have been made hot enough to melt cast-iron. These
furnaces have entirely superseded the little blast furnaces formerly made for the
portable forge, shown on page 203 of Vol. I.
Note AA, page 374.— To follow the last Foot Note.
(Berlin method of moulding delicate complicated objects.)
" One method said to be followed by the Berlin founders for producing compli-
cated subjects, such as a bouquet of flowers, is to dissect the object to be moulded,
into small parts which may be straightened out or moulded separately, and cast
in fusible metal."
•' Having cast all the parts separately in soft fusible composition, these parts
are then bent into the natural forms, and a synthetic operation is commenced, or
that of putting the parts together again by means of soldering, and tying together
by wires. When the whole object has been in this way built up, it is embedded
in the mould (with proper precautions for the escape of air), the mould is heated to
allow the fusible metal to melt and escape, and the iron is run in by a descending gait
which enters the mould at its lowest part, and the fluid metal carries up any impuri-
ties on its surface, expelling the air as it rises through the vents." Sir John Robison.
Note AB, page 424. — To follow the paragraph ending "wax is generally used."
(Fluid for lubricating draw-plates employed in India.)
" The lubricating matter for facilitating the slipping of wire through draw-plates
is perhaps not a matter of indifferent choice ; the Hindoo Sonars, who are noted
for their dexterity in drawing gold wire, uniformly use Castor oil, which they
allege prevents waste of gold by friction." Sir John Robison.
Note AC, page 410. — To follow the paragraph that precedes SECTION III.
(Foxall's patent Method of raising Vessels in sheet metal.)
Notice of the patent granted to Mr. Thomas Foxall Griffith, of Birmingham, for
improvements in stamping and shaping sheet metal. Feb. 3, 1846.
In the paragraph to which this note follows as an appendix, it was stated that
works having lofty and perpendicular sides, such as jelly moulds, could not be
produced by stamping ; but this difficulty has been very cleverly overcome under
the recent patent above cited, in .which the processes of stamping and that of
burnishing to form or spinning are successfully alternated. Quoting the words of
the specification, the patentee observes: —
" Heretofore sheet metal has been raised by the simple act of stamping in dies,
by raising and letting fall a succession of forces, and the process of burnishing to
form has been combined with the ordinary process of stamping, whereby sheet
metal, having been raised as far as possible in dies by the processes of stamping, the
shaping has been completed by the process of burnishing the stamped articles on
chucks in a lathe, and to secure such last-mentioned combined processes, letters
patent were granted on 15th February, 1834."
" In shaping sheet metal by stamping, as heretofore practised, the sides of the
articles depend materially for the height of the raising on the stretching or extend-
ing of the metal ; and to this end the metal at the outer circumference is supported
throughout the process of stamping by a projecting flanch, which rests horizontally
A IT KM) IX NOTE AC.
'.'7.')
on the upper «urf«ce of the die*, such flanoh being progressively reduced and the
metal thereof stretched or extended, to that, from the bottom to the upper edge,
the tlnckiieM of the metal is brought thinner and thinner, which U objectionable.
At the same time, owing to the severe treatment to which the abeet metal is thus
subjected, it requires to be more often annealed, in order to prevent its Buffering
injury by the successive processes of stamping, and such U the extent to which
the metal is •tretohed or extended by raising, according to the old practice, that
the disk or blank of metal employed for raising a Teasel of a few inches dism«4er
to a considerable extent, is only about three quarters of an inch larger in diameter
than the finished vessel raised therefrom by stamping. Whereas, according to
my invention, the blank or duk of sheet metal used for making any particular
article when the sides thereof are upright, is of a diameter of about the diameter
of the vessel or article added to the depth of the vessel ; thus supposing the
vessel or article produced by stamping in a die be six inches in diameter and
three inches deep, then the die or blank of sheet metal would be about nine
inches diameter, and the article when stamped therefrom, if it be cut through the
sides and bottom, all parts would be found as nearly as msy be of the same thick-
ness, and that thickness the thickness of the original sheet metal."
The figures A to Q, reduced from the specification, show the several forms
which would be given to the work originally of the diameter aa, by the employment
Figs. 974.
975.
978.
f \
\
/ YZT
\ - /
ir
Figs. 977. 978. 979.
eo
of a die such as fig. 974, with a second point of bearing at 66. The successive forett
or top dies that are employed, being so shaped as to bear only on the bottom of the
veesel so fkr as the edge 66, and not on the sloping sides ; by which scheme the
976 APPENDIX NOTES AC AND AD.
edge bb fulfils in great measure the purpose of a draw-plate, such as would be used
for drawing cylindrical tubes.
After having been progressively stamped, to the contour of G, the work is bur-
nished to form on a chuck such as fig. 977. The work is then again stamped in the
second die fig. 975, then burnished on the second chuck fig. 978, and is afterwards
Btruck in a third die fig. 976, and then burnished on a third chuck fig. 979, to make
the metal proceed through the stages H to L ; of course the work is occasionally
annealed, as will be explained.
Fluted works, such as N, are first raised nearly as cylinders with bottoms to the
shape of L by the intermittent stages already explained, and the burnishing to form
is then discontinued. The flutes require the use of two or more pairs of dies aud
forces in which the flutes are gradually developed, but which tools have not been
represented. In the first pair of tools for the object N, the flutes are shallow and
the die a little bell-mouthed ; in the second pair the flutes are of the full depth, and
as from the sides being almost perpendicular, or exactly counterparts of the bur-
nished object N, the piece when struck holds fast in the die, the latter is perforated
and has a central rammer, which is raised by a side lever to force the finished
work out of the die ; these particulars are all minutely explained in the speci-
fication.
The vessels when cut through present a nearly uniform section, and which may
be thus explained as regards the cylindrical vessel. If the disk of 9 inches diameter
could have its margin folded up without puckering, it would have a rim of li inches
high, the upper edge being of twice the primary thickness, as in fig. 271, page 400,
but the stretching from the dies, causes the height of the sides to become 3 inches,
and therefore this tapering thickness is gradually drawn out, as in tube drawing,
to constitute the increased height.
In proof of the complete efficacy of the mode, it may be stated that vessels may
be thus made in sheet-iron (known as charcoal-iron), a material far less tractible
than copper and brass. Great difficulty was experienced in carrying out this alter-
nation of the two processes of stamping and burnishing to form when working with
iron, owing to the scaling or oxidation of surface which resulted from the annealing,
and which roughness tended to prevent the employment of burnishers. This diffi-
culty was, after various trials, obviated by annealing after the method practised in
annealing articles made of malleable cast-iron, (see pages 259, 260,) in which
case the ductility and tenacity of the sheet-iron are preserved, and that with a
surface quite unimpaired by the firing. The patentee prefers for the annealing
mixture, one part of pulverised iron-ore, added to eight of coke or lime, and he
gives the preference to that iron-ore which has been once used for annealing
cast-iron.
So completely successful are the combined processes, that extinguishers have been
thus raised from round disks of sheet-i ron, and of course without a seam ; the me thod
of stamping with dies having thebevilled mouth and shoulder 6 b, fig. 974, enables
vessels to be raised much higher than by any other method of stamping, even when
burnishing to form is not employed in connection with the stamping.
Note AD, page 431.— To follow the first paragraph.
(Drawing taper bratt tubes for locomotive engines.)
Some of the brass tubes for locomotives, are made cylindrical without and a little
taper within, the metal for them is cast hollow, and drawn on a taper triblet through
,KMH\ NorKS AE, AND AF. 977
an ordinary plate. The thick end U phu>ed near the fire-box, that the tab* may be
the longer in wasting away from the action of the fire, and ahto that cinder* capable
of entering its imallcr end may readily escape at the larger.
Note AK, page 431.— To follow the aoooud paragraph.
(Rand't Patent CollaptibU Tuba.)
These thin tube* are closed at the one end by a convex dick with a projecting
•crew ; the screw being perforated for the expulsion of artists' colours or other
matters inclosed in the vessels. They were first drawn as tubes, as described in
the text, and the ends were oast and soldered iu ; but the entire vessel is now made
by means of only two blows, in dies of appropriate kinds.
By one blow of a screw press, a thick circular disk of tin of the external diameter
of the intended vessel is punched out, made concave, and perforated with a central
hole, somewhat like a washer for machinery.
By a second blow, the blank or button is converted into the finished tube. The
bottom tool is a mould with a shallow cylindrical cavity of the same diameter as
the button of tin, and terminating in a hollow screw ; the upper tool is a cylinder
exceeding the length of the tube, and with a small taper spindle of the diameter of
the hole. The cylinder is just so much smaller than the mould as to leave an
annular space equal to the intended thickness of the tube. The very soft ductile
tin, when submitted to great pressure in the contracted space within the mould,
follows the laws of liquids, and may be said literally to flow through the annular
crevice, and up the cylindrical mandril, as indeed the formation of the tube appears
to be instantaneous, and is a beautiful example both of true principle, and accurate
workmanship in the means employed.
The tube is released from the mouM, first by the ascent of the cylinder, which
leaves the tube behind ; and the screwed extremity of the mould is then driven up
by a ram and lever from below, and the screwed dies being divided on their
diameter, instantly fall away from the vessel thus elegantly produced by a mode
which was only attained after repeated variations in the process, respectively se-
cured by patents. Small tubes are thus made in screw presses, and Urge tubes in
hydrostatic presses of proportionate strength.
Koto AF, page 433. — To follow the third paragraph.
(Clay propt uted by the Asiatic* inttead of binding win m toldtr'mg.)
" The Asiatic goldsmiths seldom use binding wire for light work, they have always
beside them a little dish of a tempered mixture of clay and sand or powdered brick,
v. ith little portions of which they form connections and supports for tho pieces they
mean to solder together. Thus if two tubes have to be joined in the form of the letter
T, (inverted whilst being soldered,) they fiist warm the lower piece, and then dab on
a little at a time of the mortar, (leaving the joint clean,) until the inclined props
of the clay run high enough nearly to touch the upright piece, which being warmed
and set in its place, the connection is completed by a further addition of the mortar,
which, when heated over charcoal, becomesquito firm and supports the pieces whilst
the solder is running, even in works of pretty considerable size." Sir /«Aw Jtobito*.
3 R
978 APPENDIX — NOTES AG, AND AH.
Note AG, page 444. — To precede Section IV.
(Pumice-stone used by Dentitts instead of Charcoal, as a support in soldering.)
Dentists are much in the habit of using a lump of pumice-stone as the support in
soldering the gold work to which artificial teeth are attached. The pumice-stone is
usually filed or rubbed to a flat surface, and the work when laid on this incombus-
tible support, and subjected to the action of the blowpipe, receives a more moderate
heat than when laid on charcoal; which latter support is less convenient, as it
loses its form from burning continually away, and because at the same time, owing
to its combustion, it reverberates more heat than is required by the dentists for
their particular purpose.
The following Notes in the Appendix refer to the Second Volume,
Note AH, page 482. — To precede the last paragraph.
(Silcocle and Lowe's Patent Planes for Joiners, ii-c.)
Subsequently to the foregoing matter on planes having been printed, Messrs.
Silcock and Lowe, of Birmingham, took out a patent in January, 1844, for various
kinds of bench planes, constructed in great part of malleable cast-iron. Several
of these planes are figured and described in the " Mechanics' Magazine " for 1844,
pages 81 to 86, to which the reader is referred. A few lines are however extracted
nearly verbatim for the convenience of those readers to whom this journal is not
accessible.
" Therfrst of these planes is certainly a very remarkable instrument. It is a
double fillister plane, which is so constructed that it is capable of filleting boards
of all sizes from about \ths of an inch to about 3 inches, and may be adapted to the
several purposes of a filleting plane, a side fillister, a sash or back fillister, and a skewed
rabbet plane."
" When this tool is to be used as a filleting plane, both the right and left side
planes are combined together, and fixed at a distance from each other, correspond-
ing to the breadth of the fillet. To use it as a side fillister, the left side plane only
is required, with a stop inserted into an appropriate recess. When it is to be used
as a sash or back fillister the right side plane only ia employed, but with a slight
modification in the figure of the fence."
" To use the tool as a skewed rabbet plane, the right hand plane, with its cha«e
and fence are laid aside, and the left hand plane only is employed."
" All the parts are of cast-iron, protected by tinning or zincing from corrosion,
with the exception of the stock and the handle and body of the fence, which are
of wood, and with the exception also of the screws, the cushion of the travelling
Ecrew, and the sliding nut, which are all of brass."
" The fore and back parts are cast in one piece. The wood of the handle is not
cut across the grain, as usual, but with the fibres running in a direction at right
angles to the body of the planes, whereby a considerable increase of strength is
gained."
" The second instrument described, is a fluting or grooving plou'jh. In this tool
the body is wholly of metal, but in all other respects, as regards the materials and
mode of putting them together, it possesses the same peculiarities as the double
fillister plane first described."
" The third instrument is a dado-grooving plane, with which no less than sixteen
APPENDIX— No I l> \ I, U, AK, AL, AND AM. 979
I more different sue* of work may b« executed ; tho fourth instrument is a fryfcy
i suitable both for rough and smooth work; ihej/Uk vu<ll**ii» * moulding or
ne." Tho explanation of these peculiar tools cannot, however, be conveyed
without excelling our limit of apace and the introduction of numerous figures.
In addition to the foregoing patent planet, constructed principally in met*), the
paten Icon manufacture all the ordinary wooden bench planes with screws for fixing
the iron*, instead of the wedge* driven by the hammer.
Xoto AI, page 487.— To follow the third paragraph.
(Mr. Ltuutt Screw Router Plane.)
Mr. Wui. Lund has constructed the router, fig. 341, page 487, with a screw
adjustment to the cutter, as it is mostly necessary this should be set gradually
deeper as the work progresses. When a similar but smaller tool ia fitted with a
perpendicular cutter, he finds it very useful in reducing the level backgrounds of
small ivory carvings in bas-relief; in which case a margin U left around the «ul -
joct, if only as a temporary guide for tho router to run upon.
Note AJ, page 433.— To follow tho last paragraph.
(Mr. Falconer' t Improved Circular Plowjh.)
Mr. Falconer's plough, rewarded by the Society of Arts in the Session 1346, pre-
sents many points of improvement on the banding plane by Mr. Onwin, described
in tho text Tho principles of the plough, fig. 335, pago 486, ore nearly followed,
but instead of a variety of fences being used some concave others convex, the new
instrument has a flexible steel fence attached to the plough by two stays which are
jointed to tho ends of the elastic fence, whilst to the central port of the same U
fitted a screw adjustment, so that tho one fence may be made to assume any
required curvature, either convex or concave and of course the right line also.
Tho widths of the grooves are determined as usual by those of the cutters, which
are provided with double pointed scorers or nickers, for cutting through such of tho
fibres of tho work as lie transversely, and would otherwise be torn up. The entire
construction of this circular plough is very judicious and complete, and the tool
may bo considered aa greatly improved on those previously used for this purpose.
Notes AK, AL, and AM. — To follow the last line of page 495.
(Xvte AK, Mr. Franklin! t Screv Benck Hoot for Carpenten.)
A screw bench hook for carpenters, intended to supersede that shown at a fig. 853,
page 494, was invented by Mr. F. E. Franklin, of 1'urton, Wilts, and published in tho
Transactions of the Society of Arts for 1840, vol. 53, p. 92. There is a metal
sheath or socket fitted to tho bench, within which on iron bar with a side spring,
slides up and down under tho guidance of an adjusting screw below, the square bar
carries two or more steel teeth formed as a separate piece and screwed on. The
contrivance although quite effective is rather expensive for ordinary use.
Note AL. — To follow the above on page 495.
(Mr. Dt Bttmforft Viet or Stop for a Joiner't Benck.)
*. 973 and 979 represent the vice or stop for a joiner's bench, for which Mr.
II. I)e Jay De Beaufort, of Perigeaux received the reward of the Society of Art*
3 R 2
APPENDIX NOTES AL, AND AM.
in 1841. There are two double-ended levers moving freely on the centez-s by which
they are attached to the bed or foundation piece, so that when a board or piece of
Figs. 978.
979.
wood ic, placed on edge, is inserted between them, it catches between the tails of
the levers and separates them until the piece is grasped also by the other ends
of the same levers, and therefore at two places at once, as seen in the plan fig. 979.
The levers are about one inch thick, and the tail of the one is thinned to enter a
cleft on the other, as distinctly shown in fig. 978, to adapt the vice to very thin pieces,
and the levers being mounted on chamfered slides, may be fixed wider asunder for
very thick pieces. See Transactions of the Society of Arts, vol. 53, page 86.
Note AM.— To follow note AL, on page 495.
(Mr. S. Nickolla' Stop or Clamp for a Joiner's Bench.)
Fig. 980 is a perspective view, and fig. 981 a plan of Mr. S. Nicholls' subse-
quent contrivance for the same purpose, and rewarded by the same society in 1843.
Two inclined and undercut slips of wood « a, are firmly screwed to the bottom
board, and between them are loosely fitted two pieces b b, nearly counterparts of
Figs. 980.
981.
a a, but with projecting fillets at the end. When the board w, is inserted between
these loose jaws, or chaps, they are thrust forward until they reach that contracted
part of the angular gap, which compresses them firmly upon the board to be fixed.
This mode serves for a much greater range of size in the pieces fixed than
the last, and the straight faces of the jaws do not indent the works, as may happen
when soft woods are clamped in the vice shown in figs. 978 and 979. See Trans-
actions of the Society of Arts, vol. 55, page 42.
APPENDIX — NOTES A \O.
: o follow the paragraph oomnModaf " Th* Soak-boar J pLuu-. ' '
(Mt*n. Arfott and Marynm', Scafc-Wrf IfadUnc)
The Kale-board machine used by Mossrs. E«lailo and Margrave, at the City Saw
Mills, London, baa a wide out-iron alide plate, that works freely in chamfer ban
derated on framework about six feet above tho ground ; the power of the ateatu
engine u applied to tho alide by mean* of a stout leather strap, or rather by two
straps for tho to and fro movement ; but one U always out of action and loose.
The slide is perforated for a cutter upwards of one foot wide, placed beneath
the slide, and inclined horizontally about 40 degrees, as a skew rebate plane, but
the pitch of the iron or its vertical face, up which tho shavings slide, has only half
tho inclination of the horizontal, or about 20 degree*.
The log of wood, which is preferred wet on account of its superior elasticity in
that condition, is held down by heavy weights, whilst tho metallic piano slides
beneath it and shaves off in an admirable manner one single shaving ; the thickness
of the same is determined by the adjustment of the cutter, which is principally
held by wedges.
Mean*. Esdaile and Margrave recently patented the employment of three cutter*
situated as above, but one behind the other to remove three scale-boards in imme-
diate succession ; the scheme was effectual in its action, but in the end loss econo-
mical than the single cutter — and which must be moved by a strap or rope, a*
although racks and iron chains have been tried, they fail apparently from the want
of sufficient elasticity.
Note AO, page 505. — To follow the second paragraph.
(0» Macltinafor Planing Wood.)
Of the machine* for producing work* in wood, similar to thoee usually accom-
plished by hand planes, several hare been constructed to act by means of cutters
hiving circular motion. Thus in Paxton'a machine, various circular saws or cut tern
of different diameters and forms are placed on one spindle beneath which tho sash
bar is traversed. In machines for planing moulding* from 2 to 8 inches wide, for
house joinery, picture frames, ic., two figured cutters of the entire width of tho
moulding are screwed to a rectangular block fixed on the revolving spindle, by
which means the cutters are presented at the proper pitch or inclination of 60 or 7o
degrees to the face of the moulding. Circular cutters were also used in the earlier
experiments with Burnett and Foyer's machine, some of them with only 4, 5, or 6
edge* or teeth constructed very nearly on the principle of ordinary plane-iron*.
But circular cutters were abandoned by Meson. Burnett and Poyer from two
motives ; first, the difficulty of constructing and sharpening them, and secondly,
that notwithstanding tho rapidity at which tho cutters might be driven, they still
left marks upon the work because there U a distinct, though small interval of time,
between the passage of the one cutting edge and that next following, and during
which small interval, the uninterrupted advance of the work allowed certain portions
to be lea* reduced, or left a* little hills and ridge* slightly above the general surface.
The wood only become* absolutely smooth, when ita traverse is so far diminished,
that one point of the cutter, (or probably the highest point of the entire series,) U
enabled to touch every individual portion of the work, and which require* a much
greater reduction in the feed or traverse, than might be expected, thus mostly
leaving something to be smoothed off or removed by hand tools.
Messrs. Burnett and Poyer from the** circumstances ultimately rejected revolving
982 APPENDIX — NOTES AO, AND AP.
in favour affixed cutters, and thus in planing mouldings, they employed a stock
which contained from twelve to twenty cutters, every one figured and secured by a
separate wedge, so that the first cutter penetrated but little into the moulding, and
that every succeeding tool removed a shaving of its own ; all the cutters gradually
assimilated more and more to the last of the series, which was sharpened exactly to
the form of the moulding. Under this arrangement the machine was enabled to
work mouldings in pine wood, at the enormous velocity of 70 lineal feet per minute,
and still the work had all the smoothness of that produced by the joiner's hand
planes as usual.
Note AP, page 505. — To follow the former note having the same reference.
(Mr. Antonio Mayer's Patent Splint Cutting Machine.)
The production of an article of apparently minor importance, has led to the
invention of a very effective and important machine allied to the planes, namely,
the splint-cutting machine for cutting the wood for chemical matches.
It is necessary to premise that when these useful matches were first introduced,
they were mere shavings cut from blocks of deal, by the plane previously used iu
preparing the chips of willow and other woods from which ladies' bonnets are
woven. This plane had at the front, a series of lancet-like knives which scored the
wood in shallow parallel furrows, and immediately behind the knives was fixed au
inclined plane iron of very low pitch which cast off a shaving, thus producing
several splints at once from the edge of a board about one inch thick.
When the same splint plane was used for the stronger and less flexible matches
nearly one-tenth of an inch square now used, the splints were found to be broken
or disrupted in their fibres, by the comparatively abrupt angle at which they were
removed from the block of wood, notwithstanding that the plane had a very thin
iron sole and a cutter of very low pitch. This defective action of the hand plane
led to the invention of Mr. Mayer's Patent Splint Cutting Machine, used exclusively
at the celebrated works of the Messrs. Esdailes and Margrave of London.
The splint-cutting machine has a metal slide, which travels parallel with the
ground, but in a vertical plane, by means of a crank and connecting rod that give it
60 strokes in a minute. The slide carries first a series of 30 lancet-like knives, half
sloped on the upper surface, the other half on the lower, these penetrate the wood
about one-tenth of an inch, and are immediately followed by the cutter or plane
iron, the broad flat side of which rests directly against the wood to be cut, (no sole
being used,) the edge of this knife is very much inclined, namely, to 70 degrees, and
is ground with a very long bevil, 2 inches wide, giving to the edge the acute angle
of 12 degrees, and which, combined with the great obliquity of the knife causes the
splints to be only bent from the wood at the insignificant angle of about 4 degrees,
so as to be entirely removed by cutting, and not by splitting or rending.
The wood used for making the splints consists of whole deals 10 inches wide,
3 inches thick, cross cut into blocks 5 inches long. Three of these blocks are placed
together, constituting a length of 15 inches, sufficient for six splints or matches ;
and as there are thirty lancet knives, every traverse of the machine produces
180 splints ; this at 60 strokes a minute makes 648,000 an hour, or 6,480,000 in a
day of ten hours. There are two such machines constantly at work, and these, not-
withstanding the average production of each is upwards of three millions of splint
a day, furnish another proof that in some processes, machinery cannot overpower
hand labour ; as the larger proportion of the splints used in this country are never-
theless obtained from the hand cutters and foreign importations. The hand-cut
splint* although cheaper are inferior to those cut by the machines in question.
APPENDIX — NOTI8 AQ, AB, AS, AT, AU, AND AV. 983
Note AQ. page 5SS.— To follow the last lino but one.
(O» grinding tame of tkt toolt for turning iron.)
When thu tooU 431 or 432 p. 533 are used in both directions, that U if some-
tiiuoa moved towardi the right baud, at other time* to the left, it is then necessary
t ho chamfer or upper face of the point should be ground aquare aeroM to serve fur
cither direction of motion. But when tho tool U used exclusively from the right
hand toward* the left, the chamfer should be so ground that the left side U the
higher, as this from being then the entering angle of the tool, works much moro
y from being sloped some 30 degrees from the horizon to), as already explained.
On the very samo principle an efficient side-cutting tool for iron to be used in the
tlidt rest, is derived from the triangular tool, page 521, and represented in three
views in the annexed figure 082. A bar of steel U drawn down at tho end, to about
half its thickness, tho width, or
rather the vertical height remaining \
unaltered, Uiis narrow part is chom- ^J M |
fered on its outer face, so as to
be a little inclined from the per- V~~
pvndicular, and is then ground on
its upper surface to make a ridge parallel with the side of the tool. The ridge
which La sloped about 80° from the horizontal, is sometimes on the right, some-
times on the left, as the tools are mode in pairs; and as they will readily remove
a shaving an inch or moro wide, a cylinder of six inches diameter may be reduced
to four inched or less at one cut, in a lathe having proportionate power.
Note All, page 533. — To follow tho paragraph ending, "for general purposes."
(On lubricating metal turning toolt with water.)
When water U used for lubricating the tools in turning iron with band tools, tho
most simple plan is to dip the tool occasionally into a small vessel containing the
fluid. A more effectual way employed in turning by hand or with the slide-rest,
is to make a small mop, of a bit of rag surrounded by a loop of wire, the cuds of
which are twisted together to form a handle, as in a bottle brush, with which the
work is occasionally moistened.
lu turning with the slide-rest or self-acting lathe, practical men often fix a drip-
can to tho slide-rest, that the water may fall on tho work close by tho tool ; or in
the best mode a flexible hose is used that leads from a cistern above, the discharge
of water being regulated by a small tap. These two modes require that metal
pans should be placed beneath tho work to catch the water that runs away, and
also that some vigilance should bo exerted to keep tho lathes from becoming rusty.
Notes AS, AT, AU and AV.— To follow tho last line of page 533.
(On th« Principle* of TooU for Turning and Planing Metal*.)
The formation of the tools iftod for turning and planing the metals is a subject
of very great importance to the practical engineer, as it is indeed only when tho
mathematical principles upon which such tools act, are closely followed by tho
workman, that they produce their best effects. With a full conviction of the
advantages which result when theory and practice are thus associated, tho author
has to congratulate himself on being able to present to his readers, two original
984
APPENDIX — NOTE AS.
papers, respectively written on the subject of the principles of tools for turning
and planing metals, by Charles Babbage, Esq., F.R.S., &c., and Professor Willis,
A.M., F.R.S., &c., both distinguished by their high mathematical attainments, and
their intimate practical experience in the use of tools.
Note AS. — (Papa- on lJt£ Principles of Tools for Turning and Planing Mctah, ly
Charles Eabbaye, Esq., F.R.S., d-c. <fcc.)
Steel of various degrees of temper and under various forms, is almost universally
employed for cuttiug metals. Before deciding on the forms of the different tools
it is desirable to inquire into the principles on which their cutting edges act, and
to assign special names to certain angles on the relations of which to each other,
and to the metals upon which they are used their perfection mainly depends.
In fig. 983, c is a cylinder of steel or other metal, and T is a planiug or turning
tool acting upon it at the point a. A c is a horizontal line passing through the
center c, and the cutting point a. B a, is a line passing through the cutting point
a and along the upper plane b a, of the cutting tool T. C a, is a line passing
through the cuttiug point a and along the front plane e a, of the cutting tool.
D a, is a line from the cutting point a, at right angles to the radius c a.
The angle D a C, may be called the angle of relief, because, by increasing it, the
friction of that face of the tool upon the work is diminished.
The angle Cab, may be called the angle of the tool.
The angle B a A, may be called the angle of escape, because the matter cut away
by the tool escapes along it.
The forces to be overcome in cutting a thin shaving of metal from a cylinder
or from a flat surface are of two kinds.
1st. It is necessary to tear along the whole line of section each atom from the
opposite one to which it was attached. The force required for this purpose will
obviously be proportioned to the length of the cutting edge of the tool, and depend-
ent on the nature of the metal acted upon. But it will be quite iudepeudeut of
the thickness of the part removed.
....JV
2nd. The shaving cut off by the tool mu-t in order to get out of its way, be bent
or even curled round into a spiral. This second force is often considerable, and
when thick cuta arc taken, is usually far larger than the former force. If the bond-
ing were of small extent, then the force to be exerted would vary as the square of
the thickness of the shaving multiplied by some constant, dependent on the nature
APPENDIX — NOTE AS.
uf the metal operated upon. But the bending very frequently proceed* to such an
extent that the shaving iUelf is broken at very abort interval*, and MOM shaving*
of iron and atoel present a continued eerie* of fracture* not quite running through
but yet so complete, that it U impossible even with the most careful annealing to
unwind the spiral. This partial severance of the atoms in the shaving itself, will
require for its accomplishment a considerable exertion of force. The law by which
tliii force increases with the thickness most probably embraces higher power* than
the first and second, and may be assumed thus
force = a + bt + ct* + dt* +
i- the present illustration it U unnecessary to consider more terms than those
already mure particularly explained, namely, the constant force, and that which
varies as the square of the thickness of the shaving.
If therefore t, bo the thickness of the shaving, and A and B two constant*, we
shall find amongst the forces required fur the separation of the shaving the two
terms.
where A, and B, depend upon the nature of the metal acted upon.
Wo may learn from this expression, even without being acquainted with the
values of the constants A and B, that the force required to remove the same thick-
ness of metal, may vary considerably according to the manner in which it is effected.
For example. If a layer of metal of tho thickness of '2 t, u to bo removed. It
may be done at two successive cuts, and the force required will be equal to
But the some might have been accomplished at one cut when the force expended
would have been
A.+iB*1
Now the force required for the two cuts, will always be less than tho force
required for making one cut, if <*>— -
2 B
For let t^^-g + r then
Korco for two cut*
Force for one cut of twicej_ A + 4B/ _A \_3 A + 4 Br>
tho thickness I \ 2B /
v hich former is always smaller than tho latter force by the quantity 2 B r.
In the same manner it may bo proved that if
it nil! always require lee* force to make n separate slice.*, than to cut one slice of
M time* the thickness for
Force for M slices =» A + M Bl -^-5 + v )=(* + 1) A + * B r
Force for one slice of
times the thicknen
which former force is always less than the Litter by the quantity of (»r- x) Br.
The angle of relief should always bo very small, because the point a will in that
ease have its support nearly in a line directly opposed to that force acting upon it.
9S6 APPENDIX NOTE AS.
If a tool either for planing or for turning is defectively formed, or if it is pre-
sented to its work iu such a manner that it has a tendency to dig into it ; then a
very Bmall angle of relief, in addition to a long back a e, will in some measure
counteract this defect.
The smaller the angle of the tool, the less will be the force necessary for its use.
But this advantage of a small angle is counterbalanced by the weakness which it
produces hi the support of the cutting point. There is also another disadvantage
in making the angle of the tool smaller than the escape of the shaving requires ;
for the point of the tool being in immediate connection with a smaller mass of
metal, will not so quickly get rid of the heat it acquires from the operation of
cutting, as it would if it formed part of a larger mass.
The angle of escape A a B is of great importance and it varies with the nature
of the material to be acted upon. If this angle is very small the action of the tool
is that of scraping rather than of cutting, and the matter removed approaches the
form of a powder. If however the material is very flexible and cohesive, in that
case shavings may be removed. The angle I have found best for cutting steel is
about 27°, but a series of experiments upon this subject is much required.
After the form of the cutting tool is decided upon, the next important point to be
considered is the manner of its application. The principle which is usually stated
for turning tools is, that the point of the tool should be nearly on a level with the
axis of the matter to be turned, or rather that it should be very slightly below it.
This rule when applied to the greater number of tools and tool-holders is calculated
to mislead. Before applying the correct rule it is necessary to consider in each tool
or tool-holder, what is the situation of that point around which the cutting point
of the tool will turn when any force is put upon the tool. Let this point be called
the center of flexure. Then the correct rule is, that the center of flexure should
always be above the line joining the center of the work and the cutting point.
On looking at fig. 983 A c, is the line joining the cutting point a and the center
of the work c. By making the tool weak about Q that point becomes the center on
which the point a will bend when any unusual force occurs. On the occurrence of
any such unusual force arising from any pin or point of unequal density in the
matter cut, the point of the tool a, by bending around the center Q will dig deeper
into the work and cause some part of the apparatus to give way or break.
If on the other hand the point P is that around which the point of the tool
when resisted tends to turn, then since this point is above the line joining tlio
cutting point and the center of the work, the tendency of the additional strain
on the point is to make it sink less deeply into the work, and consequently to
relieve itself from the force opposed to it.
Fortunately the position of this point can always be commanded, for it is always
possible, by cutting away matter, to make one particular part weak. This is
indeed a circumstance too frequently neglected in the construction of machinery.
Every piece of mechanism exposed to considerable force is liable to fracture, and
it is always desirable to direct it to break at some one particular point if any
unexpected strain occurs. In many cases where danger may arise from the inter-
ference of the broken part with the rest of the machinery this arrangement is
essential. In all cases it is economical, because by making the breaking, if it
occur, at a selected spot, provision may be made of duplicate parts and the delay
arising from stopping the machine be avoided.
The results of the preceding inquiry would lead to considerable changes in the
forms of tools generally used in cutting metals; and as the time employed iu taking
\rri \ Dl \— NOTES Ai, AND AT.
087
• oat u tumidly equal whether the sharing b« thick or thin, tho saving in power
by Uk.ii,- tluit cuts separately would he accompanied by a conaiderable expense of
time. This however need not be the oa»e if proper tool-holders we employed, in
conformity with the following several conditions : thus
The tool-holders should be so contrived as to have several cutters successively
removing equal cut*. — The cutting edges should bo easily adjusted to the work. —
The steel of which the cutters are formed should bo of the be«t kind, and after it
U onoe hardened should never again bo submitted to that process.— The form and
position of tho cutter should be such that it may, when broken or blunted, be easily
ground, having but one or at tho utmost but two faces requiring grinding.- !
desirable that when being ground it should be fixed into some temporary handle, in
order that it may always be ground to tho same cutting angles. — The cutters should
bo very securely, but also very simply tightened in their places. — The center of
lies lire of the cutter should, in turning, be abort the line joining the center of the
work and the cutting point; — whilst in planing the center of flexure should be in
advance of a lino perpendicular at tho cutting point to the surface of the work
planed. Examples of some tool-holders of this kind will be given subsequently.
Tho effects of such improved tools would bo to diminish greatly the strain put
upon lathes and planing machine*, and consequently to enable them to turn out
better work in the same time and at a leas expense of power: whilst the machines
themselves so used would retain their adjustments much longer without reparation.
Note AT.— To follow Noto AS at foot of page 539.
( TTie author's description of Toolt and Tool-holdcrt for turning and planing metal,
constructed by C. Babbage, Etq. F.R.S.)
lu the course of the investigation which led Mr. Babbago to write tho foregoing
I -I ^T, he constructed various experimental tool-holders, a port of the more sue-
cessful of which I shall now attempt to describe, beginning with those in which a
F5g. 984.
single cutter in used. Tho figures are one-fourth of tho sixc of the actual tools,
but the proportions of which may of course be enlarged or reduced according to
circumstances.
988
APPENDIX NOTE AT.
Fig. 984 represents the perspective view, fig. 985 the plan, and a b c d e the details
of Mr. Babbage's tool-holder, for the general purposes both of turning and planing
metal : the tool itself c, being simply a short rectangular piece of steel cut off from
the end of a long bar, and ground at the end with one chamfer at about 60 degrees
with the length of the blade. The stock is cast of gun-metal and of a cranked form,
as seen in fig. 984, the end being pierced with a vertical hole, in which is fitted the
bolt a, having a long diametrical mortise to admit the tool freely as shown, and a
nut and washer e, below to bind all the parts together. The bolt a, passes through
two circular wedges b and d, inclined at the angle 27° on their internal faces, and
loosely united by steadying pins ; the lower circular wedge has a diametrical
inclined mortise to serve as the seat for the tool, and which is grasped by the
margins or walls of the wedges, when the bolt and nut are tightened.
Sometimes the cutter lies centrally to the shaft of the holder, as shown in fig.
984, and also by the central dotted line in the plan, the vertical branch of the
holder is pierced with a mortise, then to receive the superabundant length of the
steel cutter; but at other times the cutter is inclined about 45° in either direction,
as represented in the plan, fig. 985, and the cxitter then just escapes the stock
through a little notch filed for the purpose.
The one inclined position has been represented in the plan, fig. 985, and in this
case the point of the cutter lies in a very favourable position for turning either
cylindrical or plane surfaces, as the cutter stands in advance of the stock, and may
proceed into an internal angle, such as the joining of a mass composed as it were
of two cylindrical blocks of different diameters. The tool when simply bevelled,
or ground with one chamfer, will not perfect the inner angle of the work on both
faces, but which may be done if the tool is ground with two faces, or as a pointed
tool meeting at an angle a little less than 90°.
The figure also represents a very useful addition, applicable to all the tool-
holders and slide-rests for metal turning, namely a little eye-shade, which is no
more than a small piece of window glass, attached either to the tool-holder or
any part of the rest, in a spring clamp which retains it at about an inclination of
40 or 50 degrees, so as to be neai'ly at right angles to the line proceeding from
the point of the tool to the eye of the workman, which it effectually shields from
injury. This simple contrivance, which may be readily added to any slide-rest,
enables the workman narrowly to inspect the course and progress of the tool, and
yet defends his eye completely from the shavings.
Fig. 986 represents the perspective view, and fig. 987 the end view, (full size,) of
Mr. Babbage's tool-holder for internal
Fig. 986.
works, and the small parts are shown
detached, also full size.
The cutters c are short pieces cut oiF
from a bar of steel, fluted in the planing
machine, to give that which Mr. Bab-
bage has described as the angle of relief,
and they are sharpened almost exclu-
sively at the end, nearly square across
or slightly chamfered or rounded at the
corner. This tool-holder is made of
steel, the end is turned cylindrical,
and a cleft is sawn with a thick circular
cutter or saw, down one side nearly to the axis, and entirely across the end to the
depth of about one diameter and a half.
•
989
In the end viow fig. 987, c represent* the cutter, 6 the block against which the
cotter rests, and « the screw that panes through 6, and holds the several parts in
contact. The tool may bo mad* to out on the right or left hand aide at pleasure, at
<? and 6 each reverse. To enable the cutter to resist being drawn out, by the force
of the cutting action, the small square wire, represented black, is added, this square
wire fits a groove planed out in the tool-holder, and lies In the flute of the cutter
so as to secure it
In this internal cutting tool as in all others of similar kind, a hole must be drilled
or otherwise made in the work to admit tho shaft of the tool, before it can be used,
and from the contracted measure of tho tools used for turning the inner surfaces of
small apertures, the most suitable angles cannot be generally given to the internal tools.
Figs. 988 and 989 represent in the entire and dissected states, one of several tools
contrived by Mr. Babbage, for turning wood by means of tho slide rest. A small part
of the end of the gun metal tool-holder is inclined to the stem and the extreme en-l
is filed convex to fit the concave aide of the gouge c, which is ground on the outside,
exactly as usual with a gouge used by hand. Tho cutter is retained by means of
the strap il, which embraces the cutter, and also two little blocks a, and I fitted
together with a chamfered joint, so that the middle piece which is carried down by
the central binding screw, acts as a powerful wedge, and fills out the space within
Figs. 91)8.
989.
990.
the loop, consequently tho tool is grasped with considerable firmness against the
rounded end of the holder, even when the pressure of tho screw is very moderate.
The screw requires a groove below its head, and tho wedge b, a corresponding pin
or key, that it may be raised to release the tool when the screw is unwound.
In some of these tools tho cutter is circular as a gouge, in others straight as a
chisel, or angular as a pointed tool, and of these three varieties, some have bent
t-hafta the ends of which not only dip downwards, ss shown in the side views
'.'88 and 989, but are also inclined horizontally at an angle of 45* as in fig. 990,
in order to produce the same effect as the inclined position of fig. 985, and enable
the same tool to serve alike for turning cylindrical or plane surfaces at tho one fixing.
The whole of these cutters for wood act in a vigorous and efficient manner.
I shall now say a few words on Mr. Babbage's notions of tho employment of
cutting tools with many points, so that the work may be equally divided among all
the points.
990 APPENDIX — NOTE AT.
The most simple case quoted by Mr. Babbage, is that of the screw tap, in which
to carry out his principle, he cuts 6 or 7 longitudinal grooves instead of three only,
the faces of which grooves are- undercut or inclined to the radius, although not
fully to the approved angle of 27°, they more resemble those taps called by work-
men original taps, shown in figures 550 and 551, page 591, but they nevertheless
answer for tapping and screwing the finer class of work, as they produce true
threads and work freely. The circular tops of the threads are as usual a little
cleared with the file, unto near the cutting points, and in the larger sizes of these
taps the flutes are undercut to admit of their being sharpened on a revolving lap.
Another example quoted by Mr. Babbage is that of Messrs. Whitworth's key- way
cutter, for making the internal grooves in the holes of wheels, for the keys by which
they are fixed upon their cylindrical shafts. The cutter is a cylindrical rod of steel,
through which are made about ten or a dozen rectangular mortises, placed at equal
distances and in a right line. Every mortise is fitted with a small steel cutter, the
sides of which are made exactly true in the engineer's planing machine ; the first
cutter is sharpened so as scarcely to project beyond the surface of the cylindrical
bar, the second projects a little more than the first, and so on to the last, the projec-
tion of which equals the full depth of the key-way. When used, the bar is first put
into the hole of the wheel, and which it should exactly fit, and the bar is steadily
pushed quite through the hole of the wheel or pulley, by aid of the steady move-
ment of an appropriate screw press.
This mode of action always cuts the key-way parallel and not taper as frequently
wanted. From the subdivision of the work amongst the many cutters, the work is
well done, and almost without injury to the cutters, which should be sufficiently
close together, that the succeeding cutter may enter the groove, before the previous
one has passed through the same ; in other words, the interval between the cutters
should be always less than the thickness through the boss of the wheel. The cutters
after having been sharpened, are set forward by aid of little screws fitted in a thin
bar, inlaid in a chamfered groove extending the whole length of the cutters.
Figs. 991 and 992, represent Mr. Babbage's tool-holder with many blades for the
planing machine. This tool-holder consists of two parallel bars of gun-metal, united
to cross pieces at the ends, so as to
Fig. 991.
form a narrow central cleft ; the side
bars are pierced with several holes
which receive as many pins, that
constitute the centers upon which
a series of short parallel blades are
jointed to the holder. When in use,
| -i the blades are separated by parallel
F'g- 992. EJpPjfQS ^g^Bjyi slips of brass, and at the left ex-
T~^ ^ tremity is a block to which is given
the inclination of 27°, and the cud
screw being fastened the whole of the blades are fixed at that angle ; Mr. Babbage
says in making another tool-holder of this kind he would cast the holder in one
piece, and tighten the cutters by the method of the screw and wedge a, I, fig. 988.
In order to sharpen the cutters, the brass separating pieces and the angle block at
the end are removed, and all the flat pieces then fall down so that their chamfered
ends lie in a straight line ; when thus fixed by the end screw, their chamfers arc all
ground at once upon a lap ; on the re-insertion of the brass plates, the tools bristle
up like BO many saw teeth after the manner shown. The tool is fixed in the planing
machine at such an inclination, that the first cutter penetrates but a little way
APPKNDIX — NOTES AT, AND AU. 991
and every succeeding cutter penetrates more and more unto the required degree,
owing to the inclined position of the tool-bolder; the difference in elevation or
projection of its two ends, being exactly equal to the intended thickness of tho
shaving to be removed, and the two tails of tho tool-holder enable each and of the
•one to be securely grasped in the planing machine, (See first paragraph, page 982.)
Fig. 998, a face-cutter for the lathe, is the last of these tools which Mr. Babbage'*
occupations have given him leisure to devise. The circular block is screwed to tho
lathe as on ordinary chuck, and on its cylindrical surface are cut 10 wedge-form
grooves or notches, the one side of every notch is exactly on a diameter, the other
side of tho notch is inclined a few degrees, and fitted with a parallel steel blade,
and a gun metal wedge ; the several wedges are sent forward by tail screws, tapped
through a ring screwed on the back part of the chuck or otherwise attached.
To sharpen the blades they are removed from the chuck and placed in the rhom-
boidal cavity of a tool-holder shown in perspective in fig. 995, and in plan in fig. 996;
the sides of the cavity are parallel and in pairs, but inclined in both directions to
the angles at which the cutters are ground upon a revolving lap ; the horizontal
r. .-. N '.
1
;.
N
B
— J
0
,
angle seen in 996 U 24 degrees, the vertical is 16. By means of this holder
the chamfered ends of tho cutters are all thrown into one plane, and the sides of
the cutters iuto another plane, and secured by two equal or folding wedges, tho
ends and sides of all the cuttera are then ground en matte.
When replaced in tho chuck a distance pinto d with a central projection or boss
is first fixed to the end of the chuck, the cutters are allowed to rest in contact
with this plate, and on the screws being tightened, every cutter becomes fixed by
its wedge, and the distance plato ensures the ends of the cutters lying on one
plane, and as much in advance of the end of the chuck, as the space between tho
chuck and the reduced margin of the distance plate.
This circular cutter with removable blade*, may be viewed as a miniature and
refinement, of some of tho large boring tools and cutters with loose blades, figs. 61 6
and 517, pages 569 and 571 ; and the tool here shown has been extensively used by
Mr. Babbage in facing all kinds of rectilinear pieces, which are at the time fixed
in the slide refit, or in a universal chuck with screw jaws attached to the slide
rest, by means of which the works are carried post the end or face of the slowly
revolving cutter, which serves for several of the metals including steel, but the
most effectively for brass and gun metal.
Note AU.— To follow note AT at the foot of psge 538.
(Paper on the Principle* of Tool* for T*ni*y and Planiny Mttalt, by the Rev. Prof.
WiUit of Cambridge, A. J/., F. R. S.. *,-.)
Let FGHK,fig. 097, represents rough cylinder of metal running in a la the between
the centers II and L, and suppose that this is subjected to the action of the tool
99-2
APPENDIX — NOTE AU.
DBE, which in the figure is supposed to have travelled from A to B, for the pur-
pose of turning the surface of the cylinder. The tool is fixed in a slide rest by
which it is carried iu a direction parallel to the axis of the cylinder ; it moves at
such a rate that during each revolution of the cylinder, the point B of the tool is
carried onwards through the space B b. The proportions of the figure are greatly
exaggerated for the purpose of showing the effect proposed to be illustrated, for
in practice, as is well known, although it is true that the effect produced by the
tool in turning a cylinder, is to trace a screw upon the surface, yet the thread of
that screw is either so fine from the slow motion of the tool, that it appears as a
mei-e roughess of surface, or else it is so flattened as to disappear from sense.* In
this figure the screw mustbe considered as an exaggeration for the sake of explanation.
Since DBE and dbe represent the two successive positions of the too], at the begin-
ning and end of one rotation of the cylinder, a little consideration will show that the
shaded space between them, namely mbn, is the section of the spiral shaving which
runs off the work during the process of turning. In this diagram bn is the breadth
of the shaving, and bm its thickness ; but by varying the position or angles of the
tool, and its relative motion to the work, it may happen that the reverse may be the
case ; that is to say, that bm may be the breadth, and bn the thickness. In all
cases, however, the two cutting edges of the tool are employed in detaching the
shaving, the one, (as BE in this figure,) separating its breadth from the solid, and the
other, (as DB,) separating its thickness, or vice vend.
In adjusting the position and angles of a tool for turning or planing a given piece
of work, it appears to me essential that its action, as shown by such a diagram as
this, should be well foreseen and investigated, and I can only regret that the narrow
limits within which I am at present circumscribed, prevent me from explaining the
consequences of this principle by a variety of figures.
For example. In practice, if a tool were used iu the position of fig. 997, the
motion would be slow, and the space B6 or mb, which is the thickness of the shaving,
would be much less than in the diagram. It would be usually argued, that BE was
the real cutting edge, and that the shaving would como off without the assistance
of the other edge BD. Nevertheless, the action of this edge BD is the only one
* In fig. 997 the thread of the screw, is inadvertently drawn, so as to incline in the
wrong direction. In fact the figure now shows the lower surface of the work seen trans-
parently, instead of the upper as it ought to have done.
APPENDIX — NOTE \l.
. it left upon the surface of the work, and if the •baring b« torn off cdgcwiso
by neglecting the action of this edge the surface will necessarily bo left rough.
placing the edge BD still more nearly, or even exactly parallel to the axis of
rotation, and rounding oft* the corner D * to prevent it from catching the Mriacr
screw form may be wholly obliterated, and if the edge BD be carefully sharpened
a finished surface will result ; for it is clear, that thus the edge BE U wholly occu-
pied with the hard work of separating the breadth of the shaving, and that the
surface which it leaves at each turn is wholly removed in the next, whereas the
edge BD has the lighter work of separating the shaving edgewise, and the surface
which it leaves, is in fact the visible surface of the work when completed.
Let us now examine the angles that may be given to the tool edges. Fig. 998 shows
tho pointed tool in its simplest form, AB and AC are its cutting edges. The stem
»f the tool may bo of various shapes for convenience, but the cutting portion of the
in*t rumcut is bounded by three planes, namely, two tide plaau, one of which only,
S, U shown in the figure, and a third or upper plane U. The intersection of this
upj>cr plane, with the two side planes respectively, produces the cutting tdgtt AB, AC,
and the intersection of the two side planes produces the line of the front angle AD.
By a proper management of the inclination of these planes to each other, wo
obtain the desired form of the point of the tool, and the proper acuteness of tho
cutting edges. This is tho subject to which I wish in the next place to direct
attention.
The front angle upon AD determines the form of the point of the tool in plan,
and also the section of tho shaving, as already explained. As to the cutting edges,
a greater or less inclination of tho upper plane U of the tool to the horizon (always
supposing the tool to rest on a horizontal bed), will produce a greater or lees
degree of acuteness in these cutting edges.
If the upper plane be horizontal the cutting edges will plainly be square, whatever
be the front angle of the tool But if not, then the angle of the edges will vary
conjointly with the front angle of the tool, and the inclination of the upper plane.
Different metals, and qualities of metal, require different degrees of acutenesa
in tho cutting edges, which have not been as far an I know exactly determined.
In tho present case I will assume, that wrought iron requires an edge of 60°, cast
iron of 70°; that brass may be roughed out with an edge of 80°, and finished with
one of 00°. These angles I believe to be very near to the best ; probably a varia-
tion of a degree or two is of little consequence. But as the finishing of some
kinds of work requires that the edge of the tool should euduro through a long
process, without giving way and requiring fresh grinding, it is of some importance
that tho angles of the edged should bo carefully investigated.
In grinding a tool of this form it is convenient to consider only the angle which tbo
upper plane U makes with the line of tho front angle AD. In other words the angles of
the cutting edges AB AC being equal, if we suppose a vertical plane to pass through
AD and make equal angles with tho side planes 3, it will clearly intersect the upper
plane in a line A*, bisecting tho angle BAC, and the upper plane will be perpendi-
cular to this vertical plane. A rough goniometerf will enable us to grind this upper
* In fact, there U no occasion to round off the corner D, because the edge DD i>, in
most CMC*, inclined downward*, and the corner D carried I hereby clear of the tuiface of
the work, except in face turning.
t By this term i* meant a frame attached to a grinding machine, capable of being set at
different angles, »o ai to eniure that the tool, which rt»ta upon it during the procca*, thall
receive its proper form. A ymiottat would be a better name.
o S
991
APPENDIX — NOTE AU.
plane at any desired angle £AD, and thus to ensure tbat the cutting edges shall
be alike.
But this angle £AD is not the same as that of the cutting edges, and the question
to be answered in every case is the following : — Given the front angle of a tool (i. c,
the plan of its point), and the cutting edge required by the metal tchich it is to cut, to
jind the angle of inclination kAD of the upper plane. This is an affair of trigono-
metrical calculation, and for practical purposes is best resolved into the form of a
1000.
short table which I will give, simply remarking that I have not thought it neces-
sary to state the results nearer than to the next half degree, which is indicated in
decimals when it occurs as 69 '5.
TABLE OP THE ANGLES k A D.
rBOKT A HOLE
UPON A D.
85°
80°
76°
cur
70°
FINO EDO
65°
i:.
60°
55°
50°
u
150°
80°
74.6
69-5
64°
59° > 54°
48-5
•i:r
140°
79-5
74
69
63
58
52-5
47
41-5
130°
79
73-5
68
62
56-5
51
45
39
120"
84-5
78-5
72-5
67
60-5
55
49
42
35-5
110°
84
78
71-5
65-5
59
52-5
46
38-5
30
100°
835
77
70
63-5
56-5
49-5
42
33
23 :
90°
83
76
68-5
61
53
45
36
25
0
80"
82
74-5
66
58
49
39
27
0
70°
81
72-5
63
53-5
42
20
0
60*
80
70 58-5
47
33
0
50°
78
66
52
36
0
40°
75
•10
0
APPENDIX — NOTE 41 .
To use thU table, take the column which corresponds to the required cutting
edge. The degree placed opposite to the front angle of the tool will show the
nation of the upper plane U to the front angle, namely, the angle *AD. Thus
to obtain cutting edges of 70* for a tool whose front angle is 90% the plane U
must be ground to an angle of 61* with the line of the front angle AD.
By means of this table several curious result* may be obtained. For example,
I hare often seen tools for turning iron, in which the front angle AD ha* been
made 60*. Now referring to the table in the column for 60* (the proper cutting
edge for iron), we find zero opposite to the front angle 60*. indicating that the
desired form is impossible; that is to say, that it is impossible to place the upper
plane of the tool at an angle that will cause it to make tho desired catting edges
of 60°. The same front angle of 60°, under a cutting edge of 65*, gires the angle
*AD equal to 33°, which is still too acute for tho required strength, and erea a
cutting edge of 70* requires the weak angle tAD of 47*. In short, no proper edge
con bo given to an iron turning tool whose front angle AD is not greater than 60*.
To produce a stronger point tho front angle of tho tool is sometimes ground flat
as at / in fig. 999, so as to make a short intermediate cutting edge m n. It is clear
that the angle of this new cutting edge m n is the same as iAD in fig. 998, in tho
table, which table will therefore serve for this new form. This shows the impossi-
bility of making the front cutting edge m n, with the same angle as the other two,
for the former will be much more acute than the latter, except they be all square
edges. If it were not for this circumstance, this form would give a strong and
effective tool, BO that it is worth while to examine tho amount of the objection.
Supposing tho front angle of the tool (which in this cose is the angle at which
the two side planes trouW meet), to bo 90", the table shows that if the lateral cutting
edges are 60*, the front edge m n will be 45°. As this is too acute to stand, let
the front edge bo made 60°, this will give about 70" for the side edges. For iron
and steel tools then, this form is bad, because the difference between tho angles
of the cutting edges is too great. The best form for these metals appears to bo
one in which the front angle of the point is made as obtuse as possible, and both
the cutting edges alike.
For example, the front angle may be mode equal to 135*. This corresponds by
the table for a cutting edge of 60°, to a vertical angle IAD of 57*, and produces n
very strong tool, similar in form to tho part of fig. 999, which is included between
tho planes S and/, but having both its cutting edges of the same degree of acutenees.
The same remarks apply, but not perhaps so forcibly, to the cose of tools for east
iron, in which the cutting edge should bo about 70". Thus if we give to the form
fig. 999 lateral cutting edges Bm Cn of 70* (supposing as before that its side planes
are inclined at 90°), the front edge m n will be only 61* ; and if we make this front
edge 70°, the lateral edges will bo about 76*. Thus the difference is much leas
than in the former example, but still the form of fig. 998 is preferable, and the
more obtuse the front angle is made tho stronger will the point of the tool be.
An angle of 150* may be given to the front angle AD.
Sometimes tools are made nearly like fig. 999, but in which the front is rounded
off, as in fig. 1000, instead of being blunted by a plane as at /. These are liable to
the same objection as the form fig. 999 ; namely, the impossibility of giving an
equal angle to all the cutting edges. For, comparing fig. 999 and fig. 1000, it is
clear that the vertical angle LAD is the same in both, and that in the round point
this angle passes through all degrees of acutcuese, between that at A and that at
m, instead of abruptly changing from one to the other at IN, as in fig. 999.
3 s 2
996 APPENDIX— NOTES AU, AND AV.
Besides tins, a shaving which is separated by a round tool, aud which, conse-
quently, has a curved section, cannot roll itself off the work with the same ease
that a ribbon-shaped shaving does. It thus opposes gi-eater resistance to the edge
of the tool, and blunts it sooner. Also, a round-pointed tool is more difficult to
keep in order than a tool whose edges are formed by planes alone.
On the whole, then, I am inclined to recommend the obtuse pointed tool fur
cylinder turning and the planing of flat surfaces ; biit the tool should terminate in
an angular and not a rounded point, and the edge BD (see fig. 997), should be set
nearly or quite parallel with the path of the tool, as from A to B, in turning a cylinder,
or planing a flat surface. For more complicated figures, of course, different forms
must be adopted, as for planing into corners or turning projections ; but the same
principle of keeping the front angle AD fig. 998, as obtuse as possible, may always
be recollected with advantage.
There is yet another point to be remarked. In the above pages, the tool being
assumed to rest upon a horizontal plane, the side planes S may be supposed to be
vertical, and, consequently, the line of the front angle AD vertical also.
But Mr. Nasmyth has well explained the necessity of inclining these planes to
an angle of about 3° from the vertical. This produces in AD an inclination from
the vertical which varies according to the amount of the front angle of the tool,
but which must be taken into the account in the construction of the goniostat.
For the angles given in the table above, are the angles £AD, and not the angles
which the upper plane makes with the horizontal platform of the slide rest upon
which the tool is seated. The following table, therefore, is given to show the
angle which AD makes with the vertical line Am, under different angles of the
front, always supposing the plane S to make an angle of 3° from the vertical,
according to Mr. Nasmyth' s statement.*
I
i
FRONT ANGLE . .
150° 140°
130° 120° 110°
100°
90°
80°
70° , 60°
50°
40°
VERTICAL ANGLE
30 C'qo-i(yq°llT/Q°o>r' <*0<*fi'30 HI' i° 19'
9 1 w Aviv *t 9 At O do O t/O 4 i^
4°44'5°11' 6°
7°
8° 39
mAD.
| 1 • i
;
The above remarks are offered, in the hope that some one with the proper
opportunities will be induced to make experiments upon the best form and edge
of tools for different materials.
The relative angular positions of the planes of the tool point, and the different
kinds of edges produced, may be made clear to persons not familiar with geo-
metrical notions, by large wooden models, in which the three principal planes
being cut, the resulting edges may be measured with a goniometer.
Note AV.— To follow Note AU at the foot of page 53S.
(A Paper on a new form of tool-holder, with detached blades for turniiig or plant i.>/
metal, and on a new mode of fixing down tools upon the slide rest, by Prof>-saor
Willis, A.M., Ac.)
Instead of making the cutting portion and the stem of a tool in one piece of
steel, the cutting part is sometimes formed out of a small piece of steel, and the
•tern is furnished with some convenient contrivance for grasping it.
This principle has several advantages, especially for amateur workmen, who can
• Mr. Nasmyth'* tool gauge for showing this angle is described and figured on page
534 of the test.
APPENDIX — NOTE
shape and temper * mull pioc* of steel, but who may not be provided with a
forge and apparatus necessary for the construction of a complete tool. Besides,
the process of temperiog can be more effectually curried out with a small piece
• h .in when we have to deal with the end of a large lump. I do not know the
ry of this contrivance. Mr. HolUapffel has had for many yean on sale a tool
on tin- [>rmci|>l», and I have also seen it in other factories.*
I will proceed to describe the form into which I havo put it, for the purpose of
experimenting upon the angular forms of the tool edges deduced in the preceding
pagoa. As the cutting extremity of the tool is bounded by three planes, the piece
of steel may be arranged with respect to those planes, in different ways, according
to the purpose required.
Thus a triangular prum of steel may bo adopted of which the front sides, S, fig.
1001, make the same angle with each other as that of the side planes of tho proposed
tool. The stem of tho tool must grasp the prism so
that these planes may make an angle of 3" from the
vertical, and tho upper plane U only must be ground Fig*- 1001.
from time to time at the proper angle ; the prism
being, of course, raised in its clamp, BO that the point
•hall always coincide with the level of the axis of the
lathe. This is the arrangement of Mr. Holtzapffel's !<-'
tool. It does not allow of different angles being tried
for the aide planes, because tho grasping part of the
stem is so fitted to the angles of the prism aa not to
admit of priams of different front angles being in-
serted. And, indeed, this would not be practicable,
for, according to the second table which I have given,
it appears that the angle of inclination of the prism
would be different for different front angles. But
when tho best front angles ore determined, this
arrangement will probably be found very effectual.
Another method is to clamp the steel prism at such an angle, that its upper
surface U, fig. 1002, may coincide with the upper plane of the tool, and in this
case the side planes 8 can be ground at any desired angle, but the angle of the
upper plane remains fixed.
I have found it convenient to choose an angular position for the prism, that
shall, as in fig. 1003, lie between the mean place of the upper planes of the tools
and the places of the side planes. Thus if C, fig. 1 003, be the prism inclined at
on angle of 55* to the horizon, side planes 8 may be ground at its upper end, and
also an upper plane ub.
Tho section of the prism, being thus independent of tho relative angular positions
nf the three planes that form tho cutting extremity, may be determined solely from
1 orations of convenience, for facility of shaping and fixing. I have employed
round steel wire of the largest diameter usually kept in the shops, (namely, Lanca-
shire bright steel wire), and filed slightly flat on the upper surface, as shown in the
succeeding figures. When the side plane* have been formed, the grinding may take
• The author believe* that tool-holder*, with •mall detached cutter*, were flnt u*ed in
the block machinery at PorUmouth, and »incc 1830 he ha* largely employed variotukindi
of thete tool-holder* in lilt manufactory. See text, pages 535 — 6, where tome of the tool-
bolder* arc Jocribcd and figured.
998
APPENDIX — NOTE AY.
place oil the upper plane alone for some time; thus beginning at al, we may grind
down to cd, then we may grind the side planes afresh, and so on.
I will now describe the stem and clamping apparatus, figs. 1004, 1005 and 1000.
A bar of iron ABODE, shown in elevation in fig. 1004, serves as the foundation
of the instrument. It is straight and square from A to B, which portion is the
stem of the tool, by means of which it is fixed in the tool-holder of the slide rest.
The form of the part BCDE^ which receives the steel wire PQ, is given hi the
elevation. It is bounded, however, by the same vertical planes as the stem A.B.
An angular notch is filed at DE for the reception of the wire. The axis of the
wire, when clamped into the notch, should lie in a vertical plane parallel to the
sides of the stem, and should make an angle of 55° with the horizon. The section
of the notch is shown in fig. 1005, which is a plan of the tool, or rather projection
upon a plane perpendicular to the axis of the wire. The inner side of the notch
Figs, 1005,
1
1006.
is sunk perpendicularly to tho side of the tool, so that the flat side of the wire
may lie upwards. The wire is clamped into the notch by means of a piece F.
The form of this piece is shown in fig. 1004, and is very nearly the same as that of
the extremity of the stem piece. The screw K tapped into the stem piece,
presses F into contact with the wire along one extremity GH, and with a short
pin M, (fixed into the stem of the tool) at the other extremity. To ensure tho
firm grasp of the wire the following arrangements are made : —
The first requisite is that the clamping piece F should be left at liberty to take
a secure bearing upon the wire. If the latter were perfectly straight and cylindrical,
and the under surface of F perfectly flat, this bearing would take effect along the
line GH, which is the line of contingence of the said plane and cylinder.
But in practice a rounded or twisted surface would defeat this object, and there-
fore the middle of the bearing surface of the clamp is filed away as shown in the
front view, fig. 1006, so as to insure a pinch at or near each extremity of the line
OH. (For tho same reasons tho notch in the stem piece should be filed away in
the middle as also shown).
APPENDIX— NOTE ITi
The bearing at the other extremity M of the clamp, i» upon a round beaded,
•hort, hard steel pin, driven tight into a hole in the stem piece. The head of this
* received freely into a notch filed lengthwise in tho tail of the olamp, M
•hown by the dotted lines. ThU allows the clamp to settle itself freely upon
this bearing point, and at the same time prevents it from turning round and shift-
ing its proper position upon the stem.
Thus the pressure of the screw K is distributed upon the three points O, H and
M ; and, by the well-known principles of statics, if N be the bisection of OH, and if
the center of K lie in the straight line joining N and M, then will the pressure of
the serow be equally divided upon Q and H, whatever be the angle ONM. Fur-
ther, if MK be equal to twice NK, the pressure of the screw upon all three points
will be equal However, it is better to throw M as far from the screw as possible,
for thus lees pressure is exerted upon M, and therefore more upon Q and H.
Finally to ensure the free transmission of the pressure of the screw to the clamp
without jamming or wedging, a spherical washer L is interposed between tho head of
the screw and the clamp, and is received into a corresponding cavity turned in the
olamp. If this be thought too expensive an arrangement, the lower part of the bead
of the screw may be made spherical, and received into a conical or countersunk
cavity. Care must be taken to make the hole in the center of the clamp F, through
which the screw passes, considerably larger than the diameter of the screw ; else
all these arrangements to enable the clamp to settle itself freely upon its bearing
points may be defeated, by its being driven laterally against the screw. A short
wire spring, coiled loosely round the screw between the clamp and tho stem piece
and touching the clamping piece between K and N, serves to press this piece out-
wards against the spherical washer/and also keeps it in contact with M, and thin
prevents it from hanging loosely when the wire is withdrawn.
(A new Tool-holder for the Slide rut).
In the ordinary tool-holder or contrivance by which tho tool is secured to the
table of the slide rest, no provision is made for placing the tool in various angular
positions. The stem must lie parallel, or very nearly so, with one side or the other
of the table, or in other words, we have but the choice of two directions for its
stem. If it be desired to present the point of a tool in an oblique direction, it can
only be effected by bending the tool itself. I am aware that contrivances have
been proposed to enable the tool to be fixed angularly, as for example, " Mr. Pars-
son's Improved Box for a slide rest," (described in the Society of Art/ Trantaetiont,
Vol. xlviiL, page 240), which is, I believe, but little used, and in principle of con-
struction is entirely different from mine.
Tho contrivance I am about to describe I conducted in the spring of 1842, and
have had in use ever since, and it was also immediately adopted by Mr. Holtsapfftl,
by whom it has, I believe, been found perfectly effective.* It enables the tool to
be fixed at any required angular position upon tho table of the slide rest, and U
besides capable of being entirely removed from the table, so as to leave it free for
the reception of other contrivances, as for drilling, cutting wheels, &c. The tool-
holder is shown in plan in fig. 1008, and in elevation (partly sectional) in fig. 1007.
In this tool-holder the tool is secured in its position by the action of a single
nut A, whieh U tapped to a strong screw pillar BC. This screw has a round shoulder
• Nearly all ike riding rctu in ihe author', manufactory have been filled wilh Mr.
Willit'i apparatus for grasping the tooU, and which answer* to completely U lo be always
adopted iti sliding rc»ta for metal turning now made lk>
1000
APPENDIX — NOTE AV.
below which bears upon the surface of the table; beneath this shoulder is a short
portion of screw C, which is tapped into a hole in the table. The screw pillar can
therefore be removed or replaced by means of a key applied to flat faces filed upon
the shoulder. The pressure of the nut A is transmitted to the upper surface of a
triangular clamping piece DEF fig. 1008, through the interposed spherical washer
G, which works freely in a corresponding cavity in the triangular clamp, as shown
in the section fig. 1007.
Two short rounded studs of hard steel D E, are driven into the lower side of the
triangle, and rest upon the upper surface of the stem of the tool. At F a screw is
tapped stiffly into the triangle, and its lower end being rounded like those of the
studs D and E, it follows that when the nut A is brought into action, its pressure
upon the triangle is resolved upon the three bearing points below, namely upon
the two, D E, which press upon the tool, and clamp it to the surface of the table,
and upon the third at F which pi-esses upon the table through the intermediate
piece H, which is principally interposed to save the table from bruises.
If the nut be loosened the tool and triangle are set at liberty, and the latter may
be placed in any required angular position, when a turn of the nut at once fixes it
Fig. 1007.
completely. But as it is necessary that the tool should be under the studs D E,
and therefore always at the same distance from the center of the screw, the inter-
mediate piece H is contrived also to answer the purpose of guiding the stem of
the tool readily to this distance.
The outline of this piece is exactly the same as that of the triangle under which
it lies, with the exception of the side which is parallel to the tool. The side is
made at «uch a distance from the center of the screw that when the tool rests
against it, it is set in the proper position to receive the pressure of the studs D E,
APPENDIX— NOTKS .\ ' \v. 1001
of the triangular clamp. Tho dotUd lino k I fig. 1008, is the boundary of tho
lower piece, and at the opposite extremity of thu piece a thick lump is formed in
It a notch or groove U filed in a direction pointing to the center of the tcrew
pillar. ThU groove receives the cud of the screw F M already explained. Tho
form an.l thickness of the lump and tho position of the groove are shown by the
dotted Hues in the figure*.
The triangle and washer arc drawn in section in the upper figure, to explain the
adjustment of tho washer Q. As the upper surface of this wanner U always hori-
zontal, the hole need be no larger than is sufficient to pass freely up and down
tho screw pillar. But the case is different with the triangle DBF, for as that is
required to accommodate itself to irregular thicknesses of the tool, that may throw
it out of the horizontal position, the hole through which the screw pillar posse*,
should be largo and slightly conical as shown in the section. In fixing tho position
of the screw pillar, upon the table of the alido rest, it should be placed at such a
distance from the two edges that the bearing points, D E F of the triangle, may not
hong orer the cdgoe in any position, but that the tool may be always clamped within
the limits of tbo table; tho dotted circle in the plan explains this sufficiently.
A circular hole in the middle of the piece H fits loosely the shoulder of the screw
pillar, and as the end of the screw F is received freely in the groove of the interme-
diate piece, which latter is thereby kept in its proper place below the triangle, it fol-
lows that the whole combination of tool, triangle, and intermediate piece, may bo
swung round the central pillar without escaping from their proper relative positions.
The screw F is introduced to allow of adjustment for tools of greatly differing
thickness. But if it be necessary to put thin wedges under either end of the stem
of the tool in order to raise or depress its point, the spherical washer allows of tliU
by transmitting freely and centrically the pressure of the nut notwithstanding that
the upper surface of the triangle becomes inclined from the horizontal position.
It must be also observed that the tool may be placed either to the right or left of
the screw pillar at pleasure, and a spiral spring may be introduced below the
triangle, to prevent it from falling down when the tool is withdrawn.
The triangle should be made of such a size that the distance between its bearing
pins D E, may be the same as that which would be given to the binding screws of
an ordinary tool-holder.
Note AW, to follow the first paragraph 542.
(Mr. Franklin' t Expanding Center Bitt.}
This modification of the center bit, fig. 457, i>ng« 541, enables a series of three
tools, to bore all holes intermediate between half an inch and two inches in dia-
meter, and that with very little interference in tho general principle of the tool.
In figure 1009 the two parts of the instrument are separated beyond the distance
at whieh they are used, in order to show the construction, and from which view
it will be seen that the part a, of the expanding bit, which is squared at the end
to fit the carpenter's brace, is extended at the other end, to form the central pin <l.
by which the tool is guided. The moveablo part carries the scoring cutter or
nicker t, and this piece admits of adjustment of diameter, it being attached to tho
main stem by the rivet b, and fastened thereto by the binding screw c, that pastes
through tho mortise in the moveablo pieoe ; this latter part is formed to constitute
the lateral cutter /, by which tho shavings are as it were swept out of tho bole
that is being made.
1002
APPENDIX NOTES AW, AX, AND AY.
When the center bit is contracted to serve for its smallest diameter as in fig. 1010,
the radii of the nicker and cutter are just alike, but it is found that the radius of
the nicker may be increased above one-fourth as in the dotted position, and that still
Figs. 1009.
the cutter acts fairly, as the shavings become readily disengaged. These expanding
bits are not intended to supersede the ordinary center bits of fixed sizes, but to serve
for occasional works ; and they are extremely well suited to the wants of amateurs.
Xote AX, to follow the paragraph, page 544, commencing "another Screw Auger .'•
(The Amei-ican Screw Aug<r.)
The American screw auger, fig. 466, page 543, was patented by Mr. Wm. Ash, of
Sheffield, and is described in the " Practical Mechanic and Engineers' Magazine,"
Glasgow, 1842, Vol. 1, page 108.
This description speaks of a different modification of the screw auger, from that
described in the text, and in which a piece called a guide is employed instead of
the worm usually soldered to the shaft. The guide consists of two thin rings,
united concentrically by two fins situated on a diametrical line, leaving two large
semi-annular spaces between them. The outer ring is made as a short conical
screw, the inner embraces the central stem of the auger, upon which it fits loosely
behind the cutter.
The auger first bores a shallow hole, into which the loose guide ring is screwed
to serve for the guidance of the instrument, by the central ring or thimble which
fits the auger shaft, and the shavings have to escape through the annular spaces
betwixt the two rings. This part of the contrivance appears, however, to bo fur
less practical than that described in the text.
Mr. Phineas Cooke was rewarded by the Society of Arts in 1771 for the inven-
tion of the screw auger fig. 463, page 543, but the difficulty and expense attending
its first construction, appear long to have withheld it from general use. — See also
Smith's Panorama of Science, Vol. 1, p. 113.
Note AY, page 554, to follow the paragraph ending, "without figures."
(Preeman't Reyittered Drill Tool.)
This i« a very useful substitute for the drill bow, it consists simply of a flat
strip of wood, from about 8 to 16 inches long, by j to 1J wide, with an appropriate
handle, and on one aide of the wood is cemented a strip of sheet india rubber or
APPENDIX— NOTES AT, AZ, AND BA.
tooa
caoutchouc. The pulley of the drill or drilUtock U made of wood and cylindrical,
the diameter and length being about equal, and the extreme angles slightly
-led. The oonUct between the wooden pulley and the caoutchouc will bo
1 quite sufficient for the working of small drill*, and a* the tool U (imply
used as a violin bow, the tedious proooat of coiling on tho string of the ordinary
bow is entirely a v
Note AZ, page 557, to follow the paragraph ending " for reciprocating drills."
(Mr. MacDovalft Archived** Screw Drillttoet.)
Mr. MaoDowall's improved drillstock, fig. 1011, is a very useful instrument,
acting by reciprocating motion, and which was rewarded in 1845 by the Society of
Arta. It consist* of a rod of the so-called pinion wire (the formation of which U
noticed on page 420 and fig. 294 of voL 1. The one end of the wire U bored up
to serve as a socket for receiving the drills, the other end is formed into a center
point and contained within a handle or socket, by which the instrument a guided
towards and pressed into the work ; the remainder of the instrument consists of a
slider or nut fitted to the ribs of the pinion wire, and possessing a handle having
an universal joint.
If the grooves of tho pinion wire wore straight like tho flutes of a column, tho
nut might be slid up and down without giving any motion to tho drill, but as tho
wire U twisted to the extent of two or three turns in its
length, like a very oblique screw, every ascent or descent
of the handle causes a circular reciprocating motion of the
drillstock, to the extent of two or three revolutions to and
fro, and fulfils the office that would otherwise require tho
drill bow of the breast drill, or the cross staff of the up-
right or pump drill.
The instrument as above described answers beautifully
for very small holes, but the ingenious inventor was again
rewarded in tho following year, for additions by which the
power of this drill tool is much increased. He first added
a transverse or diametrical arm at the foot, carrying two
balls to serve as a fly and give momentum ; but incon-
venience then occurred from the weight having to be sud-
denly started and stopped. This defect was judiciously
remedied by introducing a little catch wheel or ratchet
in the nut by which, as in the Brequet watch key, and
also in the ratchet drill, page 561, tho catch slips over the
teeth of the ratchet wheel in the ascent, and only moves the drill in the descent ;
thus allowing the fly to act uninterruptedly and impel the drill with contii.
motion in the one direction only, and with increased force. With the impr
instrument registered under the name of tho "Contim *ed RerolnmgA rekimedean Drill."
holes can be pierced of fully twice the diameter of those which could be made with
tho former and more simple Archimedean drill having a reciprocating action.
Note BA.— To follow the Note AZ, on page 557.
(Mr. Mac Domic t Rectaaynlai Archimedean DrilUtock for Dental Suryery.)
This tool, which U represented in fig. 1012, is an offshoot of the reciprocating
Archimedean drilUtock. The parti a, 6, c to </, of the succeeding figure are precisely
1004 APPENDIX — NOTES BA, BB, AND BC.
analogous to the corresponding parts in fig. 1011, except that from 6, to d, extends
a straight bar that firmly unites these two parts. From d, to e, is a socket or tube
carrying at e, a small drill socket or hollow mandrel, at right angles to the length
of the instrument, and within the tube are concealed two very small bevel pinions,
the one fixed on the drill socket, the other on the end of the reciprocating drill
shaft, b d, which is continued within the tube so far as e, the bevel pinions there-
fore transfer the motion of jthe reciprocating shaft to the drill.
The tube which extends from d, to e, may be moved round in the collar at d,
and fixed in any required position by the thumb-screw, so that the drill may be
directed upwards, downwards, to the right, or to the left, according to the pontion
of the hole the dentist has to drill in the tooth of his patient.
Note BB.— To follow the Note BA, on page 557.
(Capf. G. D. Darison's Rectangular Drilhtocl' for Dental Surgery.)
Fig. 1013 represents an instrument for the same purpose as the foregoing, and
which was invented at about the same time fig. 1012, by an officer of the British
Army, engaged in the Ahmednujgur Survey in India. It consists of two slender
Figs. 1012.
ffc
bars of steel united at both extremities, and inserted by the one end into a wooden
or ivory handle a ; at c, is a small spindle for the drills with an appropriate pulley
situated between the two side bars, and at & is a similar pulley. The catgut line by
which the drill is moved passes entirely round the pulley of the drill-socket at c,
the two ends then run parallel with the stem of the tool, make each a quarter turn
in opposite directions over the guide pulley b, and then proceed to the extremities
of the drill bow, d, d, which passes through the space between the side bars of the
instrument. If the pulley c, is situated close to the end of the instrument, and the
drill bow nearly fills out the space between b and the steel frame, the cord will then
be retained in the grooves of the pullies with little or no risk of its being accidentally
detached. This instrument, like the last, may be used in all the required positions.
Note BC, page 563. — To precede Section IV.
(Mr. George Scott' t Apparatus for Boring and Tapping Cast-iron Main Pipet
for Water and Oas.)
Fig. 1014 represents Mr. George Scott's apparatus for drilling gas and water pipes,
and which wan rewarded in June, 1846, by the Society of Arts. The parts are all
APPKNDIX -NOTES BC, AND BD.
1008
grouped together M if in use, bat the pipe itself U represented in dotted lines, io
order that the point of Ute drill and the apparatus generally may b« better MM :
o, U a semicircular iron strap thai embraces the pip* 6 ft, c e, is a eroas piece with
a screwed central bole attached to the curved strap by the nuts </ </, and <•, U a
tube screwed into c c, ami which tube carries the revolving socket /, terminating
in the drill y. When the parts are all united and fixed to the pipe as in the figure,
the drill-socket f y, is handed round by means of a spanner about two feet long,
applied to the mjuare at /, and whilst the hole U being pierced, the drill is set
gradually deeper, by a screwed nut which in extended so as to constitute the
handles A A, by the movement of which at intervals, the drill is gradually forced
deeper iuto the hole it U in the act of boring.
When the hole U completed the socket and drill fy, arc removed from the cross
piece c c, and the screw tap, shewn separately at i, is inserted into the fame boh
t lie threads of c c, and /, being alike in diameter ami pitch c c, serves to guide the tap
Fig. 1014.
very truly iuto the hole previously made. I'.y introducing different saddle-pieces
of wood, that lie between the strap a, and the pipe, and by using smaller drills
and screw taps of the same thread, the same apparatus may be made available for
smaller pipes; it is very efficient for its intended purpose, and a decided improve-
ment on fonncr methods. The principal part of the tap i, is left with the thread
entiro to serve for the guidance, and the end alone is tapered and cut with several
i-s almost as a conical countersink, and which fully suffice for tupping the
thin metal of the pipe. — See also text, page 558.
Notes BD-BE— BF-BQ— BH and BI.-To follow the text, page*
M4 to 567.
On DriUt and During Bitt toed in Latktt and Boring Machines.
ols of this class have come to the author's knowledge since the foregoing
pa^cs were printed, they will bo now figured and described by way of appendix to
the text. Three of these tools are intended to maintain their several diameters
unaltered, the other three admit of adjustment for size within certain limits. To
the best of the author's belief, they are all quite separate and independent inven-
tions applied to one nearly common purpose.
1006 APPENDIX — NOTES BD; AND BE.
Note BD.— To follow the text, pages 564 to 567.
(Mr. Collas's lathe drill.)
A lathe drill described as the invention of Mr. Collas, of Paris, Engineer, is
figured in page 171, of the Engineers' and Machinists' Assistant, Glasgow, 1846.
The instrument for greater perspicuity is here represented in perspective in fig. 1015.
This drill is turned as a cylinder, and perforated to the extent of three or four dia-
meters, with a hole of about one-tenth of the exterior size. Exactly one-third the
Fig. 1015.
0(5
cylindrical end is removed, so as to form a longitudinal incision extending to the
center and having radial sides ; the extremity of the drill is ground somewhat
as in the half round bit fig. 507, page 565, to make the one edge cut ; behind the
angular part a further portion is reduced to the diametrical line, and the remainder
is either cylindrical or square, and terminates in a center for the popit head.
The work having been chucked in the lathe, and a shallow recess turned out to
admit the end of the bit, the latter bores the hole in the solid metal to any depth
that may be required ; as the core or the small portion opposite the central hole
extends up the drill shaft, (which it is considered to guide,) and the core breaks off
in small pieces as the drill progresses into the solid metal.
The ordinary half-round bits, fig. 507, may also be employed for boring holes in
the solid metal, but which is not their common application, and when exactly semi-
circular they remove the whole of the metal not leaving a core, but as usually
ground they leave the bottom of the hole as a very obtuse cone ; to make the
bottom of the hole quite flat, the half-round bits may be ground square across on
the cutting side, and bevelled on the opposite to clear the bottom. But the nearly
rectangular edges of the half-round and similar bits, require more power and work
less freely, in drilling holes in fibrous metals, than the ordinary fluted drills fig.
478, page 548, and are more troublesome to enter.
The author considers the central hole in Mr. Collas's drill not to be required for
the purpose of guiding it, which office is performed by its exterior surface, and he
sees no reason why the cutting edge should not, as in the half-round bit, proceed
beyond the center and remove the whole material, as in making a flat-bottomed
hole, in this case the central pin left by Mr. Collas's drill requires after removal.
Xote BE.— To follow the text, pages 564 to 567.
(C. lloltzapffel's boring lit with changeable cutters, derived from the half-round bit.}
This was contrived for boring holes in models of guns, howitzers, and mortars,
to avoid the expense of the many long boring bits required in making a series of
these models.
The stock is constructed as shown entire in fig. 1016, and detached in fig. 1017;
The end of the stock is turned cylindrical, and has a notch across the extremity
extending below the diametrical lino, and also a longitudinal groove on the under
side. The notch receives the cutter c, which embraces the flattened edges of the
stock, and is held by two mnall screws, the groove receives the bearing piece b
which is fixed by two other screws, that are countersunk.
APPENDIX — NOTES DE, AND BF.
LOOT
The outor parts of e, and 6, arc turned to the cylindrical form and hardened, the
cutting angle c, bciug allowed to be always more prominent than the two other part*.
One Btock wa» thus made to *erre for various diameten from J of an inch to 1 ,* ,
(or -882 to M09,) another for sixes between 1J inch to 1J. (or 1'297 to 1-66,) eo M
between thorn to answer for boring models of the entire scries of Ordnance em-
ployed by the British Government, wheu constructed on the scale of one-sixth
their true sixes.
FIT .Irilling the preparatory holes below ; diameter, the system of three tools
described in the first paragraph, page 567, was employed, so as to ensure tho exact
Figs. 1016.
ccntrolity and stnightness of tho bore ; and in forming tbc curved chamber* in
tho various models, different cutters with tail screws, were inserted in a hole
tapped in the axis of a long boring bar, also used in the lathe. The entire scheme
was quite successful, and is perhaps the smallest example of, (virtually,) half-rouud
bits with loose cutters.
Note BF.— To follow the text, pages 564 to 567.
(Tlie Cornith bit with loote cutter*.)
The Cornish bit is a useful lathe drill, apparently derived from tho boring bar,
fig. 51 4, page 569, and like it, is adapted to holes of certain fixed diameters. As
fccn in fig. 1018, the stock which is cylindrical throughout, (except where it is square
for the hook wrench,) is enlarged at the one end, and has a diametrical mortise, :
with a cutter c, notched out at the one end to embrace the flattened sides of the bar,
and secured with the wedge to, as in fig. 514. But as tho Cornish bit is used in tho
lathe, and is therefore only supported by the work at the one end, and the popit-
head at the other, a bearing piece 6 is fitted in a longitudinal chamfer groove on the
Fig. 1018.
under side of the stock, as seen in the eu-l view, in order to keep it central. Tho
three edges, of the cutter and bearing piece respectively, are all turned iu their
places. The cutter is bevelled and rounded so as to cut at tho front only, after
which the parts are hardened;
lOOS APPENDIX — NOTES BF, BG, AND BH.
The Cornish bits are not made for holes smaller than about 1| inch in diameter,
and by means of additional cutters and bearing pieces, every stock may admit of
on increase of size of fully one-half its minimum diameter, or say from about 11
to 'Ji inches, and larger sizes in proportion. This is a very effective tool, and is iu
general use amongst engineers.
Note BG.— To follow the text, pages 564 to 5<>7.
(Messrs, Mau.ddayis' bonny bits, with loose cutlers for boring the bosses of wheel*,
and small steam cylinders in the lath-.)
Boring bits of the kind represented in fig. 1019, ranging from about 3 to 12 inches
in diameter, and with a power of variation in size, were many years back intro-
duced by Messrs. Maudslays, and employed for boring the bosses of wheels, small
cylinders, pumps, &c. The stocks of the smaller sizes of these tools are made in
wrought-iron, those of the larger in cast-iron, the cutters rest in contact with a filltt
made on the stock exactly at right angles to the axis, and are held down by screws
which pass through mortises in the cutters, to enable these to be set out to various
Fig. 1019.
r
0
0
diameters. The bearing pieces beneath, although generally fitted in a chamfer
groove, are also made to admit of packing pieces by which they may be set out.
to make the three points of bearing to fall in a circle of the exact diameter of that
to be bored. The larger of these tools, the cutters of which are 3 inch thick, are
now very much less used, since the boring bars with sliding heads or blocks, re-
ferred to in pages 569 to 572 of the text, have obtained such general employment
for boring cylinders and pumps.
Note BH.— To follow the text, pages 564 to 567.
(3fr. Stivens' Registered Lathe Drill.)
Tiiis instrument is represented in perspective in fig. 1020, and iii plan with the
top plate removed iu fig. 1021, it has two cutters which are adjustable for various
diameters ; the tool is intended to be used after the manner of figs. 509, 510, and
511, page 565, that is with the loop fig. 511. The two cutters c c, lie in oblique
grooves, the ends of which are at an angle of 45 degrees, and between the cutters
in placed a wedge w w, the long shaft whereof extends through the entire length of
the drill shaft, and has the hollow center for receiving the pressure of the popit-
head. When thU long wedge is set forward, by a tail screw and nut, (not reprc-
nented,) it throws out the two cutters in any required degree, so that the bit for
holes of one inch in diameter, may be thus enlarged for any size not exceeding
about 1} inch, and so with the larger tools.
The cap piece, or plate p p, which is represented removed, and is attached by
three screws, has a shallow circular recess within which the two pins fixed iu the
cutters are loosely contained, to prevent them from being accidentally lost. The
APPKNDIX — NOTES BH AND BI.
LOOO
cutters are rounded at tbe ends, and sharpened precisely lilt* the bit fig. 509, and
the two edges of the shaft from • to b, are made symmetrical and with rectangular
edge*, in order to stick into the tide* of the loop rach an fig. 51 1, from which tola
Fig* 1020.
1021.
ia
\
o
drill receives its axil guidance, in the manner already explained on page 606 ; but
it appears objectionable that the guiding loop should from necessity bo so far
removed from the cutting edges of this expanding drill, which is proposed to be
made as large as eight inches in diameter.
Note BI.— To follow the pages 564 to 567.
(Jfr. Kittoet Expanding lioJf-ronnd Bit.)
In this instrument, three ports instead of two only arc made to adjust radially and
equally ; from the one point only being sharpened, and from there being a bottom
bearing upon the surface of the hole that is bored, the instrument is used in all
respects as the common half-round bit, and without the necessity of the loop or
guide, (fig. 511, page 565), required with Mr. Stivene* expanding drill, and of which
latter Mr. Kittoe had not the least knowledge when he constructed the present
tool.
Fig. 1022 is the perspective view of the boring bit when in condition for work,
fig. 1023 is a section of the same through a horizontal plane ; and a to t, fig. 1024,
arc the parts shown separately, the same letters being attached to tho same parU
throughout The port from c to g is of brass, and contain* all tbe mechanism, y to
3 T
1010 APPENDIX NOTES BI, BJ, AND BK.
h is an iron rod screwed into the brass to serve as the shaft of the tool, and which
is made of any required length. The portion from c to e is constructed in two
pieces, which separate nearly on their diameter, and are united jointly by steady
pins and the screwed nut d e, the division being made for the purpose of intro-
ducing the two bits a a, one of which only is made to cut; b the bottom bit, is
inserted in a similar but vertical cleft.
The three bits are simultaneously and equally advanced by the central wedge i,
shown also detached, which resembles a cone, reduced so as to form three fins at
right angles to one another, that enter the grooves for the bits ; the wedge i, is set
forward by the tail-screw t, there is a side screw, which prevents the unintended
movement of the set screw k, to arrive at which latter it is necessary to remove
the socket c g, from the stem of the instrument g h.
If the wedge with its three fins were considerably advanced beyond its present
position, it would stand before the cutter, and prevent the tool from proceeding to
the extremity of a flat-bottomed hole : in order to avoid this, Mr. Kittoe has made
the back edges of the cutters at the same angle as the wedge, so that the act of
setting forward the wedge also sets forward the cutters to keep them in advance
of the point of the wedge. The cutters have oblique mortises which pass over the
retaining pins fixed in the semicircular piece, and prevent the cutters from being
accidentally lost.
It is the intention that every instrument constructed on this mode should pos-
sess various sets of the bits, a b, so proportioned in size that the smallest instru-
ment should be capable of being expanded to the smallest size of the second
instrument, the second to the third, and so on, in order that a few of the boring
bars, or stocks, may serve for a considerable range of sizes.
Note BJ. — To follow foot note on page 572.
(Mr. George Wright, inventor of the modem system of boring large Cylinders.)
The author is informed by John Taylor, Esq., F.R.S., £c., that the mode of
boring steam engine cylinders, by means of a revolving bar with a traversing cutter
block and cutters, as slightly explained in fig. 517, page 571, was invented by
Mr. George Wright, whilst in $ie employment of Messrs. Boulton & Watt, of the
celebrated Soho Works, near Birmingham. This admirable contrivance has proved
of immense advantage to practical engineers.
It may be added that Mr. Nasmyth constructs his heaviest boring bars with three
longitudinal grooves fitted with adjustable chamfer bars, and that sustain the
pressure of the cut against those frees of the chamfer bars which are radial to the
bar. The vertical position seems now to be rather preferred to the horizontal for
this class of boring machines, so that the cylinders may be bored in the position in
which they are afterwards erected.
Note BK.— To follow the text on page 580.
(Mr. Malletfs method of describing regular and irregular spirals.)
We transcribe from the "Mechanics' Magazine" for 1844, page 65, the com-
mencement of a very useful paper by Mr. Mallett of Dublin : —
"For many purposes of the arts, a simple and rapid method of tracing spirals
upon a cylindric surface is important; carvers, wood-turners, &c., often want
such, and in larger works, such as some particular branches of mill-work and
engineering, it is also frequently wanted. The usual method, by dividing the
APPENDIX — NOTES BK, HI., \ M> BM. 1'lH
cjlindrie lurfttoe into equal portion* in circumference and length, and drawing
lines diagonally, i« tedious."
" The following method, believed to be new, U simple and ready, and sufficiently
exact fur most purposes. Two straight edges of equal length and width, and about
fths of an inch in thickness each, are to be secured on a table parallel to each other,
standing on their edges, and distant from each other bjr nearly the length of the
cylinder upon which the spiral is to be marked. Between these there is also to be
secured, in a diagonal direction, stretching from one to the other, a third straight
edge, formed of two slips of deal glued together, with a slip of straight thick Bris-
tol board between them projecting Jth of an inch at one edge."
" The entire height of the diagonal straight edge when standing on the table, must
be a iftade more than that of the two other straight edges. The three pieces being
then thus arranged, the edge of Brutol board is charged with printer's ink. Then,
ou causing the cylinder to roll over the edges of the two parallel straight edges in
the direction of their length, the diagonal slip of inked Bristol board will trace a
spiral upon the surface of the cylinder with very considerable accuracy."
Mr. Mallett then goes on to describe that by substituting a curred edye for the
inclined utraiytu edge* variable screws will be described, following any particular
condition set out in the developed surface of the screw as represented by the curve :
this he considers useful in setting out the variable screws or those of increaaiug
pitch for propellers, and he further shows that spiral lines mny be thus drawn on
cones, prisms, Ac.
Xote BL, page 696, to follow the paragraph ending "a convenient bed for the file."
(On Sharpening the teetk of Saw» by meant of Grindttones.)
A peculiar mode of sharpening the teeth of large circular saws by means of
grindstones, the author is informed, is followed by Mr. James Boag, of Johnston,
Scotland, manufacturer of Casks and various works in wood.
A small grindstone, mounted on a spindle, and turned on the edge with a narrow
ridge suited to the form of the teeth, is made to revolve by the steam engine ; the
circular saw is placed upon the surface of a slide, having a center pin to fit the axis
of the saw, and a stop to determine now nearly it shall approach the grindstone ;
the platform or slide is inclined agreeably to the angle at which the stone should
meet the saw plate, and there is a detent or hook, which by catching against one
of the teeth, holds the saw plate in the positions successively required for every
tooth around its circumference.
The grindstone from its rapidity of action U constantly employed when much has
to be removed, as in depthenuig the gullets, when but little U required to be done
to the saw, the file is employed as usual.
Sometimes also the saw remains at rest except as regards the change from tooth
to tooth, and the grindstone is mounted on a swing frame and brought down every
time to a stop.
Note BM, referring both to the Table on Rectilinear Saws, page 699, and to the
Table on Circular Saws, page 784.
On the Oayet at promt utedfor m*u*ri*g the thieknetat of ihett metab and wt'ru,
and propotaltfor a new tyttem of Oaytt, founded on At decimal lubdirition of
the Standard Inch.
Insetting out the Tables of the Dimensions of Sawn, the author could only express
their several thicknesses, in the measure always employed for that purpose, namely,
3 i
1012 APPENDIX — NOTE BM.
in the sizes or numbers of the " Birmingham wire gage," and to render these
measures intelligible to the general reader, the author then determined to introduce
in this Appendix — first, the exact values of the principal gages in use for sheet
metals and wires, a subject he believes to have been hitherto overlooked ; and
secondly, a proposal he has long desired to see carried out, namely, an easy and
exact system of gages for sheet metals, wires, and general purposes, founded on the
decimal division of the inch ; and in which system the nomenclature should be
so completely associated with the actual measures, as to convey to the mind, even
in the absence of the gages themselves, a very close idea of the several spaces of
the gage, or of the thicknesses or sizes of the works measured thereby.
It is to be observed at the outset, that the gages for measuring wires and sheet
metals, are usually thick plates of steel of several sizes and forms, around and near
the edges of which are first drilled various holes, the next step is to saw a notch
from the edge into every hole, saws of the widths of the several notches being used ;
and lastly, little parallel plates of steel, called drifts, which are hardened and tem-
pered, are driven into the notches, in order to smooth the sides of the same and
render them of uniform width, after the manner of various other applications of
drifts, explained at pages 883 to 885.
It should be further observed that the Birmingham and other gages seem to have
been originated in great measure accidentally, or almost by the eye alone, and with-
out any attempt at system, either as regards the values of the intervals between the
successive measures or numbers, or their correspondence with the subdivisions of
the inch. And as moreover gages, nominally the same, have been made by various
manufacturers with insufficient aim at unity of measures, some irregularity thence
exists amongst the gages in common use, notwithstanding that they may be
nominally alike.
In ascertaining the precise measures of the principal gages, the author has had
the valuable co-operation of Messrs. Stubs, of Warrington, who manufacture a
large number of these gages, and who tested the drifts they employ, by means of a
sliding gage constructed by Holtzapfiel & Co., for reading off quantities to the
thousandth part of an inch, by means of a vernier ; the results of these admeasure-
ments are stated in the three sections of the accompanying table.
The three series of measures or gages particularised in the annexed table, have
no relation wha^vcr to one another ; for example, the numbers 10 of the table are
respectively different and undefined quantities, or are neither aliquot nor direct
fractional parts of the inch, as the number 10 notches, are severally '184, '024, and
•190 of an inch wide; and other similar numbers are also unrelated.
The approximate measures of any one of these three series may, perhaps, be
moderately familiar to those nrtizans who use that particular gage, but these same
nrtizans will probably be as little informed of the two other gages, as the generality
of individuals to whom the whole of these, and other arbitrary ill-defined mea-
sures are vague and confused; because their nomenclatures have no relation
whatever, either to one another, or to our general standard of such quantities,
namely, ordinary linear measure; or, in other words, the standard foot and inch.
The following explanatory remarks on the three gages specified in the table, and
certain other gages derived from them, will show the complicated and uncertain
nature of the iubject of measures, for wires, sheet metals, and various small works.
VALUES OF GAGES
FOR
\YIUi; AM) SHKKT MKTALS I\ (il.M.KAL USE,
IX DECIMAL PARTS Of THK 1st II.
1 ucnoH OXB,
ucnox TWO.
•KTIOV THKUL
[ Birmingham
r Shoot Iron
aud Stool.
OM • rflbi •
MetakBrRM,
OoM, Silver, Ac.
Lancashire Oan for round 8Uel Wlro, and »l»o
for Pinion Win.
The «iu.illcr AIM diMinguithod by Number*.
The Urycr by Ixitun, and callwl the Letter Ga^o.
MARK. MM.
MARK. SUB.
MARK. UZK. MARK. MZE.
MARK. BUCK,
0000— -454
1— -004
80— -013 40— -096
006— -425
•2 — -005
! 79 — '014
39 — -098
11
00 — -330
3— DOS II 78 — 015
38— -100
c -
0— -340 4— -010 77— -016
87 — -102
D —246
1 — -300
5— -01-j 76— -018
36 — -105
E
2— -VM
6— -013 , 75 — 019
35— -107
F —-257
3 —
7— '015
74 — -022
34 —109
<;
4 —"238
8— -016
73 — -023
33 — 111
II
5 — -220
9— -019
72 — -024
32—115
I — -J7-2
6— -203 10— -024
71 —-026
31 —118
J -
7 — -180 11 — '029
70— -027
30 — -125
K
8— -165 12— -034
69 — -029
•20—134
L — -2'JO
9— -148 13— -036
68 — -030
28— -138
M
10- 14 — 041
67— -031
27—141
N -
11— -120 15--047
66 — -032
26 — '143
0 — -316
12— -109 16— -051
65— '033
25— -146
P -
13— -O'JS 17— -057
64 — -034
24 — 148
Q —-332
14 - -083 18— -061
63 —'035
23— '150
K — -330
15- -072 19— -064
62— -036
22
S —-348
16- -005 20— -067
61 — -038
21 — '157
T — -353
17— -058 21 — 072
60 — '039
20— -160
U — -3G8
18— -04:> 22— -074
59—-040
19— -164
V —377
19 — -042
23 — -077
58— -041
18— '167
W —'386
20 — -035
24 — -082
57 — 042
17— -169
X — -8»7
21 — -032
25— -095
56— -044
16 — 174
Y — -404
22— -028 1 26— -103
55— '050
15— -IT:.
'L —413
23 — 025 27— -113
54-
14_-177 Al-
24— -022 28— -120
63 — 058
13 — -180
n i — -43i
25— -020 29— -124
52— -060
12 — '185
C 1 — 443
26— -018 30-
61 — -064
11 — 189
D 1 — 452
27— '016 81 — 133
60— '067
10 — -190
Kl
28— -014 82— -143
49 -'"7"
9 — 191
Fl
29— -013 33
48 --073
8— -192
Q 1 —'484
30— -012 34— -148
47— -076
7— -195
HI— -4 '.'I
31— -010 35— -158
4«_-078
6— '198
-•009 36— -1G7
45— -080
6— -201
33 — -008
44— D84
4— -204
34 — -007
45— -OM
3— -209
35— -005
42— -091
2— -219
36— -004
41 --095
1— -227
1 '
1014
APPENDIX NOTE BM.
1. 27tc first column of the table refers to the gage used for most kinds of wire, and
is thence called for the sake of brevity, the " Wire gage," although it is also known
as the " Birmingham wire gage," the " £i>-mingham iron wire gaye," and the " Sheet
iron gage." This gage, which is specified in the column of the table headed section
one, is the most common of the three principal kinds, and is employed not only for
iron wire, as its name implies, but also for brass and other wires, for black steel
wire, also for sheet iron, sheet steel, and various other materials, and likewise for
some manufactured works, including screws for joiners' use.
On reference to the table it appears the largest notch of the Birmingham iron
wire gage is marked 0000, and measures 454 thousandths of an inch, or 4| tenths
of an inch nearly ; and further, that the smallest notch, marked 36, measures
4 thousandths, or the ] -250th part of an inch. Although this gage seems only to
possess 40 terms, in reality not less than 60 sizes of wire are made, as intermediate
sizes are hi many cases added ; and occasionally, although the sizes are retained,
their numbers are variously altered ; thus.
The sizes of wires drawn for manufacturing needles correspond with some of the
ordinary wire sizes, but the numbers are different ; thus No. 1, of the needle wire,
agrees with 18i of the Birmingham wire gages as here shown : —
Needle wires, Nos. 1. 2. 2|. 3. 4. 5. and thence to 21.
And Birmingham wire gage, Nos. 18*. 19. 19i 20. 21. 22. and thence to 38.
Are respectively alike.
.Sometimes half-sizes of both series are interpolated, and the manufactured
needles when bought and sold are designated by another series of numbers
unrelated to either of these wire sizes.
In tho wire used for the strings of piano-fortes, the sizes now commonly used, are
known as Nos. 6 to 20, and these agree very nearly with the sizes and half-sizes of
some of the notches of the Birmingham wire gages, as follows : —
Music wires, Xos. 6. 7. 8. 9. 10. 11. 12. 14. 16. 18. 20.
And Birmingham wire gage, Nos. 26. 25.|. 25. 24i. 24. 23*. 23. 22. 21. 20. 19.
Are respectively alike.
The number 6, or the thinnest music wire now commonly used, measures about
the fifty-fifth part of an inch in diameter, and the No. 20, or the thickest, measures
about the 25th of an inch.
Piano-fortes were formerly always strung with brass wire, but steel is now alone
employed, and they are " strung much Jteavier," or thicker wires are employed, from
wlu'ch cause the numbers 1 to 5 have probably fallen into disuse. The covered
Numbers Numbers
of tho of the
Screws. Wire Gage.
Numbers Numbers
of the of tho
Screws. Wire Gage.
Numbers Numbers
of the of the
Screws. Wire Gage.
Numbers Numbers
of tho of tho
Screws. Wire Gage.
23 — 000
22 — 00
21—0
17 — 1
16—2
14 3
12 4
11 — 5
10 6
9 7
8 — 8
7 9
6 10
5 11
4 12
3 13
2 14
1 — 15
0 16
00 17
000 — 18
-tiings are of nteel, upon which a fine copper wire is spirally wound; and iu very
short strings, as those of Mr. Pape's Console Piano-fortes and some others, two
•- inx — NOTE BM.
covering wire* are used, that tbo bulk of the doubly-covered strings may compen-
The nawdhotann of the patent screws mado from iron wire for joiners' use,
also giro the iutonraU of the wire gage a new system of numbers. Thus in the
annexed table, the left hand columns shew the number of the screws, the right
hand the number* of the wires from which they are respectively made.
Example* of other and similar conversions of the numbers might be shown, but
which would only servo further to illustrate the irregularity, aud arbitrary nature
of gages, used in the mechanical and other arts.
•2. The teeond column of the table, page 1013, refers to the gage employed for most
of the sheet metals, (excepting iron and steel,) namely, copper, bras*, gilding-metal,
gold, silver, platinum, Ac. This gage is called the " Birmingham metal gage," and
for brevity, simply tho "Metal yaye* or tne "Plate yage," in contradistinction to
the " Wire gage " specified in the first column of the table.
Tbo intervals in tho metal or plate gage, are closer or smaller than those of the
wire gage. Thus the No. 1, which in this series is the tmallett sized notch, u
4 thousandths or the 250th port of on inch wide, whilst the largest notch or 36
measures 167 thousandths, or is evidently meant for the sixth port of on iucb.
When thicker metals are wanted, their measures are sought in the Birmingham
wire gage, thus the 36 on the plate gage, nearly agrees with the 8 on the wire gage,
and therefore the numbers 7, 6, 5, to 0000 of tho latter, are then employed for
thicker metals than can be measured by the plate gage. Frequently the plate gogo
ends at 24, which number agrees with 14 of the wire gage, and then the numbers
13. 12. 1 1. to 000 of the latter are similarly resorted to for thicker metals. These
combinations of different series of numbers, running in reverse orders, are evidently
liable to lead to confusion.
The method in which sheet metals are commercially described, also present
much variation, for instance line has a gage thus constituted —
Sheet xinc Noa. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16 1
B. Plate gage No*. 4. 4 J. 5- «• 7. 8. 9. 10. 11. 12. 13 I*™
These thin shoots of zinc, which measure only from one to about four him-
drcdths of on inch thick, are principally used for gutters, roofs, and small works
manufactured with the hammer.
Thicker zinc plates, or those from about 5 to 18 hundredths thick, and which are
used for zincography, door plates, and engraved works, are commonly made to the
notches, 18 to 7 of the Birmingham Wire Gage, without alteration of the numbers,
but which run the reverse way of those of the other series used for sine.
Several of the metals are estimated by the weight of every superficial foot, and
that the more especially when the value of the material in the sheet, exceeds tho
value of the labour afterwards expended upon it in converting the metal to its
intended purpose ; thus
Cast and milled lead are both described as of from 4 to 12 pounds to the super-
ficial foot, the variation being one pound to the foot
Coppersmiths and braziers do not acknowledge tho plate gage at all, but reckon
their metal as from about 3 to 66 pounds to tho sheet; the sheet measures 2 feet
by 4 feet, and therefore contains 8 superficial feet
The precious metals are sometimes estimated as of so many ounces or penny
weights troy to the superficial foot ; and it will be hereafter shown, how by aid of
1016
APPENDIX — NOTE BM.
the proposed scheme, derived from the decimal subdivision of the inch, the corre-
spondence between the relative weights and thicknesses of metals, may be critically
arrived at with great simplicity.
The tldrdy fourth, and fifth column of the table, page 1013, constitute one series
of gages, employed exclusively for the bright steel wire prepared in Lancashire,
and the steel pinion wire for watch and clockmakers.
The smallest notch of this series is called No. 80, and measures 13 thousandths
of an inch, or about the 120th of an inch ; and the first part of this series continues
unto No. 1, which measures 227 thousandths, or nearly one quarter of an inch.
The steel wire gage apparently ended at this size in the first instance, but has
since been extended by a second series to the diameter of 494 thousandths, a mea-
sure doubtless intended for half an inch. In order to avoid the confusion attendant
upon two series of numerals, meeting at zero in the midst, the larger sizes are dis-
tinguished by the letters A to Z, and these terms are then continued under the
denominations A 1, B 1, C 1, D 1 to H 1, which latter size is the largest and mea-
sures 494 thousandths of an inch, as shown by the table. This second part of the
Lancashire wire gage, is called by way of distinction, the " Letter gage."
Many other gages of arbitrary characters came to the author's knowledge iu this
inquiry, several of which are applicable alone, to particular trades; amongst these
may be mentioned, the rod iron gage, the nail rod gage, the button-maker's gage,
others used in watchwork, and the gage used by gun-makers for the bores of guns
and rifles ; three of which gages alone will be described.
The rod iron gage, employed by Messrs. Bradleys, and some other iron masters,
and also by Messrs. Stubs, for steel, has measures derived from the division of the
inch into 8ths and 64ths as follows —
MESSRS. JOHN BRADLEY & CO.'S ROD IRON GAGE.
No. Inch.
No. Inch.
No. Inch.
No. Inch.
fifi i
K
11 >
n. 11
OS
10
fi U
11 2
19 '.'
/*«
18 • 1'
52
1 3
32
7 - 2
»* • 18
13 5
J.O lj
10 I3
' B
27
' 1
S . .is
10 3
14 s.
ij ig
20 - . T
sa
3 1
4 J»
•
9 A
10 - • i5
11 »
15 J
16 1
*U J.|
3i
lu te
MESSRS. JOHN BRADLEY & CO.'S NAIL ROD GAGE.
No. Inch.
No. Inch.
No. Inch.
No. Inch.
<»• - ;
11 - .13
4j>
7 — i
A-j ..I
&
OOJ -
27
3s
4J u"
8 — - i?
o — ,',
2.} — ;.;•
5 A
9 —
— ti
3 i
5J Si
10 - ?,:
i — A
»J — «
6 ii
Ui
A IT KM) IX XOTK
1017
It will be perceived that the intervals, from 00} to 3* are the 64th of an inch,
from 4 to 11 the 32nd, and above 13, the differences are I of an inch. This mode,
although systematic, is objectionable, as there is no evident relation between the
numbers ami their corresponding measures, and therefore both have to be im-
pressed upon the mind.
In guns of moat kinds, the weight of the balls determine the denominations of
their respective sites. Thus it is well known that heavy guns or ordnance are named
6. 9. 12 to 68 pounders, from having bores respectively suited to iron shots of those
respective weights, the bore is always '^tli larger in diameter than the shot, the dif-
ference being known as windage. The sizes of the bores of mortars and modern guns
intended for hollow shot, are designated in inches, as 8, 10, 13 inch mortars, Ac.
In rifles and fowling-pieces, the diameters of the bores, designated as No. 1. 2. 3.
4. 5. Ac., are the diameters respectively of leaden bullets or spheres, of which 1. ..
3. 4. 5. Ac. weigh exactly one pound avoirdupoise ; and as the subject may have
an interest for some of the readers of this volume, the following particulars of the
weights of the balls in grains, and of the dumeters both of the balls and of the
barrels in hundredth* of an inch, are transcribed from Mr. Wilkinson's gage, which
he ha* constructed with great care.
MIL WILKINSON'S GAGE FOR RIFLES AND FOWLIN'G-FIECES.
Xutor.
•JBJBMSI
. ( II .r, ;.,
HiHHlrrUthi
\\r-lh! .!
LMdrabalkt
u. SSS.
.Nimber.
DtaMUr ' Wridrtof !
•( Borr In I-radrabullct Number,
lluadmlllu. IB Urauu.
BtaMMi
.,1 H .ri- D
11,., .irr.-,..
W r,»h! ~t
im lirunv
•98
1400
15
•TOx
466]
25
•60 x
280
1
•93—
1666}
16
•69—
437J
26
•59 x
269,1,
7
•89
1000
c!7r
•67 x
411{}
27
•59
8
•85— 875
18
•••..;
;;v-;
M
•58 x
Q
•81— 777J
u
•65 x
mi
29
•58—
Ml||
10
•79 700
20
•63 x
355 . 30
•57
•j;::'
MllP
77 636,\
21
•63
833)
31
•56 x
225JJ
U
•75 x 688J
•62 x
318ft
32
•56—
•j;>;
13
74— 638ft
23
<lx
Mis)
• 14 •
•72— 500
24
•61
291 1
From the perusal of the foregoing particulars of numerous gages, employed in
different branches of mechanical art, it will have been seen that little analogy, on
the one hand, but great confusion on the other, exut in such of the gages as have
been referred to ; and the author will now briefly state the remedy he would sug-
gest to obviate the difficulty in the most simple and inexpensive manner.
Tke rtmetly pnpottd to rtmore the arbitrary infonyruout tyttcn o/gaget now tutJ,
is simply and in every one of the cases above referred to, and also in all others
requiring minute measures, to employ the decimal </iruioiu of (Ac incA, and thote
ttinltr their true appellation*.
Thus for most purposes the division of the inch into one hundred parts would be
sufficiently minute, and the measures 1. 2.5. 10. 15 or 100 hundredth*, would be also
sufficiently impressive to the mind; their quantities might be written down as 1. .'.
1018 APPENDIX NOTE BM.
5. 10. 15 or 100 hundredths, as the decimal mode of expression might if preferred be
safely abandoned, and the method would be abundantly distinct for common use
if the word " Hundredths " were stamped upon the gage, to show that its numerals
denoted hundredths of the inch, quantities which could be easily verified by all.
It does not follow that the entire hundred notches should be at all times used,
as in many cases it might suffice that below 20 hundredths, every size should be
employed; — from 20 to 50 hundredths, every alternate size, — from 50 to 100 hun-
dredths every fifth size. As at present also, the upper or lower part of the series
of terms might be omitted to any desired extent, in those cases where they were
beyond the particular wants of the artizan or the particular branch of trade, in
order to lessen the bulk and expense of the gage.
It may be objected to this scheme, that for the more valuable metals, and the
more minute purposes, the quantity of the one hundredth of an inch is too coarse
a difference. Two facile modes of remedy may be here applied. The first to make
half sizes : thus 8J or 8'5 would of course denote the medial interval between 8
and 9 hundredths. Or secondly, and preferably, below one tenth of an inch, a
finer scale might be substituted for the more minute and delicate purposes, namely
a gage based in precisely the same manner, on the thousandth of the inch as the
unit, which would give a much finer degree of subdivision than is afforded by any
of the arbitrary gages in general use ; in this case the intervals being derived from
the thousandth of an inch, the word " Thousandths," should be stamped on every
such gage.
In practice no difficulty could be seriously felt even without this precaution of
marking the gages respectively with the word Hundredth or TJiousandths ; as we
should not more readily mistake 5 thousandths for 5 hundredths, than we should,
5 tenths or half an inch, for 5 whole inches, or 5 entire inches for as many feet.
Neither is it to be admitted that no such gages are attainable as may be read off
in hundredths or thousandths. The demand would immediately create the supply,
and there could be no more difficulty in constructing the gages of the customary
forms, with notches made to systematic and defined measures, that may be easily
arrived at or tested, than with their present unsystematical and arbitrary measures,
which do not admit of verification.
Besides, for those who desire to possess them, several very correct decimal gages
already exist, amongst which may be cited the decimal sector gages long since
recommended, and published by the Society of Arts, Edinburgh, and various
eliding gages with verniers some to read off in hundreds, and finer ones in thou-
sandths, of the inch, all of which have been long and constantly used in the
author's manufactory.
To these may be added — La Rivu-re's gage, modified and enlarged from that used
for the balance springs of watches amongst the Geneva watchmakers. — Chater
and Hayward's gage for sheet metals and glass. — Walker's gage for sheet iron. —
Whitworth's micrometer gage and others — which may be severally read off to the
thousandth of the inch, and even more minute quantities, and amongst which
kinds sufficient choice exists for almost every purpose.
Tin advantages offered by this proposed application of decimal measures, appear to
be numerous and considerable, the more especially in those cases of small measures,
where the ordinary wire gages on the one hand, and the coarse division of ordinary
foot rules on the other, are obviously insufficient for accurate purposes. Amongst
these advantages may be enumerated the following :
MM'KNDIX NOTE BM. 1019
The propotod decimal scheme would introduce on* universality of system, intel-
ligible alike to all, instead of the numerous and irregular measures now used, which
are but partially and indifferently known and lead to frequent mistakes.
It would giro a superior idea of particular magnitude, and enable the theoretical
and practical man to proceed with so much more deeUon in their respective
com mnniostions.
In conveying rerbal or written instruction*, the system would bo in every way
ituperior to the usual methods, as being almost free from the chance of misunder-
standing, more especially as some of the decimal ^sliding gages are so small as
hardly to take'up more room in the pocket than an ordinary penknife, and might
be therefore continually within reach for reference.
When certain objects are required to be so proportioned as to constitute a series,
the intervals between the decimal measures would be far more easily arranged and
appreciated, than those of vulgar fractions ; and if calculation were referred to, the
decimal figures, especially when divested of the decimal point, and the zeros to the
right of the same, would be immediately intelligible to the least informed, from
being then no more in fact than simple numerals.
Quantities expressed decimally would be more easily written down, and more
rxactly defined than the compound fractions such as } and ^ of an inch — or than
the still more obscure method, of » of an inch full or bnre as the case might be,
which latter nearly sets all attempts at exactness in defiance.
The smaller aliquot fractions of the inch such as tho i A A i & i> &c.> °f *»
inch, although in themselves very precise, do not from their nature, so readily
admit of definition or comparison, as the quantities 2. 3. 4. 5. 0. 7. 8. 9. or 10 hun-
dredths of an inch ; because, in the vulgar fractions every one has a tpeeific relation
to the inch, whereas the decimal terms have one general relation, decimals being
sometimes considered as the numerators of fractions, all having the constant deno-
minator unity, or 100, 1000, &c. : and therefore the latter, or the decimal terms,
constitute a simple arithmetical series, or one in which the intervals are alike, but
this is not the case with vulgar fractions.
It would bring all foreign measures within reach of our workshops. For example,
in the United States of America, and Russia, English measure is employed, and no -
difficulty would be felt in reference to these countries. And as most of the Nation* I
Foot measures, are more than 1 1 inches English, and lew than 13, even if they are
considered for the time as equal to our own foot, and without any adjustment being
attempted, the average error would not exceed about five per cent. And further,
when two of Holtzapffel and Co.'s engine-divided scales, the one of the particular
foreign measure, and the other of English inches, are hud aide by side, they show
visually, as on a slide rule, the correspondence between any quantity of such foreign
measure with our own, as more fully explained in the author's pamphlet " On a
New System of Scales of Equal Part*," in which this and numerous other employ-
ment* of scales of equal parts are treated at length.
The decimal scheme would allow the exact weight in every superficial foot of
sheet metals and other substances to be readily arrived at — Thus, as a cubic foot
of water weighs 1000 ounces troy, the specific gravities of lead, copper, silver, &c.,
denote at tho same time how many troy ounces are severally contained in one cubic-
foot of tho same. The specific gravity divided by 1200, gives the weight of a plate
or film, tho one hundredth of an inch thick, and thence a table may bo readily
computed, by addition alone, to show the weight of plates of any thickness in trey
ounces.
These calculations would bo correct at once for gold and silver, as these metal*
1020 APPENDIX — NOTE BM.
are estimated by troy weight; but for other substances requiring avoirdupois
weight, the numbers expressing the specific gravities of the substances must bo
previously altered by one of the usual methods, namely, either by multiplying them
by 192, and dividing the product by 175, numbers which represent the ratio be-
tween troy and avoirdupois ounces ; or else instead thereof, the specific gravities
of substances may be multiplied by the decimal constant usually employed for
effecting the same end.
In this method also, constant multipliers may be readily found for thus deter-
mining from the specific gravities of the several materials, the exact thicknesses of
plates or sheets of the same, which shall precisely weigh, one ounce or one pound,
either troy or avoirdupois as may be required. This has already been done by Mr.
Hay ward as regards crown glass; for assuming its specific gravity to be 252,
when the glass is of the thickness of '1525, (or one tenth and a half nearly.) it
weighs 32 avoirdupois ounces to the superficial foot, and thence by Mr. Hay ward's
calculation are obtained the following numbers — the first line denotes the weight of
crown glass in ounces, in every superficial foot, the second line the corresponding
thicknesses hi thousandths of the inch, ranging from about 5 to 152 thousandths —
Crown glass of 1 2 4 8 12 16 20 24 28 32 ounces.
Measures '00476 '0095 "019 '038 -0571 '0762 -0952 -1333 "1429 '1524 inch.
The above and the intermediate terms are sometimes engraved on Messrs. Chater
& Hay ward's gages, alongside of the line of graduations which denotes thousandths :
and at other times, instead of the weight per foot are engraved divisions indici.tive
of the 8th, 9th, 10th, llth, 12th, &c. of the inch ; which quantities are of course
obtained by simply dividing 1000 by those respective numbers.
Tables might, in the above manner, be very readily computed, that would show
the weights hi every superficial foot of the metals and other materials for all defined
thicknesses ; and also other tables for showing how thick the metals should be, in
order to weigh exactly so many ounces to the superficial foot. These matters could
be also arrived at by the employment of scales of equal parts, laid down in the pro-
portions of the specific gravities of the substances ; and in the opinion of the author
they could be worked out with even greater simplicity and universality, by a
decimal proportional instrument he has some time since contrived, which is appli-
cable to the visual development of all ratios that have reference to decimal arith-
metic, including those of interest, discount, profit, and other calculations to which
the term Per Cent, is applied.
In conclusion, the author begs to add that he does not suggest any alteration
whatever, as regards those measures for which the division of the foot-rule into
eighths and sixteenths may be found sufficiently precise and minute. But he would
ask whether for more minute measurements, greater convenience and distinctivencss
would not result, from thegeneral employment of measures expressed in huudredths
of the inch, than from the employment of the many gages for specific uses, the sizes
and numbers of which are entirely devoid of system, and which gages may be con-
sidered as unknown beyond the particular trades in which they are employed.
How confusing would it be, if the measures by which broad cloths, linens, cottons,
silks, velvets, carpets, and other textile fabrics, are manufactured and sold, were all
different instead of being uniformly the yard measure j and yet this incongruity
fully applies to the various articles whose measurements are described under the
mystical names of Number, Size, Gage, and other appellations, which assume difercnt
Talues in different branches of manufacturing art ; as for example, in the various
APPENDIX — NOTES BM AND B.X. 1021
«f «hect metal*, various kind* of win*, in tubes, joiners' screw*, and vast
number* of «wall manufactured article*, the various sbes of which ore arbitrarily
designated aa No*. 1. 2. 3. 4. *o.
v not in all these branches of trade donoribe every thing measuring ^th of
an inch, aa No. 10 ; those of fl.tha inch, aa No. 80 F and than in aeta of object*
required to b« nearly alike, the succeeding numbers could be 31. 32. 33. 34. 35. 30.
>r if fewer and wider variation! were wanted, the aeriea might be 82. 84. 86.
38. 40.; or else 35. 40. 45. 50. 55. Every trade could select any portion of the
•erica it might require, both aa roganls general magnitude, and the greater or leaa
interval* between the sizes, and with the power of adding to, or aubtracting from,
the acale first selected, aa circumsUncca might suggest.
But there should be one common understanding that the com mtrcial numbers or
sizes, when different from the measures of the foot-rule, should be always under-
stood to be hundredth* of the inch, (in some rare instances thousandths,) as then
from the unity of system no confusion or difficulty could possibly arise.
It may be truo that some of the proposals having reference to the weights of
materials in tho superficial foot, the correspondences with foreign measures, and
some of the projects principally intended for the purposes of science, may not be
required in every -day practice : but still much remains in the system, that in the
opinion of the author, would admit of very easy introduction, and most general
and satisfactory employment.
In respect to the practical application of the method of decimal divisions, as
regards mechanical construction, the author can speak most satisfactorily from
some years' experience in his own manufactory, as he has found it to be most
readily followed by his workpeople, and also that it has avoided frequent and
vexatious misunderstandings, to which, before its adoption, he was frequently sub-
jected, from the want of a more minute and specific system of measure, than is
afforded by the common foot-rule and wire gages.
Therefore, from conviction of the usefulness and practicability of the decimal
system of measures for small quantities, he would most strongly urge its general,
or indeed universal, adoption, aa above proposed : the more especially as it is a
change that would be attended with very little temporary inconvenience or expense,
circumstances which greatly retard all attempts at generalization.
Note BN — To follow the paragraph ending the ribbon Mr, p. 751.
Mr. Bodmert Patent Tiretfor Locomotive WkttU.)
Mr. Bodmer's Patent mode of constructing the inner and outer tires of locomotive
wheels, and other annular objects, might possibly serve for making in one piece the
riband saws spoken of at page 751, and also the crown SAWS represented and
described fig. 797, pages 802—3.
In making tho tires of locomotive wheels, the first course is to prepare a mass
of wrought iron of the appropriate weight and with a central hole; this rude
annular piece of iron, when raised to the welding heat, is inserted between a pair of
roller* that overhang the bearings in which they work. The one roller is placed
within and the other without the piece of iron, which, however irregular, is soon
thereby reduced to an equal section throughout when the rollers arc set in motion ;
and a third roller, placed in the path of the nascent hoop or tire, gives it a form
almost as truly circular as if it had been turned in a lathe. The three rollers
ensure circularity in the tire upon the same principle that is employed in the three
bending rollers, tee fig. 232, page 389, Vol. I.
1022
APPENDIX — .VOTES BO AND BP.
Note BO, page 803. — To follow the third paragraph.
(Mr. Harvey's Patent Curvilinear Saws.)
Mr. Harvey took out a patent in June 1845, for an adaptation of the cylindrical
or crown saws, described in pages 800 to 803, by which they may be applied to
works of indefinite length. The hoop constituting the saw, is attached to a disk
mounted on an axis, but the disk only extends over 3 of the circumference, leaving
§ exposed for the passage of the wood ; And the saw instead of receiving con-
tinuous circular motion, as before, is now reciprocated by a crank through a few
degrees only of the circle, so that the wood sawn off may proceed through the
aperture between the saw and the disk ; which aperture somewhat resembles the
space between the spokes of a wheel having three arms and a very thin flat rim.
The square log fig. 1025 is mounted on centers, upon a drag or slide, fitted with
rack, pinion, ratchet and detent as usual for feeding the cut, so that the log is
presented with its four angles successively; and the extreme.edges having been first
sawn off with an ordinary circular saw, also attached to the machine, the four
Fig. 1025.
Fig. 1026.
annular sections a a a a, are first removed from the four angles, then four larger
b b b b, with a saw of greater diameter, and afterwards four others c c c c, the
nucleus e, is then sawn in two, and the several pieces when recombined produce the
mast of the section fig. 1026, which is said by the Patentee to be much stronger
than any mast or spar consisting of a single piece of timber.
The inventor also proposes to apply the saws to short works such as chair backs
and brushes, but which may be apparently better produced in the old drum saw,
which acts more rapidly from receiving continuous motion — he also proposes to
cut pieces of double curvature or of the ogee form, by the employment both of the
inner and outer surfaces of the cylindrical saws according to circumstances. See
Mechanics' Mag. 1846, Vol. 44, p. 18.
The reader is referred to Note BN, which suggests a new mode of constructing
cylindrical or crown saws.
Note BP, page 827, to follow the paragraph ending " fast by each foot."
(Cutting the teeth near the ends of files.)
To this paragraph it should have been added, that in cutting the ends of the files,
which parts must necessarily be laid at the time upon the anvil, the opposite end
of the blank is supported upon a wooden prop of the same height as the anvil, and
the straps are placed in the middle of the length of the file.
\ IT i:\lHX — NOTES BQ, BR, AND B8. 1023
Not* BQ, to follow the first paragraph, page 8S9.
(Mr. Mickatl KtUj$ Q*a**«t.}
Mr. Michael Kelly'* Quaunott, represented in fig*. 830 and.831, was rewarded by
the Society of Art* in 1845 ; and the instrument has been successively applied to
•craping zinc plates for the process denominated AnitsUtic Printing, invented in
Germany, and Patented in England by Mr. Joseph Woods. By this ingenioua art
impressions may be made, by the trantfcr protest, from any, eren the earliest
printed work* and engravings, provided any portion of the oil still remains in the
ink.
Note BR, page 841, to follow the paragraph ending " arc not at present uaed."
( Imvtntort of variotu JUe outing mackina.)
Since tho article on File Cutting Machine* waa written, the author find* that
Thiout was not, aa he had supposed, the inventor of the first machine for cutting
files ; as in the Memoir on the subject by M. de Montigny, read before the Com-
mittee of Commerce in 1778, the following were noticed as the more important of the
machines invented for cutting files — namely, that constructed by Du verger in 1690
—by Fardouet 1725— by Thiout 1740— by Brachat et Oamain 1756— and by
Vaucher 1778.
To these machines are to be added those subsequently made by Raoul in 1800 —
and by Ericson in 1836. See Article Lima, (Vol. 12, p. 289, of the) Dietionnaire
Tccknoioyiquedet Arttet Metiers, Paw, 22 vols. 8vo. and 2 vols. Atlas, 1822—1835.
Note BS.— Referring to page 299 of the First Volume.
During the period in which the hut sheet of this appendix waa being printed,
Mr. T. Taylor kindly pointed out to tho author that in the table for converting
decimal proportions into divisions of the pound avoirdupois, inserted on page 299
of the first volume, a clerical error had been committed from the subdivisions of the
avoirdupois ounce having been considered to consist of 8 drams, as in apothecaries'
weight, instead of 16 as in avoirdupois weight
The author much regrets thU oversight, which arose from the circumstance of the
avoirdupois ounce being rarely subdivided in common use more minutely than into
halves or quarters, and he inserts overleaf the corrected table, which Mr. Taylor
has been kind enough to calculate for this work.
1024
TABLE FOR CONVERTING DECIMAL PROPORTIONS
Into Divisions of the Pound Avoirdupois.
Decimal.
oz. dr.
Decimal.
oz. dr.
Decimal.
oz. dr.
Decimal.
oz. dr.
•39
1
12-89
2 1
25-39
4 1
37-85
6 1
•78
2
13-28
2 2
2578
4 2
38-28
6 2
1-17
3
13-67
2 3
26-17
4 3
38-67
6 3
1-56
4
14-06
2 4
26-56
4 4
39-06
6 4
1-95
5
14-45
2 5
2695
4 5
39-45
6 5
2-34
6
14-84
2 6
27-34
4 6
39-84
6 6
2-73
7
15-23
2 7
27-73
4 7
40-23
6 7
313
8
15-62
2 8
28-13
4 8
40-62
6 8
3-52
9
16-01
2 9
28-52
4 9
41-02
6 9
3-91
10
16-41
2 10
28-91
4 10
41-41
6 10
4-30
11
16-80
2 11
29-30
4 11
41-79
6 11 ;
4-69
12
17-19
2 12
29-69
4 12
42-19
6 12
503
13
17-58
2 13
30-08
4 13
42-54
6 13
5-47
14
17-97
2 14
30-47
4 14
42-97
6 14
5-86
15
18-36
2 15
30-86
4 15
43-36
6 15
6-25
1 0
18-75
3 0
31-25
5 0
43-75
7 0
6-64
1 1
19-14
3 1
31-64
5 1
44-14
7 1
7-03
1 2
•19-53
3 2
32-03
5 2
44-53
7 2
7-42
1 3
19-92
3 3
32-42
5 3
44-92 7 3
7-81
1 4
20-31
3 4
32-81
5 4
45-31 7 4
820
1 5
20-70
3 5
33-20
5 5
45-70
7 5
8-59
1 6
21-09
3 6
33-59
5 6
46-09
** /»
< 0
8-98
1 7
21-48
3 7
33-98
5 7
46-48
7 7
9-38
1 8
21-88
3 8
34-37
5 8
46-87
7 8
977
1 9
22-27
3 9
34-69
5 9
47-27
7 9
10-16
1 10
22-66
3 10
35-16
5 10
47-66
7 10
10-55
1 11
23-05
3 11
35-55
5 11
48-05
7 11
10-94
1 12
23-44
3 12
35-94
5 12
43-44
7 12
11-33
1 13
23-83
3 13
36-33
5 13
48-83
7 13
11-72
1 14
2422
3 14
36-71
5 14
49-22
7 14
12-10 1 15
24-61
3 13
37-11
5 15
4961
7 15
12-50
2 0
25-00
4 0
37-50
6 0
50-00
8 0 !
Application of the Table.
Tlie Chinese Packfong, similar to our German silver, according to Dr. Fyfe's
analysis, p. 279, is said to consist of —
40-4 parts of Copper » , 6 oz. 7 drams, full.
25-4 — Zinc / U _ i _ fuii.
QI .a x" i i / equivalent to < r , ,
ol-O — Nickel l 15 — 1 — nearly.
2*6 — Iron / ' 7 — nearly.
100-0 Parts.
16oz. 0 — Avoirdupois.
APPENDIX— NOTE BT.
Note BT.— To follow the not. :, page 44 of Vol. I.
(Mr. JoKjA Oibbi Patent Carving Mackimt.)
Mr. JoMph Oiblw' patent for " improved machinery for cutting marble, wood,
and other substances," scaled 12 NOT. 1829, WM inadvertantly overlooked by the
author, when he wrote the notee J. K. L of this appendix, on the carving machine*
subsequently patented by Irring, Jordan and Tomes, described on page* 954 — 7 ;
he now proposes to supply the omission.
A general idea of Mr. Qibbs' carving machine will be conveyed by imagining the
model and the copy, to be placed on two generate horizontal platforms, situated one
above the other ; the drill and tracer are each exactly vertical, and in one and the
same line ; but of course in an interrupted line, a* between them lies the platform
with the model. The tracer is at the top of all, and rest* on the model, the drill in
below the model and rests upon the copy that it us in the act of producing.
It is next to be explained how the tracer and drill are simultaneously and equally
moved in all directions, over the model and copy which lie at rest ; and this is
accomplished by building them in one vertical lino at the outer edge of a double
swing frame, consisting of two frame* or panels which move on joints, somewhat as
a folding door that consists of two leaves jointed in the center ; a construction
which also resembles that of the double swing frame, used in Brunei's cross cutting
saw machine, see fig. 789, page 796.
The two leaves of the swing-frame — to borrow the words of the former descrip-
tion,— give respectively the powers of moving the tracer and drill simultaneously
from North to South, and from East to West In addition to these two motions is
a third ; for the entire mass of the swing frame is moveablo vertically, as it slides
through fixed circular bearings, and is supported on a treadle which allows the
drill gradually to penetrate the work, until the further descent of the machinery is
arrested, from the tracer coming into contact with the model to be copied. As in
Brunei's saw machine and some others, the motion of the prime mover, is com-
municated by belts or straps, reeved on pulleys situated at the two axes of motion,
so that the rambling of the tool does not affect the tension of the bands.
One great application of this machine was to the cutting of the wooden letters
used for shop fronts, several in one pile, and in which case a metal templet WM
used. The machine presented all the elements required fur the purposes of carving,
and was used for that purpose ; but the duplication of the swing frame enfeebled
the construction, and gave rise to more vibration than exists in the subsequent
machines of Irving, Jordan, and Tomes, which all more or lew resemble Qibba*
original machine in principle, although severally different in construction, and more
efficient in use.
E.ND or THE APPENDIX TO THE SECOSD YOLCME.
3 u
ADVERTISEMENTS.
WORKS PUBLISHED BY HOLTZAPFFEL & Co.
64, Charing Cross, and 127, Long Acre, London.
A NEW SYSTEM OF SCALES OF EQUAL PARTS j
Applicable to various purposes of ENGINEERING, ARCHITECTURAL, and GENERAL
SCIENCE. By CHARLES HOLTZAPFFEL. Illustrated by a fac-simile of the scales
on copper-plate. 8vo. cloth, Price 2s. 6d.
" Mr. HOLTZAPFFKL could not have done a better tervice for the profeition than turning hit
attention to the conttruction oftealet tuitable for their purpotet. — We have for many yean been
in the habit ofuting tcalet made of paper, both for ettimating and drawing, on account of their
convenience. — We have very carefully examined teveral of the tcalet, and have much pieature in
tetlifying their accuracy and utility." — The Civil Engineer, and Architects' Journal.
DESCRIPTIVE CATALOGUE OF THE WOODS
COMMONLY EMPLOYED IN THIS COUNTRY, FOR THE MECHANICAL
AND ORNAMENTAL ARTS.
INTERSPERSED WITH EXTENSIVE BOTANICAL NOTES BY DR. ROYLE, F.R.S., L.S.,
AND G.S., ETC., ETC.
The Descriptive Catalogue of the Woods, commonly employed in this country, is
extracted from Vol. I. of " Turning and Mechanical Manipulation" by Charles
Holtzapffel. The Catalogue is interleaved and bound in cloth, for the use of
Collectors, Naturalists, and Travellers. 8vo. cloth, Price 2s. 6d.
A NEW SYSTEM OF DECIMAL GAGES OR MEASURES
FOR SHEET METALS, WIRES, AND SMA-LL MANUFACTURED ARTICLES GENERALLY.
Including the exact decimal values of the gages now principally used for these
purposes in the Mechanical Arts.
This paper is extracted from the Appendix to Vol. II. of " Turning and Mechanical
Manipulation," by Charles Holtzapffel. Pamphlet 8vo, in wrapper, price la.
PRINTING APPARATUS FOR THE USE OF AMATEURS.
Containing full and practical instructions for the use of COWPER'S PARLOUR
PRINTING PRESS, also the description of larger presses on the same principle, and
various other apparatus for the Amateur Typographer.
The pamphlet contains likewise, numerous specimens of plain and ornamental
types, brass rules, checks, borders, ornaments, corners, arms, &c. &c. Third
Edition, greatly enlarged. 8vo, cloth, Price 2s. 6d.
HOLTZAPFFEL AND CO/S GENERAL CATALOGUE
OF LATHKS, TOOLS, AND INSTRUMENTS EMPLOYED IN THE MECHANICAL ARTS
GENERALLY.
Stereotype Edition. 1849. 8vo. pp. 72, Price 6d., or free by Post, 1*. 4d.
BRIEF ACCOUNT OF IBBETSON'S GEOMETRIC
CHUCK.
H. & Co. beg to announce that they have purchased the remaining copies of the
j-amphlet written by the late J. H. Ibbetson, Esq., entitled " A brief Account of
Ibbeteon's Geometric Chuck, manufactured by Holtzapffel & Co., with a Selection
of Specimens illustrative of some of its Powers." — Pamphlet 8vo., in coloured
Trapper, Price 5*.
IJI II
nfl
AlAT.KTIM'.MrNTS
. beg to apprize Amateur* and th< I'u/,Hc in
era/, that they have constantly on tale a very large assortment
~j .he tool*, instruments and machines, employed in Turning, and
Mechanical Manipulation, of the extent of which variety, tome
small idea may be formed from the succeeding page* copied from
thtir last general Catalogue. Stereotype Impression, 1844. The
following Instrument* have Just been added to their Collection.
THE APOSTADOMBTER, OR OFF-SET INSTRUMENT.
Invented by W. PETRJE, ESQ.
Registered 9th Sept, 1846, and Manufactured solely by HotTZArrm. ft Co.
This Surveying Instrument is intended for measuring distance*, and their direc-
tion, \\ ith great despatch. It is applicable in a variety of operations, particularly
for taking off-set*, for checking surveys, and for facilitating chaining work gene-
rally. By this instrument off-sets are taken by one simple observation, without
the nocesMty of moving from the Chain-lino from which they are measured.
The Apottadometer is used somewhat as the Sextant, by observing the coinci-
dence of two reflection?, and is portable, simple in operation, and trustworthy in
its results. It takes off-sets of five chains or more, with the exact right angle, at
the tame time ; and their lengths are read off directly from the instrument without
any calculation, &c. Off-sets of the ordinary length are given within a small frac-
tion of a link.
A full description of the Apostadometcr may be bad on application, price 6</.,
or free by poet, 84.
HOLTZAPFFEL 4 CO.'S PEN HOLDER FOR ENFEEBLED HANDS.
Registered 16th Sept, 1846.
This was invented for the use of those persons who from age, rheumatism,
gout, stiffness in the joints of the fingers, defects in the nerves of the hand,
paralysis or other infirmity, are deprived of the free use of the fingers, so that they
cannot hold a pen in the customary position.
The shaft of the Pen-holder for Enfeebled Hands, is hold quite vertically in the
central part of the hand, and grasped by the whole of the fingers; this position
the most infirm can usually command. The lower extremity of the shaft Is allowed
to rest firmly upon the paper and thereby support the hand, whilst the tube that
actually receives the pen or nib, is jointed to the vertical shaft at about the angle
of 45 degree*, and is pressed on the paper by a feeble spring, so a* to assimilate in
the closest manner to the action of an ordinary quill pen.
The Penholder is adapted to receive a gold, steel, or quill pen at the option of
the individual, and the instrument is convenient for the pocket, as it folds into
the »ize of an ordinary pencil-case. Instructions for using the Pen for Enfeebled
Hands, with ft diagram, free by post.
HOLTZAPFFEL & Co.,
04,
(SEAmm© (DROSS, n.@S?B©S?,
ENGINE, LATHE, & TOOL MANUFACTURERS.
AMD
GENERAL MACHINISTS,
Co l&c Ran. Uoart a( Ortonanrr, tfje {{on. C«« In&u Compann, &t., \c.
TURNING, PLANING, SCREW AND WHEEL CUTTING, FRAMING,
IN METAL AMD WOOD TO DRAWINGS OR MODELS.
.fttnatntr*
AAE SUPPLIED WITH TRR APPARATUS, TOOLS, AND MATERIALS, THAT ARE REQUIRED
IX TURNING A>D THE MECHANICAL ARTS OENKRALLT, AND ARK
ALSO PRACflCALLT INSTRUCTED IN THEIR USE.
£ooJ* antt Instrument* for
ARCHITECTS.
COPPERSMITHS.
MASONS.
SEAL ENGRAVERS.
BOOKBINDERS.
KNOIHEERS.
MILLWRIGHTS.
SILTER8MITUS.
BRUSHMAKERS.
ENORATKR*.
\: I'i : . : ,.-.
SMITHS.
BUILDERS.
GARDENERS.
OPTICIANS.
SURVCTOR8.
CABINETMAKERS.
••MAKERS.
PAINT KRS.
TINSMITHS.
. u:l BJSJB Mi
IIAR.NKSSMAKERS.
PLASTERERS.
HATTERS.
PLUM BUS.
WATCHMAKERS.
x MAKERS.
J! v. i ; : M.
PRINTER*.
WHEELWR
COACH MAKERS.
MACHINISTS.
SADDLERS.
WIREDRAV
gfuiUrg of ebttfi ^wription.
AN EXTENSIVE ASSORTMENT OF
CHESTS, M DHAWINC! AM) Ml \-
1'KI.N Tl.NO I'HEdSKM. OAIIDKN TOOLS, fcc.
MANUFACTORY, 127, LONG ACRE.
ORDKR5, RECEITED KITIIER DIRECT OR THROUGH AOENCT flOCSA, KXI'<
WI1H EXACTNESS AND
1844.
IBBKTHON'H GromtMe Chtiek.-Part, Frrit. Second, and Third.
T"-n Frmlric
Mortmrnli.
HotT«ArrF«t ft Co.'»
Ornt cfirf Kccnttric f&tK*.
Each Specimen oo the other title i* the result of a different Apparatus.
This 1. 1..' .-.hows the effect of the some Apparatus, when eiupl- Auc-
tion w ith the lloee Engine.
Although only on* Specimen of each individual Apparatus u given, v*t the
i!>. \\lm-h may be considered almost eiidlcsui, dt-pvud ou the kkill <ui..
uf the Ui'Oi
- . rr«t ft C
ADDRESS.
IT is a source of extreme gratification to H. & Co., to notice the
extent to which the Mechanical Arts, and more particularly that of Turn-
ing, are pursued ; the Turning Lathe, in its various modifications, assisted
by its appendages of mechanism, being at present absolutely essential to
some stage of every manufacture.
The cultivation of Mechanics by Gentlemen who have the advantages
of general acquirements and of leisure, has given rise to many ideas and
suggestions on their part, which have led to valuable practical improve-
ments. H. & Co. have a large share of these obligations to acknow-
ledge, but it would obviously be extremely difficult to particularise them,
as the ultimate form of any successful piece of mechanism is commonly
the result of many successive modifications.
In some cases H. & Co. have been furnished by Gentlemen with the
theoretical and general sketch of machines, the details of construction
being entrusted partially, or wholly, to themselves ; and in others they have
merely carried into practical effect the finished designs.
To each of the Gentlemen by whom they have been favoured with
communications, as well as to those whose names appear in this Catalogue,
they beg to return their most sincere thanks,_with the assurance that it
would give them great pleasure to make further additions to this list under
similar circumstances.
The public is respectfully invited to inspect H. & Co/s ware-rooms,
where may be seen the principal part of the tools and machines specified
in this list; but of these numerous apparatus, some few are only made to
order, and others cannot be always in readiness; consequently, drawings
of nearly the whole are in preparation, to supply this inevitable deficiency.
The drawings are often found to assist foreign Gentlemen, and others, who
experience inconvenience from being unacquainted with the technical
names of the various apparatus.
Amateurs wno desire to receive instruction in Turning or Mechanical
Manipulation generally, can receive lessons from H. & Co.'s experienced
workmen, either in rooms fitted up for the purpose at Charing Cross, or
at their private residences, in town or country.
Mo. 64, CHARING CROSS,
October, 1844.
CVncrnl
Till: LEADING ARTICLES.
: • >OLS. (Se« al«o Drilling TooU) New. 1040 to
1066
ii:.l ..
1212 ..
1310
DKII.I.lNi; Tn«'I.->
LOG
IIS' TOOLS .
13.', 3
1II.I>. Mll.l 1 II.I.D AM) LANCASHIRE ..
1356 . .
UNG TOOLS
1367 . .
1376
s
"KJ1CAL TOOLS
1401
GRINIH.M; AITAKAITS
n.T) ..
1436
COUPLET* LATHES
..
1518
LATHES,— DeiAcutD PA&IS OF ; namely : —
1519 ..
1541
Cluifka fur Fixing Works in the Lathe • . .
1.M2 ..
1576
Chucks for Oroamen ting Works in the Lathe
..
1.-.93
Slide Rests, &c., for Ornamental Turning . .
1594 ..
16)6
Slide Rcatt, &c., fur Metal Turning - -
1617 ..
1628
'. iaucouB Lathe Apparatus .... . .
1C29 . .
PLANKS
1687 . .
1714
PLAN < HES
171.S ..
1719
rur.M.N.; AND GARDENING TOOLS - ..
..
ROSI:
;• i
1780
7'JI
1818
SA \vi.v; MACHINES
319
1832
A t UTT1NG APPARATUS ... ..
Ml
1856
SQUARES
1910
' MUSTS
..
19/8
TOOLS
198o
2027
FOOL CHESTS
• i.
•j M
\VHI;;:I.S
MM
1 • i
m K. -I:K-
• Arre.xDix A.
:vii)Ki> s.
i •
Pap
10
13
16
20
23
23
24
25
28
35
40
42
43
45
46
47
49
50
51
53
54
56
64
65
66
67
«•
GENERAL CATALOGUE
, Irestrunwnts,
MANUFACTURED AND SOLD BV
HOLTZAPFFEL AND CO.,
64, CHARING CROSS, AND 127, LONG ACRE, LONDON.
KLVISLJ) AND ENLARGED, 1844.
No.
1000
1001
1002
1003
1004
1005
1006
1007
11)08
1009
From I
: *. d.' £
M
To
2 Oi 0 4 0
ADZES. Carpenters, Coopers, and Shipwrights adzes. - Each 0
ANVILS. Small anvils, of the Ordnance pattern, witu shanks for]
the bench or vice ; some with 2 cutters .... Each 013 0| 0
Smiths anvils, from 20 to 400 Ibs. weight ... The lit. 0 100
Smiths anvils, with complete sets of Forging Tools, or coni-j
plete sets of Farriers' Tools The set 6 0 014 0 0
Tripod anvil stands of cast iron, with springs to reduce the
concussion arising from the hammer. ..... Each 210 03
AUGERS. Shell augers, from f to 1£ iuch, short with tangs 10 0 7 0
Shell augers, long, with eyes ........ |0 0 9 0
Screw augers ........ 0160
Improved American screw augers, from ^ to 2 inch, with
worms soldered on, and shifting cutters - ... Each 020060
Screw and Shell augers, in sets of 6 to 12, and from | to
1 J-inch diameter, to fit handles of beech- wood or hard-
1010
1011
1012
1013
1014
1015
HUG
1017
1018
wood, with spring sockets.
AWLS. Brad, flooring, and saddlers awls. ... The dozen
Brad-awls in beech-wood or hard-wood handles.
1
0
0
Brad-awls, sets of 6 to 12, contained ill socket handles of
horn, hard-wood, &c. ......... The set 0
AXES. Bench, blocking, broad, falling, hedge, ship, wedge, and
wheelers' axes. Handles charged extra - - The Ib.
Falling axes of American pattern, and variously handled.
II. and Co.'s make .......... Each 0
Single-hand axes, similar to the last but smaller ; used for
idling small trees, and for trimming plantations - Em-h 0
BABBACJE'S (C., Esq.), cutter bars, for turning metal, with the
slide rest. (See No. 1622.)
BAKEWKLL'S angle meter, for geological purposes. (See
No. 13'J'J.)
lluLowcil'b Geological Hammer.
(See No. U'J7.) -
16 0
0 6
10 0
1 9
3 0
4 6
7 0 1
080
260
IS C
1 0
460
6 0
7 6
2 6
10 o 0 1C 0
8 0 0 10 0
0 1 0
202
700
12 6
y o
-TO nOLTZAPFFKL AMD OO.*8 GENERAL CATALOGUE, 1844.
HOLTZAPFFEL It. CO.'S LIST OF TABLE CUTLERY.
A COMPLETE LIST Ol
w». PnoiiT. HrMrriMBir*. *«"> vrmm* KOTVMI lUana*, RCMMW, *
AancuM, wtu. •• mmo OH r*oa» 13 TO i« or T>< -urn.
«M«rri«ii> *,»(>• ni-AD*a,
. . . Ho-
•JS.-
3&
>.' ""I'.:
T nBL
4. «.«%
£ga<
*. t.4.
• • •
00*
0 • 0
{1—
i—
.1 -
4—
(*-
0—
7—
0—
V«rranted KnUM and Fork*. In cnlM Handle* of (he b»*t f *
N.tural Muck or BUf Horn. alw la Ootafna Handle* of O* J '
0 10 0
0 14 0
640
1 0 0
1 fl «
1 4 0
1 4 0
1 • 0
1 lo »>
1 13 0
1 18 0
t • •
S > 0
0 10
1
1
1
0 1
1
1
1
1 10
1 li
I
0
0
7
7
7
7
0
0 «
» u
113-
14—
10-
Lmroow M*D« BLAOB*.
Jo I*i«rjr OetajtOB Handle* 17
In l»ocy Oetafon Handle* of liner quality .... IK—
In A no Transparent African Ivory Octagon ITan-lIos with 8Ilrer ) ,n
In fin* Tnuuptrmt Afrlciui Irory Fluted Octagon Handle* ) M
withaUvfrPwrnlM (
3 10 0
300
0 13 0
SETS OF TABLE CUTLERY IN CASES.
T»« Catet art of MmMofany, or Oak, and bound frith bran . Uity art lined tcilk baift, and kavt
iffaraU t*mp*rtme*U for tack pircr.
T*t Catet art ekarptd a lilt If extra {f lined vf/k tMh or trttk eottnn retrrt.
AH U« Knlvet mrpHtd In thfit Cattt Hove lalcnced kandUt , tut Table fork*, and Detttrt Forkt.
art mot imeludtd in tke annexed Priett.
P«-f» of f down T»Wr Knlm. t dnwn PIMMJ Knlrw, > Pain of 1
Table Canrrm. and 1 Knife «t«-l . . )
tMa of 4 down Table Knlvea. 3 4oMi Dowrt Knlrt*. t Pair* of 1
Table, and t Pair, of Poultry Carrrn. anil 1 Knife M. rl . . i
•*«• of • 4«Mn Table Knrrea. 4 d.*rn Ihmert Knlr«^ a Pain '
of Table, and * Pain of Poultry Canren. 1 Knife 8te*l, and S.
1 CtMewHeonp
n
WZ
«
£.«.*.
9 10 0
15 IS 0
ft « t
80 0 0
Jt. «. «f.
It C 0
n o o
it 0 0
4. ». 4.
13 10 0
n 10 o
as 0 0
45 0 0
CPU of • dona Table Knlrea, 6 down DoMrt Knlrc.. 4 Pain '
o/ Table and 4 Pain of Poultry Carrrn, t Knife 8t«*la. and \
Damn KICITBS AMD FORKS or STKKL, PLATKD WITH SILTKA, *no COOTAIKKO IK CMC*.
P«ta of 1 dnten pain. Tarionnly mountr.1 (n Irory Handle*
•eU of 1 flnain pairs, rarinuily monn trd In Pearl ITandlea .
£. l. 4.
4 10 0
4. »A
0*0
t. ,. d
7 10 e
i
-i irltn halMirafl fcaadlai Ir tin Anmwm ntra
Knir*. without Pork* ooe third lea* the down than Knlre* aad Porks.
"r— TiliTMln ilil li i Hi i Hi in im llnilnaw
A jarnal a*»oiUiiam of fowl. ham. and arlmitar Oarrtaf Knlrre*. Porto, and Steel*. In Iwy. book,
and atac-born handle*, plain, or with aflv*r i
Ate wta of Knlvm for the k iicheo. ,
root knlTea, and »tcrU ; and cutlet, mincing, aad «u«k chopper*, with Iron. born, or wood haadtoa.
rreata. laMtela. or Name* m«rav*d on tho handle* to order.
rr«t*wy4mgtr*oan9*n*.fmmmfmm*fm*m*»*m9&im9it»*m.
I, CH4Rt«o CMML] [MAJIVFACTOIIT, 127, Lom Aou.
VDIX (C.)— TO HOLTZ APFFEL AND CO.'S GENERAL CATALOGUE. IS I !.
A NEW SYSTEM OF SCALES OF EQUAL PARTS,
Applicable to various purposes of ENGINEERING, ARCHITECTURAL, and GENERAI
SCIENCE. Illustrated by a fac-simile of the scales on copper-plate. By CHAIU.HS
HOLTZAPFFKL. 8vo. cloth, Price 2*. Gd. Published by JOHN WEALE, London. Sold
also by HOLTZ APFFEL & Co., Engine, Lathe, and Tool Manufacturers, 64, Charing
Cross, and 127 Long Acre, London.
" Mr TIoLTZAprFKL rould not have done a better ten-ice for the profession, than turning hit attention
to the construction of scales suitable for their purposes. — fF« hare for many years been in the habit oj
ujlnfi scalet made of paper, both for estimating and drawing, on account of their convenience. — We have
carefully examined several of the scales, and have much pleasure in testifying their accuracy and
y."— The Civil Engineer and Architects' Journal.
IIOLTZAPFFEL AND CO.'S.
ENGINE -DIVIDED SCALES,
APPLICABLE TO
Engineering;, STrdjttectural, anfc General Science.
As the least expensive fabric, each scale is ruled in the Dividing Engine, on a different
slip of card paper, 18 inches long, the figures and inscription having been previously
printed dry. By this arrangement the confusion of crowded scales is entirely avoided,
nnd any of them may be applied directly to the drawing, or compared with one another,
•without the employment of the compasses. The material of the scales and of the
drawing paper being IDENTICAL, they will be found well adapted to the majority of the
drawings used in common practice. Numerous experiments on this head arc detailed
in the pamphlet.
ORDINARY DRAWING SCALES.
A series of 24 scales, containing the usual reductions of the foot, from one sixteenth of an inch to 6 inches
to the foot, including three lines of inches, divided into eighths, tenths, and twelfths, and the English foot
decimally divided. Sold also in quarter-sets, or singly.
CHAIN SCALES.
A series of 12 scales in chains and links, namely, I, H, 2, 3, 4, C>, 8, 10, 16, 20, 30, 40, chains to the
Inei- • various others, and also scales of chains and miles expressed in feet.
PROPORTIONAL SCALES.
A series of 25 Proportional Scales, for the enlargement and diminution of drawings and models, so as
to suit all transpositions of scale, required by the limitation of the drawing paper, the copper plato, or
of the materials to be used in the Lathe or otherwise. The series gives 400 distinct and different ratios
of proportion, which are given in a tabular form in the Pamphlet.
COMPARATIVE SCALES.
A series of 24 Comparative Scales, by which any length in Berlin, Brussels, English, Florence,
French. I.eipsic. Lisbon, Munich, Neapolitan, Polish, lihineland, Roman, Sicilian, Spanish, Swedish,
Venetian, Vienna, measures, whether in feet, bracchi, palms, inches, or parts, can be transposed on
inspection into corresponding quantities, expressed in any other of the linear measures of the series.
The game method is equally applicable to the transposition of the measures, weights, moneys, miles,
leagues, *c. of different Countries, and for any of which purposes, scales will be made to order, from the
Measures of the National Standards given in KELLY'S CAMBIST.
A series of 24 Scales for showing the comparative bulks and weights of equal quantities of the metal*.
woods, stones, and materials principally used in the arts. Contraction Rules, used in making foundry
patterns.
Any qf the above, anil many other Ki-a 'e* (fully described in the Pamphlet), graduated on separate slips
of Card Board, JH inches Imiti, at Six. the dozen, or separately, at \s. each. ' If ruled to order, 2*. each.
Cases covered with cloth, for one dozen. Is. 6d. ; for two dozen, 2s. each.
THE LIBRARY, SKETCHING OR POCKET-BOOK SCALE.
A rectangle of card, 41 by2\ cut out in the annexed form, and divided on the several
edge*. It combines Hie Protractor, and all the usual Scales for Drawing, and it mny be
died M ft set square, or bevll, parallel rule. Marquois Scale, &c. Price, on card, 3*., 4.T.,
i». , according to the number of graduations.
THE ODONTOGRAPII,
Invented by the Rev. R. WILLIS, A.M., F.R.S., Jacksonian Professor, Cambridge, |-c.
This U an Instrument of eaxy aopllcatinn, used for describing the teeth of wheels by circular nrcs, an
llMt any two wheels of a set may .orU truly together. Price of the Odontograph on card and varnished, £&.
The theoretical explanation of this system of teeth, which has been extensively adopted by practical men,
vffl be found In the Trans, lint. Civi! KuKineers, Vol. II., and in Willis's Principles of Mechanism, ItUB.
PLEASE DO NOT REMOVE
CARDS OR SLIPS FROM THIS POCKET
UNIVERSITY OF TORONTO LIBRARY
Holtzapffel, Charles
Turning and mechanical
manipulation
v.2 v.2
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