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LATHE DESIGN,

CONSTRUCTION AND OPERATION'

WITH PRACTICAL EXAMPLES OF

LATHE WORK

A COMPLETE PRACTICAL WORK ON

THE LATHE. GIVING ITS ORIGIN AND DEVELOPMENT. ITS DE-
SIGN. ITS VARIOUS TYPES AS MANUFACTURED BY DIFFERENT
BUILDERS, INCLUDING ENGINE LATHES, HEAVY LATHES, HIGH-
SPEED LATHES, SPECIAL LATHES, TURRET LATHES, ELECTRI-
CALLY DRIVEN LATHES, AND MANY OTHERS. LATHE ATTACH-
MENTS, LATHE WORK, LATHE TOOLS, RAPID CHANGE GEAR
MECHANISMS, SPEEDS AND FEEDS, POWER FOR CUTTING TOOLS,
LATHE TESTING, TURNING TAPERS, METHODS OF MILLING AND
GRINDING IN THE LATHE, THREAD CUTTING, LATHE
INSTALLATION, ETC.

OSCAR E. PERRIGO, M.E.

Author of " Modern Machine Shop Construction, Equipment and
Management," " Change Gear Devices," etc., etc.

NEW REVISED AN ft EN^AKGWi EDITIONS

Illustrated by Three HAindrett>rld For iy-ohe; Engra^in^s^
Made from Drawings fexp>es;3y Executed for this* feoc-fc- '

NEW YORK

THE NORMAN W. HENLEY PUBLISHING CO.

2 WEST 45TH STREET

1919

Note. — Each and every illustration in this book was
specially made for it, and is fully covered by copyright.

COMPOSITION, PRINTING AND BINDING BY
THE PLIMPTON PRESS, NORWOOD, MASS., U.S.A.

PREFACE

THE aim of the Author in writing this book has been to
present in as comprehensive a manner as may be within the
limits of a single volume the history and development of the lathe
from early times to the present day; to briefly discuss its effects
upon manufacturing interests; to describe its practical use on
various classes of work; and to compare in a representative,
theoretical, and practical manner the Modern American Lathes
as now built in this country.

In carrying out these aims the early history of the lathe is
traced from its crude beginning up to the time when the foot-
power lathe was the sole reliance of the early mechanic. Then
the early history of the development of the screw-cutting or
engine lathe is taken up and carried on to the middle of the last
century. This is done to put the student and the younger
mechanic in possession of the facts in relation to the origin and
development of the lathe up to within the memory of many of
the older mechanics of the present day.

The matter relating to the early history of the lathe is
introduced for what seem to be good and sufficient reasons. If
we are always to " commence where our predecessors left off"
we shall miss much valuable information that would be very
useful to us. A retrospective glance on what has been, a review
of previous efforts, a proper consideration of the road by wnich
we came, or by which earlier workers have advanced, is not
only interesting but necessary to a full and complete under-
standing of the subject, and very useful to us in mapping out
the course for our continued advancement in contributing our
share in the development of mechanical science.

Following along these lines, the various types of lathes have

been carefully classified, engravings and descriptions of the prom-
inent American lathes are given, and their special features of
design, construction, and use are pointed out and briefly com-
mented upon.

It is a matter of much pride to every true American mechanic
that this country produces so many really good and meritorious
manufacturing machines, and in no line is this superiority more
clearly shown than in the magnificent array of Modern Lathes.

This work brings these machines together in a comprehensive
manner for the first time, and thus aims to add its quota to the
present literature on this subject, and so make it valuable as a
book of reference, alike to the student, the designer and the me-
chanic, as well as the manufacturer and the purchaser of Modern
American Lathes.

In the revised and enlarged edition of this work a chapter has
been added detailing all kinds of lathe work, treating of lathe
installation and management, milling, drilling and grinding attach-
ments and their use, methods of turning tapers, turning spherical
surfaces, making oil grooves and many other processes pertaining
to practical lathe work. Endeavor has been made to have this
information sufficiently clear so it may be readily followed by
the apprentice, student or amateur machinist.

THE AUTHOR.

January, 1919.

CONTENTS

INTRODUCTION
CHAPTER I

HISTORY OF THE LATHE UP TO THE INTRODUCTION OF SCREW
THREADS

PAGE

Tracing early history. — The lathe was the first machine tool. — The
origin of the lathe. — An old definition of turning. — The first
record of turning operations. — Another old-time definition of
turning. — English classification of lathes. — The earliest form
of the lathe proper, or the old "Tree Lathe." • — The Asiatic wood
turner. — The "Spring-pole" lathe. — The "Fiddle-bow" lathe.

— The essential features of a lathe. — The balance-wheel applied
to a lathe. — The crank, connecting rod and treadle, applied to a
lathe. — Origin of the term "Pitman."-— A foot lathe built by
the Author. — A foot lathe with the balance-wheel located over-
head. — The friction clutch for foot-power machines .... 21

CHAPTER II

THE DEVELOPMENT OF THE LATHE SINCE THE INTRODUCTION
OF SCREW THREADS

Origin of the screw thread. — Ancient boring tools. — Suggestions of
the screw form. — The "Worm Gimlet." -—Making the first nuts.

— An old device for cutting threads in wood. — Archimedes and
his helical device for raising water. — Jacques Berson's French
lathe. — Joseph Moxan's English lathes. — The French lathe of
1772. — John Maudsley's English lathes. — Maudsley's slide-rest.

— Another French lathe. — The use of a "master screw." —
A form of slide-rest. — An old-time worm and worm-gear. —
Simple method of developing the screw thread. — Anthony Robin-
son's triple-threaded screw. — The many uses of the early lathes.

— An old "chain lathe." — Cutting left-hand threads. — Crown
gear and "lantern pinion" for operating the lead screw. — Tran-
sition from wooden to iron lathe beds. — The Putnam lathe of
1836. — The Freeland lathe of 1853. — Various classes of lathes

to be illustrated and described . . . . . . ... . 35

6 CONTENTS

CHAPTER III

CLASSIFICATION OF LATHES

PAGE

The essential elements of a lathe. — The bed. — The head-stock. —
The tail-stock. — The carriage. — The apron. — The turning and
supporting rests. — The countershaft. — Taper attachments. —
Change gears. — Classification applied to materials, labor ac-
counts, and the handling of parts in the manufacture of lathes.

— The four general classes of lat-hes. — The eighteen sub-divisions
of these classes. — The first class : hand lathes, polishing lathes,
pattern lathes, spinning lathes, and chucking lathes. — The sec-
ond class: engine lathes without thread-cutting mechanism, Fox
brass lathes, forge lathes, and roughing lathes. — The third class :
complete engine lathes with thread-cutting mechanism, precision
lathes, rapid reduction lathes and gap lathes. — The fourth class:
forming lathes, pulley lathes, shafting lathes, turret lathes, and
multiple spindle lathes. — Rapid change gear devices. — Ban-
croft and Sellers device. — The Norton device. — Lathe bed sup-
ports. — The precision lathe. — The rapid production lathe. —
The gap lathe. — Special lathes. — Forming lathes. — Pulley
lathes. — Shafting lathes. — Turret lathes. — Screw machines. —
Multiple spindle lathes. — Variety of special lathes .... 50

CHAPTER IV

LATHE DESIGN: THE BED AND ITS SUPPORTS

The designer of lathes. — The manufacturer's view of a lathe. — The
proper medium. — Causes of failure. — The visionary designer.

— Conscientious efforts to improve in design. — Design of the lathe
bed. — Elementary design. — Professor Sweet's observations. —
The parabolic form of lathe beds. — The Author's design. —

/ Form of the tracks. — Bed of the old chain lathe. — The English
method of stating lathe capacity. — Method of increasing the
swing of the lathe. — The Lodge & Shipley lathe bed. — Uniform
thickness of metal in beds. — Ideal form of bed. — Cross-ties,
or bars. — Four Vs. — Flat surfaces. — Lathe bed supports. —
Height of lathe centers. — Wooden legs for lathe beds. — An
early form of braced, cast iron legs. — Cabinets or cupboard
bases. — Old style cast iron leg still in use. — Form of cabinets.

— Principles of the design of cabinets. — Cabinets for small lathes.

— The Lodge & Shipley cabinet. — The Hendey-Norton cabinet . 69

CONTENTS

CHAPTER V

LATHE DESIGN: THE HEAD-STOCK CASTING, THE SPINDLE AND
THE SPINDLE CONE

PAGE

Design of head-stock for wooden bed lathes. — Early design for use
on a cast iron bed. — An old New Haven head-stock. — The arch
form of the bottom plate. — Providing for reversing gears. — The
Hendey-Norton head-stock. — The Schumacher & Boye head-
stock. — The Le Blond head-stock. — The New Haven head-
stock. — The arch tie brace of the new Hendey-Norton design. —
Generalities in describing a lathe spindle. — Designing a spindle.

— Governing conditions. — The nose of the spindle. — Spindle
collars. — Proper proportions for lathe spindles. — Large versus
long bearings. — Design of the spindle cone 93

CHAPTER VI

LATHE DESIGN: THE SPINDLE BEARINGS, THE BACK GEARS
AND THE TRIPLE GEAR MECHANISM

Designing spindle bearings and boxes. — Thrust bearings. — The
Lodge & Shipley form. — Ball bearings. — Proper metal for boxes.

— The cast iron box. — Early form of boxes. — The cylindrical
form. — Thrust bearings for a light lathe. — Experiments with
different metals on high speeds. — Curved journals. — The in-
volute curve. — The Schiele curve. — Conical bearings. — Adjust-
ments to take up wear. — Split boxes. — Line-reaming boxes. —
Lubrication of spindle bearings. — The plain brass oil cup. —
The use of a wick. — Oil reservoirs. — Loose ring oilers. — Chain
oilers. — Lodge & Shipley oil rings. — Neglect of proper lubrica-
tion. — Back gearing. — Varying the spindle speeds. — Triple
gearing. — Theory of back gearing. — Back gear calculations. —
Triple gear calculations. — Diagram of spindle speeds. — Faulty
designing of back gears and triple gears. — Four examples. — A
14-inch swing lathe. — A 19-inch swing lathe. — A 17-inch swing
lathe. — A 30-inch swing triple-geared lathe. — Explanation of
the back gear diagrams. — Essential parts of the triple gear
mechanism. — "Guesswork" in lathe designing. — Wasted oppor-
tunities. — Designing the head-stock. — Cone diameters. — A
homely proportion. — The modern tendency in cone design. —
Proportions of back gears. — Driving the feeding mechanism. —
Reversing the feed. — Variable feed devices. — Rapid change
gear devices 110

8 CONTENTS

CHAPTER VII

LATHE DESIGN: THE TAIL-STOCK, THE CARRIAGE, THE
APRON, ETC.

PAGE

Functions of the tail-stock. — Requisites in its construction. — The
Pratt & Whitney tail-stock. — The Reed tail-stock. — The Lodge
& Shipley tail-stock. — The Blaisdell tail-stock. — The Hendey-
Norton tail-stock. — The New Haven tail-stock. — The Prentice
tail-stock. — The Schumacher & Boye tail-stock. — The Davis
tail-stock. — The American Watch Tool tail-stock. — The Niles
tail-stock for heavy lathes. — New Haven tail-stock for heavy
lathes. — The Schumacher & Boye tail-stock for heavy lathes. —
The Bridgford tail-stock for heavy lathes. — The Le Blond tail-
stock. — The lever tail-stock. — The lathe carriage. — Requisites
for a good design. — Description of a proper form. — A New
Haven carriage for a 24-inch lathe. — The Hendey-Norton car-
riage. — The Blaisdell carriage. — The New Haven carriage for
a 60-inch lathe. — Criticisms of a practical machinist on carriage
and compound rest construction. — Turning tapers. — The taper
attachment. — Failures of taper attachments. — The Reed taper
attachment. — The Le Blond attachment taper. — The Lodge &
Shipley taper attachment. — The Hamilton taper attachment. —
The Hendey-Norton taper attachment. — The New Haven taper
attachment. — The Bradford taper attachment 135

CHAPTER VIII

LATHE DESIGN: TURNING RESTS, SUPPORTING RESTS, SHAFT
STRAIGHTENERS, ETC.

Holding a lathe tool. — The old slide-rest. — The Reed compound
rest. — The Lodge & Shipley compound rest. — The Hamilton
compound rest. — The Hendey-Norton open side tool-posts. —
Quick-elevating tool-rest. — The Homan patent tool-rest. — The
Le Blond elevating tool-rest. — The Lipe elevating tool-rest. —
Revolving tool holder. — The full swing rest. — The Le Blond
three-tool rest. — The New Haven three-tool shafting rest. —
The Hendey cone pulley turning rest. — Steady rests. — Follow
rests. — The usual center rest. — The New Haven follow rest. —
The Hendey follow rest. — The Reed follow rest. — The Lodge &
Shipley follow rest. — Their friction roll follow rest. — Shaft
straighteners. — The Springfield shaft straightener. — New Haven
shaft straightener. — Lathe countershafts. — The two-speed coun-
tershaft. — Geared countershafts. — The Reed countershaft. —
Friction pulleys. — Tight and loose pulleys. — Self-oiling boxes. —

CONTENTS 9

PAGE

The Reeves' variable speed countershaft. — Design of geared coun-
tershafts. — Another form of variable speed countershafts . . 157

CHAPTER IX

LATHE ATTACHMENTS

Special forms of turned work. — Attachment for machining concave
and convex surfaces. — Attachment for forming semicircular
grooves in rolling mill rolls. — Device for turning balls or spherical
work. — Turning curved rolls. — A German device for machining
concave surfaces. — A ^similar device for convex surfaces. — Mak-
ing milling cutters. — Backing-off or relieving attachment. —
Cross-feed stop for lathes. — Grinding attachments. — The "home-
made " attachment. — Electrically driven grinding attachment. —
Center grinding attachment. — Large grinding attachment. — The
Rivett-Dock thread-cutting attachment . . . . . . . . 176

CHAPTER X

RAPID CHANGE GEAR MECHANISMS

What a rapid change gear device is. — The old pin wheel and lantern
pinion device. — The first patent for a rapid change gear device.

— The inventors' claims. — Classification of rapid change gear
devices. — The inventors of rapid change gear devices. — Paulson's
originality. — " Change gear devices" by the Author. — Le Blond's
quick change gear device. — The Springfield rapid change gear
attachment. — The Bradford rapid change gear device. — Judd's
quick change gear device. — Newton's quick change gear device.

— Flather quick change gear device 194

CHAPTER XI

LATHE TOOLS, HIGH-SPEED STEEL, SPEEDS AND FEEDS, POWER
FOR CUTTING-TOOLS, ETC.

Lathe tools in general. — A set of regular tools. — Tool angles. —
Materials and their characteristics. — Their relation to the proper
form of tools. — Behavior of metals when being machined. —
The four requisites for a tool. — The strength of the tool. — The
form of the tool. — Degree of angles. — Roughing and finishing
tools. — Spring tools. — Tool-holders. — Grinding / tools for tool
holders. — Dimensions of tools for tool-holders. — The Armstrong
tool-holders. — Economy of the use of tool-holders. — High speed
steel. — A practical machinist's views on high-speed steel tools. —
Conditions of its use. — Preparing the tool. — Testing the tool. —

10 CONTENTS

PAGE

— Speeds and feeds. — Much difference of opinion. — Grinding
the tools. — Amount of work accomplished by high-speed steel
tools. — Average speed for lathes of different swing. — Speeds of
high-speed steel drills. — Mr. Walter Brown's observations on
high-speed steel. — Its brittleness. — Its treatment. — The secret
of its successful treatment. — Method of hardening and tempering.
Method of packing. — Making successful taps. — Speeds for the use
of high-speed steel tools. — Economy in the use of high-speed steel
tools. — Old speeds for carbon steel tools. — Modern speeds. —
Relative speeds and feeds. — Modern feeds for different materials.

— Lubrication of tools. — The kind of lubricant. — Applying the
lubricant. — Lubricating oils. — Soapy mixtures. — Formula for
lubricating compound. — Improper lubricants. — Various methods
of applying lubricants. — The gravity feed. — Tank for lubricant.

— Pump for lubricant. — Power for driving machine tools. —
Calculating the power of a driving belt. — Impracticability of
constructing power tables. — Collecting data relating to these sub-
jects. — Flather's " Dynamometers and the Transmission of
Power." — Pressure on the tool. — Method of calculating it. —
Flather's formula. — Manchester Technology data. — Pressure on
tools 214

CHAPTER XII

TESTING A LATHE

Prime requisites of a good lathe. — Importance of correct tests. — The
Author's plan. — Devices for testing alignment. — Using the de-
vice. — Adjustable straight-edge. — Development of the plan. —
Special tools necessary. — Proper fitting-up operations. — Level-
ing up the lathe for testing. — An inspector's blank. — The in-
spector's duties. — Testing lead screws. — A device for the work.

— A micrometer surface gage. — Its use in lathe testing. — Proper
paper for use in testing. — Test piece for use on the face-plate. —
Testing the face-plate. — A micrometer straight-edge. — Allow-
able limits in testing different sized lathes. — Inspection report on

a lathe. — Value of a complete and accurate report .... 240

CHAPTER XIII

LATHE WORK

The use of hand tools. — Simple lathe work. — Lathe centers. — Care
in reaming center holes. — Locating the center. — Use of the
center square. — Angle of centers. — Lubrication of centers. —
Centering large pieces of work. — Driving the work. — Lathe dogs.

CONTENTS 11

PAGE

— The clamp dog. — The die dog. — The two-tailed dog. — Lathe
drivers. — Using dogs on finished work. — Clamp dog for taper work.

- Bolt dog. — Methods of holding work that cannot be centered.

— Center rest work. — Chuck work. — Use of face-plate jaws. —
Lathe chucks. — The Horton chuck. — The Sweetland chuck. —
The Universal chuck. — Face-plate jaws. — A Horton four-jaw
chuck. — A Horton two-jaw chuck. — A Cushman two-jaw chuck.

— Chucking cylindrical work. — Inside chucking. — Chucking
work supported in a center rest. — Pipe centers. — Mortimer
Parker's improved forms of pipe centers. — Spider centers. — Ball-
thrust pipe centers. — Lathe arbors or mandrels. — Kinds of
mandrels. — Expanding arbors or mandrels. — Making solid
arbors. — The taper of an arbor. — Hardened and ground arbors.

— The Greenard arbor press. — Its advantages 254

CHAPTER XIV

LATHE WORK CONTINUED

Irregular lathe work. — Clamping work to the face-plate. — Danger
of distorting the work. — A notable instance of improper holding
of face-plate work. — The turning of tapers. — Setting over the
tail-stock center. — Calculating the amount of taper. — Taper
attachments. — Graduations on taper attachments. — Disadvan-
tages of taper attachments. — Fitting tapers to taper holes. —
Taper turning lathes. — Turning crank shafts. — Counterbalan-
cing the work. — Angle plate for holding the crank shaft. — Form-
ing work. — Forming lathes. — Drilling work on the lathe. —
Chuck and face-plate drilling. — Holding work on the carriage. —
Boring a cylinder. — The Author's design for boring large cylin-
ders. — Holding work by an angle-plate on the face-plate. —
Thread cutting. — Calculations for change-gears. — Reverse gears.

— Arrangement of the change-gears. — Ratio of change-gears
equal to ratio of lead screw to the thread to be cut. — Cutting left-
hand threads. — Compound gearing. — Calculating compound
gears. — Cutting double threads. — Triple and quadruple threads.

— Boring bars. — Varieties of boring bars. — Driving boring bars.

— Boring large and deep holes. — The Author's device. — The
drill boring bar and cutters for the work. — Flat cutters for boring
bars. — Boring bar heads or arms. — Hollow boring bars. — Mill-
ing work on a lathe. — Milling and gear cutting on a speed lathe. —
Grinding in a lathe. — Cam cutting on a lathe. — Many uses for

the engine lathe 268

12 CONTENTS

CHAPTER XV

ENGINE LATHES PAGE

Definition of the word engine. — What is meant by an engine lathe. —
The plan of this chapter. — The Reed lathes. — Reed 18-inch
engine lathe. — The Pratt & Whitney lathes. — Their 14-inch
engine lathe. — Flather lathes. — Flather 18-inch quick change
gear lathe. — Prentice Brother's Company and their 16-inch engine
lathe. — The Blaisdell 18-inch engine lathe. — The New Haven
21-inch engine lathe. — Two lathe patents by the Author. — The
Hendey-Norton lathes. — Who were the pioneers in quick change
gear devices? — The Hendey-Norton 24-inch engine lathe. — The
Lodge & Shipley 20-inch engine lathe 286

CHAPTER XVI

ENGINE LATHES CONTINUED

Schumacher & Boye's 20-inch instantaneous change-gear engine lathe.

— Emmes change-gear device. — 32-inch swing engine lathe. —
Le Blond engine lathes. — 24-inch swing lathe. — The Le Blond
lathe apron. — Complete drawing of a front elevation. — The
Bradford Machine Tool Company's 16-inch swing engine lathe. —
The American Tool Works Company's 20-inch engine lathe. —
The Springfield Machine Tool Company's 16-inch engine lathe.

— The Hamilton Machine Tool Company's 18-inch engine lathe.

— The W. P. Davis Machine Company's 18-inch engine lathe. —

The Fosdick Machine Tool Company's 16-inch engine lathe . . 307

CHAPTER XVII

' HEAVY LATHES

The Bradford Tool Company's 42-inch triple-geared engine lathes. —
The American Tool Works Company's 42-inch triple-geared engine
lathe. — The New Haven Manufacturing Company's 50-inch triple-
geared engine lathe. — The Niles Tool Works 72-inch triple-geared
engine lathe. — The Pond Machine Tool Company's 84-inch engine
lathe 327

CHAPTER XVIII

HIGH-SPEED LATHES

Prentice Brothers Company's new high speed, geared head lathe. — A
detailed description of its special features. — R. K. Le Blond
roughing lathe. — Lodge & Shipley's patent head lathe. — The
prime requisites of a good lathe head. — Description of the lathe
in detail. — The capacity of the lathe. — A 24-inch special turning
lathe built by the F. E. Reed Company. — A two-part head-stock.

— The special rest. — Its two methods of operation. — Its special
countershaft. — The Lo-swing lathe, built by the Fitchburg Ma-

CONTENTS 13

PAGE

chine Tool Works. — Its peculiar design. — A single purpose ma-
chine. — An ideal machine for small work. — Builders who have
the courage of their conviction 338

CHAPTER XIX

SPECIAL LATHES

The F. E. Reed turret head chucking lathe. — Its special features. —
A useful turning rest. — The Springfield Machine Tool Company's
shaft turning lathe. — The three-tool shafting rest. — The driv-
ing mechanism. — Lubrication of the work. — The principal dimen-
sions. — Fay & Scott's extension gap lathe. — Details of its
design. McCabe's double-spindle lathe. — Its general features. —
Its various sizes. — Pulley-turning lathe built by the New Haven
Manufacturing Company. — A special crowning device. — Its
general design. — A defect in design. — The omission of a valu-
able feature. — Pulley-turning lathe built by the Niles Tool Works.
— A pulley-turning machine. — Its general construction. — Turn-
ing angular work. — Convenience of a bench lathe. — The Waltham
Machine Company's bench lathe. — A grinding and a milling
machine attachment. — Devising a special attachment. — Reed's
10-inch wood-turning lathe. — Special features of design. —
Popularity and endurance. — The countershaft. — Inverted V's . . 353

CHAPTER XX

REGULAR TURRET LATHES

Importance of the turret lathe. — Its sphere of usefulness. — Classi-
fication of turret lathes. — Special turret lathes. — The monitor
lathes. — The Jones & Lamson flat turret lathe. — Its general
design and construction. — Its special features. — Its tool. —
The Warner & Swasey 24-inch universal turret lathe. — General
description. — Its capacity. — Taper turning attachment. — Its
speeds. — The Bullard Machine Tool Company's 26-inch com-
plete turret lathe. — Its massive form and its general design and
construction. — Lubrication of tools. — The countershaft. — The
Pratt & Whitney 3 by 36 turret lathe. — Its special features. —
Its general design. — Its capacity. — Special chuck construction
and operation. — The Gisholt turret lathe. — Its massive design
and construction. — Its large capacity. — Its general and special
features. — The .Pond rigid turret lathe. — Its heavy and sym-
metrical design. — Detailed description. — Its operation. — Gen-
eral dimensions .» . 370

CHAPTER XXI

SPECIAL TURRET LATHES

The R. K. Le Blond triple-geared turret lathe. — The Springfield Ma-
chine Tool Company's 24-inch engine lathe with a turret on the

14 CONTENTS

PAGE

bed. — Turret lathe for brass work built by the Dreses Machine
Tool Company. — Special features and construction. — A combi-
nation turret lathe built by the R. K. Le Blond Machine Tool
Company. — A useful machine with many good features. — A
15-inch swing brass forming lathe built by the Dreses Machine
Tool Company. — Le Blond Machine Tool Company's plain turret
lathe. — Plainness and simplicity its strongest points. — The
Springfield Machine Tool Company's hand turret lathe. — A
modification of their 18-inch swing engine lathe. — The Pratt &
Whitney monitor lathe or turret head chucking lathe .... 391

CHAPTER XXII

ELECTRICALLY DRIVEN LATHES

System of electric drives. — Principal advantages of driving lathes by
electricity. — Group drive versus individual motor system. —
Individual motor drives preferable for medium and large sized
lathes. — The Reed 16-inch motor-driven lathe. — The Lodge &
Shipley 24-inch motor-driven lathe. — The Prentice Brothers
Company's motor-driven lathes. — General description. — Crocker-
Wheeler motors. — Renold silent chain. — The Hendey-Norton
lathe with elevated electric motor drive. — Special features. — A
50-inch swing lathe with electric motor drive designed by the
Author. — Detailed description. — Practical usefulness. — Not
strikingly original, but successful 405

CHAPTER XXIII

PRACTICAL INSTRUCTIONS ON LATHE OPERATION

Setting up a lathe. — Placing the lathe. — Plan of small shop. — Line
shaft size and speed. — Power needed to drive lathes. — Leveling
lathe. — Lubrication of lathe parts. — When to oil. — Attaching
face plate or chuck. — Lathe parts and their functions. — Head-
stock. — Tail-stock. — Carriage.— Automatic apron. — Reverse gear. —
Compound Rest. — Starting the lathe. — Operating levers. — Simple
lathe accessories. — Spur and screw centers. — Drill pads. — Turning
a steel shaft. — Drilling in the lathe. — Taper attachment for
lathes. — Milling in the lathe. — South Bend attachment. — Barnes
attachment.— Motor driven attachment.— Knurling on the lathe.—
Indicators and their use. — Boring bar construction and use. —
Adjustable boring bars. — Boring bars for heavy work. — Methods
of holding work. — Special chuck for gas engine pistons. — In-
creasing swing of lathe. — Lathes for heavy work. — Grinding at-
tachments. — Machining concave and convex surfaces. — Grooving
oil ducts. — Combination lathe dogs and their use. — Hacksaw
attachment for lathes 417

INDEX 461

INTRODUCTION

IN the great measure of success that has been enjoyed, and the
vast volume of wealth that has been produced in this, the most
industrial of all countries, the manufacturing industries easily lead
all other productive interests in which the people are engaged.
While in the earlier years of American independence the chief
dependence was upon the results of agriculture, the development
of the resources of the country in time has placed manufactures
at the head of the list so that in very recent years the value
of manufactures has been nearly double the amounts of that
produced by agricultural pursuits.

These results, like many others of a less notable character,
commenced from small beginnings, and it has been by inborn
mechanical talent, remarkable ingenuity, patient development,
and tireless energy, that mechanical undertakings large and srriall
have been developed, until the American mechanic leads the world
in originality and practical achievement in our vast manufactur-
ing enterprises.

When the early settlers, the Puritans of New England, labored
under the restrictive and harassing laws of the mother-country,
and under their administration were goaded and exasperated
beyond endurance in many ways, not the least of which was being
obliged to purhase all their manufactured articles from England
at extortionate prices, or from other countries and still paying
taxes to England, they rebelled and determining to buy no more
foreign goods, set out, at first in very primitive and clumsy ways,
to make such articles as were really necessary, and in magnificent
self-denial to get along without those which they could not pro-
duce, they little realized that they were thus laying the founda-
tions of the greatest manufacturing country in the world.

By their action they thus instituted probably the first industrial
"boycott" in the history of the country, and one that has had

'INTRODUCTION

more important anU far-reaching influences than any since its
day.

It is true that the coming of the Pilgrims, their departure
from the old country, was for religious freedom, but freedom soon
meant vastly more to them than this, and with this larger concep-
tion of their opportunities, some of which were really forced upon
them by adverse circumstances, came the inspiration of industrial
as well as religious freedom. And the determined manner in
which they set about their self-appointed task has amply demon-
strated to their posterity and to the world their grasp of the pos-
sibilities and conditions of the situation as well as their breadth
and nobility of character.

Thus sprang American manufactures into being, beginning
with crude efforts to fashion those common objects of household
necessity and daily use, which, clumsy though they were, yet
served their practical purposes, to be supplanted later on by those
more improved in form, design, and workmanship and better
adapted to the uses for which they were made. The primitive
successes of these early efforts led to greater endeavors, and the
ingenuity displayed where " necessity was the mother of inven-
tion" was naturally developed into a still broader usefulness when
the time came that necessities having been reasonably provided
for, luxuries were thought necessary in the higher plane of living
to which the people in due course had advanced.

And so it came about that the rude and crude beginnings in
which the early mechanic performed his work in his own house
outgrew these homely facilities and he built small shops, frequently
in the gardens or back yards of the dwellings. These gradually
enlarged; then came the necessity for still greater facilities, and
buildings were erected quite independent of the home surround-
ings and two or more men were associated as manufacturers, and
these became in due course of time the machine shops and the
factories, which have multiplied many hundreds of times, not only
in numbers and in value, but in influence and in importance, until
to-day our country stands the leading manufacturing nation of
the earth. And this may be said, not only as to the volume and
the value of her manufactured productions, but also as to their
great range and diversity of kind and degree. One after another

INTRODUCTION 17

the American mechanic has taken up the work formerly monopo-
lized by this country or that, failing perhaps at first, but always
progressing, always advancing, until by native ingenuity and tire-
less energy all obstacles have been surmounted, all difficulties
brushed aside, new industries spring into being and other "vic-
tories of peace greater than the glories of war" are added to the
credit of the American mechanic and his ever ready and ever con-
fident partner, the American manufacturer and capitalist. And
to this combination, each confident of and faithful to the abilities
of the other, and each in his own sphere of usefulness, is due the
immense success of the manufacturing American of to-day.

In the early stages of manufacturing in this country all the
tools and appliances were of a very crude and primitive kind and
consisted mainly of a limited number of hand tools that had been
brought with them from the old country, and occasionally a hand
lathe of moderate dimensions, operated by foot-power. Yet with
even these few facilities much important work was accomplished
in the way of useful machines such as the flax and woolen spinning
wheels and their accessories, and the wooden looms in which the
yarn thus prepared was woven into the coarse but excellent cloth
of these early times.

Then with the few tools and meager facilities possessed by them
these old-time mechanics proceeded with practical common sense,
ingenuity, and patience to design and construct other tools and
machines such as by the necessities of occasion was manifest, and the
increasing demands for them required better tools, better machin-
ery, and facilities of a wider scope. The mechanic was then, as
now, equal to the emergencies of the situation in which he found
himself, and from small beginnings, and many of the parts of his
machines made of wood, for lack of forge and foundry facilities,
particularly the latter, has developed the machine tools of the
present day.

The lack of facilities for making iron castings was very early
felt, and history tells us that as early as the year 1643 John Winthrop
arrived in this country from England, bringing with him the neces-
sary number of skilled workmen for this purpose, and built a small
iron foundry in Lynn, Mass.; and the fact that the first casting

18 INTRODUCTION

produced was "a small iron pot holding about a quart " shows
that the foundry was of very moderate capacity, and it is very
likely that the blast used in melting the iron was produced by a
hand bellows, as the blacksmith forge had preceded the foundry
here, as it did, probably, in all other countries. The quart pot was
cast from iron "made from native ore," although we do not know
where they obtained it; probably from some place in the vicinity
where it was found in small quantities. From this small begin-
ning there was very little progress made for a considerable time
in enlarging either the original scope of the work or in increasing
its facilities, so far as we have any record. In 1735, nearly one
hundred years later, we know that an iron foundry was built in the
little town of Carver, Mass., and that a second one was put up in
the same town in 1760, although we do not know the reason for
this second one coming into existence in the same town unless it
was that the first one had been destroyed by fire. However, it
was in this second foundry that the historic " Massachusetts Tea-
kettle" was cast. We do know that still another foundry was
built in this town in 1793 and that this was burned down in 1841.
Thus early did the custom begin, which is still in vogue in eastern
Massachusetts, of devoting the energy of a town to one line of
manufacture.

While these events and evidences of mechanical progress were
taking place, the active minds of ingenious workmen were busily
engaged in solving the practical problems of the growing demands
made upon the shops and embryo manufactories engaged in supply-
ing the wants of the people. New methods of manufacture, by
which the quality as well as the quantity turned out could be im-
proved, were demanded. This led to the demand for more machin-
ery, which in turn led to the demand for better machines for the
use of the mechanic, or for what we have come to know as machine
tools. In the meantime the main reliance had been upon the an-
cient foot lathe, and with it much of their mechanical work had
been accomplished. It had been improved in various ways, both
in its design and in the materials of which it was constructed, and
with the use of water-power for driving the machinery for manu-
facturing operations the lathe had become of greater usefulness
by being driven in the same manner. Yet from the first it main-

INTRODUCTION 19

tained its prominence as the first of the machine tools and the one
which made all of the others that came after it possible of con-
struction and useful in their several and respective spheres.

In the great scheme of manufacturing and the immense indus-
trial problem of supplying the wants of the people in this respect
by modern manufacturing plants equipped with all that is latest
and best in machinery, it should be said that at the very basis and
foundation of the whole stand the modern machine tools; that
it is to the great and important development of these that we owe,
primarily, our industrial prosperity as a nation. And to them
may be easily traced the gradual upward tendency of the mechanic
from the hard physical toil and laborious work of early days to
the immeasurably lighter exertions made possible by the highly
developed condition of the automatic machines of the present day.
It has been, as was said in the outset, a victory of mind over matter,
wherein brains have won where the hands made little advance;
ideas developed wonderful mechanisms that have revolutionized
the earlier methods of manufacturing, raised the standard of
mechanical excellence beyond what was thought possible years
ago, and at the same time reduced the cost to a fraction of its
former amount. But to attain these marvelous results many
machines have been required. All conceivable types and styles,
and for an almost endless variety of purposes, have been de-
signed, built, and perfected until hardly a possible mechanical
operation is performed without the aid of a machine, frequently
special in its design and automatic in its action, is brought into
use, performing the work with surprising speed and wonderful
accuracy.

The construction and perfection of all this magnificent array
of highly developed machinery has only been made possible through
the use of the machines for the use of the machinist, the machine
tools of the present day, which must first have been perfected and
adapted to the many needs and requirements which the advanced
state of mechanical science demanded. These machine tools were
made possible by the earlier examples of the most simple devices
in this direction, chiefly, in our own time, the foot lathe, by which
many of the earlier tools and machines were for the most part
built; and as new uses for it were found new devices, attach-

20 INTRODUCTION

ments, and accessories were devised and applied, and in this
gradual development and improvement in its design, its con-
struction, and the materials of which it is built, the early and
crude foot lathe has become the magnificent machine of the
present day, and in which the American mechanic takes a just
and pardonable pride.

As to how this development progressed will be discussed in the
opening chapters, and it is hoped that it will be found interesting
to every American mechanic and particularly to the apprentice
who is about to start out with learning the honorable trade of a
machinist, and the student who would know from whence our
modern machine tools were derived, that he may perhaps, in due
time, become one of those who shall aid in their further develop-
ment and perfection, as well as to the elder mechanic who uses
these machines, and the mechanical engineer who is busy with their
present development. It is always profitable to take a retrospec-
tive glance at the former state and condition of the matter upon
which we are engaged, in order that we may not only realize from
whence came the models built by the men who came before us,
and to draw therefrom an inspiration for our own best efforts, but
knowing the mistakes that have been made by others, to seek to
avoid repeating them in our own experiences, our experiments and
our designs by which we seek to add to the sum total of mechanical
knowledge and improvement.

CHAPTER I

HISTORY OF THE LATHE UP TO THE INTRODUCTION OF SCREW THREADS

Tracing early history. The lathe was the first machine tool. The origin
of the lathe. An old definition of turning. The first record of turn-
ing operations. Another old-time definition of turning. English
classification of lathes. The earliest form of the lathe proper, or the
old "Tree Lathe." The Asiatic wood turner. The "Springpole"
lathe. The "Fiddle-bow" lathe. The essential features of a lathe.
The balance-wheel applied to a lathe. The crank, connecting rod and
treadle applied to a lathe. Origin of the term "Pitman." Afoot
lathe built by the Author. Its detailed construction. A foot lathe
with the balance-wheel located over-head. The friction clutch for
foot-power machines.

THE subject of the present work being the lathe and its work,
and more particularly its design, construction, and develop-
ment in our own country and in recent years, and as briefly com-
prised in our title of Modern American Lathe Practice, our
efforts will be directed, first, to a brief notice of its origin and early
development and use as a simple hand lathe; second, to its more
modern development as one of the most important machine tools
in the equipment of machine shops; and, third, to the various
modifications of it, following its development through all its vari-
ous forms and for the diversity of manufacturing purposes to which
it has been adapted up to its present degree of efficiency.

In considering a subject of the vast importance of the modern
lathe and its far-reaching influence upon the mechanical world
of to-day, it cannot but be interesting to go back to its early his-
tory and to trace its progress and development from as far back
as we have any authentic knowledge, and step by step to note the
changes in its form and usefulness as the mind of the early mechanic
developed, new requirements manifested themselves, and improve-
ments in design, construction, tools, and attachments were devised
to meet the growing needs.

22 MODERN LATHE PRACTICE

It is conceded that of all the machines employed by the me-
chanic to aid him in his work the lathe holds the honor of having
been the first machine tool, From it, in one way or another, all
other machine tools have been developed; as they are, practically
considered, but modifications of it, or special tools for doing quicker
and better, the several operations which may be, and formerly were,
performed upon the lathe, as we shall later on have occasion to
describe and illustrate.

At present we will look into the origin of the lathe and then
trace its gradual evolution and development up to comparatively
recent years, say an hundred years or so ago, as their development
into anything like mechanical importance has been confined to
the last century which has been so remarkable in this respect.

Upon referring to the older records on the subject of lathes
and their uses we find this statement: " Turning is the art of
shaping wood, metal, ivory, or other hard substances into forms
having a curved (generally circular or oval) transverse section,
and also of engraving figures composed of curved lines upon a
smooth surface, by means of a machine called a turning-lathe.
This art is of great importance and extensive application in me-
chanics, the most delicate articles of luxury and ornament, equally
with the most ponderous machinery, being produced by it. The
art of turning dates from a very early period, and Theodorus of
Samos, about 560 B.C., is named by Pliny as its inventor; but long
before this period, the potter's wheel, the earliest and simplest form
of turning-machine, was in general use, as is evidenced by numer-
ous references in Holy Writ."

Again we read in an old-time definition of what turning really
consists of: "The immense variety of work performed by turning-
machines necessitates great variations in their construction; but
mode of operation is always the same, and consists essentially in
fixing the work in position by two pivots, or otherwise, causing
it to revolve freely around an axis of revolution, of which the
two pivots are the poles, and holding a chisel or other cutting-tool
so as to meet it during its revolution, taking care that the cutting-
tool be held firmly and steadily, and moved about to different parts
of the work till the required shape is obtained."

In England the various methods of driving a lathe gives a

HISTORY OF THE LATHE

classification to them somewhat different from that in this country.
Hence the following: " Lathes are divided, with respect to the
mode of setting them in motion, into pole lathes, foot lathes, hand-
wheel lathes, and power lathes; and with respect to the species of
work they have to perform, into center lathes, which form the
outside surface, and spindle, mandrel, or chuck lathes, which per-
form hollow or inside work, though this distinction is for the most
part useless, as all lathes of good construction are now fitted for
both kinds of work." Another peculiarly English idea in refer-
ence to lathes is this: "Bed lathes are those used by turners in
wood, and bar lathes for the best sort of metal work; and the small
metal center lathe employed by watchmakers is known as a turn-
bench."

The earliest form of a lathe proper, that is, "a machine for
shaping wood into forms having a curved, and generally a circular
transverse section, by the
action of a chisel or other
cutting tool upon the piece,
which is rotated for the pur-
pose," is shown in the en-
graving Fig. 1, and consists,
as will be seen, of two pointed
pieces A, A of wood serving
as centers and each bound to
a tree, and supporting the
ends of the piece C to be
turned, while on the opposite
side of the tree is fixed in
the same manner a straight
piece of wood B, which acts
as a rest for the chisel or
other tool with which the
turning or cutting is to be done. The power for rotating the
piece C to be turned is obtained by attaching a cord D to a flexi-
ble limb of the tree, passing it one or more turns around the piece
and forming in its lower end a loop for the foot of the operator,,
who rotates the piece towards himself by depressing the foot,
bending down the limb by the. movement, which, when he. raises

FIG. 1. — The Old Tree Lathe

24 MODERN LATHE PRACTICE

his foot, returns to its original position, rotating the piece back-
wards in readiness for another pressure or downward stroke of
the foot. The work was slow and laborious, yet from old samples
of the pieces thus produced we may see that an extraordinary
good quality of work could be done, particularly considering the
primitive methods used.

We read that:

" Wood-turners in some of the Asiatic countries go into the
deep forests with axes, and with a few rude turning tools and
hair ropes build their lathes and turn out objects of beauty and
grace, says the Wood Worker. Two trees are selected which stand
the proper distance apart near a springy sapling. With his ax
the turner cuts out his centers and drives them opposite each
other into the trees, which serve as standards. From one tree
to the other he places a stick of wood for a tool-rest. With his
ax he trims the branches from the sapling, fastens his hair rope
to the little tree, gives the rope a turn around one end of the
block of wood he desires to turn into shape, and fastens the free
end of the rope to a stick which he uses as a foot treadle. When
he presses down on the treadle the wood he is turning revolves,
and the spring of the sapling lifts the treadle so that it can be
used again."

The next form of lathe to which these crude efforts seem to
have led was one in which the flexible limb, though in another
form, was used, but the device became very nearly a self-contained
machine. A piece of wood formed a bed for the lathe and to this
was fixed the blocks forming the centers, which have since become
the head and tail stocks of the lathe. The machine appears to
have been used in doors, as the flexible limb of the tree had been
replaced by a flexible strip or pole, " fastened overhead" and called
a "lath" from which circumstance some writers think that the
name "lathe" was derived. The driving cord was still wound
around the piece to be turned. No mention is made of the method
of supporting the tool, but it is probable that a strip of wood was
fastened to the "bed" for that purpose.

The next improvement in developing the lathe brings its form
within the memory of the older mechanics and is shown in Fig. 2.
In this case there is a rude form of head-stock B, and tail-stock E;

HISTORY OF THE LATHE

both constructed at first of wood, and the tail-stock continuing
to be so constructed for many years. In this form of lathe the
head spindle is first found, having in the earlier examples a plain
" spool" around which the driving cord D was wound, and later
on a cone pulley constructed as shown in Fig. 3, by which a faster
speed was possible with the same movement of the foot. The
lower end of the driving cord was fastened to a strip of wood F,
the farther end of which was pivoted to the rear leg, in the later
examples of the " spring-pole lathe," as it was then called, the
bed having been mounted upon legs as shown.

The bed A, was formed of two pieces of timber set on edge and

FIG. 2. — The " Spring-Pole " Lathe.

a short distance apart, properly secured at the ends. This afforded
a space down through which passed a long tennon formed upon a
wooden block answering for a tail-stock E. This was held in any
desired position by a wooden key, passing through it under the bed.

What was the early form of rests for this lathe does not seem to
be known, but somewhat later the rest was constructed of cast iron
and very much as in an ordinary hand lathe of the pattern-maker
or wood-turner of the present day, and as shown in Fig. 2.

This lathe was used for both wood and metal, the tools being
held in the hand as the slide rest had not yet been invented, as
will be seen later on in this chapter.

In the use of the spring pole and cord in connection with the

MODERN LATHE PRACTICE

cone pulley, as shown in Fig. 3, some workman discovered, prob-
ably by turning a heavy piece, that its forward motion would con-
tinue when the foot was raised, provided the tool was withdrawn
from contact with the work. It was but natural to make the cone
pulley of heavier material, as of cast iron, or to weight it with
pieces of iron or with lead plugs cast into it, and thus make it serve
the office of a balance-wheel and so keep up the forward revolution
of the work as long as it was given the proper impetus by the down-
ward strokes of the foot.

Another style of lathe that was used mostly for small work,
generally metal work, was called a " fiddle-bow lathe," on account
of the method of driving it. In this lathe, which is shown in Fig. 4,

FIG. 4. — The " Fiddle-Bow" Lathe.

the same idea of propulsion is used as in the former examples, that
of a cord passing around either the piece to be turned or a rotating
part of the mechanism by which the piece was revolved. In this
case, however, instead of the resistance of the flexible limb of a
tree or of a " spring pole" acting to keep the driving cord taut,
it is held in that condition by the flexible bow F, which is bent to
the form shown by the driving cord D. The engraving is an exact
reproduction of a lathe, the bed A of which was about twelve

HISTORY OF THE LATHE 27

inches long and it had a capacity of about two inches swing, that
was made by an older brother for the use of the author when he
was nine years old, and in the use of which he became quite a
boyish expert in turning wood and metals. The head-stock B,
and rest C, were formed of bent pieces of wrought iron, and the
"spur center" was formed upon the main spindle, the point being
used as a center for metal work.

Lathes driven in this manner are still in use by watchmakers
and jewelers and a great deal of very fine hand work is performed
with them.

The main features in all these lathes were, first, to suspend
the work to be done, or the piece to be operated upon, between
two fixed pivots or centers; second, to revolve it by means of a
cord wrapped around it, or some part of the machine fixed to it,
and kept tightly strained by means of some kind of a spring, as
an elastic piece of wood; and third, to reduce the piece to be oper-
ated upon by means of a tool having a cutting edge which was
held tightly against the material to be operated upon, thus reduc-
ing it to the circular form required; fourth, that to accomplish
this it was necessary to revolve the piece to be operated upon,
first towards the cutting tool for a certain number of revolutions,
then by a reverse motion of the taut cord to reverse the circular
motion, at the same time withdrawing the cutting-tool for an
equal number of revolutions. By this method one half the time
was lost, as no cutting could be done while the work was running
backward.

It was later found that if the flexible pole or "lath" was rather
weak and the piece of work to be operated upon was quite heavy,
acting as a balance-wheel, its forward revolution was not wholly
arrested, but only checked as the foot was raised, provided the
cutting-tool was withdrawn from contact with the work a moment
before the upward motion of the foot began.

By this it was seen that great advantages might be gained if
the lathe could be made to not only revolve continuously in the
direction of the tool, but also with the same force, whereby the
tool might be kept in constant contact with the work.

Already the pulley, as applied to the spindle of the lathe, was
known. The cord wrapped around it and used to rotate it was

28 MODERN LATHE PRACTICE

known. Doubtless an assistant had furnished the power to drive
the lathe while the mechanic handled the tools. What would be
more natural than the arrangement of a large wheel, journaled to
a suitable support at the front or rear of the lathe, and having the
cord connected with it as a driver. And with this device and the
problem of revolving it by hand, a handle set between its center
and circumference would be natural also, and thus came the crank.
We do know that somewhat later than this machines were driven
in exactly this manner, the large wheel being constructed with
a heavy rim and acting as a balance-wheel.

At this stage of development the large driving-wheel was rather
an attachment than a part of the machine itself, and doubtless so
remained for a considerable time. The next change was to locate
it beneath the lathe bed, directly under the head-stock, and in-
stead of the use of the handle forming practically a crank of long
leverage it was constructed as it is in the sewing-machines of the
present day; that is, the wheel journaled upon a fixed stud and
the previous long handle reduced to a wrist-pin for the attach-
ment of a connecting rod, or in the older phrase a " pitman," which
term was given to one of the men handling the vertical saw used
in sawing up logs into timber and planks in the olden times (and
even now in oriental countries), wherein the log was supported
over a trench or pit, the upper end of the saw being handled by
the "topman" and the lower end by the " pitman" or man in the
pit. When these saws were later on mounted in a rectangular
frame or "gate" having a vertical, reciprocating movement and
operated from a crank-shaft by a connecting rod from the one to
the other, this rod took the name of the former man who performed
this office, hence the term "pitman."

The location of this pitman or connecting rod, as has been said,
was directly under the head-stock and well within the convenient
reach of the operator when attached to a suitable "treadle" whose
rear end was pivoted to the back of the machine and whose front end
formed a resting-place for the operator's foot. This arrangement
answered very well and was useful when the work of the lathe was
near the head-stock, but was not adapted to long work, to accomplish
which the operator would need to stand near the tail-stock or even
midway between that and the head-stock. To remedy this defect

HISTORY OF THE LATHE 29

a strip of wood was hinged to the front leg of the lathe at the tail-
stock end and its opposite end to the front end of the treadle. This
was of considerable use, its principal drawback being that while
at the treadle end its vertical movement was the same as the latter,
this movement was gradually lessened until at the tail-stock end
of the lathe it was nothing. Hence, much more power was required
to drive the lathe at its center than at the head-stock, and this was
rapidly increased as the work was nearer the tail-stock end of the
lathe.

To remedy this defect the large driving-wheel was mounted
upon and fixed to a revolving shaft upon which was formed two
cranks, one near the wheel and the other at the tail-stock end of
the lathe. This shaft was properly journaled in boxes formed
upon or attached to cross-bars fixed to the legs at each end of the
lathe. From these cranks hung two connecting rods whose lower
ends were pivoted to two levers pivoted to the rear side of the
lathe, and whose front ends were connected by a wooden strip or
" foot-board." The length of these levers was such that the move-
ment of the foot-board was about twice the " throw" of the cranks,
so that with a foot movement of twelve inches the two cranks
were about three inches, center of shaft to center of connecting
rod bearing.

This was then and for many years the prevailing form of foot
lathes and was quite extensively used, not only for turning wood
but for iron, steel, and other metals as well.

There were many of the older mechanics who would work the
entire day through. At that time a day's work was not eight, nine,
or ten hours, but "from sun to sun," or from daylight till sunset,
day after day, treading one of these foot lathes and turning out
a much larger quantity of work than these crude facilities would
seem to render possible.

In Fig. 5 is shown this form of foot lathe that was in use for
many years for turning both wood and metals. The illustration
is a drawing of a lathe built by the author when he was between
fifteen and sixteen years of age. The bed A, legs B, the cross-bars
C, C, the back brace D, and treadle parts E, F, were built of wood,
as was also the tail-block G, which was of the form shown in Fig. 4,
except that beneath the screw forming the tail center was a wooden

MODERN LATHE PRACTICE

key g, for keeping this screw always tight, as there was a tendency,
from strain and vibration, for the screw to work loose.

The tool-rest was of the usual form, except that instead of a
wedge, in connection with the binder H, to hold it in position, or
the use of a wrench on the holding-down bolt, an eccentric of hard
wood with a handle formed upon it, as shown at J, was used. This
was the first occasion where the author saw an eccentric used for
a similar purpose. It worked so well that he fitted similar eccentrics
to the stops of the three windows in his little workshop to hold
the sashes in any desired position when they were raised, and by

FIG. 5. — Foot Lathe for Turning Wood or Metals.

a turn in the opposite direction to secure them when they were
closed.

The large wheel was of cast iron, rescued from a scrap heap,
and had only the grooves for the two faster speeds K, L, the part
M being made of wood and fastened to the arms of the wheel. A
friendly blacksmith forged the cranks in the shaft N, and the eyes
in the lower ends and hooks in the upper ends of the connecting
rods P, P. These were first made of wood similar to the connect-
ing rods on a sewing-machine with a closed bearing at the top, but
the tendency to pinch one's toes under the treadle when they
happened to be accidentally placed in this dangerous position soon

HISTORY OF THE LATHE 31

led to the iron connecting rods with the hooked ends whereby the
worst that could happen was the connecting rods becoming un-
hooked. The shaft N rested in wooden boxes, the lower half being
formed in the cross-bars C, C, and a wooden cap held down by two
wood screws forming the top half. The bearings of the shaft and
the cranks were filed as nearly round as they could be made by
hand with the means and ability available.

The pattern for the head-stock was made as shown in side ele-
vation in Fig. 5, with the housings for the spindle boxes as shown
in Fig. 6. The boxes were made in halves, of babbitt metal and
cast in place in the head-stock in this manner.
The head spindle was located in place and held
by a thin piece of wood clamped on the inside
and outside of the housing and having semicir-
cular notches in their upper edges and a slight
recess on their inner sides so as to provide for

making the box slightly thicker than the hous-

inv FIG. 6. — Spindle-

The lower halves of the boxes, having been
cast slightly higher than the center of the spindle bearings, were
removed and filed down to the proper level and then replaced, the
spindle again laid in, the strips of wood clamped on in an inverted
position and the top half of the box cast. This part projected
slightly above the top of the iron casting and was held down by
an iron cap having two holes drilled in it which fitted on the
threaded studs R, R, which had been cast into the head-stock
for this purpose. The spindle had been turned up in an old-style
chain-feed lathe, of which more will be said later on. The cone
pulley S was of cherry, simply driven on tightly and turned up to
the form shown.

The front end of the spindles was threaded but not bored out.
Upon this thread was cast a babbitt metal bushing T, having a
square hole in its front end, which was formed as follows: With
the spindle in its place a wooden mold of proper form was placed
around it and, while it fitted the collar on the spindle at one end,
was open at its front end. A tapering, square piece of iron of
proper dimensions to form the square hole was placed with its
small end against the nose of the spindle and held in that position

32 MODERN LATHE PRACTICE

by the tail screw. The opening around it was closed by a piece
of wood of proper form and the job was " poured," and the bushing
afterwards turned up with a hand tool. Into this square hole
could be fitted proper centers for turning wood or metal, and by
removing the babbitt metal collar a face-plate could be put on for
face-plate work.

It will be noticed that the lathe had been arranged for two
speeds proper for turning wood and the softer metals, and one speed
considerably slower for iron. A piece of belting was provided
which could be easily removed to shorten the belt the proper
amount for this purpose.

The lathe would swing eight inches and take in between centers
four feet. It was found that the round belt did not give sufficient
driving power and a new spindle cone of only two steps was put
on, the iron balance-wheel lagged up for a flat belt, and the pulley
M turned down for the same purpose. This permitted the use
of a belt an inch and three-quarters wide, and as no regular belting
was available when the job was done an old trace from a harness
suffering from general debility was ripped open and a single thick-
ness of the leather soaked up in water, dried out, treated with
neat's-foot oil and used with such good results that it was never
replaced.

To this lathe was fitted a small circular saw provided with an
adjustable, tilting table upon which not only wood but sheet brass
could be cut. Another attachment was a small jig-saw that would
cut off wood up to half an inch thick.

One of the disadvantages of the usual form of foot-power
lathe was the short connecting rod or pitman which thereby formed
too great an angle to the center line from the wheel center to the
point of attachment to the treadle, thereby increasing the friction
and decreasing the useful effect of the foot-power. It was appar-
ently to avoid this condition that a somewhat peculiar form of
lathe was devised and built in the railroad shops at Plattsburgh,
N. Y., about 1860, and which is shown in end elevation in Fig. 7.
This was an engine lathe of about fourteen-inch swing, built with
cast iron bed A, legs B, and all the parts of metal that are now so
constructed. Instead of placing the large driving or balance wheel
beneath the lathe bed as formerly, the lathe was belted from a

HISTORY OF THE LATHE

cone pulley of three steps^on an overhead countershaft C, provided
with the usual hangers D. This countershaft was of a length equal
to the length of the lathe and had fixed at the end over the head
of the lathe a heavy wheel E, into the hub of which was fixed a
stud or wrist-pin F, while on the opposite end of the countershaft
was fixed a disc for carrying a similar stud. These formed two
cranks to which were fitted long connecting rods G, the lower ends
of which were pivoted to the treadles H, whose rear ends were
pivoted to the legs B, as at J. The treadles
H are located outside of the legs B, and
connected by the foot-board K. The
weight of the connecting rods G, the tread-
les H, and the foot-board K are balanced
by the proper counterbalance added to the
fly-wheel E, as shown. The author knows
from personal observation that this lathe
would run very steadily and with a good
deal of power, and that its general perform-
ance was much better than foot lathes of
the usual type. Doubtless the momentum
of the balance-wheel, cone pulley, and
countershaft was very beneficial in main-
taining an equable speed under varying
conditions of resistance from the operation
of cutting-tools and the like, while the cast
iron cone pulley on the main spindle did
some service in the same direction.

The only disadvantage in this lathe was
that it required too long a time to get it
up to its regular speed and necessarily too
much time was consumed in stopping it, as
there was no provision for disconnecting the

main spindle from the driving-cone by a clutch mechanism or
similar device, as is frequently the case with special forms of the
lathes of recent design.

There has been manufactured for some years a special
type of friction clutch that is very useful in driving foot-power
machinery. It consists essentially of a drum mounted upon and

FIG. 7. — Foot Lathe,
Driven from a Coun-
tershaft.

34 MODERN LATHE PRACTICE

loosely revolving around the shaft to be driven, and having a friction,
clutch mechanism contained within it and so operating that the
drum will turn freely in one direction but the moment it is revolved
in the opposite direction the friction device comes into operation,
the drum is firmly clamped to the shaft, which is thus caused to
rotate with it. To this drum is attached one end of a flat leather
belt, which is wrapped around it several times and its free end
attached to the movable end of a treadle, which is usually hinged
at the front instead of the back of the machine. In operation the
pressure of the foot acting on the drum by means of the belt
rotates it in the forward direction, which causes its friction mechan-
ism to act and revolve the shaft through as many revolutions as
there are convolutions of the flat belt around the drum. The
rotary motion thus set up is continued by the momentum of a
balance-wheel, and as the foot is raised the treadle is caused to
follow it, either by the action of a spring similar to a clock spring
within the revolving drum, or a spiral spring acting upon another
strap, also wrapped around the drum, but in the opposite direction
to the one attached to the treadle. By this device several revolu-
tions of the driving-shaft could be produced at each depression
of the foot, the treadle frequently passing through an arc of thirty
to forty degrees.

This device was particularly applicable to the driving of light
foot-power machinery which it did very successfully, and as the
strokes of the foot need not be of the same length and were not
confined to any certain cadence it was not nearly as fatiguing as
the crank device in which the strokes of the foot were always the
same distance and with the same speed.

In the above described device, however, the balance-wheel was
more necessary and it was also necessary that it should be so
arranged as to revolve with a much higher rate of speed than the
large wheel of the older form of foot lathe. There was one advan-
tage in this condition, however, that in consequence of its higher
speed the balance-wheel could be made of much smaller diameter
and consequently much lighter in weight, and therefore occupying
much less space under the machine.

CHAPTER II

THE DEVELOPMENT OF THE LATHE SINCE THE INTRODUCTION OF

SCREW THREADS

Origin of the screw thread. Ancient boring tools. Suggestions of the screw
form. The "Worm Gimlet." Making the first nuts. An old device
for cutting threads in wood. Archimedes and his helical device for
raising water. Jacques Berson's French lathe. Joseph Moxan's Eng-
lish lathes. The French lathe of 1772. John Maudsley's English lathes.
Maudsley's slide-rest. Another French lathe. The use of a "master
screw." A form of slide-rest. An old-time worm and worm-gear.
Simple method of developing the screw thread. Anthon Robinson's
triple-threaded screw. The many uses of the early lathes. An old
"chain lathe." Its detailed construction. Cutting left-hand threads.
Crown gear and "lantern pinion " for operating the lead screw. Transi-
tion from wooden to iron lathe beds. The Putman lathe of 1836. The
Freeland lathe of 1853. Various classes of lathes to be illustrated and
described.

THE origin of the screw thread, or the threaded screw, reaches
so far back into ancient times that it is impossible to determine
when, where, or by whom it was first conceived or used. That it
was known in one form or another as far back as the use of iron
for tools is altogether probable. Holes must have been made in
wood by some kind of an iron instrument which was the predecessor
of the gimlet. This instrument was most likely square or of some
form nearly approaching that. In order to be at all effective it
must have had sharp corners.

As the straight-edged sharp knife was first accidentally and
then purposely hacked into notches and became the first saw, so
may the corners of the early boring instruments have had notches
formed in them to facilitate their action upon the material to be
bored. These notches may have been gradually deepened for the
same purpose, with the idea that the deeper they were the more
useful they would become. We can very readily conceive that

MODERN LATHE PRACTICE

in making these notches the tool was laid on its side and gradu-
ally revolved as the notches were made, beginning at the point
and working upwards as the tool was revolved. This of itself
would have a natural tendency to produce a semblance of a screw
thread, which would increase the efficiency of the tool by drawing
it into the wood to be bored. When this tendency was noticed
it was also natural to see why it acted in this manner and to in-
crease this action by more carefully making these notches. In
time the "worm gimlet" was undoubtedly evolved.

The form of a screw thread having once been arrived at, the
realization of its usefulness for various purposes was only a ques-
tion of time. It is altogether probable, however, that for the
purpose of holding parts of a machine together, or for similar
mechanical purpose, screws were first made of wood. It is also
pretty certain that they were first made in a very crude form
without much regard to the exactness of the pitch or form of the
thread, although the V-thread would be the most natural because
the most simple form. It is also generally conceded, of course,
that they were made by hand and probably with the rude knives
then used, as hand tools were the only ones in use.

As to the methods used in making the first nuts for use
with the screws, it is probable that they were quite thin as com-
pared with the pitch of the thread, possibly containing but two

or three complete revolutions
of the thread, which was
worked out by sharp-pointed
instruments, as the point of
the knife or by similar means.
This method may have led
to the insertion of a metal
tooth in a wooden screw and
the cutting of the thread in
the nut in this manner. We
do know for a certainty that a somewhat similar means was used
many years later, as the author saw a device such as is represented
in Fig. 8, which was preserved as a curiosity, representing the
early mechanical method of doing this work.

This device consisted of a turned and threaded screw D, of

FIG. 8. — Screw Threading or Tapping
Device for Wood.

DEVELOPMENT OF THE LATHE 37

very hard wood, having one end turned down to a diameter equal
to that at the bottom of the thread, while the opposite end was
made much larger and contained a hole for passing a bar or lever
by means of which it was rotated. At the termination of the thread
and beginning of the smaller straight portion the thread was cut
away, leaving an abrupt termination, and at this point was inserted
a tooth of steel formed in a rough manner to the shape of the
thread.

In a wooden nut A a thread had already been cut, by some
manner unknown, and through this the screw D was fitted. The
piece B, to be tapped or threaded, was clamped to this by means
of the steel clamps E, E, binding the two firmly together. To all
appearances the tooth or cutter d could be set in or out so as to
cut merely a trace of the thread the first time through, then an-
other deeper cut, and finally finished to the full depth. The author
had no means of ascertaining the origin of the device, but the wood
of which it was composed was black with age and the man who
possessed it could not tell how many years his father had owned
it or where he got it. It was certain, however, that both of them
had been mechanics who had made and repaired the old-time
wooden spinning-wheels in which a wooden screw about one inch
in diameter had been used for tightening the round band by which
the twisting mechanism was operated.

Archimedes, the most celebrated of the ancient mathematicians,
certainly had a good idea of the screw thread, as is shown in his
famous screw made of a pipe wound helically around a rotating
cylinder with which he raised water fully two hundred years before
the Christian era. Still it was doubtless a long time after this period
before the screw was constructed so as to be applicable to the uses
of the present day. Of the progress and development of this and
other similar mechanical matters in these early times we have
little authentic information. The development of such simple
machines as the lathe preceded much that was mechanically
important, and to its influence we owe a great deal of the early
advancement in the mechanic arts.

We know that a Frenchman by the name of Jacques Berson,
in 1569, built a lathe that seems to have been capable of cutting
threads on wood. An engraving of his lathe is given in Fig. 9.

MODERN LATHE PRACTICE

As will be seen in this engraving it was a large, clumsy and cum-
bersome affair, considering the work it was designed to perform.
While the various parts of the machine are not very clearly shown,
enough is given to show us that he had a wooden lead screw to
give the pitch of the thread by means of a half nut which appears
to have been fixed in a wooden frame, to which in turn the piece
to be threaded was attached by being journaled or pivoted upon
it. The lead screw and the piece to be threaded were both re-
volved by means of cords wound around spools or drums upon a
shaft overhead, and held taut by weights instead of the flexible
spring pole already described. These cords were fastened to a

FIG. 9. — Berson's French Lathe, built in 1569.

vertically sliding frame, also balanced by cords and weights, and
to which was attached a sort of stirrup adapted to the foot, by
which the machine was operated.

Considering the early time at which this lathe was constructed,
it shows a good deal of ingenuity and may well have been the fore-
runner of the developments in this line which came after it.

It is a matter of record that in 1680 a mechanic by the name
of Joseph Moxan built lathes in England and sold them to other
mechanics, but we do not possess any certain or authentic knowl-
edge of their design, as to whether or not screw threads could be
cut with them or whether they were designed for work on wood
or metals, or both. In all probability they were foot lathes and

DEVELOPMENT OF THE LATHE 39

used on all materials that had been formed in a lathe up to that
time.

In the year 1772 the French encyclopedia contained the illus-
tration of a lathe which was provided with a crude arrangement
of a tool block or device for holding a lathe tool and adapting it to
travel in line with the lathe centers. By this it would seem that
the inventor had some idea of the slide rest as it was known at a
later day by its invention in a practical form by John Maudsley
in England, in the year 1794. Whether Maudsley had seen or
heard of the invention shown in the French encyclopedia or not,
it would seem fair to assume that he must have seen that or some-
thing akin to it, as the twenty-two years elapsing between the one
date and the other must have served to make the earlier invention
comparatively well known in the two nearby countries, both of
which contained, even at this early day, many mechanics. It is
interesting to observe that the slide rest invented by Maudsley
over a hundred years ago has been so little changed by all the
improvements since made in this class of machinery.

There seems to have been an early rivalry between the French
and English mechanics in the development of machines and methods
for advancing the mechanic arts!" The next development of the
screw-cutting idea seems to have been of French origin. In this
lathe there was an arbor upon which threads of different pitches
had been cut. These threads were on short sections of the arbor
and by its use the different pitches required could be cut. While
the exact manner of using this arbor was not described, its
probable method of use will readily suggest itself to the mechanic,
and was, no doubt, used at an earlier period, and in fact was what
led up to the use of a lead screw or arbor with a multiplicity of
different pitches. The principle is analogous to that used in the
"Fox" brass finishing lathe so well known and extensively used,
not only in finishing plain surfaces but in " chasing threads."

This machine is shown in Fig. 10, which is a perspective view
giving all the essential parts of the mechanism. The head-stock
A and tail-stock B are of the usual form in use at the period, and
were mounted upon the wooden bed C in the usual manner. The
piece D to be threaded, and an equal length of lead screw or " master
screw," as it was then called, were placed end to end in the lathe,

40 MODERN LATHE PRACTICE

the outer ends held in the lathe centers, and their inner ends, evi-
dently fixed to each other by a clutch of some kind, were supported
by a kind of center rest F. Fixed to the front of the bed C was a
cast iron supporting bar G, of T-shaped section, extending nearly the
entire length of the lathe bed. Upon the bar G, the top of which
was of dovetail form, was fitted the carriage H, which was adapted
to slide upon it and to support a thread-cutting tool J, and a tool
or " leader" K, which fitted into the thread of the "master screw"
E, and served the same purpose as the lead screw nut of the present
day. Evidently the operation was that by revolving the piece D
the "master screw" E was also rotated, and this rotation of the

FIG. 10. — Thread-Cutting Machine using a "Master Screw."

threaded screw, acting upon the "leader" K, forced the carriage
H forward, causing the thread-cutting tool J to cut a thread upon
the piece D, of a pitch equal to that upon the "master screw" E.
It is probable that no better means of adjusting the thread-cutting
tool J was provided than setting it in by light blows of the hammer.
While the threads thus cut were probably rather poor specimens
of mechanical work, they answered the requirements of the times,
and as usual better means were devised for making them as the
need of better and more accurate work created new demands and
a higher standard of workmanship.

As will be seen in the above example the idea of the slide-rest
is used. In this case some such device was a necessity. Doubtless

DEVELOPMENT OF THE LATHE 41

threads had been cut with some sort of a " chaser," or tool with
notches shaped to the form and pitch of the thread. These were
very extensively used later and for many years in brass work, and
the old-time machinist was very expert in their use. The slide-
rest, as we know it, while it relieved the workman from the fatigue
of holding the tool firmly in his hands and depending entirely
upon them for the position of the tool, with the exception of such
support as the fixed rest gave him, was comparatively slow in
coming into general use. While its usefulness must have been
apparent to the average mechanic, the conservative ideas then in
vogue must have retarded its prompt adoption, as they did many
other meretorious inventions.

By the use of the device shown in Fig, 10, it is plain that a
different " master screw" was needed for each different pitch of
thread to be cut, although the diameter of the work might be any-
thing within the range of the lathe to hold and drive, so that pro-
vision was made for supporting the inner ends of the piece to be
cut and the " master screw," and for driving the latter by the
former. The idea of driving the "master screw " or lead screw at
a different speed from that of the piece to be threaded had not yet
been thought of, and it was years before this development took
place.

But before proceeding to this phase of the development of
thread cutting, and consequently with the further development of
the lathe, let us look a little farther into the methods of generating
threads. That is, of producing the "master screw," from which
other screws might be made.

The author well remembers during his boyhood an old curi-
osity shop out in the country in which various kinds of hand
machines were made and repaired. Among other things made
were various appliances and devices for spinning woolen yarn and
reeling it up into skeins of forty threads to a "knot," as it was
called. To furnish an automatic counter for this reel a worm-
gear of forty teeth was used which engaged with a single threaded
worm on the reel-shaft. Both the shaft having the worm formed
upon it and the worm-wheel were of wood, usually oak or maple,
and the thread was formed by wrapping a piece of paper around
the turned shaft and cutting through this with a knife so as to

42 MODERN LATHE PRACTICE

make its length equal to the circumference of the shaft, its width
representing the longitudinal distance on the shaft. This piece
of paper was then divided into equal parts at each end and in-
clined lines drawn upon it as shown in Fig. 11, the divisions being
equal to the pitch of the thread, found by spacing the circumference
of the worm-gear blank for the forty teeth. The
paper was then glued around the shaft and the
diagonal lines gave the correct development of
the screw thread, which was worked out with a fine
saw, a chisel, or knife, and a triangular file. The
teeth of the worm-gear were similarly cut to the
proper V-shape, and the result was a perfectly prac-
tical and really workmanlike piece of mechanism that
Thread be- answered the purpose remarkably well.

same method of laying off screw threads
was in practical use many years ago and was used
by one Anthony Robinson in England as early as the year 1783,
at which time it is recorded of him that he made a triple-threaded
screw 6 inches in diameter and 7 feet 6 inches in length. It is
said that he first laid off one thread by the method above de-
scribed, leaving a sufficient space between the convolutions for the
other two threads. This first thread was then worked out by
hand with the time-honored hammer, chisel, and file, and he after-
wards used this thread as a guide for making the other two by
the same primitive means.

In the light of the present facilities for cutting threads this
process seems most tedious and laborious, and yet much of the
machinist's work of that time was equally slow and must have
sorely taxed the patience of the workman, whose principal and
often only machine was a lathe of very crude design and work-
manship, and in which he managed to do not only turning and bor-
ing but slotting, splining, milling, gear-cutting, and an endless variety
of similar jobs, and in lieu of a planer having recourse to his ever
ready cold chisel, hammer, and file, which with a straight-edge en-
abled him to make many a flat surface of remarkable nicety con-
sidering his limited facilities. And from these pioneer machinist's
came the American machinist of to-day, the most thorough, best
educated and expert mechanic the world has ever seen.

DEVELOPMENT OF THE LATHE

FIG. 12. — End Elevation of
"Chain Lathe."

It will doubtless have been noticed that in the earlier examples
of the lathe, as in most of the machines in use, the framework of
the machine in the lathe, the bed, and legs, were made of wood
with the various metal parts se-
cured to them. A good example
of this method of construction,
as well as the general construc-
tion of the lathes of the date
when this one was built, is shown
in front end elevation in Fig. 12,
and in front elevation in Fig. 13.
The history of this lathe is well
known to the author, who was
well acquainted with the old
Scotchman, one John Rea, who
had a small machine shop, wood
shop, iron foundry, and sawmill
in East Beekmantown, Clinton
County, New York State, during and for many years prior to the
civil war.

This lathe had, as will be seen by an inspection of the drawings,
a bed composed of two timbers, placed at the proper distance apart
and supported upon wooden legs, which in turn rested upon a cross
timber supported by the floor. The timbers were of hard maple,
those forming the bed being about 5 inches thick and 12 inches
deep and were about 15 feet long. The lathe would swing about
32 inches over the bed. The patterns were made by Mr. Rea, the
castings made in his foundry, and the machine work done in the
nearby village of Plattsburgh.

The "ways" or V's of the lathe were of wrought iron about
f x3 inches let into a " rabbit" cut on the inside edges of the
timbers forming the bed, and fastened by large wood screws.
The top edges of these iron strips were chipped and filed to an angle
of about 45 degrees to the sides, thus making the V an angle of
about 90 degrees. The head-stock had cast in it square pockets
in which the boxes for the main spindle were fitted by filing, and
were held down by a rough wrought iron cap through which passed
two threaded iron studs which had been cast into the metal. Upon

MODERN LATHE PRACTICE

these were two nuts as shown. The main spindle was of wrought
iron and carried a wooden cone pulley built up on cast iron flanges
keyed to the spindle. There were no back gears.

The carriage was of the roughest description and had a hand
cross feed for the tool block, which carried the old-fashioned tool-

I,;, clamping device held in
place by studs and nuts.
The longitudinal hand feed
was by means of a crank-
shaft and pinion with cast
teeth and a rack similarly
formed, fastened to the
front of the bed by wood
screws. The longitudinal
powrer feed was by means
of an ordinary iron chain
(hence the common name of
" chain lathe" given to a
lathe having this method of
feeding). This chain ran
over a very clumsy form of
sprocket-wheel made some-
what similar to those used
in chain hoists of the pres-
ent day. At the head end
of the lathe this sprocket-
wheel was fixed upon a
shaft which carried on its
front end a very crude form
of a worm-wheel arranged
to engage with an equally
crude worm upon a shaft
journaled in boxes at the
front of the bed, one of
which was pivoted to the front of the bed and the other capable of
sliding vertically and therefore making provision for dropping this
worm out of contact with the worm-gear when it was desired to
" throw out the feed." To keep this feeding mechanism in gear a

DEVELOPMENT OF THE LATHE 45

lever was pivoted upon the front side of the lathe bed, one end
connected with the sliding box of the worm-gear shaft and the
other hooked under a pin driven into the front of the lathe bed, as
shown in the engraving.

This worm-shaft was driven by a round leather belt working
in one of the grooves of a three-step cone pulley fixed upon it,
and extending up to a similar three-step cone pulley fixed upon the
rear end of the main spindle. These pulleys were of hard wood and
attached to cast iron flanges fixed in place. The belt was a " home-
made" production but very much resembling the best twisted
round leather belts of the present day, and was about three quarters
of an inch in diameter.

The belt on the cone pulley upon the main spindle was about
three and a half inches wide, the large step on the cone being about
twenty inches in diameter.

It will be noticed that no provisions was made in this lathe for
cutting left-hand threads. It seems altogether probable that the
use of left-hand threads began many years after right-hand threads
were developed and used, as the need of them no doubt did not exist
until the mechanical arts were much farther advanced and possibly
not until they were wanted for producing a contrary motion in
devices using the worm and worm gear.

The tail-stock was of very simple construction, as will be
seen in the engraving, the tail spindle having formed upon its rear
end a downwardly projecting arm which embraced a screw tapped
into the main casting and being provided with a crank by which
it was operated. To bind the spindle in any desired position a
ring was provided, through which the tail spindle passed, and to
which was welded a bolt end passing up through the casting and
being provided with a lever nut as shown. It will be noticed that
by this construction the operation of binding or clamping the tail
spindle tended to raise it out of its true bearing position and hold
it suspended by this binder and its contact with the top surfaces
of the holes through which it passed in the main casting. This
continued to be the practice for clamping a tail spindle for many
years before the present method of splitting the bearing at the
front and fastening it by a clamping screw was first used.

The lead screw was placed at the back of the lathe and had

46 MODERN LATHE PRACTICE

fitted upon it a curved forging, carrying a solid nut and capable
of being attached to the carriage by two bolts when it was desired
to cut threads. This forging was frequently called a " goose neck,"
from its peculiar curved shape. The thread of the lead screws was
square and four threads to the inch. It was, of course, made of
wrought iron, the use of steel for this purpose being of much later
date.

The method of driving the lead screws was characteristic
and peculiar and is one of the main reasons for introducing this
lathe to the attention of the readers of this book, as it marks one
of the first known methods of changing the ratio of speed between
the main spindle and the lead screw by means of gears of a varying
number of teeth, which is here done in a very crude but compara-
tively effective manner. This method was as follows: Upon the
rear end of the main spindle was fixed a flange having in its face a
series of pins which formed the teeth of a " crown gear" and which
engaged with a " Ian tern pinion" fixed upon an inclined shaft
journaled in a bracket fixed to the lathe head and lining with the
lead screw. This lantern pinion was made of two heads fitted
upon the shaft and having pins running through the heads in a line
parallel with the axis of the shaft, similar to the method seen in a
brass clock.

Upon the lead screw was a crown wheel similar to that upon the
rear end of the main spindle, and whose pins, or teeth, engaged
with those formed by the pins or rods in the lantern pinion upon
the lower end of the inclined shaft. The fact that this lantern
pinion was of much greater length than that on the upper end would
seem to indicate that the designer or builder of the lathe had in-
tended to use different sized wheels on the end of the lead screw
for the purpose of producing different ratios between the speed
of the lead screw and that of the main spindle, and therefore to
cut threads of differing pitches. This seems to have been the
earliest method of producing this result by a change of gearing, and
probably antedated the method of using differing diameters of
spur gears, as it is well known that the crown wheel or pin gear
and lantern pinion were the oldest form of gearing, and in use in
Egypt at a very early date, and that an imitation of our spur gear
was made in a similar manner by inserting the pins in the periphery

DEVELOPMENT OF THE LATHE

of the wheel instead of its face. The builder of the lathe in ques-
tion probably borrowed his idea from some lathes very much older
and which he had seen in his native country, as regular spur gearing
for the same purpose had been used at a considerably earlier date
than the building of his lathe, and as he was a man past middle life
at that time. The lathe was built about 1830 and was in active
service as late as 1875, although the lantern pinions and pin gears
had been discarded and hung up on the walls of the old shop, and
in their place were the usual spur gears, and a stud plate had been
added for the purpose of carrying an idle gear so as to accommodate

FIG. 14. — Putnam Lathe built in 1836.

different sizes of change gears, and a second idler when left-hand
threads were to be cut. Otherwise the old lathe remained as it
was originally built.

The transition from wooden to iron beds and legs for lathes
was probably made by the early builders of these machines about
1840 or a few years later. It is certain that in 1850 lathes with
iron beds were made in New Haven, Conn., and that from this
time on iron was universally used for this purpose.

A good example of these lathes built about the time of the
from wood to iron beds is furnished in Fig. 14, of one of

48 MODERN LATHE PRACTICE

the lathes built by J. & S. W. Putnam, in Fitchburg, Mass., about
the year 1836, or somewhat earlier, and shows in a remarkably
sharp contrast with those of the present day when all possible
devices are adopted for powerful drives, rapid change gear devices
for both feeding and for thread cutting, to the common inch stand-
ard and those measured by the metric system; with micrometer
gages and stops; with turrets located upon the bed or upon the
carriage; and with all manner of attachments and accessories for
doing a great and almost endless variety of extremely accurate
work, as well as for turning out an immense quantity of it.

One other example of the early lathes is shown that was in
some respect somewhat ahead of its time, as will be pointed out.
It is a 20-inch swing lathe built by A. M. Freeland, in New York
City, in 1853. It is shown in Fig. 15. It is said that Mr. Freeland

FIG. 15. — Freeland Lathe built in 1853.

used English machines as his models and was an admirer of Whit-
worth and his ideals of what machine tools should be. In this
lathe the flat-top bed is used as in many English and some very
good American lathes at the present time. It will be noticed that
the apron is in a somewhat abbreviated form, only sufficient to
support its very simple operative mechanism.

The carriage carried a cross-slide upon which were two tool-posts,
one in front and one in the rear, which were connected by a right
and left cross-feed screw, while there was a short supplemental
screw for adjusting the back tool independently of the front one,
and also a longitudinal screw for adjusting the tool lengthwise of
the work being turned, so that the second or back tool would cut a
portion of the feed, as the roughing cut and the front one take the
remainder. It will be understood that the back tool is used upside
down as in the modern lathes carrying the second tool.

DEVELOPMENT OF THE LATHE 49

There was no rack and pinion arrangement for lateral hand feed
for the carriage, the lead screw being used for this purpose by
engaging with its thread a pinion fixed to the shaft operated by
the crank at the right-hand end of the apron.

It will be noticed that the driving-cone on the spindle has five
steps, as in a modern lathe. The bed seems so light that it would
now be called frail, in view of the present duty expected of a lathe
of this swing, and in sharp contrast with the massive beds now
used.

In future chapters will be shown the modern American lathes
with all their peculiar features illustrated, explained, and com-
mented upon as this work progresses, taking up, not only the regu-
lar types of engine lathes, but also those of a more special nature
such as turret lathes, pattern lathes, bench lathes, high-speed lathes,
gap lathes, forming lathes, precision lathes, multiple spindle lathes,
and so on, including lathes driven with belts from a countershaft
in the usual manner, and also those driven by electric motors
with the most modern appliances.

In illustrating and describing these lathes much care has been
exercised to have both the illustration and the description correct
as to the facts shown and commented upon, and to this end the
builders themselves have furnished the necessary facts so that the
statements herein given are from proper authority and may be
relied upon in considering the proper selection of the lathe best
suited for the work for which it is to be purchased.

CHAPTER III

CLASSIFICATION OF LATHES

The essential elements of a lathe. The bed. The head-stock. The tail-
stock. The carriage. The apron. The turning and supporting rests.
The countershaft, Taper attachments. Change-gears. Classification
applied to materials, labor accounts, and the handling of parts in the
manufacture of lathes. The four general classes of lathes. The eighteen
sub-divisions of these classes. The first class: hand lathes, polishing
lathes, pattern lathes, spinning lathes and chucking lathes. The second
class: engine lathes without thread-cutting mechanism, Fox brass lathes,
forge lathes, and roughing lathes. The third class: complete engine
lathes with thread-cutting mechanism, precision lathes, rapid reduction
lathes, and gap lathes. The fourth class : forming lathes, pulley lathes,
shafting lathes, turret lathes and multiple spindle lathes. Rapid change
gear devices. Bancroft and Sellers device. The Norton device. Lathe
bed supports. The precision lathe. The rapid production lathe. The
gap lathe. Special lathes. Forming lathes. Pulley lathes. Shafting
lathes. Turret lathes. Screw machines. Multiple spindle lathes.
Variety of special lathes.

IN considering what are the essential elements of a lathe they
may be briefly stated, if we assume that in a simple lathe the work
is to be what was originally intended, that is, held on centers, and
may be stated in these terms, viz. The essential elements of a
simple metal turning lathe are : suitable means for supporting and
holding the work upon centers; proper mechanism for rotating the
work; and a cutting-tool properly held and supported upon a
traveling device actuated by suitable mechanism.

The first of these essentials comprise the bed, head-stock, and
tail-stock, with their proper parts and appendages, so far as the
fixed parts and centers are concerned, and including legs or other
supports for the bed. The second essential comprises the driving
mechanism, consisting of the driving-cone, back gearing, etc., and
the third essential consisting of the carriage, tool block, and cutting-
tool, with the necessary gearing for moving it, and the connecting

CLASSIFICATION OF LATHES 51

parts for transmitting power for that purpose from the main
spindle of the lathe.

This classification of the essential elements of the lathe naturally
suggests certain groups of related parts which compose a complete
lathe, and correspond with the experience and practice of the
author in the designing and construction of the various types of
lathes. They are as follows :

1. Bed and appendages, including the legs or cabinets, lead-
screw and its boxes, the feed-rod, its boxes and supports, carriage
rack, tail-stock, moving rack (when the lathe is large enough to
require one), stud-plate and studs, and such necessary bolt,s and
screws as are needed to fasten these parts.

2. Head-stock and appendages, including such feed-gears as
are necessary to connect with the feed-rod in case of a geared feed.
Also the holding-down bolts and binders (if used), for fastening
the head-stock to the bed, and the large and small face-plates.
(Where a quick change gear device is used and is not an integral
part of the bed or head it forms a separate class.)

3. Tail-stock and appendages, such as holding-down bolts,
binders, and, when the lathe is large enough to require it, the mover
bracket, gears, shafts and crank; and if the tail-spindle is handled
by a hand-wheel in front, the brackets, shafts, spur and bevel
gears, etc.

4. Carriage and appendages, including gibs and a solid tool
block if one is used, but not a compound rest where these are
furnished at the order of the purchaser. If the lathes are habitually
built with compound rests they may be classed with the carriage.

5. Apron and appendages, including the apron in its complete
assembled form ready to attach to the carriage, together with the
screws for making such attachment.

6. Rests, including the compound rest (when not classed
with the carriage, the full swing, pulley or wing rest (as it is vari-
ously named), center rest, back rest, (when one is furnished),
together with bolts, binders, and similar means of attachment.

7. Countershaft and its appendages, including the hangers,
boxes, shipper rod, etc., and any similar parts for tight and loose
pulleys or friction pulleys as may be necessary to make it complete
and ready to put up.

MODERN LATHE PRACTICE

Taper attachments, special tool holders, or tool-rests, and all
similar parts are deemed extras and not included in regular lists.

Change-gears are sometimes listed as a part of the bed and
appendages. When these are a part of a special quick change
device they are made a separate class. This is understood to be
when the change gear device is detachable. When made a part
of the head-stock or the bed such parts as are attached to the one
or the other of these main parts will be listed with it and become
a portion of its appendages.

This classification is carried into all lists of materials of what-
ever kind and into all accounts of labor in the designing, construct-
ing, and handling of these parts, whether in groups or as single
pieces, during their progress through the various departments of
the shop.

The classification of these lathes as entire and complete ma-
chines, and according to their various types of design and con-
struction and the uses to which they are to be put, will be next
considered, and in so doing it seems appropriate to commence with
the more simple forms, and to proceed with such types as are com-
monly recognized and in use at the present time, dividing them
into four general classes and these into such sub-divisions as their
construction and uses seem to demand By this method of classi-
fication we shall have:

FIRST
SPEED LATHES.

SECOND

METAL TURNING
LATHES.

THIRD
ENGINE LATHES.

FOURTH
SPECIAL LATHES.

Hand Lathes, for floor or bench.

Polishing Lathes.

Pattern Lathes.

Spinning Lathes.

Chucking Lathes, with or without a turret.

Engine Lathes, without thread-cutting mechanism.

Fox Brass Lathes.

Forge Lathes.

Roughing Lathes.

Complete Engine Lathes with thread-cutting mechanism.

Precision Lathes.

Rapid-Reduction Lathes.

Gap Lathes.

Forming Lathes.

Pulley Lathes.

Shafting Lathes.

Multiple Spindle Lathes.

Turret Lathes.

CLASSIFICATION OF LATHES

In the first class we understand by speed lathes a lathe
without back gears and without the carriage and apron of an
engine lathe, although as chucking lathes they may be provided
with back gears, as they are frequently used for boring quite large
holes, and are therefore made much larger and heavier than those
of the other sub-divisions of this class.

Hand lathes are supposed to be for the usual operations of hand
tool turning, filing and light metal turning by means of a detach-
able slide-rest. They may have legs of sufficient height to support
them from the floor as in Fig. 16, or with very short legs, making

FIG. 16. — A Hand Lathe.

them convenient for setting upon the usual machinists' bench as
in Fig. 17. Otherwise their design and construction is the same.

Polishing lathes are, as their name implies, mostly used for
polishing cylindrical work, although a hand-rest or a slide-rest is
sometimes used upon them.

Pattern lathes, as shown in Fig. 18, are usually so called when
used by wood pattern-makers and while usually used with hand
tools, as chisels and gouges with the support of a hand-rest, at the
present time a majority of them are provided with a slide-rest.

MODERN LATHE PRACTICE

Those of larger swing have the rear end of the main spindle threaded
for attaching a face-plate upon which is fixed large face-plate work
of too great a diameter to be turned on the ordinary face-plate, as
this supplemental face-plate overhangs the end of the bed and
consequently the diameter of the work that can be turned is only
limited by the height of the main spindle above the floor. In this

FIG. 17. —A Bench Lathe.

class of work a hand-rest is supported by a tripod stand that may
be moved to any desired position on the floor and is heavy enough
to stand steadily wherever it may be placed.

Spinning lathes are used for forming a great variety of shapes
from discs of quite thin metal, usually brass, with various shaped

tools held either by hand or in
the tool post of a slide-rest.
These tools form the metal in a
manner similar to the action of
a burnisher instead of cutting it,
usually over a former, by which
the same shape is produced in
all the pieces. Such work is
not usually of large diameter,
therefore a spinning lathe is
generally of small and medium swing and is of substantially the
same construction as the ordinary hand lathe, except when built
for large or special work.

Chucking lathes, shown in Fig. 19, are used to a great extent
for boring and reaming circular castings, as pulleys, gears, hand-
wheels, balance-wheels, sleeves, bushings, flanges, and all similar
work that require only the formation of the hole, although some

FIG. 18. — A Pattern Lathe.

CLASSIFICATION OF LATHES

of these machines are provided with a cross-slide and tool-post by
means of which the hubs or bosses of the work may be faced. Many
of them are now provided with a turret, by means of which several
tools may be carried so that not only boring and reaming, but
recessing, facing, etc., may also be done without removing the
work from the chuck. These lathes usually have a very large
driving-cone with a broad belt surface, or they are constructed
with back gears similar to those in an engine lathe. It was from
this form of lathe that the elaborate lathes built by Jones & Lam-
son and others of similar design and construction originated.

FIG. 19. — A Chucking or Turret Head Lathe.

In the second class we have what used to be called the " plain
engine lathe," that is, one not provided with any thread-cutting
mechanism. Formerly the smaller sizes of these lathes did not
usually have the power cross-feed, although at the present time
there are very few of them built by any of the manufacturers, unless
by a special order, practically all the modern engine lathes having
the thread-cutting mechanism, and frequently it is made an elabo-
rate and expensive feature and covers a wide range of work. When
these lathes were built to a considerable extent the feeding mechan-
ism was nearly always driven by a belt, gears being very seldom
used for this purpose. No sub-division has been here given for
foot-power lathes, as any of those so far described can and have
been operated by foot-power when not too large to be thus driven.

MODERN LATHE PRACTICE

The Fox brass lathe, Fig. 20, is built upon similar lines as the
engine lathe without a carriage or apron, but in place of it there
is a swinging tool post slide whose rear end is journaled upon a
lead screw which gives a longitudinal feed when the slide is brought
over to the front by means of a handle for that purpose. With this
driver, straight turning, facing, and thread cutting is quickly and
conveniently done. There is also a hand-rest and sometimes a
cutting-slide or cross-slide. The tail spindle has a long run and
is sometimes worked with a lever, particularly when chucking
work is to be done. Occasionally the tail-stock is replaced by a
turret carrying a variety of tools such as are convenient for the

FIG. 20. — A "Fox" Brass Finishing Lathe.

brass finisher. These lathes are usually made without back gears.
They are run at very high speeds and in the hands of an expert
brass finisher do the work very rapidly, both as to turning and
boring or inside finishing, while they cut threads very rapidly by
means of " chasers."

Forge lathes are a very heavy design of the plain engine lathe,
without thread-cutting mechanism (although some manufacturers
add this feature so as, to make the lathes available as a complete
engine lathe for much work that cannot be classed as forge work).
The purpose of these lathes is to rough down large forgings, the
users claiming that it is more economical to thus bring the work
to the " forging sizes" than to do so by the process of hammer-

CLASSIFICATION OF LATHES

ing, and that all the chips thus removed may be worked into
other forgings by which this waste is economically recovered. It
is therefore their practice to forge the work (cylindrical work,
of course) to dimensions much over the forge sizes, and by the use
of the heavy forge lathe to finish them to customers " rough
turned" to within reasonable limits of " finish sizes."

By the term " roughing lathe " we understand that the design
is heavy and massive with a very powerful driving mechanism,
lateral and cross feeds and a very rigid tool holding device. Such
a lathe is seen in Fig. 21. While it is somewhat analogous to the

FIG. 21. — A Roughing Lathe.

forge lathe it is usually understood to be of much less capacity.
And while the forge lathe, being for handling forgings almost ex-
clusively, holds the work on centers, the roughing lathe should
be made with a large hole in the spindle so that work may be
"roughed out" from the bar as well as when held on centers, or
with one end in a chuck and the other on a center. And here it
encroaches upon what may be considered the field of the so-called
" rapid reduction lathe " ; with this difference, however, that in the
former lathe the work is simply roughed out, while in the latter
it is supposed to be not only roughed out or rapidly reduced to near
finished sizes, but in many cases entirely finished, or finished to
dimensions suitable for being finished by grinding.

In the third class we commence with the complete engine lathe,
with thread-cutting mechanism, back geared or triple geared, with

58 -MODERN LATHE PRACTICE

a compound rest which in the larger sizes is capable of power feed
at all angles. Such a lathe should also be supplied, especially
in the larger sizes, with a tool-rest to attach to the front wing of the
carriage on the left-hand side for turning the full swing of the lathe.
The larger lathes, particularly those that are triple geared, should
have a tail-stock arranged with two sets of holding-down bolts, by
means of which one set may be loosened and the tail-stock set over
for turning tapers without removing the work from the lathe, as
the other set of bolts still holds the tail-stock to its place on the
bed. There should also be a tail-stock moving device consisting
of a rack attached to the bed, with which is engaged a 'pinion
fixed to a shaft journaled in a bracket attached to the tail-stock
base. By means of a crank on this shaft the tail-stock can be
easily moved to any desired point upon the bed.

In lathes of 42-inch swing and larger, this arrangement should
be back-geared by the introduction of a second shaft, the gears be-
ing in ratio of 2 to 1. In lathes of 60-inch swing and larger this
ratio should be 3 to 1. The tail-spindle in the smaller lathes has
the usual screw and hand wheel for moving it back and forth. In
large lathes this is inconvenient and laborious. The hand wheel
should be placed in front of the tail-stock and near the center, being
mounted upon a short shaft at right angles to the spindle and
journaled in a bracket fixed to the tail-stock. Upon this short
shaft is also a miter gear engaging with another fixed to a shaft
parallel to the spindle and extending to the rear end of the tail-
stock where it passes through another bracket and has fixed upon
it a spur pinion which engages a spur gear fixed to the tail-spindle
screw, and by which mechanism it is operated. The ratio of this
spur gear and pinion is usually 2 to 1 on lathes of 42-inch swing, and
proportionately more on larger lathes. By the use of this mechan-
ism the operator may stand opposite the tail center in adjusting his
work and easily reach the hand wheel controlling the movement of
the spindle, which would otherwise require an assistant to operate.

In the triple-geared head-stocks of this class of lathes it is cus-
tomary to attach the face-plate to the main spindle by a force-fit
and key instead of making it readily removable by a coarse thread,
for the reason that it is to be driven by means of a very large
internal gear bolted to its rear side and engaged by a pinion fixed

CLASSIFICATION OF LATHES 59

to a shaft driven by the cone through a suitable system of triple
back gearing. In this case the cone is not placed upon the main
spindle, but upon a separate shaft placed sometimes in front and
sometimes in the rear of it. The front position is the more con-
venient for the operator in making the necessary changes of speed.

It is upon this class of lathes that many improvements have
been made in the last few years in the thread-cutting devices, the
original idea having been to avoid removing and replacing " change-
gears" when threads of different pitches were required to be cut.
The first attempt in this line, so far as the patenting of a device
shows, was made by Edward Bancroft and William Sellers in
1854, and taken up by various inventors with more or less success
but never brought prominently into the market until the patent
was granted to Wendel P. Norton in 1892, when somewhat later
on the mechanism was adopted by the Hendey Machine Company,
since which time it has been manufactured with much success.
In the meantime many other devices for the same purpose have
been devised and built, so that now every tool room and nearly
every machine shop making any pretense to modern equipment
possesses lathes having some one of these " rapid change gear attach-
ments " included in their design or arranged to be attached when
desired by the customer.

In the development of the engine lathe proper, much attention
has been paid to the supports for the bed, and instead of the former
pattern of light and, later on, heavy legs, substantial cabinets of
liberal dimensions and weight, have been designed and are now
used upon nearly all such lathes, the only exceptions seeming to
be upon those where the selling price renders economy in the use
of cast iron essential; upon lathes too small and light to justify
their use; and upon lathes built by the more conservative manu-
facturers who have not yet come to consider this class of improve-
ments as necessary to the efficiency of their machines.

A precision lathe is designed to be a lathe in which fineness and
exactness in all its parts is the prime consideration rather than a
great range of work or capacity, or from which a large output may
be realized. It is therefore not necessary that it should be very
heavy or massive except in so far as its weight may render it capa-
ble of greater precision. While the entire design and construction

MODERN LATHE PRACTICE

of the lathe is as exact as possible, the effort is also made to provide
against all conditions and causes that shall be detrimental to its
one object, that of turning out its work in as perfect a manner
as possible.

These being the conditions under which it is designed and built,
it is an expensive lathe, as the most skilful labor is used in its con-
struction and the time devoted to this work is always liberal.
It is, therefore, essentially a lathe for the tool room and the labora-
tory rather than the manufacturing department, and with it
master screws of very great exactness and all similar work is per-
formed. It is, of course, an engine lathe in its general design,

FIG. 22. — A Rapid Reduction Lathe.

although there are more or less changes of form and manner of
assembling the parts introduced for the purpose of avoiding the
effects of strains, protecting bearings from dirt, insuring accuracy
of movement of the several parts, and so on, everything in the
design and construction being subordinated to the one condition
of the greatest precision and accuracy, not only in the entire
machine but in all its individual parts.

The rapid-reduction lathe, shown in Fig. 22, is another form of
a complete engine lathe, built heavy and strong, with a powerful
and somewhat complicated driving mechanism and very strong
feed. The tool holding device should accommodate at least two
tools and hold them very rigidly. It should have thread-cutting

CLASSIFICATION OF LATHES

facilities so that pieces requiring threads may be entirely finished
in this respect. It should be an accurately working machine so
that it may not only rapidly reduce the stock to near the finishing
dimensions, but finish all ordinary work to the given sizes, or to
such dimensions as may be called for when the piece is to be finished
by grinding. Such a lathe may be arranged with a series of stops
both for diameters and lengths and thus do much of the work done
in a very much more expensive turret lathe. It will be of much
convenience to have a hollow spindle, bored out as large as pos-
sible so as to admit of running a bar of round stock through it,
holding it in a chuck and forming one end of the pieces, then cutting
them off, leaving the remainder of the work on the opposite end

FIG. 23. — A Gap Lathe.

of the piece to be done at a second operation in this lathe or some
similar machine. In working up round stock in this manner the
lathe should be provided with a cutting-off slide constructed
similar to that on a turret lathe.

A gap lathe, shown in Fig. 23, is one in which the top of the
bed is cut away for a space immediately in front of the face-plate
for the purpose of increasing the swing of the lathe so that much
larger work may be turned or bored, either when held upon centers
or in a chuck. This type of lathe is more in favor in English
machine shops than those of this country, where the gap lathe is
seldom seen. When the work of the lathe is not of such a nature
as to require the gap, it is usually closed up in one of two ways.
The first method is to have a portion of bed exactly like the main
part and of such a length that it will exactly fit in the space form-

62 MODERN LATHE PRACTICE

ing the "gap." The other method is to have that portion of the
bed upon which the head-stock is attached, of the full height, while
the remainder of the bed is lowered sufficiently to furnish a support
for a sliding supplemental bed whose depth is equal to the depth
of the gap. This supplemental bed when closed up to the face of
the head-stock completes the bed by filling the entire cut-away
portion completely to the rear end. When it is desired to form a
/'gap" this supplemental bed is moved, toward the rear end of the
bed proper to any desired distance to leave the required space or
gap for the work in hand, and secured by bolts arranged for that
purpose. In a large machine shop, with the proper lathes for
handling whatever work the shop is called upon to do, the gap lathe
is not usually necessary and will seldom be found, but in jobbing
shops, particularly those with a modest equipment of tools, the
gap lathe may often be found convenient for doing exceptionally
large jobs such as pulleys, balance-wheels and the like, as these
jobs may come along so seldom that it would not be advisable to
incur the expense of a lathe large enough to swing them, and which
would be liable to be idle a large portion of the time.

The gap lathe is provided with the usual thread-cutting
mechanism and is in all respects a complete engine lathe. It is
not usually as rigid as a solid bed lathe and therefore not as effi-
cient in taking heavy cuts.

The fourth class, including the various types of special lathes,
would of necessity be a very large one if an attempt were made
to enumerate them all, and the list might prove tiresome to the
busy reader. Those introduced in the foregoing list are of the
well-known and recognized types and seem to be sufficient for
the purposes of this work.

Forming lathes are of heavy and massive design and construc-
tion, and provided with powerful driving mechanism, adapted
to rather slow speeds, and with fine feeds, owing to the large extent
of the cutting surface of the tools used in them. These tools
require special forms of rest for supporting them which are of
strong but simple design, as many of the forming tools are simply
flat steel plates with the form to be turned cut in the edge, so
that when dull they may be sharpened by grinding the top face
and not changing the form. Forming lathes should have hollow

CLASSIFICATION OF LATHES 63

spindles, bored out much larger in proportion than in other types
of lathes. The author has designed and built these lathes of
28-inch swing with a spindle 7J inches in diameter and bored out
to 5J inches, so as to take in a bar of 5-inch steel. As this size
weighs about 85 pounds to the foot, or a bar 16 feet long weighs
over 1 ,300 pounds, it will be seen that ample provision was needed
for the weight to be borne upon the main spindle bearings in ad-
dition to the weight of the lathe parts, and that while the driving
power necessary for operating with a wide forming tool on steel of 5
inches diameter was a serious matter, that of providing for the
rotating of this unusual load was a considerable addition to it.
However, they met the required conditions and succeeded in
turning out much work even of this comparatively large diameter.

Naturally the forming lathe requires no provision for thread
cutting, but a geared feed should be used and will need to be of
ample power to withstand the very severe strain to which it will
be put.

Pulley lathes, as they are commonly termed, might more
appropriately be called pulley-turning machines, or even pulley-
making machines, since some of them make the pulley complete,
with the exception of splining and drilling and tapping for the set-
screws. In some of these machines the boring is going on and the
reaming is also done while the turning is taking place. In other
forms, one machine does the boring and reaming, which may be done
at quite high relative speed, while the turning must be compara-
tively slower and is done in another machine. Thus one machine for
boring and reaming may furnish work enough for several turning
machines.

In the pulley-turning lathes there must be a strong driv-
ing mechanism since comparatively large diameters are turned,
although even the roughing cut is light when compared with that
frequently taken by other lathes. Two and sometimes more
tools are used, being located both at the front and back of the bed,
(those at the back being bottom side up). In some machines the
tools commence the operation in the center of the face of the pulley,
and each tool or pair of tools (one roughing and one finishing),
are fed away from the center, and with the slide upon which the
tool block travels set in a slightly inclined position with reference

64 MODERN LATHE PRACTICE

to the axis of the lathe so as to produce the properly " crowned
face" of the pulley. With four tools thus arranged, the pulley
is completely turned during the time necessary for a tool to travel
across one half of the face of the pulley plus the distance apart
of the roughing and the finishing tool, say from an inch to an inch
and a half.

When the pulley-turning lathe is arranged for turning cone
pulleys it is customary to have as many tools as there are steps
to the cone pulley, each held in a separate tool post fixed in a single
tool block having a lateral power feed and a transverse adjustment
for setting to the proper diameter. The tool posts set in T-slots
and the tools are set with relation to each other so as to turn the
proper relative diameters of the several steps. The tool block and
the slide upon which it runs is adjustable to the right inclination
or "taper" to properly crown all the steps of the cone at once,
and when the tools have passed over one half the face of the steps,
this block and slide may be shifted and properly adjusted to turr
the other half of each step. In this form of pulley turning it is
usual to make two cuts, a roughing and a finishing cut, and when
turning up to the face of the different steps to draw back the entire
number of tools by means of the transverse slide which may be
fed back by hand for that purpose.

Pulley-turning and boring lathes or machines are built very
broad as compared with an engine lathe and with very short beds,
as the width of a pulley face, or the combined faces of the several
steps of a cone pulley, is the extent of their lateral feed in any case.

The boring and reaming mechanism should have a power feed
so as not to require the constant attendance of the operator, who
may easily run one boring and reaming machine and two surface
turning machines.

Shafting lathes or shaft-turning lathes may be arranged from
any good engine lathe provided the bed is long enough for the
purpose, by adding to it a three-tool shafting rest and a shaft
straightener. Still a lathe that is especially designed as a shaft-
turning lathe will be better adapted for the purpose and will turn
out more good shafting with the same expenditure of capital and
labor than the engine lathe arranged with attachments for the
purpose. In the properly designed shaft- turning lathe there is a

CLASSIFICATION OF LATHES 65

heavy shaft running the length of the lathe bed and arranged to
communicate power to a face gear and driver journaled on the
front end of the tail-stock, by means of which the shaft to be
turned may be driven from this end as well as from the head-stock
end. This is very useful in turning long shafts in which the tor-
sional strain would be great, as the power may be applied at the
tail-stock to turn one half of the shaft and then applied direct from
the head-stock, or it may be applied at both ends continuously and
simultaneously.

There should be a force pump to keep the cutting-tools constantly
supplied with a stream of whatever lubricant is being used. This
pump may be driven from the shaft above mentioned, which is
located at the center of the bed and below the bridge of the car-
riage. The three-tool rest carries its own center rest, but it is
customary to support the shaft being turned by easily removable
rests used between the carriage and the head-stock or tail-stock,
as the operator finds necessary. These are generally composed
of two wooden blocks resting on the V's of the lathe and somewhat
lower than the lathe centers. The upper block has a V-shaped
groove for the shaft to rest in and is raised up and held in place by
a wooden wedge inserted just far enough to give proper support
to the shaft so as not to permit it to sag during the process of turn-
ing. There are three turning tools usually employed. The first
is a roughing tool; the second cuts the shaft very closely to size,
while the third takes an extremely light cut, completing the
work, so that by running once over the shaft from end to end it is
completely finished. Two tools are placed at the left of the center
rest fixed to the tool block, and one, the final finishing tool, at the
right. As these three tools and the center rest occupy considerable
length upon the shaft the lathe is provided with extra long centers
so as to reach the work. The center rest is provided with split
collars bored to the size that the second tool leaves the shaft.

The turret lathe, shown in Fig. 24, now so well and favorably
known, is a comparatively recent invention and doubtless origi-
nated in the use of a multiple tail-stock which was formerly used on
small work where more than one tool was desirable. Our English
friends recognize its value and usefulness, and one author speaks
of it as "the common capstan tool-rest." In this country much

MODERN LATHE PRACTICE

has been done to develop and bring into popular form the turret
lathe by such builders as Jones & Lamson, Warner & Swasey,
Potter & Johnson, Bullard and others.

While the turret lathe in its perfected form is now a complete
machine, the turret idea was first applied to engine lathes, and turret
attachments are so universally popular that most of the lathe
manufacturers now make them of dimensions suitable for their
lathes, and attach them either to the lathe carriage or to a special
bed which may be fastened to the lathe bed upon the removal

FIG. 24. — A Turret Lathe.

of the tail-stock. A great variety of work may be done in the
turret lathe, its principal rival being the automatic screw machine,
whose economy lies principally in the fact that one operator may
take care of a number of machines, each of these machines depend-
ing principally for their success upon the turret with its multiplicity
of tools. And this idea of a turret carrying from four to eight tools
is applied in a great variety of ways and to a large variety of
machines on account of the ease with which any desired tool may
be brought into a working position.

The head-stock of a turret lathe is made in several ways, from
that of a plain head without back gears to one with a large variety
of speeds, controlled by handles operating clutches, or friction
driving devices, or both, and which may be operated while the
machine is in motion. In some cases the head-stock is cast in one
piece with the bed, in others fitted to it in a similar manner to that
of an ordinary lathe. In still others the head has a transverse
movement on the bed upon which it slides and its movement is
easily controlled by the operator.

CLASSIFICATION OF LATHES 67

The turret is designed and constructed in a variety of forms,
but principally either circular or hexagonal. It is mounted usually
in a horizontal position, that is with its axis vertical, but still in
some of the best machines, notably the Gisholt, it is pivoted in an
inclined position, the object being to bring the long tools, made
necessary by a large machine, up out of the way of the operator as
they swing over the front of the machine.

In the smaller hand machines and in many of the turrets fur-
nished upon ordinary engine lathes the turrets are rotated by hand
as each change is required, but in the larger and more complete
machines the sliding movement of the turret effects its rotation
at the proper time near its extreme rear position.

There 'is no carriage, properly so called, upon a regular turret
lathe. A cutting-off slide carrying two tool-posts, one in front
and one in the rear, serve to carry a cutting-off tool and a facing
tool, or one for doing forming within certain limits. The spindle
being hollow, and a large part of the work of the turret lathe
adapted for steel work being made direct from the bar, these tools
are very useful.

Some turret lathes are particularly adapted for a large variety
of chucking and forming work, which they perform very accurately
and economically, an elaborate system of stops for the turret slide
rendering them very efficient for this work.

The tools that may be used in a turret are almost without num-
ber, and the expert operator readily attacks the most complicated
pieces and brings them out with excellent finish and with surprising
accuracy. Internal and external threads are readily cut very true
to size and with rapidity.

The screw machine is very closely allied to the turret lathe,
so called, and the smaller sizes are fitted with what is called a "wire
feed," which will automatically feed in the bar against the turret
stop as soon as it is released by opening the chuck. This is in the
hand screw machine. In the automatic screw machine all these
movements are made automatically when once the machine is set
up, the tools properly adjusted, the bar of stock once introduced
and the machine started, and, barring accidents, the machine con-
tinues to run, dropping its work into a pan as it is completed and
cut off, until the bar of stock is almost entirely used up.

68 MODERN LATHE PRACTICE

Multiple spindle lathes are usually those having two spindles.
These may be side by side for the purpose of performing two similar
operations simultaneously; or one spindle may be considerably
higher than the other, above the bed, thus giving two different capac-
ities as to the diameter of work that can be accommodated on
the same lathe ; the larger swing being frequently used for boring
or similar work. Notably of this type of lathe is that put in the
market by J. J. McCabe.

While the general and well-marked types of lathes have been
specified in this classification it must not be understood that the
list is complete, as there are many special lathes, each of excellent
mechanism and well adapted to the special work for which it is
designed, that do not appear here, and that it is manifestly impos-
sible to classify and describe in detail. Frequently they may be
assigned to some one of the classes or sub-divisions here set forth,
as all lathes must partake in some respect of the essential parts of
those described.

Further on in this work many practical examples of the lathes
described in this chapter will be found, their builders' names being
given and their particular features pointed out and commented
upon, and to them the reader is referred for the better examples of
each of the classes enumerated in this chapter.

CHAPTER IV
LATHE DESIGN: THE BED AND ITS SUPPORTS

The designer of lathes. The manufacturer's view of a lathe. The proper
medium. Cause of failure. The visionary designer. Conscientious
efforts to improve in design. Design of the lathe bed. Elementary
design. Professor Sweet's observations. The parabolic form of lathe
beds. The author's design. Form of the tracks. Bed of the old chain
lathe. The English method of stating lathe capacity. Method of
increasing the swing of the lathe. The Lodge & Shipley lathe bed.
Uniform thickness of metal in beds. Ideal form of bed. Cross-ties, or
bars. Four Vs. Flat surfaces. Lathe bed supports. Height of lathe
centers. Wooden legs for lathe beds. An early form of braced, cast
iron legs. Cabinets or cupboard bases. Old style cast iron legs still
in use. Form of cabinets. Principles of the design of cabinets. Cabi-
nets for small lathes. The Lodge & Shipley cabinet. The Hendey-
Norton cabinet.

To the experienced and conscientious designer of machine tools
the condition is frequently forced upon him that it is often easier,
and usually far more agreeable, to design machines as he really
believes they should be, than to design such machines as will meet
the popular requirements of the market. He may be sure that a
certain plan would make really a better and more efficient machine,
yet he must, from the outset, consider the kind of a machine the
customers want and will buy and pay for, since they are, as has been
often said, "the court of final resort" in the matter, and machine-
tool builders manufacture machines to sell, and not for the pur-
pose of exploiting individual opinions, however good they may be,
or the fads and fancies of draftsmen who are sometimes imbued
with visionary and impractical ideas.

The manufacturer himself may be perfectly sure that the ma-
chines he is turning out are not the best adapted for the purposes
for which they are used, or the best he could build for the money.

70 MODERN LATHE PRACTICE

He may so far have the courage of his convictions as to build for
his own use machines quite different from those he manufactures
for his customers. Yet for sale he must build what his customers
want with small regard for his own personal opinions.

By this it is not meant that the builder does not use his judg-
ment in a mechanical way, or that he does not endeavor to build the
best machines possible, inasmuch as he does give this very question
much time, attention, and study. Yet he must, from the very
nature of the case, always keep in mind the question, "What will
the customers think of this new machine? " " Will this device be
a success, or will it prove a failure?" Some machines that have
been put on the market with feelings of much trepidation have
proven great money-makers, while other machines possessing much
mechanical excellence have fallen flat and a large majority of the
customers refused to endorse them. The author has seen many
such cases, and this has probably been the experience of every man
who has designed and built machine tools.

The proper medium in the matter seems to be to keep as closely
in touch as possible with the purchasers of machinery; to ascer-
tain their needs and preferences as closely as may be; to anticipate
their wants when possible, but at the same time with conservatism;
and to avoid putting entirely new devices on the market until
they have been thoroughly tested in the home shop and by a few
friendly shops outside of it. And by entirely new devices is meant
substantially new and complete machines, as the builder will fre-
quently have parts of, or attachments to, the regular line of ma-
chines that are made to the order of a particular customer and that
he feels perfectly sure of being well suited to the work that it
is expected to perform; yet in these cases considerable caution is
necessary.

The one fruitful source of difficulty, disappointment, and failure
to be most avoided in the production of new devices is the mania
often manifested by designers to produce something absolutely
new, decidedly novel, the like of which no one has ever seen or
dreamed of, and that will startle the mechanical world, revolu-
tionize the business, and prove its author a veritable Napoleon of
mechanical science.

When confronted with such a man or such a condition, the

LATHE DESIGN: THE BED AND ITS SUPPORTS 71

wiser course will be to abandon such ambitious attempts to
eclipse all previous efforts, get down out of the clouds, design
something of practical utility, even if it is not strikingly new; some-
thing that past experience gives some guarantee of success;
something that will surely bring the proper financial return and
be a credit to the shop. It is always well to remember, when
tempted to go off on a tangent after something new and mar-
velous, that "a good adaptation is better than a poor original,"
and that when Solomon said that " there is no new thing under the
sun," he did not come far from the truth, since many of the things
we think are new may be found in almost the identical form, that
have been invented, used, and discarded years ago, as the records
of many mechanical libraries as well as the United States [Patent
Office will furnish abundant evidence.

By the foregoing remarks it is not intended to discourage
originality, original thought and research, or the proper ambition
to improvement, for we often produce more of real value by the
effort to evolve mechanical improvements than by the design of
entirely new machines, and the studious and observing designer
will always be on the alert to devise improvements upon existing
forms and processes.

These observations and suggestions apply with as much force in
the efforts to improve the lathe as any other machine in common
use. Being the oldest machine in the machine shop does not in
any respect limit the field for improvements in it. Neither does
it preclude the design of entirely new machines that may have,
perhaps, very little of the characteristics of a lathe, although we
must necessarily be confined to the essentials heretofore discussed,
namely, a bed, upon which rest the head-stock, tail-stock, and car-
riage, or their equivalents, if we would claim that our machine is a
lathe.

With these preliminary statements relative to the conditions
and requirements of good and successful designing, we may take
up the designing of lathes somewhat in detail and inquire into the
design of the individual parts and groups of parts, giving some of
the ideas of men prominent in this field, and adding such comments
and suggestions as seem proper and pertinent to the case as the
matter is proceeded with.

MODERN LATHE PRACTICE

In carrying out this plan it will be natural to commence with
the bed, considering its use and purpose, and the proper form to
fulfil the requirements of this particular part.

The lathe bed, considered in an elementary way, and in the
case of a lathe of moderate length, may be taken as a beam, sup-
ported at each end and in its turn supporting at one end the head-
stock, at the other end the tail-stock, and in the center the carriage,
as represented in Fig. 25.

FIG. 25. — Elementary Form of Lathe Bed.

This being the problem, and as the head-stock and the tail-
stock stand directly over the legs or supports, we might consider
the problem as that of a beam loaded at the center, which would
naturally suggest that the under side of the bed instead of being
straight should be a parabolic curve. This would result in the
form shown in Fig. 26, which would, if the carriage was stationary,

FIG. 26. — Parabolic Form of Lathe Bed.

conform to the conditions of the problem. But, while the carriage
is not stationary, it is located at what would normally be the weak-
est point along the length of the bed, namely, a point farthest
from either support. So far the parabolic curve, then, is correct.
But while we have been placing our supports at the extreme
end of the bed we have no condition of the case which makes it
incumbent upon us to do so. In other words, we may add a por-
tion to each end of the bed, outside of, or beyond the line of these
supports, in the form shown in Fig. 27, showing a modified form

LATHE DESIGN: THE BED AND ITS SUPPORTS

of the lathe bed, the extensions at each end being in the form of a
beam supported at one end. Theoretically, then, this would seem
to be the proper form of a lathe bed in order that it might conform
to the necessary requirements as to form and its ability to sustain
the usual weights and strains to which it will be subjected, and
at the same time not be of excessive weight, which would entail
unnecessary expense.

This is substantially the view taken by Prof. John E. Sweet in
reference to machine beds. He says:

"No reasoning can make it out that the place for the support
of an ordinary sized lathe bed at the tail-stock end of the lathe is at
the end. If placed a considerable distance from the end, and the
tail-stock is at the end, it is better supported than when in the
middle of the present style of lathes and also better supported at

FIG. 27. — Modified Parabolic Form of Lathe Bed.

all other points. At the head-stock end it is quite a different matter
as the head-stock is always fixed and is usually heavier loaded,
exclusive of its own greater weight. Where the head-stock end
support is a closet, there is no way to make it look right except to
have the closet the same width as the head-stock is long.

"In the case of a planing machine bed up to 12or 15 feet in length
there is no reason for having three pairs of supports. Unless the
foundation is absolutely unyielding — a thing that is more rare
than the other kind — the three or more pairs of supports are
especially bad, and to attempt to hold the foundation true with a
frail planer bed is foolish. The distance between the supports in
Fig. 28 is no greater than in 29, and as in no case would the center
of the load in planing overhang the supports more than a slight
distance the style shown in Fig. 28 is quite as well supported as the
other; and when the iron in the legs and the work to fit them are
taken into account, if they were all put into the casting the bed

MODERN LATHE PRACTICE

could be brought down to the floor as in Fig. 30, greatly improv-
ing the structure.

" Another improvement is to use the iron usually put in the cross-

FIG. 28. — Prof. Sweet's Form of Bed, supported at Two Points only.

girts — which do not stiffen the bed in any way to any great extent
— and use it in bottom and top webs, making the thing a f our-

FIG. 29. — A Common Form of Lathe Bed, Supported at Three Points.

sided box, which is from four to a dozen times stiffer in all direc-
tions, and then rest the whole thing on three points, one under the

FIG. 30. — Prof. Sweet's Design Applied to a Planer Bed.

back of each housing and one under the middle toward the other
end. The whole thing, including patterns and setting, will cost
no (or very little) more and be four times better than present
practice.

LATHE DESIGN: THE BED AND ITS SUPPORTS 75

"If the bed is supported at the same points when it is planed
and fitted up, no attention or skill is required in the erection —
just set it anywhere and on anything solid, and that is all that need
be or can be done."

There is "meat for reflection" in what Professor Sweet says
(as there usually is), and the principle upon which he makes his
deductions is undoubtedly correct.

To render the comparison more apparent and in a practical
manner the two views shown in Figs. 31 and 32 are given. In

FIG. 31. — The Parabolic Design of a Lathe Bed.

Fig. 31 the parabolic design is shown in proper proportion for
supporting the head-stock, tail-stock, and carriage, and the propor-
tions laid out are ample for all purposes, as is also the supports
and their distance from each other. In Fig. 32 is shown a rectangu-
lar design of bed of like length and of sufficient depth to give the
requisite strength, provided there is a central support added to
prevent a sinking in the center of the bed, as the distance between
supports would otherwise be too great. While nothing has been
added to the strength or the stiffness of the bed, we have been

FIG. 32. — The Rectangular Form of Equal Strength.

obliged to add the central support and in addition to this the
weight of the parabolic form of bed is 1,390 pounds, while the rect-
angular form is 1,550, a very material addition without compen-
sating advantages; and at the same time we have the disadvantage
referred to by Professor Sweet, that the nearer together we can
get the supports and still retain the condition of rigidity the less
we shall have to depend upon the correctness of the foundations,

MODERN LATHE PRACTICE

and this of itself is a matter of very important consideration, since
in some of the popular forms of machines their truth and correct-
ness depends to a very considerable extent upon the accuracy and
continued stability of the foundations upon which they rest.

It was from such considerations and conditions as has just
been illustrated and described that the author designed and built
the 21-inch swing engine lathe shown in Fig. 33. This lathe met
with exceptional success in the market both in a mechanical and
financial way and a large number of them were built and sold,
although they were brought out during a season of great depres-
sion both in mechanical and financial circles, when hardly a machine

FIG. 33. — A 21-inch Lathe with the Parabolic Form of Bed.
Designed by the Author.

shop in the country was running full time, and many of them but
eight hours a day for three days only in a week. After a couple of
years these beds were changed to the rectangular form in order to
satisfy the demands of customers, the depth being nearly as great
as the one here shown is in its deepest part, and the weight much
increased. The ends were made square and the rear box leg
made a regular cabinet similar to the front cabinet. The lathe is
still built with very little change in its general design except as
above specified, although it was originally designed over a dozen
years ago.

It will be noticed in the design shown in Fig. 33 that the front
end of the front cabinet is in a vertical line with the front end of the
head-stock, as suggested by Professor Sweet, and about twelve

LATHE DESIGN: THE BED AND ITS SUPPORTS

years before his article was published, although it is probable that
he had held the same opinions therein expressed for a much longer
period than this would indicate.

There is much diversity of opinion as to the proper method of
designing the "shears," "ways," "tracks," "V's" or by what-
ever term we may designate the top portion of a lathe bed.

It has been shown in the "old chain lathe," Fig. 13, when beds
were made of wood, that the V's were made of strips of wrought
iron set on edge and fastened in rabbits cut in the wooden bed,
their upper edges chipped and filed in the form of an inverted V.
There were only two of these, the head-stock, tail-stock and car-
riage, all resting upon the same V's. Consequently, the carriage
was not able to run past the head-stock or the tail-stock, as is the
case with the modern lathe-bed having four V's.

The usual form of construction is shown in cross section in
Fig. 34, which is drawn to the usual proportion of the component
parts of a bed. As a matter of
strength, stability, and rigidity,
the center, at the top, of the in-
side V's A, A, and the lathe
center or center of the head
spindle B, should form an equi-
lateral triangle. An arc C, of a
radius struck from the center B,
and just clearing the V at A,
will be the radius of the swing of
the lathe

This matter of determining
"the swing" of a lathe differs
materially as between the prac-
tice of this country and Eng-
land. An English author, Mr.
Joseph Horner, states it thus :
"The 'centers' signifies the distance from the top face of the bed
to the centers of the spindles. English and continental lathes are
designated thus, but American by twice the centers, or the 'swing,'
in other words — the maximum diameter which a lathe will carry
over the bed." And with all due respect to the opinions and prac-

FIG. 34. — The Usual Form of Cross
Section of Bed with Four V's.

MODERN LATHE PRACTICE

tice of our cousins "on the other side/' it would seem the proper
designation, and the one in which a prospective purchaser would
be most interested, to tell him how large a piece of work could
be done in the lathe, rather than to tell him the half of this diame-
ter, or the radius, and let him have the trouble of the mental cal-
culation of multiplying this dimension by two every time it is
mentioned. It may seem all right when one is accustomed to it,
but, like the English monetary system of pounds, shillings, and
pence, it seems unnecessarily cumbersome when compared with
the directness of the American expression.

In order to increase the swing
of the lathe without raising the
head spindle in relation to the
bed, some builders prefer to omit
the inside V's, as shown in Fig.
35, by which means the arc C, as
given in Fig. 34, and here shown
as a dotted line, is increased to
the arc D, and the swing of the
lathe increased by twice this dif-
ference. In this case the head-
stock and the tail-stock are both
fitted to the flat top of the bed
and also have a projecting rib or
its equivalent built down and
fitted to the inside of the inwardly

FIG. 35.

- The English Form of Bed
with only Two V's.

projecting flange of the top of the
bed. This method of construc-
tion is that in use in English and continental lathes and in recent
years has been adopted by some lathe builders in this country.

Still another method for increasing the swing is shown in Fig.
36. This is by lowering the inside V's, upon which the head-
stock and tail-stock rest, and leaving the outer V's supporting the
carriage in their original position. In this engraving the arcs,
representing the radius of the swing in the two former examples,
are shown in dotted lines, and the increased arc E by a full line.
There are other advantages in the form of construction shown in
Figs. 35 and 36, which will be noticed later on.

LATHE DESIGN: THE BED AND ITS SUPPORTS

In Fig. 37 is shown the form of bed adapted by Lodge & Shipley,
which will be seen to be a modification of the preceding examples
in that, in this case, the English form of a flat surface is used in
place of the front V, while at the rear the inverted V-shape is
retained. There are several advantages in this form. The rear
V is preferred by some as a better method of locating the head-
stock and tail-stock in perfect alignment, inasmuch as that while
the head-stock, once located and securely bolted down, remains in
its fixed position whether resting on V's or upon a flat surface and

FIG. 36. — Bed with Depressed Inside
V's, giving Increased Swing.

FIG. 37. — The Lodge & Shipley
Form of Bed.

between vertical faces as in the English lathe. With the movable
tail-stock this is different. There is a constant tendency to wear
in all directions of contact, and if fitted between vertical surfaces
this tendency will in time throw it out of line. When resting upon
the inclined surfaces of the inverted V, the wear is likely to be
equal on the two sides and the lateral alignment is maintained,
while the vertical wear will be considerably less than that of the
head spindle in the boxes, which should be vertically adjustable
to compensate for this wear and so a proper and perfect alignment
of the two be maintained.

The bed shown in Fig. 37 is considerably deeper than the former

MODERN LATHE PRACTICE

examples, but corresponds very nearly to the proportions that have
been found necessary to the proper strength and rigidity of the
modern lathe when used under the severe strains and hard usage
incident to modern shop methods and to the use of high-speed
tool steels, with the necessity for the rapid reduction of the diameter
of the stock which would in former times have been considered
very wasteful of materials, but which in these days of cheap ma-
chine steel are much more economical than the usual processes
of forging the parts to nearly the diameters necessary, as was
formerly the usage when the price of steel was very much above
what it is now and the cost of labor considerably less.

It will have been noticed in the engravings of the cross sections
or beds thus far given, that the "side plates" or outer walls have
been uniform on the two sides and across the ends. Also, that the
bed is very much strengthened by the track or flat upper member.
To obtain a casting of nearly uniform shrinkage throughout, and
to diminish as much as may be the unequal strains, as well as to

add to the strength and
stiffness of the bed, the
lower edge has been reen-
forced by an additional
thickness for a short dis-
tance from the lower edge.
This has been made of
different forms by different
designers, but is substan-
tially as shown in these
engravings.

In Fig. 38 is shown an
ideal form of bed combin-
ing great strength and
stiffness with a minimum amount of material when its rigidity
is considered. Much is said in machine tool design of the "box
form," and while in some instances its merits may have been over-
rated it certainly is a form possessing most excellent qualities of
strength, stiffness, and power to withstand torsional strains as
well as to rigidly support heavy loads. It is for these reasons that
this bed is designed as it is, and for these reasons it seems fair to

FIG. 38.

- Ideal Form of Bed to Resist
Torsional Strains.

LATHE DESIGN: THE BED AND ITS SUPPORTS

call it an ideal form. The entire length of the sides or " side plates,"
are double, or of the "box form," tied together at frequent inter-
vals so that the outer and inner wall properly support each other.
To " balance the casting," there is not only an additional thickness
of metal at the bottom of the outer wall, on the outside, but an
inwardly projecting flange along the inside of the inside wall at
the bottom. As far as possible the casting and all its component
parts are of as nearly as may be the same thickness, so as to reduce
to a minimum the internal strains of the casting as it cools after
being "poured."

A further reference to the form and disposition of the cross-
braces or cross-ties is made a little further on in describing these
members of the casting.

Thus far the cross section of the bed, and its component parts
of the side plates, the track or top portion and the V's, have been

Iba

FIG. 39. — Forms of Cross-Ties or Braces.

shown, in addition to the front elevations and the various forms
of beds for supporting the weight of the head-stock, the tail-stock,
and the carriage. The next feature to be considered will be the
"cross-bars," or "cross-ties" as they are sometimes called.

The cross sections of these various forms are shown in Fig. 39
at A, B, C, D, and E, which give the principal forms in common
use. At A is the simple form or single bar, set on edge and used in
the earlier forms of cast iron lathe beds for many years. The
desire to get some form more rigid laterally led to the addition of a
horizontal rib, first on the top edge only and then on the bottom also,
making the I-beam section shown at B. This was for many years
considered quite sufficient for the purpose until the desire for more
strength and stiffness led to the adoption of the "box form" shown
at C. Later on this form was still further strengthened by the
addition of outwardly projecting ribs or flanges at the bottom

MODERN LATHE PRACTICE

edges forming the section that is shown at D. To this form has
since been added the top ribs as shown at E, and the question has,
for the time at least, been solved, of making as strong and rigid a
cross-bar as is possible.

It will be noticed that wherever these forms are with double
walls the internal space is closed at the top. This occurs, first, as
the bed is cast bottom side up, and it is more convenient to pour
the molten iron into this form and have a solid casting; it gives a
better appearance to the top of the cross-bar in the finished lathe;
and a cross-bar open at the top would furnish a receptacle for dirt,
chips, and small articles that would occasionally drop into it.

These cross-bars were located at right angles to the length
of the bed as shown in plan in Fig. 40, their distances apart in

FIG. 40. — The Usual Manner of Placing the Cross-Ties.

the earlier forms of beds being two or three times the width of the
center of the bed. This distance was gradually reduced as the
beds were made heavier and stronger, until ten or fifteen years
ago it was frequently the case that the cross-braces were spaced con-
siderably less distance apart than the width of the bed, particularly
in the wider beds used for heavy lathes, say from 36-inch swing
and larger. This method of locating them prevailed in the use
of the forms shown in cross section at A, B, and C, Fig. 39.

As still stronger and more rigid beds were called for, the braces
were placed at an angle, generally crossing each other, and of the
form and proportion shown in plan in Fig. 41. In this case it was
usual to use the forms shown in cross section at B, C and D, Fig. 39.
The angle at which these were set was varied by different builders,
that here shown being 45 degrees, and the most usual angle used.

In Fig. 42 is shown a plan of the ideal bed, a cross section of
which is shown in Fig. 38. These cross-braces are made of the

LATHE DESIGN: THE BED AND ITS SUPPORTS

sectional form shown in Fig. 39, at E, and are placed at an angle
of 30 degrees with the side of the bed, and in the illustration the
spaces between the walls of the braces as well as the bed are shown,
and also the proper spacing from the head end of the bed. It
will be readily seen that such a form of casting insures great stiff-
ness and rigidity and guarantees the casting against torsional

FIG. 41. — Angular Bracing with the Cross-Ties.

strains, as well as against unequal strains as the casting is cooling.
As a matter of design in providing a rigid bed this form seems to
realize all the desirable qualities that leave nothing more to be
desired. Yet it is possible that in the continual development of
the lathe, better methods and stronger beds will be brought out,
for what we consider to be of ample strength to-day may be
relegated to the scrap-heap a dozen years- from now.

FIG. 42. — Ideal Manner of Arranging Angular Bracing with Cross-Ties.

The form of the " track" or upper portion of the lathe bed has
much to do with the form and strength of the carriage which it
supports. In the early form of wooden beds, with two V's formed
from wrought iron bars set upon edge and chipped and filed to
the inverted V form, with the head-stock, tail-stock, and carriage
all resting upon them, the carriage had, of necessity, to be made

MODERN LATHE PRACTICE

with scant bearing on the V's, that is, very narrow, measured
along the length of the bed, as it could not pass the head-stock and
the tail-stock as the "wings" of the carriage do in the later forms
of bed with four V's, or their equivalent. Consequently, the head
center of the lathe had considerably more " overhang" than it has
at present, in order to permit the tool to be worked up near the
lathe center; and the same was true of working up closely to the
tail-stock center.

With the advent of cast iron beds four V's were usually pro-
vided for. Whether the idea of four V's came in with the cast
iron bed is not certain, as it is entirely possible that some ingenious
machinist fitted the wrought iron strips, not only to the inside but
to the outside of the two wooden beams composing the bed, and so

FIG. 43. — A Carriage on a Bed with Inside V's.

accomplished the same results as to providing a "wing carriage,"
capable of passing the head-stock and the tail-stock as we have
them to-day.

The lathe bed with four V's and the carriage suitable for it is
shown in Fig. 43, by which it will be seen that the portion of the
carriage coming over the inside V's at A must be cut away so as
to clear them entirely, as the carriage must rest wholly upon the
outer V's. The necessity for this cutting away to clear the inside
V's is a source of weakness to the carriage, and the only way to
compensate for it is to make this part of the carriage broader,
which does not add much to its strength, or to make it deeper, which
lessens the capacity of the lathe by decreasing its possible "swing
over the carriage."

In Fig. 44 is shown the effect when the inside V's are omitted,
and the carriage at A may be made of much greater strength with-
out raising its top line so as to decrease the swing over the carriage.

LATHE DESIGN: THE BED AND ITS SUPPORTS

It is clear that so far as the convenience of design and the strength
of the carriage is concerned this form of bed is preferable to the
one having four Vs. There is one disadvantage, however, which
occurs in fitting the head-stock and the tail-stock to this vertical
inner surface of the " track" at B, B. The head-stock, being fixed
to the bed, may be tightly fitted and remain so, but the tail-stock,

FIG. 44. — A Carriage on a Bed when Inside
V's are Omitted.

from its being a movable part and frequently run back and forth,
will in time wear sufficiently to throw its center out of line with
the center of the head spindle. This disadvantage may be obvi-
ated by making these vertical surfaces B, B, slightly inclined.

This inclination to the inner surfaces of the track of the bed is
shown in Fig. 45, which gives the form of a carriage when designed
to fit the ideal form of bed shown in Figs. 38 and 42. In this case

FIG. 45. — Form of Carriage for Ideal Form of Bed.

the full strength of the carriage is maintained and a second support
is furnished it inside of the outer V at the front and back by
the contact of flat, horizontal surfaces in the place where the inside
V would be in the form of bed having four V's. This construc-
tion shortens very much the "span" of the carriage between
supports and consequently renders it much more stiff and rigid,

86 MODERN LATHE PRACTICE

adapting it to much more severe strains in heavy work than either
style of carriage preceding it. In fact it is the strongest carriage
now known, in proportion to its weight.

The form and proportions of the lathe bed having been duly
considered, its different component parts illustrated and described,
and these detail matters criticised and commented upon, the next
part of the lathe to be dealt with would naturally seem to be the
legs, cabinets, or like supports upon which the bed is to rest.

The usual height of the centers of a lathe from the floor is about
43 inches, and in designing lathes this height is maintained without
regard to the capacity or swing of the lathe until its swing becomes
so large that with the bed resting on a properly built foundation on
a level with the floor, it becomes necessary to raise this height

FIG. 46. — Early Form of Cast Iron Legs with Braces.

sufficiently to obtain a bed of proper depth and a head-stock of
sufficient swing to meet the requirements.

Therefore the smaller the capacity of the lathe the higher will
be the legs or other supports under the bed.

In the early style of wooden beds, these supports were simply legs
of square timber bolted to the bed and either vertical or spread out
at the floor, according to the notion of the builder. When cast iron
beds came to be used the legs were also of cast iron and of rather
frail design. Later, when the necessity for more rigidity was found
desirable, not only the beds but their supporting legs were made
heavier.

In a shop near Boston was found a lathe provided with an ex-
ample of the earlier form of cast iron legs strengthened by cast iron
braces as shown at A, A, A, A, Fig. 46. The lathe was 12-inch
swing and of the hand lathe pattern, with a wooden cone pulley

LATHE DESIGN: THE BED AND ITS SUPPORTS 87

on the spindle, probably built about 1840. The legs were quite
light, the different members being about j inch thick and 2 inches
wide. The braces were of the same dimensions and secured at the
ends by J-inch "tap bolts" of the old square-head style, the ends of
the braces being thickened somewhat to accommodate them.

How this lathe happened to endure the wear and tear of shop
use for so many years without the legs being broken is a mystery.
Their frail and slender appearance beside the modern deep bed,
supported by heavy cabinet legs, is an object lesson in the practical
evolution of the American lathe.

With the continually increasing weight and rigidity of the lathe
beds to meet the hard service of modern shop methods and high-
speed steels, first represented by the Mushet tool steel, it became
necessary to furnish much better supports for the lathe beds, and
the fact was apparent that these supports must extend for a greater
distance along the length of the bed than the older form of legs ever
had. At this time there were several of the different machine tools
supported on a " cupboard base," or a base of rectangular form-
having a door giving access to its interior for the purpose of stowing
away tools, change-gears, wrenches, and like articles. This form
of base was prominently used in the Universal Milling Machine.
Whether the " cabinets" for supporting a lathe bed were suggested
by this use of them or not does not appear, although it seems prob-
able. We know that wooden cupboards had been used under
lathes, being fastened to the legs and used for the same purposes as
the cabinets or cupboards formed in the bases or, as sometimes
called, the " standards" or columns of the later machines.

At the present time a number of lathe builders still use the old-
style legs, made heavier and with the material better distributed
for strength, and, as a rule, the top portion of the leg extending
farther along on the under side of the bed for the purpose of giving
better support.

It is also the case that the cabinet form of bed supports is used
more upon expensive lathes, such, for instance, as those designed
more particularly for tool room and precision work. For turret
lathes and screw machines they are also much used, and are often
cast as an integral portion of the bed itself instead of being made as
a separate piece and bolted on.

88 MODERN LATHE PRACTICE

Cabinet supports for lathe beds are made in various forms by
the several builders, some of which will be illustrated in this chapter.
These will be such as have some general features common to nearly
all of them, and in addition a few of the forms having special
features.

The correct principle governing the dimensions of cabinet
supports should be properly understood. Obviously, the reasons
for substituting cabinets for the earlier form of legs was to obtain
a better support. It was certainly possible to so design the leg as
to amply support the weight of the lathe and all that could be put
upon it by way of work to be done by it. The disadvantage
was that a leg placed at each end of the bed and extending only a
short distance along under it left a long stretch of bed with no

FIG. 47. — Lathe Bed Supported by Old Style Legs.

support at all. This necessitated " center legs " and, in a long lathe,
two or three of them. Under these conditions it was a difficult
matter to so set up a lathe that these center legs should all sit
level and support the bed in a correct, level, straight line.

These difficulties are in a great measure avoided in the lathes
provided with cabinet supports. In Fig. 47 the effect of the old-
style legs is seen. Attention is called to the fact that the head-
stock is only supported by the leg at the outer end, while the point
at the front journal where the heaviest weight comes has no sup-
port whatever from the leg. The same may be said in a lesser
degree of the rear end, where the tail-stock has only partial support
in a similar manner. And when the tail-stock is moved out of its
extreme rear position the case is much worse and identical with
that of the head-stock. This condition will, of course, necessitate
the use of a center leg, which if not supported upon the floor or

LATHE DESIGN: THE BED AND ITS SUPPORTS 89

foundation in a perfectly correct position will do as much harm as
good. If it is too low it will be of no benefit since the center of the
bed may sink under the weight, and strain of the work upon the
carriage. If it is too high the lathe will be thrown out of line.

In sharp contrast to these conditions is the bed shown in Fig.
48. In this case the front cabinet is of a length on the bed equal to
the length of the head-stock, hence the front bearing of the head
spindle has a support of solid iron down to the foundation, or floor
upon which the cabinet supports rest. The tail-stock is similarly
supported by a cabinet occupying the distance equal to its length
upon the bed. An argument in favor of this method of sup-
porting the bed is not necessary as the conditions are self-evident.

FIG. 48. — Form and Proportions of Cabinet Supports.

But there is still another reason why the cabinet support is
the more rigid, and that is the fact that with the long distance on
the bed to which the cabinet is firmly and solidly bolted comes
additional stiffness and rigidity, not only in a vertical direction for
sustaining weights, but also to withstand the torsional strains to
which every lathe bed is subjected, and which are multiplied rapidly
as we load the lathe with heavier work, take heavier cuts, and use
high-speed tool steel, by which much greater speed may be used.

The next matter to be considered is the form of the cabinet,
although this is a secondary consideration, the first being that we
have the cabinet and that it reaches out under the bed to the prac-
tical length as shown in Fig. 48.

For small lathes, say from 12 to 20-inch swing, the cabinet is
frequently made nearly square While this is wrong in theory, as
has just been explained, it is an improvement upon the old-style

MODERN LATHE PRACTICE

leg. The form shown in Fig. 48 is substantially that used by
Lodge & Shipley in their smaller lathe. Its peculiar feature is
the strength, vertical end walls, without projections at the base,
while the regular projection is made in the front and the rear. This
form is less expensive in its pattern work and somewhat easier to
mold, but its appearance is not as good as the one shown in Fig. 50

FIG. 49. — The Lodge
& Shipley Cabinet
for Small Lathes.

FIG. 50. — Ideal Form of
Small Lathe Cabinet.

which has equal projections on all four sides and at the top and
bottom, thus giving it a more symmetrical appearance. It may
have only three sides enclosed, the side walls turning the corner
for only an inch or so, and this side be placed underneath the lathe
bed, as is now done by some of the builders. But as this cut-away
portion would come directly under that point of the head-stock
where the most support is needed, it is of doubtful utility to cut it
away, or to reduce the support of solid iron at this point.

FIG. 51. — Cabinet and Cupboard.

Lathes for light work, of 12 to 18-inch swing, may be supported
by square cabinets, but if for heavy duty and continuous hard
work the cabinets should be considerably longer than they are
wide and support the bed as shown in Fig. 47.

In Fig. 51 is shown a form for head and tail cabinets, or " Cabinet

LATHE DESIGN: THE BED AND ITS SUPPORTS

and Cupboard," for medium-sized lathes, say from 20 to 28-inch
swing. These answer the conditions as represented in Fig. 48, and
are not excessively expensive. They also furnish one closed cabinet
and an open cupboard, both of which are available for storing tools,
gears, and similar articles. The arched opening at A affords a

FIG. 52. — The Lodge & Shipley Form of Cabinet
for Large Lathes.

convenient space for introducing a lever or bar for the purpose of
moving the lathe. This arch should be placed in the cabinets of all
but the smallest ones, and even in them a small arch suitable
for the use of a crowbar will be found convenient.

In either of the styles of cabinets shown the shelves may be
cast in, but the usual method is to cast strips upon which the ends
of wooden shelves may rest, thus making not only the pattern
work but the foundry work more simple and economical.

FIG. 53. — The Hendey-Norton Form of Cabinet
for Large Lathes.

In Fig. 52 is shown the form of cabinet used by Lodge & Shipley
for large lathes and which gives an excellent support to the bed and
its superstructure.

In Fig. 53 is shown a similar cabinet used by the Hendey-Norton
Company, differing from the last one in having the inner end cut
away. This cabinet does not, of course, admit of the introduction

92 MODERN LATHE PRACTICE

of shelves. In the larger lathe, say from 30 to 40-inch swing, inclu-
sive, doors are not usually provided, as the height does not admit
of it. Above 40-inch swing the bed usually rests directly upon the
foundation.

The cabinets here shown are given simply as examples, but
they give a good idea of the forms used by most of the modern
lathe builders at the present time, and the reasons for their con-
tinued and enlarged use. It is altogether probable that the future
will witness an increase rather than a decrease in the use of the
cabinet for supporting machines of all kinds where it is possible
to introduce them, on account of their great rigidity in proportion
to the weight of cast iron used, as well as the fact that they furnish
a safe and convenient receptacle for tools.

CHAPTER V

LATHE DESIGN; THE HEAD-STOCK CASTING, THE SPINDLE AND THE

SPINDLE CONE

Design of head-stock for wooden bed lathes. Early design for use on a cast
iron bed. An old New Haven head-stock. The arch form of the bottom
plate. Providing for reversing gears. The Hendey-Norton head-stock.
The Schumacher & Boye head-stock. The Le Blond head-stock. The
New Haven head-stock. The arch tie brace of the new Hendey-Norton
design. Generalities in describing a lathe spindle. Designing a spindle.
Governing conditions. The nose of the spindle. Spindle collars. Proper
proportions for lathe spindles. Large versus long bearings. Design
of the spindle cone.

THE subject of lathe design is continued by the consideration
of the design and construction of the head-stock, which in some
respects is the most important part, and with it and the parts which
go to make up the complete head-stock, the most important
group of parts in the lathe.

In the earlier form of lathes this piece was, like most of the
other parts, simple and crude in design as well as in the workman-
ship bestowed upon it. It generally consisted of a base and the
two upright ends in which provision was made to receive the boxes,
and when wooden beds were thought sufficient for a lathe a strip
was added beneath that filled the space between the two timbers
forming the bed. Such a design for a head-stock is shown in Fig.
54, which is taken from an old lathe that did many years' service in
a general repair shop. It will be noticed that the housing for the
spindle boxes do not have square edges, but are of V-shaped form.
They were finished with a file only and the boxes made of cast iron,
filed to a fit and lined with babbitt metal which was said to have
been poured around the lathe spindle after it was finished, set in
place, and lined up as well as might be with the crude appliances

MODERN LATHE PRACTICE

at hand. The top portion of the boxes were held down by a straight
bar cap with two holes which fitted over fixed threaded studs
that had been cast into the head-stock for this purpose.

The lathe was devoid of a back gear and the spindle carried a
three-step cone, the largest part of which was as large as was possible
to get into the head, and a belt quite wide, considering the power
then thought necessary to drive a lathe carrying the diminutive
chip which was considered proper for a lathe to take at the time this
lathe was in use.

Later on, when the cast iron bed was adopted and when back
gears were added to the lathe, the requirements of additional
strength were recognized and not only the base plate, but the up-

FIG. 54. — Early Form of Head-Stock for Wooden
Lathe Bed.

rights or housings at the front and rear end, were made thicker and
heavier. One of these head-stocks is shown in Fig. 55, which
gives a good general idea of the form of the casting and shows also
a strengthening brace A. While it would seem at first thought
more necessary to brace the housing of the front box than that
carrying the rear journal, it should be remembered that the latter
must withstand the strain of the " thrust" or endwise pressure of
the spindle due to holding work upon centers, and the pressure of
drilling work, one end of which is held in a chuck and the other in
a center rest, and similar kinds of work. While in the modern
lathes this thrust device is usually a part of the rear box, the earlier
method was to fix two studs in the rear of the head-stock, one in

LATHE DESIGN: THE HEAD-STOCK CASTING, ETC. 95

each side of the rear box and on a horizontal line with it, and across
these to fix a strong bar carrying an adjustable thrust screw for
taking the end thrust of the spindle. The details and design of
this important device will be taken up further on.

FIG. 55. — A Later Form of Head-Stock with Back
Gears and a Strengthening Brace.

In Fig. 56 is shown a peculiar form of head-stock upon an old
lathe in one of the older shops in New Haven, Conn. The lathe
was broken up for old iron after an indefinite period of idleness.
It was of about 16-inch swing and the various members of the head-
stock were about one and one-half inches square. The bed of the
lathe, and the legs which supported it, were of cast iron and very
much like those shown in Fig. 46. The head was provided with
back gears of very light design and the lathe had a lead screw and

FIG. 56. — Form of Head-Stock on Old Lathe found
in New Haven, Conn.

feed-rod adapting it for thread cutting. It was undoubtedly con-
sidered a proper engine lathe "in its day."

The next form of head-stock which followed that shown in Fig.
55 seems to have been of the form shown in Fig. 57. In this case

96 MODERN LATHE PRACTICE

the base of the casting was raised in arch-like form and the under
side recessed to the same form so as to maintain an equal thickness
of metal throughout. This form seems to have been a favorite one
and many lathes were built by various makers with substantially
this form, the variations from it not being of sufficient importance
to justify a further classification.

As yet the housings had not been made thick enough to suggest
coring them out in order to save iron or for the purpose of avoid-
ing unequal contraction of the metal upon cooling after casting,
by making all members of the casting of as nearly an equal thick-
ness as possible. Of late years these points have received much
attention and study by the designers of machine tools, and rightly

FIG. 57. — One of the Older Favorite Forms of
Head-Stock.

so, as their importance was to a large extent overlooked in the
earlier designs, the reason probably being that all castings were
made so much lighter and had much less strain to withstand in the
regular service to which the machine was put.

In Fig. 58 is shown a modification of the arch form shown in
Fig. 57, which has for its purpose the strengthening obtained by
the rib A in Fig. 55, only in a better form, as the method is " cored
out," or formed with a " green sand core" under the head-stock, so
as to provide for an equal thickness of metal over the entire base.
This raised portion could be introduced quite conveniently as the
small end of the spindle cone was located over it, thus insuring
ample space for building it up.

In the examples thus far shown of lathe heads the feed gears

LATHE DESIGN: THE HEAD-STOCK CASTING, ETC. 97

were located outside the housings, except in the case of that shown
in Fig. 56. As the change came to be made of locating " tumbler
gears," or reversing gears, inside of the housing, it naturally fol-
lowed that the metal of the head-stock base must be cut away
under that part of the main spindle upon which *was fixed the
spindle gear or feed gear from which the feed mechanism was
driven. This was the case for perhaps fifty years, and at the present
time, now that reversing devices are constructed as a part of the
apron mechanism, the feed gears may be placed outside of the
housing, although some good builders still keep it inside and con-
nected in practically "the same old way," even if the "yoke gears"
or reversing gears are omitted.

FIG. 58. — Another Form of Strengthening Brace.

When reversing gears were thought necessary to be upon the
inside of the housing, a hole was cut out for them in the raised
arch A, Fig. 58, and this practice was followed in any head-stock
having this or a similar obstruction to these gears, and provided,
of course, that they were to be located inside of the rear housing.

One of the recent modifications of the above form is that shown
in Fig. 59, which is a type of the Hendey-Norton manufacture.
The central figure is a front elevation with the sectional form indi-
cated by dotted lines. The figure at the left is a rear end elevation
with the internal form on the line A, A, of the central figure, while
the figure on the right is a similar elevation of the front end with
dotted lines showing the section on the line B, B.

It will be seen that the portion of the base on the line A, A, is of
arched form, somewhat as shown at A, Fig. 58, while the form at

MODERN LATHE PRACTICE

the line B, B, is of an inverted arch, or as frequently called by the
shop men a "pig trough" shape. This latter form enab'es the
metal to be carried higher up at the front and back while the center
is depressed to give proper clearance for the larger steps of the cone
and the face gear. At the lowest part of this depression there is
usually an opening through which oil may drip so as not to collect
inconveniently at this point. The arch-like form near the rear
housing adds very much to the strength and rigidity of the casting.
It will be noticed that in this design the main spindle boxes are
not " capped in," that is, held down by removable caps. More
will be said of this peculiarity in describing boxes and spindles.

The cores beneath the base are carried up into the housings in
many of the modern head-stocks as far as possible, and still leave
ample support for the boxes and spindles. The advisability of

FIG. 59. — The Hendey-Norton'Form of Head-Stock.

this method of lightening the weight of the casting is still an open
question among machine tool designers who have endeavored to
avoid unequal strains in the shrinkage of castings by making all
members of as nearly equal thickness as possible. Sometimes this
idea is carried too far and the result is liable to be that of sacrificing
the necessary rigidity to prevent vibration, in the effort to follow
out the ideal as to strains.

Fig. 60 shows a head-stock in which the inverted arch form is
continued the entire length between the housings, but is carried
upon a curved line as shown and forms a very graceful curve. The
three figures are arranged the same as those comprising Fig. 59.
The height of the curve might be greater at the line A, A, as will
be shown in some others further on in this chapter, and the strength
of the casting considerably increased.

LATHE DESIGN: THE HEAD-STOCK CASTING, ETC. 99

This form is used with few modifications to adapt it to the diam-
eters of driving-cones, the nature of the back gears and the feed
gears and similar conditions that tend to somewhat alter the
construction outlines of its design. This form seems to be a favorite
one with designers, since among all the different builders and
the variety of designs there are more builders using this form
than all the others put together.

FIG. 60. — Form of Head-Stock built by a Majority of Lathe Builders.

While the above form of design carries a reversed curve for the
top of the base, the form used by Shumacher and Boye, shown
in Fig. 61, is of a single curve from rear to front housing and the
inverted arch in its transverse sectional form. In this design the
front and back is carried high up near the rear housing and com-
paratively low down near the front housing.

FIG. 61. — The Schumacher & Boyce Form of Head-Stock.

This is a design of much strength and rigidity in proportion to
the weight of the casting, the metal being well distributed to resist
heavy strains in the operation of the lathe.

The Le Blond type is shown in Fig. 62. In this we have a
straight line at the back and front, with a modification of the re-
versed curve and the combination of the arch proper and the in-
verted arch as shown in Fig. 59. The form is pleasing to the eye,

100

MODERN LATHE PRACTICE

and the strength of the casting is quite sufficient for the require-
ments. In this case the housings are made of ample width,
especially the front one. They are cored out inside so as to
have substantially an equal thickness of metal at nearly all parts.
The New Haven type of head-stock is shown in Fig. 63. In

FIG. 62. — The Le Blond Form of Head-Stock.

this case the inverted arch is used all the way through, but it is
upon straight lines, that form a cross section at A, A, continuing
straight and on a proper incline to a point near the line B, B, from
whence it is horizontal.

This design gives great strength, and with the proper propor-
tions and thickness of metal throughout it is as rigid as it is possible
to design a head-stock. The housings are unusually thick and cored
out underneath as shown by dotted lines.

The design shown in Fig. 64 is by Hendey-Norton, and is prac-

FIG. 63. — The New Haven Form of Head-Stock.

tically the same as that shown in Fig. 59, except for the arched
brace C, from the front to the rear housing, effectually tying
them together and thus adding considerably to the rigidity of the
spindle-bearing boxes, which is always an excellent point to be
considered.

The fact that these housings are solid, that is, not held by separ-
ate caps, permits the addition of this very strong brace, which could

LATHE DESIGN: THE HEAD-STOCK CASTING, ETC. 101

not be efficiently added to a head-stock whose boxes are held in by
a separate cap.

While this idea is now quite common in the design of milling
machines, it has not been applied to the head-stocks of lathes by
any builders but these so far as is known.

There are many classes of work in which a head-stock so braced
would be very valuable, as its strength and rigidity is much increased
by it and the strain and vibration is considerably reduced, which
has the effect of increasing the efficiency and also the life of the
cutting-tools. This question of increased rigidity and the impor-
tance of obtaining it has received much attention in the past few
years, and the result has been the constant increase in the pro-

FIG. 64. — Special Form of Hendey-Norton Head-Stock.

portions and the weights of all parts of metal-working machinery
which form the supports of cutting-tools or their intermediary
parts. It is altogether probable that in this increase in weight the
limit has not been reached, but that it will continue in years to
come, although not perhaps in the same proportion that it has dur-
ing the last decade. The use of high-speed steel will, doubtless,
be extended to other uses than at present, and its price will be
materially reduced, thus increasing the amount used and conse-
quently demanding stronger machines and more power to drive
them, so as to continually reduce the cost of the product by reduc-
ing the time of machine operations.

Having designed a good head-stock with ample proportions in
general, the metal so distributed as to withstand not only the
strains to which it will be subjected in performing its appointed

102

MODERN LATHE PRACTICE

functions, but with proper considerations for the changes which
will take place in the process of casting and cooling, and not for-
getting that castings will change their form more or less for weeks
after being cast, our next concern will be the spindle.

It is not enough to say, as catalogues sometimes do, that "the
spindle is of hammered crucible steel of large diameter and runs
in hard bronze boxes." This may all be relatively true and yet it
may be neither properly designed or properly constructed for the
uses to which it is to be put.

To design a lathe spindle we must consider the work it has to do,
the points at which it will be supported, the points where it must
support the material that is to be machined, and the parts with

FIG. 65. — Lathe Spindle showing Principal Weight on
Front Bearing.

which it is loaded and which become a part of its attendant mech-
anism ; not only these points, but others that are equally important,—
the torsional strains to which it will be subjected in performing its
regular functions, and which include that of driving the piece
to be turned, of the strains of the cone when driving direct, or
the back gears or triple gears when they are in action, and of the
feeding mechanism which derives its motion from the rear end of
the spindle.

If we are to consider principally the weight of the face-plate
and the material to be turned, which falls almost entirely upon the
front journal, we should have the form of the lathe spindle as repre-
sented in Fig. 65. In this case the front bearing would necessarily
be very large and strong and with ample support. The rear bear-
ing need not be a matter of serious consideration, as it is quite a

LATHE DESIGN: THE HEAD-STOCK CASTING, ETC. 103

distance from the front bearing, while the weight of the face-plate
or chuck carrying the work, or the center which supports one end
of the work, if supported by this means, carries nearly all the strain.
Therefore the rear bearing may be small and short as shown.

Again, if the weight of the cone and its parts are to be prin-
cipally considered, we should have a spindle more nearly conform-
ing to the outline shown in Fig. 66, the rear bearing being larger
and the front bearing smaller than is shown in Fig. 65. This would
also be the case if the upward pull of the belt were a governing
factor in determining the form and proportion of the spindle. But
the fact is that the cone and its action upon the spindle, so far as
its weight or the belt pull upon the spindle, while in reality a factor

-B £-

FIG. 66. — Form of Lathe Spindle when undue prominence
is given to Cone Pulley.

to be considered, as will be referred to later on, is not the prime
factor by any means. Therefore we must recur to the form shown
in Fig. 65 for the points necessary for the proper consideration of
forms, the determination of the contour, and the proper propor-
tions of the lathe spindle.

This view of the case leads us to the choice of a medium between
the two extremes presented and an ideal form as shown in Fig. 67,
wherein the conditions governing both the former examples are
properly considered and met.

There is one more condition to be considered, however. This
is the upward or lifting tendency supposed to exist by reason of the
cutting-tool forming a fulcrum, which, in connection with the cir-
cular motion of the piece being turned, tends to lift the spindle in
the front box and so throws an upward strain on the cap over the

104

MODERN LATHE PRACTICE

front journal. This tendency is represented in Fig. 68, wherein
the arrow shows the direction of the belt and revolution of the
material being turned. It is doubtful, however, if this point is of
much importance, particularly in a lathe properly designed as to
the dimensions and weights of its parts, especially of the spindle
and its appendages.

FIG. 67. — Ideal Form of Lathe Spindle.

Taking all these matters into consideration we shall find that
the proper proportion and design of the spindle with the face gear,
cone pinion, and the feed gear, will be substantially as shown in
Fig. 68, leaving out of the design for the time being the special

FIG. 68. — The Ideal Spindle shown in Practical Form.

form of journal oiling devices, the thrust bearing for the rear end
and the special form of the nose of the spindle, which will next
receive attention.

As to the nose of the spindle. It is customary by many builders
to cut the thread on the nose of the spindle nearly up to the collar,

LATHE DESIGN: THE HEAD-STOCK CASTING, ETC. 105

against which the chuck-plate or the face-plate takes its bearing.
It is a well-known fact that it is extremely difficult to accurately
center such a plate upon a threaded portion of a spindle. As the
purpose of the thread is simply to prevent the plate from coming
off the spindle, it naturally follows that the length of this thread
may be very much reduced without in any way reducing its capac-
ity to securely hold the plate in place. It is also quite as evident
that we can hold the plate perfectly true in its place and exactly
concentric with the front bearing if we grind a portion of the nose
of the spindle to a truly cylindrical form when we grind the front
bearing and then fit a sufficient portion of the bore in the plate to
this ground surface. This may be accomplished by threading the
nose of the spindle through only one third of its length, and grind-
ing the remaining two thirds to which the chuck-plate or face-plate is
fitted. This centers the plate accurately with the axis of the spindle.
If the face of the collar is accurately ground, and the hub of the
chuck-plate or face-plate fits fairly against it, there will be no diffi-
culty when removing the plate of always being able to replace it in
exactly its former position, perfectly true in the running of its face
and perfectly concentric with the ground bearings of the spindle.
Even the wearing of the thread will not effect its true running,
since the only office of the thread is to hold it on, while the ground
surfaces insure its trueness. This is
shown in Fig. 69.

In this connection it is noticeable,
that some manufactures omit the large
collar on the front end of the spindle
and furnish only a small shoulder on
the spindle, due to the nose being some- FlG' 69' ~ Nose of sPindle'
what smaller than the front bearing, against which the face-plate
or chuck-plate rests, and assuming that its close fit upon the ground
surface between this shoulder and the threaded portion will be
quite sufficient for all purposes. This would seem to be an errone-
ous view of the question as this comparatively small shoulder can-
not possibly afford the support and rigidity that may be obtained
by a collar or thrust surface of two or three times the area. It is
true that as a matter of economy in furnishing the stock for these
spindles the question favors the omission of the shoulder. But

106 MODERN LATHE PRACTICE

as a matter of good design and proper shop practice it will hardly
be disputed that the larger collar, forged on, is the proper design
and construction.

Referring again to Fig. 68, there are several points to which it is
proper to call attention. The spindle boxes represented are of
bronze and such as are now commonly used in good lathes. The
formation of the front end of the spindle with its fixed collar formed
in the forging is also the usual practice, except in some of the lathes
of newest design and development, in which it is probably omitted
as being considered an unnecessary expense. The thrust bearing
is similar to that represented in Fig. 74, but an improvement upon
it, since a hardened steel ring is interposed between two bronze
rings, which render cutting well-nigh impossible.

The cone pinion is made of machine steel and has a long sleeve
forced into the small end of the spindle cone. While it is not good
practice to run two steel surfaces together unless one is hardened,
it is still perfectly practicable in this case as the pinion is of ordinary
soft machine steel while the spindle is 50 to 60-point carbon crucible
steel, which answers the conditions in practice and many lathes are
now built in this manner.

The spindle is shown bored out, as a large majority of lathes are
now so constructed and the demands of the customers require
hollow spindles in nearly every instance when the lathe is over
12-inch swing.

The proportions upon which this design is made may be inter-
esting. Using the full swing of the lathe in inches as a unit, repre-
sented by A, the proportions of the spindle will be as follows:

Diameter of the front bearing, A -f- 5.7"

Length of the front bearing, A -j- 3.6"

Diameter of the rear bearing, A -=- 6"

Length of the rear bearing, A -=- 4.5"

Length of the nose of the spindle, A -r- 6"

Distance between bearings, A X 1.2"

Diameter of bore through spindle, A -=- 10"

In Fig. 70 we have a spindle of somewhat overgrown propor-
tions, yet one of proportions advocated by an eminently practical
mechanic who is said to have remarked that he " didn't want a
lathe spindle with a front bearing so many inches diameter and so

LATHE DESIGN: THE HEAD-STOCK CASTING, ETC. 107

many inches long, but he wanted it with a bearing so many inches
large and so many inches short," by which we may readily under-
stand his idea that a large and short front bearing was much better
adapted to the work than one of medium diameter and extra
length.

Thus if we have a front bearing of 3J inches diameter and 5
inches long, and we increase the diameter 50 per cent and reduce
the length in the same proportion, viz., one third, we shall have about
the same area of bearing surface, but we shall gain the advantage
of bringing the driving-cone closer to the work, of shortening the
whole length of the spindle, and of making the front end of the
spindle much more rigid and better adapted to withstand
the strain of a heavy cut on work of the usual diameters, and still

FIG. 70. — Lathe Spindle with Extra Large Bearings.

better when large facing work is to be done and the cut is carried

I out near the periphery of the largest diameter that can be handled.
It does not follow, however, that the proportions of the en-
larged diameter of the front bearing need be carried all the way
through, by which a spindle of unnecessary weight would be pro-
duced, as practically all important advantages may be gained if its
dimensions are as shown in dotted lines in the engraving.

In Fig. 71 is shown the opposite method of designing a lathe
spindle, that is, by making the bearings of the usual diameter, but
increasing the length to a considerable extent. It is evident that
while there are always certain advantages in increasing the dis-
tance between the supporting boxes, there is an apparent tendency
to weakness, or lack of rigidity of the spindle at the vital poiot.
namely, the overhanging portion of the front end of the spindle

108

MODERN LATHE PRACTICE

which supports the face-plate, the chuck, or the work as it bears
upon the lathe center.

As between the two designs of extra large bearings and extra
long bearings, the practical advantages seem to be in favor of the
former.

FIG. 71. — Lathe Spindle with Extra Long Bearings.

The spindle cone should receive due attention. The method
of introducing the cone gear sleeve into the small end of the cone
has been referred to in connection with Fig. 68. The large end-ef
the cone may have an inwardly projecting flange cast integral with
it or made separate and attached by screws. In either case the
locking bolt must be accommodated in it. Between this head and
its bearing it should be well supported from the central quill. This
may be done by providing for four or more radial plates extending
from the connection with the central quill under the smallest step
to one half the remaining distance toward the large end of the
cone, as shown in Fig. 68.

FIG. 72. — Form of Cone Steps.

In finishing the outside of the cone the rising steps should be

faced up as shown in Fig. 72, that is, with the face cut back from

to a6 of an inch, according to the size of the cone, for the pur-

LATHE DESIGN: THE HEAD-STOCK CASTING, ETC. 109

pose of lessening the friction on the edge of the belt. In cases
where this relief is not given to the belt it is not an unusual con-
dition to find the edges of belts running over cones, particularly at
high speeds, to be turned up, the corners where the belt is joined to
be distorted or worn away, and in a short time the belt well-nigh
ruined.

In purchasing lathes or other machines provided with speed
cones, the purchaser should insist that the faces of the cones should
be made as shown, as it is a matter of much importance in belt
economy and belt efficiency.

CHAPTER VI

LATHE DESIGN : THE SPINDLE BEARINGS, THE BACK GEARS, AND THE
TRIPLE GEAR MECHANISM

Designing spindle bearings and boxes. Thrust bearings. The Lodge &
Shipley form. Ball bearings. Proper metal for boxes. The cast iron
box. Early form of boxes. The cylindrical form. Thrust bearings for
a light lathe. Experiments with different metals on high speeds. Curved
journals. The involute curve. The Schiele curve. Conical bearings.
Adjustments to take up wear. Split boxes. Line-reaming boxes. Lu-
brication of spindle bearings. The plain brass oil cup. The use of a
wick. Oil reservoirs. Loose ring oilers. Chain oilers. Lodge &
Shipley oil rings. Neglect of proper lubrication. Back gearing. Vary-
ing the spindle speeds. Triple gearing. Theory of back gearing. Back
gear calculations. Triple gear calculations. Diagram of spindle speeds.
Faulty designing of back gears and triple gears. Four examples. A 14-
inch swing lathe. A 19-inch swing lathe. A 17-inch swing lathe. A
30-inch swing triple-geared lathe. Explanation of the back gear dia-
grams. Essential parts of the triple gear mechanism. "Guesswork"
in lathe designing. Wasted opportunities. Designing the head-stock.
Cone diameters. A homely proportion. The modern tendency in cone
design. Proportions of back gears. Driving the feeding mechanism.
Reversing the feed. Variable feed devices. Rapid change gear devices.

GREAT care ought always to be used in the design of the bearings
of the spindle and the boxes in which they run. To a great extent
these determine the life and usefulness of the lathe, for with an
improperly made spindle or poor boxes, either of design or quality
of material, the lathe is soon worn so much out of true as to bejDrac-
tically worthless.

Mention has been made of the thrust bearing at the rear box.
It is important that this should be well designed and constructed,
as the quality of the lathe's work, particularly face-plate and chuck
work, depends upon its proper performance.

One form is shown in Fig. 73, which is a style used for a number

LATHE DESIGN: THE SPINDLE BEARINGS, ETC. Ill

of years on the New Haven lathes. It consists of a hardened steel
ring B, forced into an annular groove in the end of the hollow
spindle A. The rear end of the bronze box C is extended as shown
and tapped out with a fine thread. Fitted to this is the thrust
sleeve D, whose forward end bears against the ring B. The sleeve
D is adjusted by means of two slots (one of which is shown) cut
across its face, and is held in position by the check-nut E. This
device is much improved by the addition of a hard bronze ring,
loosely interposed between the thrust sleeve D and the hardened
ring B. The sleeve D was made of a steel casting, as was also the
check-nut E, which had holes drilled around its circumference for
the accommodation of a spanner for adjusting it. The device was
very successful in practical use.

FIG. 73. — New Haven Lathe
Thrust Bearing.

FIG. 74. — Lodge & Shipley
Thrust Bearing.

The form of thrust bearing used on the Lodge & Shipley lathes
is shown in Fig. 74, and is constructed as follows : Upon the spindle
A is keyed the cast iron ring B. Next to this is a bronze washer C;
next a hardened steel washer D; then another bronze washer E,
which in turn rests against the faced end of the rear box F, which in
this case is formed of the head-stock casting itself.

While this is an efficient form of end thrust it has the disadvan-
tage of occupying some space inside the rear box and consequently
increasing the distance between the front and rear boxes, increasing
the length of the head-stock by just its own width, or the space
occupied by the cast iron collar and the three friction washers.
Unless covered by a projecting portion of the casting, or by a
special guard over it, there will be more or less trouble on account
of dirt working in between the washers. This, however, is easy
to prevent by a proper design and construction.

112 MODERN LATHE PRACTICE

The popularity of the ball bearing and its successful application
to many different uses no doubt suggested it as a proper device for
the thrust bearing of a lathe. It has been objected to in a lathe
designed for fine work, on account of the possible influence of any
slight vibration caused by the rapid rotation of the balls, owing to
any inaccuracy in their perfect spherical shape or diameters. Yet
the device is in apparently successful use on many lathes at this
time. The construction is shown in Fig. 75. Upon the spindle A

is fixed the collar B, having a ball-
race cut in its rear side as shown.
Fixed to the end of the box, or the
inside of the rear housing, as the
case may be, is the collar C, which also
has a ball-race formed in it, and set
deep enough to form a sleeve which

projects out over the balls and the
FIG. 75. — Ball Thrust Bearing. • r J

collar B, so as to protect the balls

from dirt. This thrust is open to one of the objections urged
against the form shown in Fig. 74, namely, the space it occupies on
the lathe spindle.

It is entirely feasible, however, to place this device, or the one
shown in Fig. 74, near the rear end, or even at the center of the rear
box if so desired. In this location it would have the added advan-
tage of position for ample lubrication and absolute protection from
dirt.

There has been a great deal of discussion on the question of
what is the proper metal, and what is the proper form for a lathe
spindle box. Any number of different metals have been used for
this purpose, from cast iron at a cost of two and one half cents per
pound to a fine quality of nickel-bronze worth thirty one cents
per pound.

It is an old and a true saying that with a good, true, and well
finished journal, and the bearing kept free from dirt, always clean
and well lubricated with good oil, a cast iron box is as good as
anything that can be made. Every practical shop man of even
moderate experience can cite instances of the excellent record of
the old-time cast iron box, and the fact that it is still used by some
of the oldest and best lathe manufacturers is certainly a strong

LATHE DESIGN: THE SPINDLE BEARINGS, ETC. 113

argument in its favor. But one condition is always insisted upon :
it must be kept clean and free from dirt. It will not stand dirt.
Under adverse conditions many bronze boxes withstand success-
fully dirt, grit, and poor lubrication that would put the cast iron
box out of business in a few hours.

Of course it is assumed in all these remarks that the lathe
spindles are made of 50 to 60-point crucible steel, and that they
have been accurately ground, as this is the only method by which
we can insure the perfect cylindrical form of the bearing that is so
necessary to the successful operation of a lathe.

The older form of designing the housing of the head-stock for
the reception of the boxes was to have the opening at the head and
rear end of square form and covered by a straight bar of cast iron
or machine steel, secured at the ends by hexagonal headed cap
screws. Later on it was found more economical to make these
spaces circular and to have them bored out with a boring bar, the
boxes being fitted to the circular opening and capped down, when
the inner surface of the box itself was bored out and hand reamed.

For small lathes, such as bench lathes and precision lathes, it is
necessary to carefully exclude dirt as well as to have correct
bearings, since a good, true bearing will not long remain so if ex-
posed to dust and dirt or even to poor and dirty oil used as a lubri-
cant.

In Fig. 76 is shown a thrust bearing for a light lathe that is pro-
vided with an adjustment on
both the front and the rear side
of the rear housing. This is
done by providing the steel col-
lars B, B, threaded to fit the
spindle A, so as to allow adjust-
ment at either end, and that one
of these collars at each end shall FlG" 76 s~a^eLat^eearing for
act as a check-nut to the other,

while the wear is taken by the loose bronze collars C, C, interposed
between the steel collars and the face of the housing.

The faced sides of the housing project to the front and rear a
short distance, and this projecting part is threaded and has fitted
to it the dust-caps D, D, which may be made of steel, as shown,

114

MODERN LATHE PRACTICE

but are frequently made of brass. They are bored to fit the spindle
rather closely so as to more effectually exclude dirt. In some in-
stances it may be advisable to place outside of the outer collar B
a felt washer closely fitting the spindle, which will be an effectual
means of insuring a clean bearing.

If the thrust on the spindle is considerable, it may be well to
interpose two washers so as to decrease the friction, and for still
heavier thrusts we have always recourse to the plan of using a steel
washer with a bronze one on each side of it, which will in nearly
every case be found sufficient even with a very heavy end pressure.
In the case given in Fig. 76, it will be noticed that the spindle runs
in a reamed hole in the cast iron of the head-stock itself. This
has been so arranged purposely and forms a very good bearing
when carefully protected from dirt. Such bearings may, of course,
be lined with genuine babbitt metal or with brass, bronze, or any
of the so-called " anti-friction metals."

In an extended series of experiments, the purpose of which
was to ascertain the best materials for a shaft and a box running
at high speeds, in this case 7000 to 8000 revolutions per minute, it
was demonstrated that a hardened and ground tool steel spindle,
running in a box of cast tin, bored, reamed, and scraped, would
far outlast any of the dozen or more materials tested. The inner
surface of the box soon took on a glaze that was nearly black and
very glossy, and this was retained during over a year's wear to the
author's personal knowledge, and probably much longer. In this
series of experiments a steel shaft and steel box was ruined in less
than an hour's run.

Hitherto attention has been
directed to straight or cylindri-
cal bearings, that is, those of
the same diameter at both
ends. Where a very accurate
bearing is required, and one
that will stand a great amount
of wear and still maintain its

correct alignment, the involute
FIG. 77. — Involute Front Bearing. , . <* -n. f-n . ,-,

bearing shown in Fig. 77 is the

proper form. About one half the length of this bearing may be a

LATHE DESIGN: THE SPINDLE BEARINGS, ETC. 115

straight line, but conical, inclined two degrees from the axis. The
remainder of the length has either an involute or elliptic form to a
diameter 60 per cent larger than the small end of the bearing. The
involute form is preferable, while the "Schiele curve" is, of course,
the ideal contour. The spindle is held in place by the collars B, B,
threaded upon the spindle A, and a bronze washer C, interposed to
eliminate friction. While this is theoretically correct and entirely
practicable, it is an expensive bearing to make and to fit up in
small numbers, and when special tools are made for it they are ex-
pensive to maintain.

For these reasons there was designed a sort of compromise
form which is shown in Fig. 78,
and which is not subject to
the disadvantages referred to
above. The conical portion
has an inclination of three de-
grees with the axis, and the
angle at the large end is twenty
degrees from a right angle with
the axis. In practice it is much
more economically made and FlG- 78- — Conical Front Bearing,
fitted and answers all conditions nearly as well.

The arrangements for taking up wear are the same as those
shown in Fig. 77. In neither case is a thrust bearing required at
the rear box. In some respects, particularly in small lathes, this
is considered the better practice.

In Fig. 79 is shown
another form of adjustable
bearing which, like the de-
signs shown in Figs. 77 and
78, has the very important
advantage of always main-
taining the correct align-
ment of the spindle. One
of the difficulties of all spin-

7Q dies running in " split

79. — Adjustable Conical Front Bearing.

boxes is that the lower
half of the box wears more than the cap and consequently the

116 MODERN LATHE PRACTICE

spindle is gradually but surely wearing lower. This is corrected by
placing pieces of paper or very thin metal under the lower box.
But as sufficient attention is seldom given to this point in keeping
a lathe in proper condition, it is most unusual to find a lathe
whose centers are in perfect alignment.

In the present case the spindle A is cylindrical, that is, with no
taper, and runs in a hard bronze sleeve B, which has a taper of two
degrees on each side and fits closely in the taper reamed hole in the
head-stock housing. This bronze sleeve is split through its length
and arranged to be drawn into the taper hole by means of two nuts
C, C, threaded upon its small end. One of these nuts acts as a
check-nut to the other. Therefore the bronze sleeve may always
be drawn as tightly around the spindle bearing as may be desired,
and effectually held in that position. As the compression is the
same through the entire circumference, the spindle will retain its
central position and correct alignment even after a very consider-
able amount of wear, and a new bronze sleeve may be readily fitted
when the first one is worn out. This substitution is not only
economical but the exact alignment is still preserved.

It may be argued that this sleeve, like the split box, will wear
most at the bottom. This is perfectly correct, but an occasional
turning of the sleeve through a quarter or a sixth of a revolution,
effectually corrects this tendency.

As shown in Fig. 79, this bearing is protected by dust-caps or
rings D, D, which may still further be reinforced by the introduc-
tion of felt washers.

However these bearings are made and whatever care may be
exercised in machining and fitting the boxes or in securing a correct
alignment of the circular or square receptacles in the housings for
receiving the boxes, it will be found generally necessary and always
safe and advisable to " line-ream" the boxes after they are in place
and securely clamped. This is done by fixing very carefully ground
shell reamers upon a perfectly true arbor or mandrel, and hand
reaming both boxes at the same time. The previous diameters
should have been made very close to the finished dimensions so as
to leave as little as possible to ream by hand. Really the cutting
edges of the reamer should barely scrape out a very trifle of the
metal. In fact, it should be rather a scraping than a reaming job,

LATHE DESIGN: THE SPINDLE BEARINGS, ETC. 117

but it will generally be found in practice that the reamer will scrape
a little harder in one place than in another, showing the practical
necessity for its use.

In the drawings illustrating the different forms of bearings and
spindles the devices by which the journals are lubricated have been
omitted so as not to confuse the question. The matter of lubrica-
tion is, however, an important one, and will next claim our atten-
tion.

In many cases the spindle bearings are lubricated by means of
a simple oil hole closed by a plug of brass. In others a short vertical
tube is inserted and covered by a cap which entirely encloses it.
In still others the " plain brass oil cup" is used, that is, a simple
receptacle, usually urn-shaped, whose top is closed by a cover
screwing into it. Again, various patented devices are employed,
ranging all the way through "good, bad, and indifferent," whose
object is to furnish easy access to the oil tube and to provide, in
many cases, for the automatic closing of the oil tube or reservoir
for the purpose of excluding dirt.

An improvement upon the plain brass oil cup is shown in Fig. 80.
This improvement consists in the intro-
duction of a vertical tube A, whose
lower end opens into the hole leading
to the journal bearing. This tube is
fitted with a wick B, whose lowrer end
rests upon the journal C, and whose
upper end is coiled loosely about in
the oil chamber. When the oil in the
reservoir is above the top of the tube
the wick prevents the oil from run-
ning down too rapidly. When the oil
is below the top^of the tube the wick
acts as a siphon and thus insures the
lubrication of the bearing.

The use of a wick is resorted to in the next example, shown in
Fig. 81. In this case an oil reservoir is formed in the housing of
the head-stock A, and a suitable opening in the form of a slot parallel
to the axis of the spindle is cut through the lower box. Into this is
fitted a flat wick B, or piece of coarse soft felt whose upper edge

FIG. 80. — Siphon Oil Cup.

118

MODERN LATHE PRACTICE

rests against the bottom of the journal C, and whose lower end is
immersed in the oil filling the reservoir. Capillary attraction is
depended upon for drawing the oil up to the bearing, although with
oil at the height shown in the cross section, on the right of Fig. 81,
the oil is gradually forced up to the under side of the journal.

FIG. 81. — Lubrication by Capillary Attraction.

This plan has the advantages of keeping the journal and its
lubricant free from dirt; of straining the oil so that any dirt it may
contain will not reach the bearing; of providing for a quantity of
oil so as to make frequent additions to the supply of oil unnecessary ;
and of furnishing a handy method of introducing a new supply of
oil, by way of the hole D, closed by the stopper E.

In large machines, using a con-
siderable quo-: tity of oil, a drain-
age tube is" provided through
which the sediment and dirt may
be gotten rid of when necessary.
This tube is closed by a stopcock.
This method of lubrication is
very largely and successfully used
in countershaft boxes, which, from
their comparatively inaccessible
position are very liable to be neg-

FIG. 82. — Loose Ring Oiler.

lected in the matter of proper lubrication.

The use of a loose ring for raising oil to the journal bearing is
shown in Fig. 82. In this case a loose, flat ring B, of considerable
larger inside diameter than the diameter of the journal C, is placed
around it and allowed to hang down into the oil in a reservoii

LATHE DESIGN: THE SPINDLE BEARINGS, ETC. 119

formed in the head-stock A, similar to that shown in Fig. 81. The
revolution of the spindle is usually sufficient to keep the ring in
motion so as to draw up a sufficient supply of oil to lubricate the
bearing. In this case, also, oil may be introduced through the hole
D, usually closed by the stopper E. One ring is sufficient for a
bearing and is placed in the center of it, the box or box lining ma-
terial being grooved out for this purpose.

In Fig. 83 is shown a similar
device to the above, except that a
flat linked chain is used instead of
a circular ring. It is obvious that
by lengthening the chain it will
necessarily dip deeper into the oil
than a circular ring possibly could,
while the openings in the links of
the chain will more readily carry
up the oil than will a smooth ring
devoid of openings or raised parts. Fl<5' 83' ~ The Loose Chain Oiler'
In both the above cases an internal groove is cut in the inside of
the journal box to accommodate the ring or chain, and an opening
made entirely through at the bottom for the entrance of the oil.

FIG. 84. — The Lodge & Shipley Type of Oiler.

A modification of the ring device is shown in Fig. 84, which illus-
trates a type of lubrication used in the Lodge & Shipley lathes. It
consists of a ring B fixed to the journal and having formed upon it
four buckets G, G, G, G, opening in the direction of rotation, whose
function is to dip up the oil as they pass through the reservoir and

120 MODERN LATHE PRACTICE

to pour it over the journal as they successively pass over the
highest point of their revolution. Suitable ducts distribute the
oil length wise of the bearing and return it to the oil reservoir
to be used again and again. Thus a positive provision is made
for supplying the journal with oil, and the manufacturers assert
that a spindle so fitted up will run for a month without a new
supply of oil. The oil reservoirs are said to hold about a pint
and the supply is introduced through the oil hole D, which is pro-
vided with the glass tube F, closed by the stopper E, and through
which the height of the oil in the reservoir may be observed
through the opening cut in the metal surrounding the glass tube
as shown in the engraving.

The practical utility of such a means of lubrication is at once
apparent, as the neglect of workmen to attend to the proper lubri-
cation of lathe spindles, as well as many other parts of the machine
where oil is necessary, is one of the most fruitful sources of lathe
difficulties that occur. And a spindle that has been allowed to
"run dry" and its finely ground and polished surface to become
cut and "roughed up" is very difficult to ever get in as good working
condition again as before this kind of abuse happened.

The author has known of instances where the designer had pro-
vided an oil reservoir which had been filled when the lathe was being
tested and which had operated well and lubricated abundantly.
The lathe was shipped to a customer, set up and run, and in a few
months the parts returned completely destroyed from lack of lubri-
cation, the fact being evident that no oil had ever been placed in
the reservoir when the supply first introduced, as above stated, was
exhausted. Such neglect of the most ordinary precautions is a
good illustration of the very poor shop conditions which still
exist in some otherwise well-managed shops.

The gearing in the head-stock of a lathe by which the speed of
the spindle is varied is in general terms called the "back gearing,"
since the purpose of it is to "gear back," that is, to reduce the speed
of the spindle.

There are three methods of changing the speed of the spindle,
namely: by running the driving-belt on the different steps of the
cone; by means of the usual back gearing; and by means of what
might be termed a secondary back gear, or as generally termed the

LATHE DESIGN: THE SPINDLE BEARINGS, ETC. 121

"triple gear." This is by some manufacturers of lathes called the
1 double back gear."

In Fig. 85 is shown a diagram of the driving mechanism of a

Countershaft, 140 R.P.M.

FIG. 85. — Diagram of the Driving Mechanism of a Back Geared Lathe.

back geared engine lathe. At the top of the engraving is shown
the countershaft cone A, as this performs an important part in the
changing of speeds. The spindle cone B runs loose upon the lathe
spindle and is fixed to it at will by a lock bolt passing through the
face gear C, which is permanently keyed to the spindle. U#on the

122 MODERN LATHE PRACTICE

small end of the cone is fixed the cone pinion D, which meshes into
the back gear E, which is fixed at one end of the back gear quill, or
sleeve G, which carries at its opposite end the quill pinion F. This
quill runs freely upon a shaft called the back gear shaft, which is
provided at each end with eccentric bearings, and at one end a
lever for operating them, by means of which the back gear quill G,
with the back gear E and quill pinion F, may be thrown out of
engagement with the cone pinion D and the face gear C.

The operation of the device is as follows: the cone B, rotating
the cone pinion D at a certain speed, and the back gear E being
engaged with it, will rotate the latter at a speed proportional to the
number of teeth in the two gears. In this case the cone pinion
D having 32 teeth, and the back gear E having 88 teeth, the ratio
of their respective revolutions will be as 2f to 1 ; therefore, if the
cone were running at 275 r.p.m. (revolutions per minute), the back-
gear quill would run at 100. This speed is still further reduced by
the quill' pinion F and the face gear C. These two have respectively
24 and 96 teeth and consequently a ratio of 4 to 1, so that the
spindle speed, by the introduction of the back gears and the with-
drawal of the lock bolt attaching the cone B and the face gear C to
each other, will be reduced to 25 revolutions.

Therefore, if we divide the revolutions per minute of the spindle
cone by the ratio of the cone pinion with the back gear multiplied
by the ratio of the quill pinion with the face gear, we obtain the
spindle speed. Or, in detail, in this case, 88-^32 = 2.75, and
96 -r- 24 = 4, and 2.75 X 4 = 11, which is the combined . ratio or
the normal back gear ratio. In short, the cone speed divided by
the back gear ratio will give the spindle speed, thus : 275 -^11 = 25.

The various speeds given to the spindle cone by belt changes
depend, of course, upon the porportions of the diameters of the
various steps of the cone. When there are five steps on the cone,
the central step on each cone is usually of the same diameter, and
as the two cones are generally cast from the same pattern, so far
as the outer shell is concerned, it is simply a question of reversing
one so that the belt shall be on the largest step of one and the
smallest end of the other, or the intermediate step above or below
the central step.

In the diagram shown the steps are respectively 20, 17, 14, 11;

LATHE DESIGN: THE SPINDLE BEARINGS, ETC. 123

and 8 inches in diameter, and the ratios as follows, viz. : 20 to 8 =
2.5; 17 to 11 = 1.545. These ratios multiplied or divided (accord-
ing as to whether the step on the countershaft cone is larger or
smaller than the one used on the spindle cone) by the revolutions

FIG. 86. — Diagram of the Driving Mechanism of a Triple Geared Lathe.

per minute of the countershaft will give the various cone speeds.

Figure 86 is a diagram of the driving mechanism of a triple
geared lathe. So far as the countershaft cone, spindle cone, and
the back gearing are concerned it is identical with the mechanism

124 MODERN LATHE PRACTICE

shown in Fig. 85, except that the quill pinion E is so constructed
as to slide out of engagement with the face gear, and also that
there is a third gear on the back gear quill G, namely the pinion
H, which engages the gear J fixed to the triple gear shaft K,
which also carries the internal gear pinion L, which in turn engages
the internal gear M fixed to the back of the face-plate P, which is
attached to the front end or nose of the lathe spindle N.

The triple gear shaft K is adapted to slide endwise in its bear-
ings, and to be retained in either position so as to bring the gear J
and pinion L out of engagement with the pinion H and internal
gear M when the triple gear is not in use. This position is repre-
sented in the engraving by dotted lines.

As the pinion H has 30 teeth and the triple gear J has 90 teeth,
the ratio existing between them is 3. And as the pinion L has 20
teeth and the internal gear has 200, their ratio is 10. Therefore,
these two ratios multiplied together is 30, which multiplied by the
ratio of 2.75, existing between the cone pinion D and the back
gear E, produces 82.5, which is the triple gear ratio. It will be
noticed that in this calculation the face gear C and quill pinion
F are not taken into account, as they are not engaged when the
triple gear is in operation.

The following summary of back gear and triple gear, as well as
cone conditions, is given for convenient reference:

Cone diameters, 8, 11, 14, 17, and 20 inches.

Countershaft speed, 140 revolutions per minute.

Cone pinion, 32 teeth; back gear, 88 teeth; ratio, 2.75.

Quill pinion, 24 teeth; face gear, 96 teeth; ratio, 4.

Combined ratio, or back gear ratio, 11.

Triple gear pinion, 30 teeth; triple gear, 90 teeth; ratio, 3.

Internal gear pinion, 20 teeth; internal gear, 200 teeth; ratio, 10.

Combined ratio of the triple gearing alone, 30.

Triple gear ratio, including first back gear ratio, and as is usually
given, 82.5.

The spindle speeds, with the countershaft running at 140 r.p.m.,
are given in the following table:

LATHE DESIGN: THE SPINDLE BEARINGS, ETC. 125

Cone speeds Back Gears and
Triple Gears not in use.

Back Gear speeds; Triple
Gears not in use.

Triple Gear speeds, including
first Back Gear.

56.QO
9t08

5.09

8.82

.690
1.175

' 140.00

12.72

1.696

216.30

19.63

2.621

350.00

31.81

4.240

To graphically illustrate the spindle speeds the diagram in Fig.
87 is given. The principal curve beginning at the bottom of the
diagram shows the five cone speeds and the five back gear speeds,
while the diagram at the top on a much larger scale gives the five
triple gear speeds. From this diagram a good idea of the propor-
tions and the regular progression of speeds may be obtained.
While the progression of speeds shown are those proper under
the circumstances, it will be found that there are many lathes in the
market in which they are not realized, often, doubtless, owing to
careless designing. In making this statement it is not meant that
the slowest and the fastest obtainable speeds are not proper.. It
does not mean that the high speeds are not fast enough, since we
can readily get a faster speed by speeding up the countershaft.
In the same way we may obtain a slower range of speeds by reduc-
ing the speed of the countershaft.

But what is meant is that as between the three series of speeds
known as cone speeds (or open belt speeds), back gear speeds, and
triple gear speeds, there will be too much of a break between these
divisions or groups, or there will be an overlapping of speeds so that
one or two speeds of one group are very nearly duplicated in the
next higher or lower. In this way a triple geared lathe of nominally
fifteen speeds will give but thirteen practically different speeds.
In the example given in Fig. 87 it will be noticed that the speeds
rise in a very regular progression, the numbers up the sides of the
diagram giving the speeds and those beneath giving the serial num-
ber of the fifteen speeds from slowest to fastest.

To illustrate some of the common faults in the designing of
back gears, attention is directed to the four examples shown in
Figs. 88, 89, 90, and 91.

In Fig. 88, there is too much of an increase of speed between the

126

MODERN LATHE PRACTICE

7 8 9 10 11 12 1.8 U

FIG. 87. — Speed Curves of a Triple Geared Lathe.

fastest speed of the back gear and the slowest of the cone speed.
This amounts to a difference of 47 revolutions, as the former is
48.9, and the latter 96. The entire range of speeds is :

LATHE DESIGN: THE SPINDLE BEARINGS, ETC. 127

Cone Speeds

395

234

149

Back Gear Speeds

48.9
29.
18.4
11.9

The countershaft runs 130 revolutions per minute. The back
gear ratio is 8.08 to 1.

In this lathe a four-step cone is used, therefore giving only
eight speeds. The lathe is a small one, the swing being 14 inches
and intended for light work and a comparatively fast range of

130 R.P.M.

FIG. 88. — Back Geared
Lathe, 8 speeds.

FIG. 89. — Back Geared
Lathe, 10 speeds.

speeds. It will be noticed that the countershaft cone is consider-
ably larger than the spindle cone, which is an unusual condition.

In the next example a lathe having a five-step cone is selected.
It is a 19-inch swing lathe and intended for much heavier work
and back gears having a much wider face, in fact 50 per cent, while
the pitch of the teeth is in about the same proportion.

Figure 89 shows the driving mechanism for this lathe, whose
back gear ratio is 13.46 to 1, and whose countershaft speed is 130
revolutions per minute.

128

MODERN LATHE PRACTICE

In this case the increase of speed between the fastest back
gear speed and the slowest cone speed is 23.7, while the next speed
below varies only 10 revolutions, which is a palpable fault in the
caclulation of the speed progression. The following are the spindle
speeds :

343.0

206.0

Cone Speeds

130.0

82.2
49.2

Back Gear Speeds

25.50
15.30
9.65
6.10
3.65

For this size of lathe the highest and lowest speeds are as they
should be, but the proper progression is at fault.

Figure 90 is a diagram from a lathe of 17-inch swing and having
a five-step cone, a back-gear ratio of 12 to 1, and a countershaft
speed of 150 revolutions per minute. The same fault of too great
a difference between the fastest back gear speed and the slowest
cone speed is observed.

The spindle speeds are as follows:

Cone Speeds

371.0

231.0

150.0

97.5

60.6

Back Gear Speeds

30.90

19.25

12.50

8.10

5.05

The difference above referred to is 29.7, while the next differ-
ence below is only 11.35.

The next example is of a 30-inch swing, triple geared lathe in
which the speed calculations show an error only too common among
lathes of this type. It will be noticed by reference to the engrav-
ing, Fig 91, that the countershaft cone is considerably larger than
the spindle cone, which is entirely unnecessary since the same object
might have been secured by running the countershaft faster and
the parts need not be so heavy or expensive. The questions of
proportion and progression of speeds can be easily taken care of
when both cones are alike, if the proper calculations are made.

The countershaft speed is 110 revolutions per minute.

LATHE DESIGN: THE SPINDLE BEARINGS, ETC. 129

The back gear ratio is 15.23 and the triple gear ratio 57.74 to 1.
The spindle speeds are given below :

Cone
Speeds

372.0
212.0
137.0

88.7
52.5

Back Gear
Speeds

24.40

13.90

9.00

5.82
3.45

Triple Gear
Speeds

6.44
3.67
2.37
1.53

.81

By reference to these figures it will be seen that the triple gear
speed of 6.44 exceeds both the back gear speeds of 3.45 and 5.82,
which renders them comparatively useless, ^or which makes the two

110 R.P.M.

150 R.P.M.

FIG. 90. — Back Geared
Lathe, 10 speeds.

FIG. 91. — Triple Geared Lathe,
15 speeds.

higher speeds given by the triple gears of no effect in practical
work. Otherwise, of the five triple gear speeds two are of no prac-
tical use.

Hence, we have a lathe provided with fifteen nominal speeds,
which really has but thirteen. This point will be more readily
appreciated by referring to the speed curve shown in the diagram,

130

MODERN LATHE PRACTICE

1 2

10 11 12 13 14 15

FIG. 92. — Speed Curve of a Triple Geared Lathe
Wrongly Designed.

Fig. 92, and the faults of designing more clearly brought out by
comparing this diagram with the two curves shown in the diagram
given in Fig. 87, being careful to note that the upper curve repre-

LATHE DESIGN: THE SPINDLE BEARINGS, ETC. 131

senting the triple gear speeds is drawn to a scale ten times larger
than the curve for the back gear speeds and the cone speeds. The
object of this was to show more clearly the progressive increase of
the triple gear speeds, whose continued upward tendency would
properly join with those of the back gear if the latter were drawn to
the same scale, which the dimensions of the page would not admit.
The figures for these speeds are given on a previous page, to
which the reader is referred, and a comparison with the speeds
given in the last example is suggested.

FIG. 93. — Triple Gearing of a Lodge & Shipley Lathe.

In the diagrams of driving mechanisms in Figs. 85, 86, 88, 89, 90,
and 91, the countershaft cone is shown above the spindle cone and
the back gear and triple gear mechanisms below. This is so
arranged for convenience in giving the relative dimensions and
proportions of the parts. While it is the usual method to place
the back gear device at the back of the lathe head-stock or in the
rear of the spindle, it is not at all necessary that it should be so
placed, and in fact, on some of the larger lathes, it is placed in front
of the main spindle as a matter of convenience.

The essential parts of the triple gear mechanism in connection
with the usual back gears are well represented in the rear view of
a head-stock shown in Fig. 93, in which the triple gear device is
shown engaged and the quill pinion thrown out of engagement with

132 MODERN LATHE PRACTICE

the face gear. In this case a clutch connection between the back
gear shaft and the triple gear shaft serves to handle the pinions on
both so as to be moved into and out of engagement at one and the
same time, thereby running the lathe as a back geared or a triple
geared lathe, by a very simple and convenient change. The design
is of a lathe built by Lodge & Shipley.

While it is not the intention of the author to assume to present
in this work an exhaustive treatise on lathe design, for the reason
that the scope of the plan is not extensive enough to permit it,
and for the further reason that it does not seem necessary in view
of the objects for which it is written, it does seem thoroughly in
keeping with what is proposed, to give such facts as to some of
the more important points of design as will serve as cautions to
the designer, as interesting lines of thought to the machinist, and
as information to the buyer of lathes.

These have been the considerations governing what has been
presented in relation to back gearing and triple gearing as well as
dimensions of cone steps.

There are several matters intimately connected with this sub-
ject which seem to merit still further consideration.

Any one who will take the trouble to examine, as the author
frequently has, a lot of lathes in almost any machine shop and to
make the most superficial calculations of their speeds, will be sur-
prised at the amount of apparent "guesswork" that has entered
into their design. The speed curve shown in Fig. 92 is a case in
point. Narrow-faced back gears without any calculations, so far
as one may see, of the strain which they must bear; small pinions,
whose teeth are soon ground away on account of the sharp angles
of their action; a lack of proper proportion between cone dimensions
and back gear dimensions; and many other similar faults.

We have all seen lathes with a 3-inch vertical belt on a 5-inch
cone, while the overhead horizontal belt driving the countershaft
was 4 inches wide on a 15-inch pulley; when every mechanic
knows that a horizontal belt will drive more than a vertical one,
aside from the difference in the diameters of the pulleys being all
in favor of the larger pulley.

When we consider these questions we cannot avoid the conclu-
sion that there have been many good opportunities wasted and

LATHE DESIGN: THE SPINDLE BEARINGS, ETC. 133

that the money spent for these machines should have produced
much more really practical and useful machines than it has, and
that they should have been capable of turning out a much larger
output than we find them doing.

In designing a lathe head-stock the triangle formed by the dis-
tance from center to center of the inside V's, as a base, and the
lathe center the apex, should be an equilateral triangle. Sufficient
material must be provided under the largest step of the cone and
the face gear to give the requisite strength and rigidity. The
large step on the cone should, fill the remaining space with the
exception of a sufficient clearance for the belt. The large diameter
of the cone having been thus fixed the diameters of the other steps
are a question of proportion, according to how many steps there are
and what is to be the smallest diameter. It is common practice
to make the steps of the spindle cone and the countershaft cone
identical. This, on a five-step cone, will give a spindle speed
(without back gears) equal to the countershaft speed when the
belt is on the middle step. The spindle speed will be correspond-
ingly faster or slower according as the belt is on the smaller or larger
steps of the spindle cone, and in the same proportion as the cone
steps are to each other.

The cone diameters having been fixed the back gear ratio must
be made to correspond. We cannot have an arbitrary cone pro-
portion and an arbitrary back gear ratio. Only one can be fixed,
and the other must be arranged to correspond with it.

A homely proportion, but one that will come out very nearly
right in practice, in determining the proper width of face for the
cone steps, will be one seventh of the swing of the lathe when no
triple gears are used. If triple gears are used it is common practice
to make the belt a trifle narrower. The present tendency is towards
wider belts and it seems to be a very proper development made
necessary by modern shop, conditions and the use of high-speed
steel tools. It is altogether probable that belts will be made wider
rather than narrower in the future.

There is also a tendency to make the differences between cone
step diameters less, which gives a larger diameter to the smaller
steps, and consequently more power in the driving mechanism of
the lathe and avoids the necessity for very tight belts.

134 MODERN LATHE PRACTICE

Ordinarily, the width of the face gear should not be less than
eight tenths of the width of the cone steps, and the width, of the
back gear not less than six tenths. Of course, the pitch. -v
teeth should be in proper proportion to the width of the fact, <1
in the larger lathes the pitch of the teeth of the face gear should be
one number coarser than that of the back gear.

Usually the face gear has an outside diameter about equal to
that of the largest step of the cone, but should not be larger. The
outside diameter of the cone pinion should not be much smaller
than the smallest cone step. These dimensions thus coming with-
in rather narrow limits, the diameter of the back gears and that of
the quill pinion will be governed by the ascertained or the arbi-
trary back gear ratio.

In order to avoid the interference of a large back gear with
the desired form of the head-stock at this point, and to secure a
symmetrical contour, the back gear shaft can advantageously be
raised above the level of the main spindle. This is permissible
to the extent of 1 J inches on a 36-inch swing lathe.

The method of transmitting the power from the spindle to the
feeding mechanism, formerly done almost exclusively with a belt
on cone pulleys, one of which was upon the head shaft (located
below the spindle and driven by it through the medium of gears),
and the other on the feed rod. The lead screw was, of course,
driven by gears so as to obtain a positive motion. In modern
lathes nearly all have gear-driven mechanism for both the rod feed
and the screw feed.

The former practice of reversing the feed in the head-stock is
now to a large extent abandoned, and this function performed at
the apron, and is much more convenient to the operator.

The mechanism for driving the lead screw in thread cutting and
for a large range of feeds is now very popular and is accomplished
wholly by gears with appropriate levers, shafts, and clutches. Those
for driving the feed rod are usually known as " variable-feed de-
vices" and those for thread^ cutting are known as "rapid change
gear devices." It is not unusual to find these combined so that
one set of variable-speed gears is adaptable to both functions.

These devices will be considered further on in this work, and
representative inventions for these purposes will be given.

CHAPTER VII
LATHE DESIGN: THE TAIL-STOCK, THE CARRIAGE, THE APRON, ETC.

Functions of the tail-stock. Requisites in its construction. The Pratt &
Whitney tail-stock. The Reed tail-stock. The Lodge & Shipley tail-
stock. The Blaisdell tail-stock. The Hendey-Norton tail-stock. The
New Haven tail-stock. The Prentice tail-stock. The Schumacher &
Boye tail-stock. The Davis tail-stock. The American Watch Tool tail-
stock. The Niles tail-stock for heavy lathes. New Haven tail-stock for
heavy lathes. The Schumacher & Boye tail-stock for heavy lathes. The
Bridgford tail-stock for heavy lathes. The Le Blond tail-stock. The
lever tail-stock. The lathe carriage. Requisites for a good design.
Description of a proper form. A New Haven carriage for a 24-inch lathe.
The Hendey-Norton carriage. The Blaisdell carriage. The New Haven
carriage for a 60-inch lathe. Criticisms of a practical machinist on
carriage and compound rest construction. Turning tapers. The taper
attachment. Failures of taper attachments. The Reed taper attach-
ment. The Le Blond taper attachment. The Lodge & Shipley taper
attachment. The Hamilton taper attachment. The Hendey-Norton
taper attachment. The New Haven taper attachment. The Bradford
taper attachment.

THE function of the tail-stock is to support the end of the piece
of work opposite to the head-stock; to furnish a movable center
for various forms of drills, reamers, and similar tools; and to carry
one end of boring bars when the work is clamped to the carriage.

For these purposes it must be of sufficient strength and rigidity
to withstand the strain to be put upon it; it must have a traveling
spindle to carry the tail center; and be capable of being "set over"
in a direction at right angles to the center line of the lathe, for the
purpose of turning tapers, and in some types of lathes for boring
operations.

It is fitted to the two inner V's of the lathe the same as the
head-stock, so as to permit the carriage wings to run past it, and
must be capable of being securely clamped in any position along

135

136 MODERN LATHE PRACTICE

the length of the bed. The spindle must, be adapted to be handled
by a hand wheel upon the traverse screw in small and medium
sized lathes, and in large lathes located conveniently in front1 and
connected with the screw by suitable shafts and gearing. The
spindle should be adapted to be clamped at its front end in an
efficient manner so as to hold it firmly and at the same time not to
force it out of correct alignment with the head-stock spindle.

The tail-stock should have a long bearing upon the V's, which
should be at least two thirds of the swing of the lathe. The bolts
for clamping it down should be considerably nearer the front than
the rear end so as to counteract the lifting tendency due to pressure
against the center. In lathes of 12 to 30-inch swing two bolts will
be sufficient to rigidly secure it to the bed. In larger lathes, four
bolts should be used.

For the purpose of setting over for turning tapers the tail-stock
is composed of a low base and the movable part of the tail-stock
proper, the transverse adjustments being made with a cross screw
furnished with a square head. The two parts are held together by
the holding-down bolts which secure the tail-stock to the bed.
In larger lathes, say from 30-inch swing up, the division between
the two parts is near the top, which should be secured by an ad-
ditional set of four bolts so that the spindle may be set over with-
out releasing the holding-down bolts which secure it to the bed.
Thus, if a heavy piece of work is supported upon centers the tail
spindle may be set over for turning tapers without removing the
work from the centers.

In lathes of 24-inch swing and over there should be a rack and
pinion device for moving the tail-stock to any desired position on
the bed. In lathes of 36-inch swing and over this device should
be back-geared so as to give sufficient power to easily move the
heavy mass.

This back gearing should begin with a ratio of two to one, and
increase as the lathe is larger and the tail-stock is heavier, so that
one man may conveniently do the work.

Engravings of tail-stocks, as designed by prominent builders,
are introduced to illustrate these conditions and the manner in
which they have been met.

The Pratt & Whitney tail-stock is shown in Fig. 94. Its par-

LATHE DESIGN: THE TAIL-STOCK, ETC.

137

ticular feature is the overhang at the front end for giving extra
support to the spindle. The spindle is larger than usual, which
gives better support to the center and is very useful when using it
to support the rear end of a
drill or reamer when long holes
are to be drilled or reamed. It
is secured to the bed by an

eccentric and lever device
which is quick and conven-
ient.

Figure 95 shows a front FIG. 94. — 14-inch Lathe Tail-Stock, built
view of a Reed tail-stock for b^ the Pratt & Whi^ey Company,
a 27-inch swing lathe. It will be noticed that the holding-down

bolts are in line with the bed
and both at the front of the
upright supporting the spindle
sleeve. They are so placed to
permit the upright to be cut
away in front so as to permit
the compound rest to swing
around to a position much nearer
parallel with the line of the bed
than with the ordinary form.
A rear view is shown in Fig.

FIG. 95. -Front View of 27-inch Lathe 96> which is of the same tail-
Tail-Stock, built by the F. E. Reed stock except that a three-bolt

crank replaces the hand wheel.

The form of the casting is well shown as seen from the rear,
form is called the "off-set tail-
stock."

Figure 97 is an excellent
view of the Lodge & Shipley type
of tail-stock for small lathes, and
shows their device for clamping
the spindle, and the mechanism
of the tail-spindle screw. The
contour of the casting might be
improved so as to appear more

This

FIG. 96. — Rear View of the Reed
Tail-Stock.

138

MODERN LATHE PRACTICE

clean and symmetrical, without detracting from its solid and sub-
stantial appearance.

Figure 98 is the tail-stock used on 20-inch swing lathes built
by P. Blaisdell & Company. The only noticeable feature is the
unusual diameter of the tail-spindle sleeve in proportion to its sup-

FIG. 97. — Tail-Stock of the Lodge & Shipley
Lathes.

porting parts. The cap at the rear end is of such form and dimen-
sions as to increase this top-heavy appearance.

The Hendey-Norton tail-stock for 20-inch swing lathes is shown
in Fig. 99. It is a clean, symmetrical, and well-designed piece of

work and a considerable improvement
on the one just before it. It is se-
cured to the bed by a lever and eccen-
tric arrangement similar to that shown
in Fig. 94.

Figure 100 shows the New Haven
Manufacturing Company's tail-stock
for 24-inch swing lathes. A finished
sleeve screwed into the rear of the

FIG. 98. — 20-inch Lathe Tail-
Stock, built by P. Blaisdell
& Company.

main casting furnishes the support for the tail-spindle screw and
adds to the otherwise clean outline and substantial appearance of
the base. It is very rigid and substantial.

Figure 101 shows the Prentice Bros. Company's tail-stock, which
they claim as their invention so far as American lathes are con-
cerned. Other than this fact there is nothing particularly notice-

LATHE DESIGN: THE TAIL-STOCK, ETC.

139

able in its design except that there are two ribs and grooves, one
to each bolt for preventing the undue strain on the holding-down
bolts. These bolts are well spread apart, which is a good feature in
some respects if not in others.

FIG. 99. — 20-inch Lathe Tail-Stock,
built by the Hendey Machine
Company.

FIG. 100. — 24-inch Lathe Tail-Stock,
built by the New Haven Manufactu-
ring Company.

The Schumacher & Boye tail-stock shown in Fig. 102 is a good
general design and resembles that of the' Hendey-Norton manu-
facture. Aside from the very prominent cap at the rear end it is
a very creditable appearing device, and considerably better than
some of those short and square forms which appear " all in a bunch,"
as it were.

FIG. 101. — 22-inch Lathe Tail-Stock,
built by the Prentice Bros. Company.

FIG. 102. — 18-inch Lathe Tail-Stock,
built by Schumacher & Boye.

Figure 103 shows the W. P. Davis machine Company's produc-
tion, which is of fairly good proportions and has ample strength.
While it is for only a 28-inch swing lathe, it is provided with a
rack and pinion device for moving it along the bed.

The Bench lathe tail-stock is well shown in Fig. 104, the engrav-
ing being of the type made by the American Watch Tool Company.

140

MODERN LATHE PRACTICE

It is chiefly noticeable for the very long spindle which it carries.

This type of tail-stock does not usually have the set-over feature.

It is clamped to the bed by a lever-nut turning horizontally.

Of the heavier tail-stocks,
for large lathes, the Niles type
is shown in Fig. 105. This is
divided near the bottom, as in
the usual design for small lathes,
and secured to the bed by four
bolts. It has a rack and pinion
device for moving it along the
bed, and otherwise is of ordinary
design and construction, with-
out special features to which at-

FIG. 103. — Tail-Stock built by the W.
P. Davis Machine Company.

tention need be called.

The tail-stock shown in Fig. 106 is of the same general form
as that shown in Fig. 100,
by the same concern, the
New Haven Manufacturing
Company. This is for a 60-
inch swing lathe, and is a
very massive and rigid tail
center support. It has pro-
portionately a lonff bearing; FIG. 104. — Bench Lathe Tail-Stock, built
, . , ., . by American Watch-Tool Company.

on the bed, to which it is

secured by four heavy bolts. It is divided near the top and the

upper portion secured to the lower

TI _^nf\ fay four Other bolts of ample di-

ameter, by which means heavy
work held on the centers need not
be removed or blocked up when
setting over for turning tapers. As
the spindle sleeve is very long and
the tail spindle large and heavy,
a spur gear is keyed to the spin-
dle screw and engages a spur pin-

FIG. iqs.-42-inch Lathe Tail-Stock, ion on a shaft in front. Upon the
built by the Niles Company. front end of this shaft is a miter

LATHE DESIGN; THE TAIL-STOCK, ETC.

141

gear which engages with a similar one fixed to a short transverse
shaft upon whose front end is a large hand wheel by which the
tail spindle is easily and conveniently operated. The ratio of this
gearing is 3 to 1. The tail-
stock, which is very heavy and
massive, is moved along the
bed by a rack and pinion de-
vice, also back-geared at a
ratio of 3 to 1, by which one
man may easily move the tail-
stock from one point to
another, although it weighs
nearly a ton.

The establishment of Schu-
macher & Boye make a some-
what similar tail-stock for their
48-inch swing lathe. It is
shown in Fig. 107. It is pro-
vided with the same features
as the one just considered, but has the hand wheel set at an angle,
with the intention, probably, of rendering its position more con-

FIG. 106. —60-inch Lathe Tail-Stock,
built by the New Haven Manufac-
turing Company.

FIG. 107. — 48-inch Lathe, built by
Schumacher & Boye.

FIG. 108. — 42-inch Lathe Tail-
Stock, built by Bridgford
Machine Tool Works.

venient to the operator. It is not as massive or rigid as the last
one shown, but doubtless serves a good purpose.

Figure 108 shows a design of tail-stock made by the Bridgford

142

MODERN LATHE PRACTICE

Machine Tool Works for their 42-inch swing lathe. It is of peculiar
design and the base has the appearance of having been " built up
in the sand," from the pattern designed for a lathe of much less
swing. It is not a handsome design by any means, although it
probably serves the purpose of supporting the tail spindle. It has
a rack and pinion device for moving it along the bed. Its length
on the bed is not as great as it should be, nor do the holding-down
bolts seem large enough for a lathe of 42 inches swing. It has four
bolts for holding down the base and a second set for securing the
top part carrying the tail-spindle sleeve.

At A, Fig. 109 is one of Le Blond's favorite designs and which

are used upon most of the lathes
built by this concern. Its pe-
culiar feature is the form of
the tail-spindle sleeve with its
very much enlarged front end.
While it has a strange and un-
usual appearance, its form is
based on sound principles of
construction and is no doubt
practical in giving more sta-
bility and rigidity to the tail
center, which is a very desirable feature.

From the foregoing illustrations and descriptions the various
features of tail-stocks, made by the different manufacturers, may
be quite readily studied and their good and bad points duly con-
sidered, either for the pur-
poses of designing a new
lathe or for purchasing one
suitable for the special line
and class of work to be per-
formed.

At B, Fig. 110, is the
ordinary form of what is
known as the "lever tail-
stock," which is mostly used upon hand lathes. As its name im-
plies, the tail spindle is moved lengthwise by a lever rather than
a screw and hand wheel.

FIG. 109. — The Le Blond Form
of Tail-Stock.

FIG. 110. — Lever Tail-Stock for Hand
Lathes, built by the F. R. Reed Company.

LATHE DESIGN: THE TAIL-STOCK, ETC. 143

This form offers facilities not possessed by the other form, or
possessed in a less convenient form. In this spindle may be carried
drills, reamers, etc., for use on light work held in a chuck. It may
carry a small face-plate against which work may be held and drilled
or reamed by a drill or reamer held in a chuck. It may carry an
inside boring tool, and if made with a " set-over" device, such as is
used on the tail-stock of an engine lathe, its usefulness is still further
extended, particularly when working brass or other soft metals or
materials. This design is by the F. E. Reed Company.

In addition to all the requirements thus far enumerated, which
a lathe must possess in order to do good and heavy work, it must
have a substantial carriage and compound rest or other tool-hold-
ing mechanism.

The carriage must support the compound rest on top and the
apron hanging down at the front. Through the latter it must re-
ceive its driving mechanism as the lathe is now constituted. If we
were to design a lathe with a view only to the theoretical require-
ments, we should, of course, put the device for moving it along the
bed "on the cut/' as near the cutting- tool as possible, and there-
fore the lead screw and feed-rod would be inside the bed and at
some point between the front V and the central line. But we
all know the practical objections to this and recognize it in lathe
design.

There are a few points in the design of a good lathe carriage
that it will be well to call attention to, since they are those that are
frequently lost sight of, if we consider many of the present-day
designs, and that the buyer of lathes as well as the machinist
will do well to give attention to.

Figure 111 shows the design of an ordinary engine lathe car-
riage intended to be rigid and substantial. It has a wide center
part, which is properly supported by the two ribs, thick and deep
in the center. The only opening through it is one of moderate
dimensions for permitting the chips to pass through.

The entire top is on one level so that large work to be bored
may be bolted down upon it when the compound rest is removed
for that purpose. Some lathe carriages have the dovetail, upon
which the compound rest shoe runs, raised above the general
level of the carriage. When work is to be bored it must rest upon

144

MODERN LATHE PRACTICE

this in the center while the sides are supported upon parallels with
attendant inconvenience in bolting down rigidly. In this design
there are four T-slots in front and two in the rear for the accom-
modation of bolts, while others may be passed through the chip
opening in the center if necessary.

FIG. 111. — Engine Lathe Carriage Design.

The front wings of the carriage are broad, for the purpose of
properly accommodating a full swing rest, an additional tool-post
or other tool-holding device. The T-slots in the rear may serve a
like purpose, or in conjunction with those in front serve for holding
down any special attachment necessary.

The design of the bed is such as to furnish additional bearing

LATHE DESIGN: THE TAIL-STOCK, ETC. 145

surfaces for the carriage inside of the V's, the inner V's being
replaced by flat surfaces, thus permitting the swing to be increased
and the carriage very materially strengthened.

The carriage is gibbed to the bed on the outside of the V's,
both back and front, thus spreading the gibbed surfaces as far
apart as possible.

Following this will come in due order illustrations of a few of the
carriages and compound rests built by some of the prominent manu-
facturers.

Figure 112 shows the carriage, apron front, and compound rest of
a New Haven 24-inch swing lathe.
The T-slots in the rear wings of the
carriage are as shown in Fig. Ill, but
those in the front wing are at right
angles. In some cases this is pre-
ferable, but if the carriage is to be
used much for boring purposes the
slots will be found most desirable if
all in one direction. The top of the

carriage is level, with no obstruc-

. . FIG. 112. —The New Haven

tions when the compound rest IS re- Carriage, Apron, and Com-

mMTaA pound Rest for Lathes up

to 32-inch swing.
The apron front is clear of gears

and other similar obstructions, and the uses of the levers are indi-
cated by plain lettering on the front of the apron. As the levers
are set in the engravings all feeds are "out." The "star nut"
closes the friction of the driving bevel gear, and the feed is "on"
to the right or left according as the lever, marked "to reverse all
feeds" is thrown to the right or left. To operate either the lateral
or cross feeds the upper lever is thrown to the left for "lateral
feeds," and to the right for "cross-feed." The lever at the ex-
treme right closes the "split nut" on the lead screw, provided
the feeds are not engaged. That is, if the levers are as shown
the lead screw nut may be closed. But if the lever "to reverse
all feeds" is moved to the right or left, the split nut is locked
"open" and cannot be closed.

The feed rod carries two bevel pinions arranged in a sliding
frame, operated by the lower lever, the two bevel pinions being

146

MODERN LATHE PRACTICE

adapted to be engaged on either side of the driving bevel gear which
transmits the motion through the medium of a conical friction
clutch operated by the "star nut" in front of the apron.

Further than these bevel gear connections there are no gears
but those leading up to the cross-feed screw and back to the rack
pinion and hand-wheel shaft. No worm or worm-gear is used.
Consequently the parts are large, strong, and durable.

The compound rest, as will be seen, is of ample proportions, has
a graduated base, a convenient removable double crank, and a
tool-post provided with a concave ring and washer adjustments
for the tool.

The entire mechanism has proven very satisfactory in practical
use.

The Hendey-Norton carriage, apron, and compound rest is

shown in Fig. 113. It is not as
conveniently arranged in front
of the apron as in the last ex-
ample. The carriage has the
projecting dovetail in the cen-
ter instead of the flat surface,
and only two T-slots are shown
in the front wing of the car-
riage.

The compound rest is a nice
piece of designing and construc-
tion. It has a graduated base
and a tool-post of unusual
strength and rigidity. The
single crank on the compound
rest screw is not as convenient for many uses as a double crank.
The cross-feed screw carries a very convenient graduated disc,
which ought to be provided for all lathes up to 32-inch swing, and
is useful in many ways for even larger lathes where fine work is to
be done.

Figure 114 shows the carriage, apron, and compound rest of
the Blaisdell lathes. While the construction is strong and sub-
stantial, it cannot be said that it is very symmetrical or with
any attempt at fine lines. The arrangement of the apron front is

FIG. 113. — The Hendey-Norton
Carriage, Apron, and Compound
Rest.

LATHE DESIGN: THE TAIL-STOCK, ETC.

147

hardly modern, although there is no gearing or unnecessary part
exposed.

A single T-slot is located in the front carriage wing. The car-
riage and apron are the same
length, which usually indicates
that the bearing of the carriage
on the bed is not as long as it
might be to good advantage.
The cross-slide dovetail projects
above the general level of the car-
riage so that it would be in the
way for boring operations.

Figure 115 shows the front of

FIG. 114. — The Blaisdell Carriage,
Apron, and Compound Rest.

the carriage and the compound

rest of a 60-inch swing, New

Haven lathe. The top of the carriage is level and has three T-slots

on each side, in the front wings. The carriage is very massive,

weighing about 1,600 pounds, and the compound rest considerably

over half that amount.

The compound rest has a large, circular, graduated base and
supports a very broad and heavy tool block. The tool is held by

FIG. 115. — The New Haven Carriage and
Compound Rest for Large Lathes.

heavy steel clamping bars held up under the nuts by large spiral
springs so that the tool may be readily introduced. These clamp-
ing bars project, at the ends, beyond the holding-down studs so
that the tool may be placed outside the studs when the nature of
the work requires that position.

148 MODERN LATHE PRACTICE

The entire device is very strong and rigid and capable of with-
standing very heavy cuts. There is a power cross and angular feed
in addition to the facilities for hand feeding in all directions.

Further illustrations and comments upon the various features
of this class on the lathes built by different makers will be found in
later chapters of this work, describing the entire lathes, and to
which the reader is referred for further information.

A practical machinist has recently made the following criti-
cisms upon one of the popular lathes which shows the standpoint
from which the practical men look at some of the lathe features.
It is so eminently commendable as to be well worth preserving.

First. — The tool block will not travel beyond the line of centers
to permit holding small boring tools directly in the tool-post by
means of any of the holders so often described which
use V-block clamps and make a handy tool-holder. This distance
is short 8\ inch. It is often convenient to get beyond the centers,
and to my mind, at least, an inch is a great advantage.

Second. — The stock in the tool-post is so short that it is impos-
sible to use packing on top of the tool when doing delicate work
with small tools made of wire or small straight bars, and without
such packing the value of this style of tool is lost. The top of a
J x 1-inch tool can be raised but T36- inch above the centers.

Third. — The tool-post screw is so short that the wrench runs
into the clamp handle of the tail spindle, and either the rest must
be removed or the wrench taken off and the screw turned with the
fingers when more than a bare loosening is required. The addition
of f inch to the length would avoid this difficulty and also permit
the wrench to swing clear over the small face-plate.

Fourth. — The key in the lead screw for change-gears is of the
Woodruff style, and falls out every time a gear is taken off. Of
course this gear does not require changing often ; if it did this nuisance
would be unbearable and call for a properly fitted and fastened
key, but as it is, the gear is changed so seldom that one forgets this
key, and so it drops and must be hunted for nearly every time a
gear is changed.

Fifth. — The centers are of No. 2 Morse taper, but the holes are
reamed just enough larger or deeper so that no tool of that taper
as fitted to the regular Morse socket can be held without a sleeve

LATHE DESIGN: THE TAIL-STOCK, ETC. 149

of metal or paper. This may have its advantages in preventing the
too common use of such tools in the center holes, but is sometimes
a great aggravation in a tool-room lathe, where every convenience
would be duly appreciated.

Sixth. — The face-plate fit, so far as the screw thread is con-
cerned, is all right, but the part chambered out next the shoulder
is TV inch larger than the top of thread, which makes it quite
difficult to start the thread true when putting on plates or chuck,
with the results that the thread often jams in starting, especially
with a heavy chuck.

The turning of tapers is often accomplished by " setting over"
the tail-stock to the front or rear as may be desired, so as to be out
of line with the head-stock center and thereby inclining the axis
of the piece to be turned with the axis of the lathe. While this is a
convenient and efficient manner when the taper is one of moderate
inclination, it can only be done within comparatively narrow
limits.

We must therefore resort to some other method when the taper
is greater than will be possible to do by setting over the tail-stock and
throwing the centers so much out of line with each other as to wear
them out of shape as well as to distort the form of the center-
reamed holes in the ends of the piece of work.

The taper attachment was devised to meet this condition and
consists essentially of fixing to the bed a bar capable of being ad-
justed horizontally to any desired angle, and upon which is fitted
a sliding block, moving with the lathe carriage, and so attached to
the tool-supporting mechanism as to cause the cutting-tool to
follow in a line parallel to the inclined bar as the carriage is moved
to and fro on the bed. This is accomplished by different devices
by the various lathe builders, whose efforts are usually directed to
three principal objects: first, to so construct the taper attach-
ment that it may be attached to any lathe without special arrange-
ment or preparation of the bed. It was formerly necessary in
nearly every case to have planed grooves or flat surfaces at the back
of the bed for this purpose whenever a lathe was to have a taper
attachment fitted to, or sold with it; second, to have the attach-
ment so designed and constructed that it may be brought into use
or detached with the least possible time and trouble; and third, that

150 MODERN LATHE PRACTICE

the parts are so constructed as to be as absolutely rigid as possible,
particularly against any strain that would tend to throw them out
of the predetermined line of inclination.

Among the failures of taper attachments the most common is
that of turning a taper so that the inclined line of the surface of the
turned piece is curved rather than straight; sometimes convex and
sometimes concave. The operator should always use special care
to have the attachment perfectly rigid in all its movable parts,
clamp screws tight and adjustments perfect; and that the cutting
tool is set correctly at the height of the centers.

Figure 116 shows a rear view of the taper attachment as

FIG. 116. — Taper Attachment built by the
F. E. Reed Company.

designed and constructed by the F. E. Reed Company. The
inclined guide-bar A is graduated on the end so as to show the
amount of taper that is being turned. This bar is secured to a
plate B, which slides upon the bar which is attached to the lathe
carriage. The bar A, and plate B, are secured against longitudinal
movement by means of the rod D, secured to the bracket E,
clamped to the bed.

By this means there need be no special preparation of the bed
of a lathe in order to use the taper attachment. The carriage
must, however, be of special construction. An intermediate slide
E is proyided, with its rear end pivotally connected with the slid-
ing block G, which travels upon the inclined bar A and thereby
produces the variation of alignment in the travel of the cutting-
tool necessary to turn a taper.

The inclined guide-bar A may be minutely adjusted by the
screw H, which may be placed as shown, or in the hole shown at B,
as may be desired.

LATHE DESIGN: THE TAIL-STOCK, ETC. 151

It would appear that this attachment would not be of sufficient
strength and rigidity to withstand the strain of heavy turning on a
very severe taper, and still do accurate work.

The R. K. Le Blond taper attachment is shown in Fig. 117.
The slide supporting bracket A is attached to a dovetail formed
upon or attached to, the bed. Upon it is swiveled the guiding
bar B, upon which is fitted the sliding block C, pivotally connected
with the compound rest shoe D, by means of the block E and con-
nection F.

FIG. 117. — Taper Attachment built by the R. K.
Le Blond Machine Tool Company.

This taper attachment is of new design, and is very rigid. It is
changed from straight to taper work by simply removing a taper
pin from one hole to another. The cross-feed nut is never discon-
nected and the compound rest can be moved by the screw when
turning both straight and taper work.

When extra heavy work is done the compound rest can be
clamped to the taper attachment by a brace. By this arrangement
all thrust is relieved from the screw, insuring greater accuracy. The
guiding bar is graduated to taper per foot and is clamped in posi-
tion by two T-slot bolts. A graduated screw adjustment is provided
for accurately setting the bar.

Figure 118 shows the Lodge & Shipley taper attachment. It is
constructed in a similar manner to that made by the F. E. Reed
Company, as will be seen by the engravings of the two devices.

152 MODERN LATHE PRACTICE

It is supported by the carriage, and the supporting bar upon which
the inclined guide-bar A rests is secured against longitudinal move-
ment by a rod D and bracket E; the latter clamped to the bed the
same as in Reed's device.

The taper attachment is extremely simple, and composed of
less parts than any in the market. In operation it is changed

FIG. 118. — Taper Attachment built by the
Lodge & Shipley Machine Tool Company.

from straight to taper by tightening or releasing one screw on the
dog. When attached for taper work the sliding shoe connects
directly with the tool-rest and not with the screw, making its opera-
tion instantaneous. The nut is made to release and slide in a
groove. The stud for the sliding shoe also engages into a groove,
and to attach or detach requires nothing more or less than the
releasing of one screw and tightening another, or vice versa.

The cross-feed nut cannot fall over as in ordinary taper attach-
ment when in use, because it is never disconnected. The bolt
simply slides in a slot in the compound rest slide.

Figure 119 shows the taper attachment made by the Hamilton
Machine Tool Company. Like that made by the R. K. Le Blond
Machine Tool Company, this has its supporting bracket carried
upon a slide formed upon or attached to the bed. It is thereby
rendered very rigid and substantial. The swiveling of the inclined
guiding bar is similar to those already described, and the attach-
ment of the connecting block to the cross-feed screw is easily under-
stood by reference to the engraving in which it will be seen that the
end of this block passes through the bracket attached to the rear

LATHE DESIGN: THE TAIL-STOCK, ETC.

153

cf the carriage. The sliding block runs in a dovetail in the inclined
guide-bar instead of on a square raised rib on top of it.

FIG. 119. — T^per Attachment built by the Hamilton
Machine Tool Company.

This dovetail form is not at all necessary, as a square form is as
good, if not better, and much more economical. There is no ten-

FIG. 120. — Taper Attachment built by the Hendey
Machine Company.

dency to lift the block that would make the dovetail form advisable.
The Hendey-Norton Taper attachment is shown in Fig. 120.

154

MODERN LATHE PRACTICE

It is supported by the carriage as in the Reed and the Lodge &
Shipley designs, and travels with it and is therefore always ready
for use. All operations necessary to use the attachment are made
from the front of the carriage, and consist of first setting the taper
bar to any desired degree, binding the sliding bar clamp to the back
V, loosening the post screw at the end of the carriage arm which
releases the cross-feed screw connecting block, and clamping the con-
necting link onto the taper-bar slide by means of the binding handle.
The top link and the binding bolt, which is fitted to a reamed
hole in the head of the block, furnish a double connection (and one
that is absolutely rigid) between the two slides, preventing any
back-lash.

FIG. 121. — Taper Attachment built by the New Haven

Manufacturing Company.

Figure 121 shows the taper attachment as made by the New
Haven Manufacturing Company. The supporting bracket is adapted
to travel in an upper and lower groove planed in projecting ribs on
the back of the bed, thus rendering the support very rigid. The
plate B is heavy and rigid and supports the swiveling guide-bar C,
upon which slides the block D. In the later development of this
device the dovetail is replaced by a square projecting rib. There
is also an improvement in the connection E with the cross-feed
screw, consisting of a heavy flat bar attached to the rear of the
compound rest shoe and sliding through a strong and rigid guide
block. Its rear end is pivotally connected with the block D, mak-
ing a very accurate and rigid design.

In all these attachments making use of the cross-feed screw as

LATHE DESIGN: THE TAIL-STOCK, ETC.

155

an adjusting member, it must be so arranged as to be detachable
from its front bearing, or permitted to slide through it so that the
inclined movement of the block on the guide-bar may gradually

FIG. 122. — Plan of the Bradford
Taper Attachment.

work the compound rest forward and back to form the taper as
the cut proceeds.

Figure 122 is a plan of the Bradford taper attachment, and Fig.
123 is a cross section of the same device. It is of the type of carriage-

FIG. 123. — Cross Section of the Bradford Taper Attachment.

156 MODERN LATHE PRACTICE

suspended devices similar to several heretofore shown and de-
scribed.

From the accompanying sectional view it will be seen that the
rear end of the cross-feed screw is held by collars and journaled
in a bearing, which is bolted to a bar connecting it with the sliding
shoe on the inclined slide, so that the screw always moves with the
bar and carries the compound rest with it.

The tool is controlled by the screw at all times without inter-
fering with the handle, the end of the screw telescoping into the
sleeve on which is the pinion governing the power feed. Where
it telescopes it is splined, and so the screw is under control of the
operator, irrespective of the position of the tool due to the taper
bar. When turning tapers the lower slide of the compound rest
should be tightly clamped to the bar by the square head screw,
shown in cut. Consequently there is no disconnecting of any of
the parts when engaging or disengaging the attachment. Simply
tightening the dog to the ways brings the attachment into service,
and loosening the same disengages the attachment, leaving the lathe
in proper shape for straight work; and in neither case does the use
of the attachment interfere in the slightest degree with the full and
complete use of the compound rest, should it be desired to face off
a piece the full swing of the lathe.

The construction further makes the attachment of exceptional
value on lathes of extra length, in that it is available the full dis-
tance between centers by reason of its being bolted to, and traveling
with, the lathe carriage.

CHAPTER VIII

LATHE DESIGN; TURNING RESTS, SUPPORTING RESTS, SHAFT

STRAIGHTENERS, ETC.

Holding a lathe tool. The old slide-rest. The Reed compound rest. The
Lodge & Shipley compound rest. The Hamilton compound rest. The
Hendey-Norton open side tool-posts. Quick-elevating tool-rest.
The Homan patent tool-rest. The Le Blond elevating tool-rest. The
Lipe elevating tool-rest. Revolving tool holder. The full swing rest.
The Le Blond three-tool rest. The New Haven three-tool shafting
rest. The Hendey cone pulley turning rest. Steady rests. Follow rests.
The usual center rest. The New Haven follow rest. The Hendey
follow rest. The Reed follow rest. The Lodge & Shipley follow rest.
Their friction roll follow rest. Shaft straighteners. The Springfield
shaft straightener. New Haven shaft straightener. Lathe counter-
shafts. The two-speed countershaft. Geared countershafts. The Reed
countershaft. Friction pulleys. Tight and loose pulleys. Self-oiling
boxes. The Reeves' variable speed countershaft. Design of geared
countershafts. Another form of variable speed countershafts.

WHILE the old principle of holding a lathe tool in a tool-post or
under one or more clamping bars is still largely used to securely
hold the tool in a rigid position for performing its work, there have,
within the past few years, been designed and come into use a
number of very convenient, rigid, and practical tool-holding devices!

The use of high-speed steel, and consequently of heavy cuts,
have rendered the use of very rigid tool-holding devices impera-
tively necessary.

Some of the more prominent of these are here shown and their
special features commented upon.

The old familiar slide-rest of our apprenticeship days still lives
and is much used on hand lathes, bench lathes, and the like. Fig.
124 shows this form of turning rest as made by the F. E. Reed Com-
pany. Its construction is so familiar to every mechanical man
that any description is unnecessary.

157

158

MODERN LATHE PRACTICE

Figure 125 shows a very efficient compound rest made by the
same establishment to which attention is called as to the very rigid
method of holding and clamping the tool by two heavy clamping

FIG. 124. — Plain Slide-Rest, made by the
F. E. Reed Company.

screws. Also to the important fact that the tool is held at
the extreme left-hand edge of the tool-holding device, in which
position it is nearly always used. At the same time the entire
top, tool-holding block is adapted to turn in any direction and to be
securely held at any angle, thus making it invaluable for turning up

FIG. 125. — Compound Rest made
by the F. E. Reed Company.

FIG. 126. — Compound Rest for Two
Tools, made by the F. E. Reed
Company.

to close shoulders or other obstructions at the right, and also when
turning or boring inside work wherein it is necessary to set the tool
nearly parallel to the center line of the lathe.

Figure 126 shows a similar device, made by the same company,
with arrangements for holding two tools under the same conditions

LATHE DESIGN: TURNING RESTS, ETC.

159

as above noted. This is very useful when heavy cuts are to be
made upon work where rapid reduction of the amount of stock is
called for, as the inverted back tool assists very much to balance the
resistance by dividing it between two points.

Figure 127 is of the compound rest and tool-holding device as
made by Lodge & Shipley. It is neat and substantial and the
forward prolongation of the shoe adds rigidity on heavy cuts.
Both the upper and lower
slides are fitted with taper
gibs, which, besides being
tapering, are tongued and
grooved into the slides, so
that no amount of strain will
displace them. These gibs
are provided with two screws
only, and at each end, which
take up the wear evenly the
entire length, and are possi-
ble of delicate adjustment.

FIG. 127. — Compound Rest and Tool-hold-
ing Clamps made by the Lodge &
Shipley Machine Tool Company.

They will not require resetting perhaps more than once a year.

The-tool clamping bars are arranged the same as those of
the New Haven device, shown in Fig. 114. These slide loosely
into the T-slots and may be removed and replaced by the arch clamps
shown at A, A, the tool passing through one or both of these as
occasion may require. They may be located at any desired position
in the T-slots. This alternate device will be found very convenient
on many unusual jobs as well as upon regular work.

In Fig. 128 we have the compound rest with its tool-clamping
device as made by the Hamilton Machine Tool Company. It is
quite similar to that shown in Fig. 124, and made by the F. E. Reed
Company, and possesses its good advantages of adjustment of the
tool to point in any direction and to work up closely to a shoulder
on either side. Lodge & Shipley make a similar device with the
tool clamp almost identical with this one.

Figure 129 shows the " open-side tool-post" made by the Hendey
Machine Company. It is so arranged that it may be substituted
for the slotted tool block and ordinary tool-post of their lathes. It
may be swiveled to any desired angle and accurately adjusted

160

MODERN LATHE PRACTICE

by the graduations at the base. It is a good example of a rigid
and substantial tool-holding device.

Figure 130 shows the " quick-elevating" tool-rest made by the
same company. The tool is raised or lowered by using the tool-post
wrench on the short lever indicated in front in the engraving. It
carries the old-style tool-post and is not, therefore, as rigid as that
shown in Fig. 128.

FIG. 128. — Compound Rest and Tool-holding
Device, made by the Hamilton Machine Tool
Company.

Figure 131 shows the Homan patent tool-rest, which is also
made by the Hendey Machine Company, which has a screw adjust-
ment as to height and a graduated base for setting to any required
angle. It is, perhaps, the most rigid device of the kind using a

FIG. 129. — Open Side Tool-Post,
made by the Hendey Machine
Company.

FIG. 130. — Quick-Elevating Tool-
Post made by the Hendey Ma-
chine Company.

single tool-post, and is a very well made, accurate, and convenient
piece of mechanism.

In Fig. 132 is represented the Le Blond elevating tool-rest pro-
vided with a thread-chasing stop which is clamped to the dovetail
upon which the rest slides. The device is very simple and effective

LATHE DESIGN: TURNING RESTS, ETC.

161

for ordinary work. It would not seem quite so well adapted, how-
ever, for very heavy cuts on account of the fact that a heavy verti-
cal strain would be rather severe on the inclined screw which holds
the tool block up to its position.

FIG. 131. — The Homan Patent
Tool-Rest made by the Hen-
dey Machine Company.

FIG. 132. — Elevating Rest with Thread
Chasing Stop, made by the R. K. Le
Blond Machine Tool Company.

A very substantial device is shown in Fig. 133, and known as
the Lipe elevating tool-rest. It is made by the Lodge & Shipley
Machine Tool Company. In this device the tool-holder proper has
formed upon its lower end a cylindrical portion which fits into the
main casting and is secured thereto in any desired position by a
strong clamping screw. It is ad-
justed vertically by a screw through
the upper, and bearing upon the
lower casting as shown in the en-
graving. The entire device fits
upon the dovetail of the carriage
in place of the compound rest.
This device is as rigid as is possible
to make an adjustable tool-holding
device and is amply strong for
heavy cuts.

The revolving tool-holder,
shown in Fig. 134, is made by the Lodge & Shipley Machine Tool
Company, the R. K. Le Blond Machine Tool Company, and others.
It is a very useful form and is equally adaptable to the carriage
of an engine lathe or the slide of a turret lathe.

It is a very strong and rigid device and holds four tools, either
at the corners or sides. The locking pin withdraws automatically

FIG. 133. — The " Lipe Elevating
Tool-Rest," made by the Lodge
& Shipley Machine Tool Company.

162

MODERN LATHE PRACTICE

when the clamping bolt is released to revolve the turret. It is
interchangeable with the compound rest, simple in design, rigid in
construction, and a great time-saver where the number of pieces

reduced to the- same dimensions per-
mits the several tools in the tool-post
to be used alternately.

Its greatest advantage seems to be
that by its use we practically add the
features of a turret to the ordinary
engine lathe and at a very nominal
cost. It is true that we do not get the
drilling and reaming features, but still
many turret operations may be accom-
plished by its use.

Figure 135 shows what is variously
termed as a "full swing rest," or a
" pulley rest," or a "wing rest," etc.,
by different lathe builders. First, be-
cause it is for turning work the full
swing of the lathe and which the tool
in the compound rest will not conven-

FIG. 134. — Revolving Tool-
Holder, made by the Lodge
& Shipley Machine Tool Com-
pany.

iently reach ; second, because it is principally used for turning pul-
leys, and work of that nature, and third, because it is attached to
the front "wing" of the lathe carriage.

It is frequently made at an angle,
inclining downward from the center
of the lathe so that it may be made
conveniently low to fit the low car-
riage of a large swing lathe and still
have the general line of the tool on a
radial line from the lathe center.
This rest is practically the same as
the plain tool block used on the car-
riage, with a base suitable for bolting
down over a T-slot.

Figure 136 represents a three-tool turning rest, adapted to be
used on ordinary engine lathes. It is made by the R. K. Le Blond
Machine Tool Company.

FIG. 135, — Full Swing Rest
made by the R. K. Le
Blond Machine Tool Com-
pany.

LATHE DESIGN: TURNING RESTS, ETC.

163

It consists of a special base or slide, carrying three tool-holders,
two in front and one in back. These may be advanced towards
each other simultaneously by means of the cross-feed screw, in
addition to which each has
an independent forward
and backward movement.
The rear tool-holder has
also lateral adjustment.
The base is surrounded by
a groove for collecting the
oil, soda-water, or other lu-
bricant used. The device
is invaluable for many
purposes.

Figure 137 shows the FlG i36. _ Three-Tool Turning Rest, made
three-tool shafting rest by the R. K. Le Blond Machine Tool Corn-
made by the New Haven

Manufacturing Company. This is adapted to be located on the
carriage of an ordinary engine lathe in place of the compound
rest, and in addition to the three-tool slides, tool-posts, etc., in the

FIG. 137. — Three-Tool Shafting Rest, made by
the New Haven Manufacturing Company.

last example there is a fixed standard in the center providing a
center rest in which bushings of various diameters, to suit the
different sizes of shafting, may be carried, and which serve to
hold the shafting to be turned steady and firm for the action of
the turning tools. In the last example this function must be

164 MODERN LATHE PRACTICE

performed by a separate " steady rest/' attached to the carriage

or to the lathe bed.

The turning of cone pulleys is usually a tedious and expensive

job unless some special device is in use for the purpose. In Fig.

138 is shown such a device built by the Hendey Machine Tool

Company. It should of neces-
sity have a special carriage to
accommodate it. The center
part of the carriage should be
as wide as the length of the
largest cone to be turned in
order to have ample support for
the end tools. The tool-carry-
ing block is adapted to swivel

FIG. 138. — Cone Pulley Turning Rest,

made by the Hendey Machine Com- SO as to accommodate the loca-

pany* tions of the tools to the vary-

ing diameters of the cone, as the difference between the diameters
of the smallest and largest steps will necessarily vary considerable.

As one T-slot holds all the tool-posts it is only necessary to
provide as many tool-posts as there are cone steps.

The crowning of the pulley faces is effected by a taper attach-
ment device, or its equivalent, at the back of the carriage. This may
be effected by using straight tapers and making two settings, the
inclined lines meeting in the centers of the pulley faces; or, the proper
curve or " crown" may be given to the device by a curved guiding
bar instead of a straight one.

Under the general name of steady rests we may include any
attachment to a lathe which has for its purpose or function that of
furnishing a support at one or more points around the circum-
ference of the piece being turned, opposing the pressure of the
cutting edge or point of the tool and holding the work up to its
original position and alignment as before the tool commenced
cutting.

Ordinarily there are two classes of these rests which may in a
general way be called "center rests " and " back rests." The center
rests usually have jaws bearing upon the work at three points
spaced equally around the circle, while a back rest bears upon the
work generally at the back and on top only. Sometimes such a rest

LATHE DESIGN: TURNING RESTS, ETC.

165

FIG. 139. — Center Rest, as
made by nearly all Builders.

consists essentially of a forked or V-shaped piece firmly held and

embracing the circle of the work.

Sometimes these rests are attached to the carriage and follow

the work of the cutting-tool closely so as to continue the support

given the work as near the tool as possible. These are often called

" follow rests." They may be made with two or three adjustable

jaws resting against the work, or they

may carry a bushing having a hole

reamed just large enough to admit of

passing rather closely over the work,

sometimes in advance of the work (in

case of previous turning), but usually

following the tool.

Figure 139 is of the well-known

form of a center rest, substantially as

made by all lathe builders, the varia-
tions of design being in matters of de-
tail, and not in general form, functions

or methods of support or attachment.

Figure 140 is of the follow rest as made by the New Haven
Manufacturing Company. It will be noticed that
the top jaw inclines to the front, so that, acting in
conjunction with the back and the bottom jaw,
it serves to embrace more than half of the circle
of the work in the process of turning. The base of
this rest is fitted to the
dovetail on the lathe car-
riage and fits in behind
the compound rest.

Figure 141 represents

the Hendey follow rest for use on light

lathes. It is bolted to the side of the

carriage and "steadies" the work by

means of the adjustable jaw which is set

up against the back and top of the piece

to be turned, and held in that position

by two set-screws as shown.

In Fig. 142 we have the follow rest used by the F. E. Reed

FIG. 140. — The
New Haven
Follow Rest.

FIG. 141. — The Hendey
Follow Rest.

166

MODERN LATHE PRACTICE

FIG. 142. — The Reed Follow Rest,
with Bushing.

With one

Company. This rest has but two jaws, one at the rear and one
over the work. Its peculiar feature is that the jaws may be re-
moved and a special piece substituted, which is bored out to receive

bushings which may be bored
and reamed to fit the different
sizes of work to be machined.
This feature will prove advanta-
geous, particularly when a large
number of parts, say shafts, are
to be turned.

Figure 143 represents a very
solid and substantial follow rest
made by Lodge & Shipley Ma-
chine Tool Company. It is
adapted to very heavy work and
will be found useful on any
rapid-reduction lathe,
exception it is the strongest follow rest made.

Figure 144 shows the strongest fol-
low rest made and is a product of the
same establishment. Being provided
with friction rolls for reducing the
friction of the work, it is adapted to
the heaviest work the lathe is capable
of carrying. It is well designed for
the purposes for which it is to be used
and its parts are so made as to be
easily adjustable to suit the work.
Its special points of, construction are
interesting as showing the thorough-
ness of the design.

The two jaws carrying hardened-
steel rollers move in and out in a cir-
cular path, being actuated by a worm
and knob. When set in any position
they are adapted for a variety of
diameters by simply moving the en-
tire rest backward or forward. This is accomplished by connecting

FIG. 143.— The Lodge & Shipley
Follow Kest.

LATHE DESIGN: TURNING RESTS, ETC.

167

the rest to a screw which telescopes the regular cross-feed screw and
is operated by the same hand wheel which sets the tool-rest. The
position of the rollers is such that in approaching a shoulder
they support the shaft upon the smaller diameter until the cutting-
tool has turned a portion of the next larger diameter, when the
position of the rest is changed to bear on that portion.

Those having quantities of shafts,
with a number of shoulders to turn,
will recognize in this rest an attach-
ment entirely new in principle and
of the greatest importance in the sav-
ing of time.

One of the indispensable acces-
sories or attachments, if it may be so
called, to an engine lathe, particularly
one provided with a long bed, is some
kind of a "straightener," by which
not only rough bars of stock, but
partly finished and finally entirely
finished shafts, may be straightened. sPecial RoUer F

The general plan of doing this work is to rest the shaft upon two
points at some distance apart and then apply pressure on the oppo-
site side, and at a point midway between these two points.

These attachments or accessories are sometimes attached to
the carriage of the lathe; sometimes mounted so as to slide on the
V's of the lathe; again upon wheels that run in the space between
the inner and outer V's; and in still other cases, for small and com-
paratively short work, they are mounted upon a bench. In this
case they either have attached to them a pair of centers in which
the work to be straightened may be placed and its correctness or
incorrectness as well as the location and extent of the inaccuracies
may be determined, or a pair of V-blocks in which the shaft may
be laid while being straightened.

In Fig. 145 is represented one of the latter forms of this acces-
sory made by the Springfield Machine Tool Company, the uses of
which will be readily understood by any mechanic. It is intended
to be placed upon a bench and to be used when centering work by
hand, and for straightening work centered by hand or machine,

FIG. 144.— The Lodge & Shipley
ollow Rest.

168 MODERN LATHE PRACTICE

It is a familiar fact that work straightened in a press is more likely
to remain straight in the lathe than when hammered straight, and
that it is better in every way.

The general arrangement of this machine is in itself very con-
venient, as any work within its range of centers may be tested and
straightened without the unnecessary walking from press to lathe
each time in straightening rough or finished work. This, how-
ever, does not limit the length of shaft that can be straightened,
as any length may be operated upon, thus making it a great labor
saver.

^xar

FIG. 145. — Shaft Straightener for Bench Use, made by
the Springfield Machine Tool Company.

In the tool-room it is especially valuable, not only for centering
and straightening work in the rough, but for straightening pieces
which have been accidentally sprung in use, or reamers, etc., which
have been sprung in tempering.

The blocks upon which the work rests when being straightened
are removable to or from the screw and are kept in line by tongues,
which fit the groove shown. The shaft is movable through the
arm which supports it, being held in any desired position by the
set-screw shown, which has a piece of brass over its points to avoid
marring the shaft. The centering heads are clamped in any desir-
able position on the shaft, by the binding screw shown. The top
of the arm which supports the shaft forms a pocket for chalk or
other material used in marking.

The center at the right is pressed forward by a spring and has
a knurled head for drawing it back, both centers being provided
with small oil wells. The body of the machine has three lugs
cast upon it, by means of which it is bolted to the bench. The block

LATHE DESIGN: TURNING RESTS, ETC.

which is on the end of the screw is of cast steel, case hardened, and
the centers of tool steel tempered — the whole machine being so
designed and constructed as to make it worthy of a place and useful
in any tool-room or machine shop where much small work is done.
Figure 146 shows the shafting straightener made by the New
Haven Manufacturing Company. The base A has cast upon it at
the rear a curved standard B, made very strong by proper ribs and
extending over to the front. Through the top of this passes a
vertical compression screw C, running in a long bronze nut and
carrying loosely upon its lower end a V-block D, adapted to fit

Fig. 146. — Shaft Straightener for use on Lathe
Bed, made by the New Haven Manufactur-
ing Company. s

down upon the round shaft, which is laid into two other loose V-
blocks E, E. To insure great rigidity when handling large work
the forged stay rod F is provided, its head being held in a T-slot
in the base casting and its upper end in a slot cast in the head and in
front of the compression screw C, and secured by a heavy nut.

At each corner of the base casting is bolted a leg G, G, G, G,
carrying loosely journaled therein the shafts H, H, on the outer
ends of which are fixed the wheels J, J, J, J, which are adapted to
run in the spaces between the inner and outer V's of the lathe bed,
which permits it to be moved to any point where its use may be
desired.

170 MODERN LATHE PRACTICE

In ordinary cases a countershaft is a very simple mechanism.
In the older form of engine lathes all that was necessary was a cone
pulley identical with the spindle cone, and upon the other end of
the shaft a tight and a loose pulley for receiving the driving-belt
from the pulley on the main line shaft. Then, as threads required
a backward motion of the lathe spindle, a second pair of pulleys
was added and a cross-belt applied for that purpose. The shifting
of these belts was too slow for practical work and clutches were
used. These were of the old "horn clutch" type, making consider-
able " clatter" in their use and starting the work with too much
shock.

Later on friction clutches or friction pulleys were devised, and
these in one form or another are largely in use at the present time.

Up to a comparatively recent date the lathe had but two speeds,
so far as the countershaft controlled it. One was the usual for-
ward speed, the other a considerably faster speed backwards, mostly
used in thread cutting. Occasionally, for special work, this "back-
ing" speed was taken advantage of by changing the cross-belt for
an "open belt," and thus getting another range of speeds. Doubt-
less this suggested the advantages of a regular two-speed counter-
shaft which has now become quite common, as a convenient and
economical method of adding another series of speeds to the
lathe.

There are now used on a number of popular lathes geared
countershafts as well as various devices for producing a variable
speed by a gradual increase or decrease of the number of revolutions
per minute. This result has been sought by a number of different
devices with more or less success. Some of them have had good
features to commend them while others were more in the line of
makeshifts that accomplished the results sought very inefficiently
and partook too much of the nature of "traps" as understood by
the machinist, and hence were comparatively short-lived and un-
popular.

Figure 147 shows a good example of the regular type of lathe
countershafts. It is made by the F. E. Reed Company, and con-
sists of the cone pulley, a counterpart of the spindle cone part, and
two friction pulleys mounted upon the shaft, which is supported in
two hangers having self -oiling boxes. The friction pulleys consist of

LATHE DESIGN: TURNING RESTS, ETC.

171

the pulley proper A, which is turned on the inside of the rim for the
reception of the friction band B, or has cast with it a rim projecting
from the pulley arms and finished inside for the same purpose, as
shown in the engraving. The friction band B is divided at one
point as shown, the two loose ends having projecting lugs at b, 6,
drilled for pivot bolts by which it is connected with the levers C, C,
whose ends are adjustably connected by the screw and nuts shown
at d.

Friction Pulley,
complete.

FrictionJRing,
or Clutch.

Wedge.

FIG. 147. — Friction Countershaft for Engine Lathes, made by the
F. E. Reed Company

Sliding upon the shaft between the pulleys is the clutch collar
E, whose horns e, e, are adapted to enter between the ends of the
levers C, at /. These horns being wedge-shaped will, when thrust
between the free ends of the levers C, C, spread them apart, and as
their fulcrum ends are connected, and by means of the pivot bolts
connected to the free ends of the friction band B, tend to extend
the opening of this band, enlarge its diameter, bring it in contact
with the inner surface of the pulley (or of the rim cast upon it for
that purpose), and cause sufficient friction to transmit the required
power.

The clutch collar or sleeve E is provided with a square groove
at its center to accommodate the shipper fork, by means of which

172 MODERN LATHE PRACTICE

it is moved to and fro on the shaft, according as one or the other
clutch is to be thrown into an active position and the lathe to be
driven by the belt on the one or the other pulley. One of the pulleys
carries an open belt and the other a cross belt.

There are various forms of friction pulleys and friction clutches
used on countershafts, but all are designed with analogous parts to
the above and perform similar functions. Therefore there is no
need for a detailed description and illustration of them. In all of
them the pulleys run loose on the shaft, except when clamped to
it by means of the friction device, the disc or friction band B, or its
equivalent, being fixed to the shaft.

In the center of the shaft between the pulleys is usually a sliding
sleeve that operates the friction mechanism, as here shown, and
by which it is connected to the shipper lever within easy reach of
the operator.

The tight and loose pulleys are still used on very heavy lathes,
and in this case, when both the forward and backward motion is
desired, there is one tight pulley a little greater in width than the
belt, and on each side of it a loose pulley of double this width. The

- .Exterior View -^Longitudinal Section Cross Section

FIG. 148. — Self-Oiling Boxes for Countershafts, made by the
F. E. Reed Company.

belts are so located that each is on one of the loose pulleys when
the shipper handle is in its middle position. When it is moved to
the right of this position the left belt is moved on to the tight pul-
ley and the right belt travels to the right on its loose pulley. By
moving the shipper handle to the left the reverse effect is produced,
and the right-hand belt becomes operative. The pulley on the
line shaft is, of course, as wide as all three on the countershaft.

In Fig. 148 is given a good illustration of the self-oiling counter-
shaft box, which is used on the countershaft shown in Fig. 146.

As will be seen by the engraving (Fig. 147), the journal box A

LATHE DESIGN: TURNING RESTS, ETC. 173

has formed beneath it an oil reservior B for holding a quantity of
oil sufficient to last several weeks. Near each end is a groove
containing a wick or strip of felt C, C, surrounding the shaft and
reaching down into the oil reservoir B, by means of which an ample
supply of oil is always delivered to the journal bearing. The wick
may be introduced and oil supplied by opening the hinged covers
D,D.

As the supply of oil is so profuse there is the liability of waste
by its running out at the ends of the journals. This is prevented

FIG. 149. — Reeve's Variable Speed Count ershalft.

by providing the return oil grooves E, E, "at the ends, which con-
duct the oil back to the oil reservoir. The design and arrangement
is very simple and at the same time very effective. It is used with
slight modifications for many similar purposes with like success.

In Fig. 149 is shown the Reeves' variable speed countershaft,
which has proven a' valuable device when the speeds required
are not excessive. It is well adapted to nearly all machine-shop
tools and by its use a great range of speeds may be obtained.

It consists of two shafts B and C, journaled in the frame A, in
the usual manner. Upon the shaft B is splined the rather flat cones
D, D, and similarly connected to the shaft C are the cones E, E.
These cones are adapted to slide freely to or from each other on

174 MODERN LATHE PRACTICE

their respective shafts, and their movement is governed by the
levers F, F, which are fulcrumed at /, /, and pivotally attached to
the hubs of the cones D, D, E, E, by suitable collars. The farther
ends of these levers are pivotally connected to a screw G, by suitable
nuts running on right and left threads, whereby the nuts may be
drawn together or forced apart as may be necessary, carrying with
them the ends of the levers F, F, and consequently the cone discs
D, D, E, E, but by an opposite movement; that is, as the discs D, D,
approach each other the discs E, E, recede from each other. Upon
the end of the screw G is the sprocket-wheel H, from which a chain
runs to another sprocket-wheel near the operator, who may handle
it by means of a crank upon the shaft of the latter wheel.

Running within the cone discs D, D, at one end, and E, E, at
the other, is a series of wooden lags connected by a chain mechanism
by which it becomes in effect a belt, the ends of the lags bearing
against the inner, inclined surfaces of the cone discs.

The length of the wooden lags being constant, it follows that as
the cone discs are forced closer together the lags will ride up on a
larger diameter, and simultaneously the cone discs on the opposite
shaft will, by the mechanism described, be drawn farther apart,
permitting the lags to run closer to the shaft and on a correspondingly
smaller diameter.

Now, as one of the shafts B, C, is driven by a belt from a pulley
upon the main line shaft, while the other carries the pulley (in this
case a cone pulley) driving the machine, the speed of the same may
be varied at will, as one pair of cone discs are forced nearer together
and the other pair farther apart, thus, in effect, changing their
relative diameters and consequently their speeds.

Geared countershafts are also used upon lathes for producing
variable speeds. They depend, of course, upon the usual methods
of Bringing into active operation pairs of gears of varying diameters
by means of clutches, sliding gears, and similar devices. The noise
of the gears is one great objection to their use. This has been
partially avoided, or smothered, by enclosing them with a casing,
which partially obviates another objection, that of throwing oil
and dirt upon the floor, the machines, and the workmen.

Another form of variable-speed countershaft was brought into
use some years ago which consisted of two comparatively long

LATHE DESIGN: TURNING RESTS, ETC. 175

cones placed side by side but in reverse positions so that their ad-
jacent sides were parallel. They were mounted upon parallel shafts,
one being the driven and the other the driver. Motion was trans-
mitted from one to the other by means of a short endless belt running
between the surfaces, with the slack end hanging below them. This
belt was controlled by a sliding belt guide by means of which it
could be moved from end to end of the cones, whose varying diam-
eters at the point of contact determined the speed transmitted
from one shaft to the other.

While this device was entirely operative and, with light loads,
reasonably successful, it was not well adapted to transmitting any
considerable amount of power, owing to the very small area of
contact surface between the cones and the belt, the pressure upon
which had to be excessive in order to transmit the power required
even for light work.

Unusually large cones would no doubt have added materially
to its transmitting power, but as a practical mechanism it was not
the success that its admirers hoped it would be.

CHAPTER IX

LATHE ATTACHMENTS

Special forms of turned work. Attachment for machining concave and
convex surfaces. Attachment for forming semicircular grooves in
rolling mill rolls. Device for turning balls or spherical work. Turning
curved rolls. A German device for machining concave surfaces. A
similar device for convex surfaces. Making milling cutters. Backing
off or relieving attachment. Operation of the device. Cross-feed stop
for lathes. Grinding attachments. The "home-made" attachment.
Electrically driven grinding attachment. Center grinding attachment.
Large grinding attachment. The Rivett-Dock thread-cutting attach-
ment.

WHILE an engine lathe will readily turn straight and taper
work, and will "face" work at right angles to the center line of
the lathe, or by means of the compound rest will turn or face at
any angle, no means is provided for turning curved contours, as
spheres, curved rolls smallest in the center, or largest in the center,
as the case may be, or to "face up" convex or concave surfaces.
These and many other forms must be made by the aid of some kind
of a device built for the special purpose and usually known under
the general name of a "lathe attachment."

There are, of course, a great variety of jobs that can be economi-
cally performed on a lathe if we are provided with the proper tools
and a suitable "attachment" for handling them.

It is not proposed to give here a complete Jist of these ever vary-
ing kinds or types of lathe attachments or to exhaust the list of
forms of work that may be machined by one or another of these
devices, yet it may be interesting to present a few of the attach-
ments that are most likely to be needed, and in a general way those
that the machinist may easily make for himself.

It often happens that a large number of concave or convex sur-

176

LATHE ATTACHMENTS

177

faces have to be machined to accurate spherical forms, the pieces
being of such dimensions or material that the usual forming tools
are impractical, or that the variety of dimensions would render
them too expensive.

In these cases a special device must be designed which will
properly fulfil the conditions and be capable of adjustment within
a reasonable range of diameters of the work and the radii of the
curves to be machined.

FIG. 150. — Plan of Lathe Attachment for
Forming Concave and Convex Surfaces.

This may be accomplished by a special device attached to almost
any ordinary lathe having a compound rest with a circular base,
such as are now nearly always designed and built. The author
has had occasion to design several of these devices, and the general
form and arrangement of them has been as shown in the accom-
panying engravings, in which Fig. 150 is a plan of the lathe
carriage showing the circular feeding device; Fig. 151 is a front
elevation showing the method of varying the feed to suit the
material to be machined; and Fig. 152 shows a modification of
the device for a different form of work.

The various forms of work required to be done by a device of

178

MODERN LATHE PRACTICE

this kind are most frequently for concaving vertical step bearings
of various diameters from three inches up, and of radii varying in
proportion, for forming concave and convex surfaces for ball and
socket joints, for turning large spherical surfaces, and for forming
semicircular grooves in rolls for rolling iron and steel bars.

The construction and application of this device, as arranged on
an ordinary lathe, is as follows. A machine steel ring A is forged,
turned up, bored to a force fit to the circular portion of the com-
pound rest. Its outer surface is properly formed for a worm-gear,
its teeth cut and hobbed and it is forced on, and pinned if thought
necessary. Engaging the teeth of this is the worm B, fixed to a
shaft C, journaled in the brackets D, D, which are fixed to the car-
riage as shown. Upon the front end of the shaft C is the gear E,

FIG. 151. — Front Elevation of Attachment.

which may be removed and another size substituted for varying
the rate of feed. Upon the front end of the cross-feed screw F is
fitted a removable gear G. Connecting the gears E and G is the
intermediate gear H, carried upon a movable stud located in the
stud-plate J, which is pivoted upon a projecting sleeve formed upon
the front bracket D and held in any desired position by the clamp-
ing screw K. By this arrangement the rate of feed may be con-
veniently changed to suit different diameters of work and materials
of varying degrees of hardness, the same as the usual change-gears
of a lathe. By releasing the stud-plate J, the gears G and H may
be thrown out of engagement temporarily, while the stud-plate J
and the brackets D, D may be easily removed altogether, if it is
desired to use the lathe for ordinary turning for any length of time.
As the feed for this device is derived from the cross-feed screw

LATHE ATTACHMENTS 179

F, it is necessary to replace the usual solid nut in the shoe by a split
nut (not shown) with the usual lever or eccentric device for open-
ing and closing it as may be desired. A clutch device on the front
end of the cross-feed screw F may be adopted, if desired, by having
the cross-feed pinion N formed upon a sleeve projecting through
to the front of the carriage and the gear G mounted upon it, and
connected with, or disconnected from, the cross-feed screw F by
sliding a double-faced clutch.

In using this device for concave work held in a chuck or strapped
to the face-plate, care must be taken to have the compound rest
so adjusted on the carriage that when set parallel with the center
line of the lathe its center will be exactly under that line, and that
the horizontal distance from the point of the tool to the center
of the compound rest will be the exact radius of the curve to be
produced.

If convex work is to be done the compound rest tool block must
be drawn back far enough past the center to give the required
radius of the convex curve.

Figure 152 shows a compound rest tool
block arranged for forming the semicircular
grooves in rolling mill rolls. In this case the
tool-post M may be made in two or more sizes,
as some of the grooves are small enough to ne- ^g^f ' Attachment01
cessitate quite a small tool-post. If a lathe
is to be used exclusively for this work the compound rest may be
removed entirely and a circular base provided, having worm-gear
teeth cut in its edge. This will be held down in the same manner
as the compound rest, and have fixed in a raised central portion
tool-posts proper for the work for which it is designed. In any
event it will be found necessary to construct the device in as strong
a manner as possible, in order to prevent, as far as may be the
chatter or vibration of the tool.

The device as shown will be found to be economical to make
and apply, as well as very convenient and efficient in its opera-
tion.

All machinists who have ever undertaken to turn balls or par-
tially spherical surfaces know how difficult it is to produce a satis-
factory piece of work, either as regards finish, time required, or

180

MODERN LATHE PRACTICE

accuracy. In Fig. 153 is shown a compound rest containing
an attachment for doing this work. In Fig. 154 is a bottom view
of the same for the purpose of showing the operative parts.

In its operation the lower slide or shoe A of the compound rest
is fixed to the carriage. The cross-feed nut B is fixed to the rack

FIG. 153. — Side Elevation of Ball Turning
Attachment.

C, which engages with the idle pinion, D, which in turn engages the
gear E, which is fixed to the central stem of the compound rest
tool block F.

When in use the cross-feed is connected and started, and in-
stead of moving the entire compound rest across the carnage as
it ordinarily would, it moves only the rack C forward or back,
which motion, being transmitted by the pinion D, and gear E,

FIG. 154. — Bottom View of Ball Turning
Attachment.

swings the compound-rest tool block F around on the center of the
gear E, the shoe A being fast to the carriage.

The diameter of the work is regulated by the ordinary compound
rest screw crank G, in the usual manner.

The turning of curved rolls such as shown in Fig. 155 is not pro-

LATHE ATTACHMENTS

181

vided for in the ordinary attachments sold with an engine lathe,
and where this work is not done regularly so as to warrant the
designing and building of an at-
tachment for the purpose, some
mechanism must be arranged for
doing the work.

The engravings in Fig. 156,
which is a cross section, and Fig.
157, which is a plan, show how an
ingenious machinist managed to
do this.

In the engravings, A is the bed
of the lathe, B is the carriage, and
C the compound rest. The curved
bar D is attached to the bed by
means of suitable brackets at each end, as shown in Fig. 157.
This bar is made exactly to the curve which the rolls are to have,
both on its concave and its convex edges, and serves as a guide
for moving the compound rest forward and back so as to produce
the proper curve in its travel across the work.

FIG. 155. — Forms of Convex and
Concave Rolls to be Turned.

FIG. 156. — Cross Section of Attachment for Turning Convex
and Concave Rolls".

To accomplish this travel the cross-feed screw nut E travels
in a slot in the compound rest and may be fixed at any point therein
by the screw F. Fixed to the rear end of the compound rest shoe

182

MODERN LATHE PRACTICE

C is a bracket G, in which is pivoted the small friction roller H,
which bears against the edge of the curved former bar D. Attached
also to the compound rest is the weight K, by means of a cord
which runs over a sleeve L, attached to the lathe carriage.

In the use of this device the clamp screw F is tightened up so
as to fix the cross-feed screw nut E in its place and the rough forging
for the roll turned down nearly to the finish size and form in the
usual manner. The clamp screw F is then loosened and the fric-

FIG. 157. — Plan of Attachment for Turning Convex
and Concave Rolls.

tion roll H brought against the curved guide-bar D by the weight
K, and the finishing cuts taken to the proper curve.

When the rolls are to be made largest in the center, the guide-
bar D is reversed, bringing its convex side next to the friction
roller H.

A similar attachment, or in fact this one, may be used to finish
other curves, whether simple or compound, so long as the contour
is made up of easy curves capable of being followed by the friction
roller H, as shown in the engraving. Small pieces, say less than

LATHE ATTACHMENTS

183

six inches in length, may be more economically finished by means
of forming tools.

Another very desirable attachment for machining concave and
convex surfaces is of German origin. Figure 158 shows a front
elevation and Fig. 159 a plan of a lathe fitted with this attachment.

FIG. 158. — Front Elevation of Attachment for Turning Concave Surfaces.

It is very simple in its construction and consists of a radius bar A,
which is pivoted at its rear end to a block D, and at its front end
to the tool block of the compound rest at B. By reference to the
plan in Fig. 159, it will be readily seen that as the cross-feed is
operated, the compound rest must swing upon its center according
to the radius of the bar A, and be governed by it.

FIG. 159. — Plan of Attachment for Turning Concave
Surfaces.

It is necessary for its practical working that all fits and adjust-
ments must be nicely made and accurately set in order to have this
attachment operative. Also, that unless the parts are all com-
paratively heavy and rigid, the cuts made would of necessity be
light ones, otherwise the tool would be likely to have considerable
vibration and leave " chatter marks" in the work.

It should also be remembered that for a large radius the tool

184

MODERN LATHE PRACTICE

must project out farther from the center of the compound rest as
in other attachments of the kind, since the radius bar has nothing
to do with determining or governing the radius of the curve
machined.

Figure 160 is a front elevation and Fig. 161 a plan of a similar

FIG. 160. — Front Elevation of Attachment for Turning Convex Surfaces.

attachment to the above, and of like origin, having for its object
the machining of convex surfaces. This is a more complex matter,
and the manner in which it is accomplished is at once ingenious and
practical, and, so far as the author is aware, is new in this country.
In the design of an attachment so arranged as to effect the
proper movement of the tool to produce a convex curve, tliat is, a
drawing back of the cutting-tool as it advances, it is obvious that
the length of the radius bar must be the same as the radius of the
curve which it is to produce. The bar A is made to this length and

FIG. 161. — Plan of Attachment for Turning Convex Surfaces.

is pivoted at I to a slide K, free to move longitudinally on the lathe
bed. The other end of the bar A is pivoted to a cross-slide F,
which moves on a guide E, rigidly secured to the lathe bed. The
carriage cross-slide has attached to it the roller G, which engages
jaws in the slide F, and hence, as it is fed across the surface of the

LATHE ATTACHMENTS 185

work, the slide F is carried along with the carnage cross-slide. The
resultant effect of the movement of the bar A is to move the block
K along the lathe bed, and this movement is transmitted to the
carriage by means of the connecting bar L, this compound move-
ment causing the point of the tool to describe an arc of which the
length of the bar A is the radius.

In this device, also, it is necessary to have all the parts strong
and rigid, with bars, studs, bolts, etc., much larger and of better
mechanical construction than those shown in the engraving, in
order to insure accurate and well finished work as well that which
will be economical in point of the time required to perform it.

In making cutters for use in milling machines, gear cutters and
the like, it is not sufficient that the correct form be given to the
face or cutting edge of the teeth only. This form must be carried
on to the back of the teeth so that in grinding the face of the teeth,
when they have become dulled from use, they will still maintain
their original and correct form.

This would be a simple matter and might be readily accom-
plished in forming up the blank in the lathe previous to cutting
the teeth, if it were not for the fact that there must be some "side
clearance" allowed to the teeth. In other words, the teeth must
be widest and the diameter of the cutter the largest across the
cutting edge and the points of the teeth respectively, and the "form"
carried back from this in a decreasing radius.

This form is produced by the process known by the technical
term of "backing off."

There are various attachments in the market for performing
this operation. The conditions of the case require that for each
tooth of the cutter the forming tool must commence to cut
at the cutting edge of the cutter, quickly move in toward the center
until the cutting edge of the next tooth approaches, then fly back
to the original position ready for cutting the next tooth. This
motion is repeated for each tooth, and the tool-holding device must
be likewise capable of being constantly adjusted to the depth of
the cut as the metal is cut away so as to reduce it until the cut
comes quite near the cutting edge.

From these conditions it will be seen that there must be a quick
advance and an instantaneous return of the forming tool for each

186

MODERN LATHE PRACTICE

tooth of the cutter. To produce this movement is the function
of the "backing-off" or "relieving" attachment.

An ingenious device of this kind is illustrated in Figs. 162, 163,
and 164, of which Fig. 162 is a plan of the attachment, Fig. 163

G j F

FIG. 162. — Attachment for "Backing-off" or
"Relieving" the Teeth of Cutters.

shows one of the actuating cams, and Fig. 164 .shows the bracket
and friction roller that rests against the actuating cam shown
in Fig. 163.

The construction of the device is as follows: Upon the small
face-plate A of the lathe is fixed the actuating cam B, shown in Fig.
163. Upon the swivel bar of a regular taper attachment C is fixed
the bracket D, in the upper end of which is journaled the friction

FIG. 163. —
Ratchet Cam
for "Backing-
off" Attach-
ment.

FIG. 164. — Brac-
ket for Cam Rol-
ler of "Backing-
off ' ' Attachment.

roller E, which bears against the actuating cam B. The swivel bar
is pivoted at F, as usual, and when used for the purposes of this
attachment the clamping screws at either end (not shown) are left
slightly loose so as to permit it to swivel slightly, and the friction
roller E held tightly against the actuating cam B by means of a
strong spring at H. K is the cutter to be "backed off," and L is
the forming tool doing the work.

The compound rest, or cross-slide, as the case may be, is con-
nected to the taper attachment sliding block J by a pivot bolt G,
in the usual manner.

LATHE ATTACHMENTS

187

The operation of the device is this. The swivel bar of the taper
attachment forms a lever by which the motion derived from the
actuating cam B is conveyed to the tool-holding device of the com-
pound rest, the forming
tool being drawn in as the
friction roll E rides up on
the cam tooth, and suddenly
dropping back to its original
position as the roller drops
off the point of the cam
tooth, the actuating cam
always revolving in the di-
rection indicated by the ar-
row.

There are two impor-
tant advantages possessed
by this arrangement. First,
it is very economically and
conveniently applied to an
engine lathe having a taper
attachment. Second, as the taper attachment swivel bar is used
as a lever in obtaining the motion desired, this leverage may be
as small or as great as desired by bringing the pivot bolts F and
G nearer together or farther apart. Thus the amount of "clear-
ance" given to the teeth
of the cutter is entirely
under the control of the
operator, who can change
or modify this condition
at any time, even while
the work is in progress, by
simply moving the taper-
attachment brackets to
the right or left on the
lathe bed.

In Fig. 165 is shown the plan, and in Fig. 166 the elevation,
of a convenient and practical stop for the cross-feed of an engine
lathe. It is not only very useful in thread cutting but in getting

FIG. 165. — Plan of Micrometer Stop Attach-
ment for Cross-Feed of Lathes.

FIG. 166. — Front Elevation of Micrometer
Stop Attachment for Cross-Feed of Lathes.

188 MODERN LATHE PRACTICE

accurate dimensions of both inside and outside work, as well as to
accurately turn different diameters with the same tool and at the
same setting.

The construction of the device is as follows: Upon the cross-,
slide A is fitted the cross-feed stop B, constructed as usual.
Through this piece and into the tool block C passes the stop stud

D, being fixed in the latter piece. This stud is threaded 20 to
the inch, and the micrometer nuts E, E, graduated in 50 spaces,
thus giving a reading of .001, upon which quarter thousands may
be easily determined.

The micrometer nuts are recessed on the side next to the feed
stop B, and provided with a washer and short spiral spring. The
washer is prevented from turning except with the nut by a small
pin in the nut and fitting in a suitable notch in the edge of the
washer. This washer is threaded the same as the nut E, and the
action of the spring causes friction enough on the thread to prevent
the nut from turning by any jar to which the lathe may be sub-
jected. This construction also excludes dirt and takes up wear
when the device has been in use for any great length of time.

Two micrometer nuts are used so that inside as well as outside
work may be accurately turned.

When different diameters are to be turned, stop levers of vary-
ing thickness, one of which is shown at F, are used by placing them
on the stud G, and secured by the nut H and its spiral spring.
This stop must, of course, be exactly one half the difference between
the large and the small diameter in thickness. In use it is turned
down so as to come between the stop B and the micrometer nut

E. When not in use it is turned over against the pin J. Two or
more of these stops may be used without removing either of them,
provided the one next to the stop B is used first and the others
added successively to it, or vice versa.

While such an attachment as the one here shown is a valuable
aid to a careful operator, it is not an assurance that accurate diam-
eters will be continuously turned out when the operator becomes
careless and "runs hard against the stop," or is guilty of the oppo-
site error of not coming closely up to it. Both these errors have
caused a great deal of trouble to shop foremen.

In these modern days and days of modern methods, when me-

LATHE ATTACHMENTS 189

chanical accuracy is the great desideratum, the subject of grinding
cylindrical surfaces has absorbed a great deal of attention. It was
long ago realized that it was next to impossible to construct a lathe
so accurate that it was possible to turn a perfectly cylindrical piece
of work upon it.

Grinding was formerly used principally in the construction of
gages of various forms, but particularly cylindrical gages. As
grinding machines were simplified and improved it was found that
the grinding processes were continually becoming more economical,
and that therefore the extreme accuracy which such processes made
possible could be applied to many other kinds or classes of work.

Grinding as performed in an engine lathe was accomplished by
a " home-made" grinding attachment, more or less crude, and bolted
down to the lathe carriage, tool block, or compound rest. The
spindle carried a grooved pulley from which a round leather belt
went up to a wooden drum hung up over the lathe and driven by a
short belt from the lathe countershaft. This drum was as long as
any grinding job was expected to be, since the round belt must
needs travel to and fro upon it as the lathe carriage carried the
grinding attachments over the length of the piece of work to be
ground.

It must be admitted that even with these crude devices much
good work was accom-
plished, and that the way
was thus opened for the
much better work that
followed later on.

With the introduction
of electrical power and
the ease with which
small and compact mo-
tors could be constructed, FIG. 167. — Tool-Post Grinding Attachment,
the convenience of driv- made by Cincinnati Electric Tool Company.

ing grinding devices was much increased and the old overhead
wooden drum is fast becoming a thing of the past.

In Fig. 167 is given a view of one of the electrically driven lathe
grinder attachments made by the Cincinnati Electrical Tool Com-
pany. It may be held in the tool-post or tool-clamping device, and

190

MODERN LATHE PRACTICE

is entirely self-contained, the emery wheel being attached to the
shaft of the small electric motor within the metallic case. It is
driven by the current coming through an ordinary incandescent
lamp cord. Its movements are regulated by the crank seen in
front of the case, as well as by the cross and lateral feeding
mechanism of the lathe.

Its compact form, portability, and the convenience of attach-
ing, using, and detaching, render it a very useful lathe grinder. It
can be set at any angle so as to grind taper work as well as straight,
and the centers of the lathe in which it is used.

Figure 168 is of a center-grinding attachment made by the

FIG. 168. — Lathe Center Grinding Attachment, made
by the Hisey-Wolf Machine Company.

Hisey-Wolf Machine Company, and is shown attached to a lathe
in the proper position for grinding the head-stock center. Like
the last example it consists of an electric motor whose shaft carries
the emery wheel. The shaft is arranged to travel endwise as is
necessary in center grinding, and is operated by means of the double
crank shown at the left. It is driven by the current from an ordi-
nary lamp cord.

Figure 169 represents a larger grinding attachment made by the
same company and designed for larger and heavier work than either
of the above devices. It is arranged to be bolted down upon the
lathe carriage, or a block attached to it so as to bring its center at
the same height as that of the center line of the lathe. It is driven
in the same manner as the last two devices.

LATHE ATTACHMENTS

191

The entire motor and case is attached to a square block having
a vertically sliding surface planed upon it, and fitting the bolting-
down and supporting bracket upon which it slides vertically, being
adjusted as to height and held in any desired position by the double
crank seen at the top.

By extending the shafts of these motors, either temporarily
or by having them so constructed when built, to the proper distance
so as to carry the emery wheel at a considerable distance from the
motor, they may be used for grinding the inside of cylindrical work,
the longitudinal feed of the lathe being made use of to give the
required travel for the wheel.

FIG. 169. — A Larger Lathe Grinding Attachment,
made by the Hisey-Wolf Machine Company.

Should the inside work be conical it is entirely practical to
attach the grinder to the compound rest, set at the proper angle and
the wheel fed back and forth quite as readily as on straight work.

Being electrically driven the device may be set with its shaft at
right angles to the center line of the lathe, and face grinding may
be conveniently performed.

In fact there are hardly any of the ordinary grinding operations
that are required to be done on centers that may not be performed
by one of these grinders, even to cutters, reamers, and the like, by a
little ingenuity in arranging for them.

These points make such grinders of a great deal of value in
ordinary machine shops and manufactories, and almost indispen-
sable in the smaller shops where it is not always possible to get a
regular grinding machine.

192

MODERN LATHE PRACTICE

The Rivett-Dock thread-cutting attachment, shown in Fig.
170, may with propriety be classed as a tool, but from its impor-
tance in design, use, and effect it seems to deserve being classed as
an attachment and so it is made a part of this chapter.

Its construction and operation is as follows : The angle plate A
is adapted to be bolted down on the tool block of the lathe, and
upon its upright face is fitted the horizontal slide B, which may be
moved forward and back by means of the lever C. The slide B has
pivoted to it the circular cutter D, whose ten teeth are shaped in the

FIG. 170. — The Rivett-Dock Thread Cutting
Attachment.

form of the thread. However, the full form of the thread is only
given by the last one used in cutting the thread, the others being
gradually cut away so that the first one hardly more than marks
the location of the cut, the design being to cut the full thread at
ten cuts, each successive tooth of the cutter cutting a little deeper
until the tenth tooth shall have but a trifle to cut to finish the
thread.

It will be noticed that the tooth marked 0 in the engraving
rests upon a projection E, which supports it in its cutting position
to act upon the piece F which is being cut. The cutter having
made one cut is withdrawn from contact with the work by the

LATHE ATTACHMENTS 193

handle C, by which motion the pawl G, pivoted at the top of the
angle plate A, engages in the space between the teeth of the cutter
D, and causes it to rotate to the left just far enough to bring the
next tooth into the cutting position. The withdrawal of the cutter
from the support E permits its revolution. The cutter is then
thrown forward and the next tooth is ready for the cut. This
operation is repeated until all the teeth have been brought into the
cutting position and made their cut in succession, and the thread is
completed.

The important point accomplished by this device is that as
there should be ten cuts made to complete a thread, the keen edge
of the tool for finishing is liable to be lost in the earlier roughing
cuts. With this device the roughing cuts are made with teeth
designed for that work particularly, and the thread is brought to a
state of completion by what is practically ten different tools.
Hence a saving of time, both in cutting and in grinding tools, and the
production of a smooth, accurately finished, and perfect thread.

CHAPTER X

RAPID CHANGE GEAR MECHANISMS

What a rapid change gear device is. The old pin wheel and lantern pinion
. device. The first patent for a rapid change gear device. The inven-
tors' claims. Classification of rapid change gear devices. The
inventors of rapid change gear devices. Paulson's originality.
"Change gear devices" by the author. Le Blond's quick change gear
device. The Springfield rapid change gear attachment. Criticism of
the device. The Bradford rapid change gear device. Judd's quick
change gear device. Newton's quick change gear device. The Flather
quick change gear device.

BY the term "rapid change gear" we understand that the mech-
anism so denominated is one capable of performing all the func-
tions of the former change-gears but without the necessity for
exchanging one gear for another or one set of gears for another,
that is, without removing a gear.

These gears were formerly called ' 'change-gears" because they
were subject to change for each new operation of the lathe in which
their use was essential.

In the old-fashioned " chain lathe," having a lead screw driven
by "pin wheels" and " Ian tern pinions," which is illustrated and
described in Chapter II, it will be seen that the builder had pro-
vided for changing the pitch of the thread to be cut by changing
only one gear. This was about the year 1830. In 1882, George A.
Gray, Jr., obtained a patent, No. 252,760, for a change gear arrange-
ment whose principal feature was that only one gear need be re-
moved and changed to cut any of the usual threads.

The first effort in the direction of devising a rapid change gear
mechanism was, so far as the United States Patent Office is con-
cerned, made by Edward Bancroft and William Sellers, who on
February 7, 1854, obtained Patent No. 10,491, for a device con-

194

RAPID CHANGE GEAR MECHANISMS 195

sisting of two cones of gears intermeshing, one set fast to the shaft
and the other set adapted to fix any single gear to the shaft by
means of a pin passing through a fixed flange and into a hole in
a gear or the hub of a gear; the set being made with telescoping
hubs, the ends of all coming against the fixed plate. It is interest-
ing, in the light of present developments in this line, to read the
first claim of their patent, so prophetic of the developments to come,
as follows: "The method of varying the motions of the mandrel or
screw-shaft, or leader, by means of two series of wheels of different
diameters, and all of the wheels of one series being connected and
turning together, and imparting motion to all the wheels of the
second series with different degrees of velocity, substantially as
described."

While a number of the later inventors claimed these same
features of the mechanism and apparently considered themselves
as the original inventors, it will be readily seen that the mechanical
ideas involved in this invention anticipated their claims by a goodly
number of years.

In considering the question of rapid change gear devices it .will
be well to adopt fome classification based upon their design or
structural differences. We may then illustrate and describe these
general classes by well-known or readily understood examples,
whereby all devices of this kind may be more easily understood and
their special features appreciated at their proper value.

Thus we may classify these devices in their general groups as
follows :

First, those in which the gears representing the former change-
gears are all placed on one shaft;

Second, those in which these gears wrere placed on several
shafts or studs, and arranged in a circle ; and

Third, those in which neither of these arrangements existed.

Of the first class, using what has become well known as the
"cone of gears," the most notable inventors are Bancroft and
Sellers, Humphreys, Miles, Riley, Hyde, Joseph Flather, Peter and
William Shellenback, Norton, William Shellenback, Herbert L.
Flather, Ernest J Flather, Wheeler, Isler, Le Blond, Johnson and
Wood.

Of this number it was usual to use one or two cones of gears,

196 MODERN LATHE PRACTICE

but this number did not seem to satisfy the ambition of some of the
inventors, since one of them, Isler, used no less than six cones of
gears. Usually these cones of gears were located under the head
or in front of it, but sometimes within the bed. But Johnson,
apparently being determined to have a cone of gears somewhere,
places them on a loose sleeve running on the main spindle. It
remained for Wheeler to find a new location for his cone of gears by
placing them in the apron.

Among all these devices, as in other spheres of mechanical
effort, the inventors produced mechanisms ranging all the way from
"good and bad, to indifferent."

Of the second class, that is, those who located the gears on short
shafts arranged in a circle, the first to devise this arrangement was
Edward Flather, who obtained patent No. 536,615, on April 2,
1895, and was later followed by Benj. F. Burdick, William L.
Shellenback, Edward A. Muller, and Herman R. Isler, in the order
named, the latter 's last patent having been granted in 1902.

Of the exceptional examples, included in class third, the most
notable one is the invention of Carl J. Paulson, who adopted
the very original method of making a series of rings fitting inside
each other, cutting gear teeth on a portion of the face of each and
arranging the proper mechanism to thrust out from its fellows, the
gear having the desired number of teeth that might be needed.
This was probably the most original of all the methods employed
up to the present time.

While this device was not a commercial success, it had a counter-
part and was the prototype of a quite similar arrangement consist-
ing of two sets of sleeves in line with each other and having teeth
cut on their outer surfaces precisely as Paulson had done, and
arranging them and their connecting gears in a more practical and
operative combination.

An interesting review might be written and illustrated of the
various patented change gear mechanisms that have been invented
since the days of Bancroft and Sellers, but it is hardly within the
scope of this work to give the necessary space to this portion of
lathe description. If the reader desires to pursue the subject in
detail and to have dates, patent numbers, and illustrations from the
drawings in the patent office, he is referred to a book by the author

RAPID CHANGE GEAR MECHANISMS

197

entitled " Change Gear Devices," wherein all this data is presented
in detail.

For the purposes of this work it will be sufficient to present a few
of the more recent examples in this chapter and to call attention to
the engravings of a number of others in other chapters wherein the
lathes of prominent builders are illustrated and the change gear
devices shown. Among these are the lathes built by Hamilton
Machine Tool Company, Bradford Machine Tool Company, Hendey
Machine Tool Company, Prentice Brothers Company, Springfield
Machine Company, etc.

FIG. 171. — End Elevation of Le Blond's Quick Change Gear Device.

The quick change gear device designed by R. K. Le Blond is an
interesting example of this type of mechanism. Figure 171 shows
an end elevation of this lathe, and Figs. 172, 173, and 174 some of
the details of the gearing.

The lathe, with the exception of these features, is the same as
the standard engine lathe built by this company, and the head-
stock end is shown in Fig. 171, which gives a good idea of the
exterior appearance of the change gear device.

198

MODERN LATHE PRACTICE

FIG. 1,72. — Sectional View of
Le Blond's Quick Change
Gear Device.

The line drawing, Fig. 172, shows the connection between the
feed box and the lathe spindle. The spindle gear A drives gear D
on the stud D1; through tumbler gears B and C. The tumbler gears

are of the regular construction used for
reversing the motion of the carriage in
screw cutting, so as to cut either right
or left hand threads, as required.

Motion is transmitted from the
tumbler gears through gears D, Ew G,
and H, which latter is on the driving-
shaft of the feed box. In order, how-
ever, to obtain a second series of feeds
there is a telescopic slip gear located
on the stud D1 which can be made to
mesh with gear G in place of pinion ^
which is shown in mesh with gear G in the engraving. To accom-
plish this, G rotates on a pin in a quadrant Gt, which, by means of
the clamping handle G4 and the stops G2 and G3 can be brought
into the correct position for gear G to mesh either with pinion Et
or gear F, as required. The hub of gear F is recessed so that it can
be slid over pinion Ex, thus bringing this gear in the same plane
with gear G. Gears D and F and the pinion Ex all rotate with the
stud, which is journaled in a bearing in the head-stock casting.
The introduction of the telescopic gear F makes a change in the
feed ratio of 4 to 1.

Figure 173 is reproduced from the patent specification and
shows clearly the mechanism of the feed box. A is the driving shaft
and B the driven shaft, which in this case is represented as being
one end of the lead screw, but in the actual lathe is connected with
the latter by suitable intermediate gearing. However, the prin-
ciple of the feed changes is the same in either case. Shaft B carries
a cone of gears and shaft A an elongated spur gear C, which is the
driving gear of the mechanism.

Surrounding this elongated gear C is a cylindrical barrel D,
which serves the double purpose of a casing for the gear and a
bearing for a sliding bushing E, by means of which the adjustment
of feed is effected. This bushing carries at F an intermediate
gear which at all times is in mesh with gear C and can also be brought

RAPID CHANGE GEAR MECHANISMS

199

into mesh with one of the gears in the cone by giving the bushing E
a combined sliding and rotary motion on the barrel D.

The portion of the barrel D which is toward the cone of gears is
provided with a longitudinal slot, to allow the intermediate gear
F to project through and mesh with gear C. The front portion of
the barrel is provided with a series of holes, corresponding in num-
ber and position to the gears of the cone, so that the bushing which

EXTERIOR VIEW

FIG. 173. — Details of Le Blond's Quick Change
Gear Device.

carries the intermediate gear F can be locked in its proper position
for each gear by means of a spring pin, after the usual manner.
The bushing which acts as carrier for the gear, and the barrel which
encases the elongated gear, are clearly represented in the detailed
view of the mechanism, Fig. 173.

Figure 174 is a view looking at rear of the mechanism and its
casing, and shows the modifications that have been made in the
device to adapt it to the engine lathe. The cone shaft carries be-
sides the eight gears of the cone, an additional gear, K, and below
this shaft, which is marked B, is the shaft L, which is connected
directly to the feed rod R, and carries a sliding sleeve S, on which
are two pinions, M and N.

200

MODERN LATHE PRACTICE

In the position shown in this view power is transmitted from
the cone shaft B to the gear N by means of the auxiliary pinion K,
and as the sleeve S is splined to shaft L the motion is transmitted
to this shaft and thence to the feed rod. By sliding the sleeve to
the right, gear N no longer meshes with pinion K, but instead pinion
M meshes with one of the gears of the cone, causing the feed rod
to rotate at a faster speed. The lead screw T is driven from the
feed rod by a slip gear W, in the usual manner.

From the above description it will be seen that with the* gear
box itself eight changes of feed are obtained. The slip gear on the
auxiliary shaft in the feed box makes 16 changes, and these 16
changes are again doubled by the telescopic gear on stud Dl; in

FIG. 174 — . Rear View of Le Blond's Quick Change Gear Device.

Fig. 2, making 32 changes and giving a range of threads from 3 to
46 per inch, covering every standard thread, including 11J.

This entire range of threads can be made without stopping the
lathe or removing a single gear. The feeds are four times the num-
ber of threads per inch. It will be noticed that the compounding
generally adopted on this style of lathe is done away with, and that
wherever there are coarse feeds or heavy threads the increase comes
directly from the 4 to 1 gear on the stud D17 speeding up the
feed mechanism of the feed box in the same proportion, so that it
is placed under no additional strain.

Figures 175 and 176 illustrate the "rapid change gear at-
tachment" of the Springfield Machine Tool Company's "Ideal"
lathe. They make use of the design placed in the second class,

RAPID CHANGE GEAR MECHANISMS 201

that is, those which have their change-gears mounted upon studs
or short shafts arranged in a circle.

The change-gears are mounted in a gear box, shown at the left-
hand side of the engraving, Fig. 175, the intermediate and head-
stock spindle gears being those ordinarily used. The cover of the
gear box is rotated about a central stud, and the gears are carried

FIG. 175. — Rapid Change Gear Attachment built by the
Springfield Machine Tool Company.

on the inside of the cover, arranged in a circle concentric with the
case, and this circle brings the change-gears opposite the end of the
lead screw by revolving the cover of the case.

Referring to Fig. 176, the small clutch C moves a telescopic
extension of the lead screw and enters it into a hole in the change-
gear before the driving clutches between the change-gear and the
extension come into contact. This device takes the bearing of
the change-gear upon the extension for its support, and secures the
change-gear to the lead screw as firmly as if fastened by a nut. In
order to change the gear, the cover is revolved until the desired

202

MODERN LATHE PRACTICE

gear is opposite the center of the lead screw extension, when the
small clutch is thrown. All of the eight change-gears are protected
by the case except the top of the one which is in mesh with the
intermediate gear.

To give a sufficient range of pitches, a set of three pairs of gears is
provided in the head-stock to vary the speed of the intermediate

FIG. 176. — Longitudinal Section of Rapid Change Gear
Attachment built by the Springfield Machine Tool Company.

gear. These are housed in the gear cases shown at the extreme
end of the head-stock. These are clutched to their spindles by
slipping them on until their clutches engage the spindles, which
have clutches with their end sections reduced, as in the case of the
lead screw shown at F in the sectional drawing, Fig. 176. These
gears furnish ratios of from 1 to 1, 2 to 1, and 4 to 1. The last
two may be reversed and five speeds may be given to the fixed
pinion driving the intermediate gear. The intermediate gear

RAPID CHANGE GEAR MECHANISMS

203

revolves on a fixed stud on a quadrant to which the handle is
attached, and is removed from contact by raising the quadrant.

This lathe has a range of threads from 2 to 56 per inch, and a
range of turning feeds from 8 to 224 turns per inch, and all the
changes for any of these feeds or threads may be made while the
lathe is running.

The objection to this device is the inherent weakness of the
mechanism when the gears are arranged upon short studs or shafts
set around a circle. These cased-in gears must of necessity be

FIG. 177. — End Elevation of the Bradford Rapid
Change Gear Device.

comparatively small and of narrow face. The teeth must, from
the same conditions, be of fine pitch. Their support must be by
comparatively small shafts. All these conditions render the
mechanism structurally weak and less rigid than such a device
should be to stand the strains of high-speed steel and modern cuts.

The Bradford Machine Tool Company build an ingenious
rapid change gear device which is shown in the accompanying
engravings, of which Fig. 177 is a front elevation, Fig. 178 an
end elevation, and Figs. 179 and 180 are sectional views.

The method of transmitting motion from the head spindle to the
change-gear mechanism will be readily understood by reference to

204

MODERN LATHE PRACTICE

Figs. 178 and 179. This mechanism is contained in a gear box
located in front of the bed, as seen in these two figures. It contains
at A a cone of eight gears carried on a shaft for driving the feed
rod and screw, and a sliding gear B, which acts as a driver for the
cone and may be dropped into mesh with any one of the eight gears
forming that member. The shaft-driving gear B carries loosely
at the outer end three gears C, any one of which may be connected
by a sliding key to the shaft. The three gears are rotated by gears

FIG. 178. — Front Elevation of the Bradford Rapid Change Gear Device.

mounted freely at D, the intermediate E carried on a long stud on
quadrant F being engaged with one of the three in the set D.

Now, leaving the gears in the positions shown, it is obvious that

by operating the plunger controlling the key in gears C, twenty-four

ates of feed may be obtained, or eight for each gear in set C. Then,

by the three positions for intermediate E, the number of feed change

is increased to seventy-two.

At G will be noted a support for the driving gear which is formed
dly on its shaft. The bracket G is bolted to the quadrant and
the under part cut out to allow the intermediate gear to mesh

RAPID CHANGE GEAR MECHANISMS

205

in the pinion, and as the bracket turns with the quadrant it sup-
ports the pinion no matter which one of the three gears the inter-
mediate may be in mesh with.

Figure 180 shows the quick change gear cut entirely out, and
ordinary change-gears used. It shows also on an enlarged scale the
plunger and sliding key
whereby one of the three
gears C may be keyed to the
shaft, allowing the other two
to rotate loosely. The
knurled knob can be taken
off, allowing a gear of any
required size to be put on
the lead screw. The three
gears are fitted with tool
steel bushings, hardened and
ground. The center gear has
a keyway cut through, and
each of the outside gears a
keyway cut on one side only,
allowing the knurled knob
and plunger to be pulled in,
out, or to central position.
A spring pin holds the plun-
ger when set.

The locking device for the
handle which controls the
position of gear B is shown
at H, Fig. 179, and consists
of a shoe with a semicircular
recess at the end which snaps under the heads of the locking
screws, each screw head being of a conical form, as in the enlarged
detail at P, Fig. 180, to fill a cavity in the under side of the con-
trolling handle.

The screws can be raised and lowered to allow the gear in the
frame to mesh correctly with the gears of the case, thereby enabling
the operator to use gears other than those ordinarily used, simply
by adjusting the screws until the gears mesh properly. The rela-

SECT10N M.N

FIG. 179. — Sectional Views of Bradford
Rapid Change Gear Device.

206

MODERN LATHE PRACTICE

tive positions of the eight screws will be seen in the front view near
A, Fig. 178

The threads cut with this gear range from 3 to 46 per inch, the
screw-cutting feeds being 4| times the feeds for turning.

The quick change gear device shown in section in Fig. 182, and
in front elevation in Fig. 181, is the invention of Joseph Judd, a
draftsman employed by the New Haven Manufacturing Com-
pany.

It is unique in that in all other efforts at devising a quick change
gear mechanism the shafts have been located parallel to each other.

SECTIONAL VIEW

FIG. 180. — Sectional View of Bradford Rapid Change Gear Device.

After much study of the subject in conjunction with the author, and
after all former devices known in the patent office had been thor-
oughly investigated and studied and their features carefully classi-
fied, after they had in fact all been dissected, as it were, the question
of obtaining the most simple and direct acting device was sought
by the process of elimination of the undesirable features of other
devices, and Mr. Judd hit upon the idea of making the faces of
the gears composing the "cone gears" slightly inclined instead
of straight, and thus make it in reality what it had been before
in name, a veritable cone of gears.

While this form is not theoretically correct the difference is

RAPID CHANGE GEAR MECHANISMS

207

very slight when applied to a full-sized gear, and the device operates
much more smoothly than many would suppose.

The device includes a cone of gears composed of seven members
L, and mounted upon the lead screw shaft P, to which they are
fixed. Above this cone of gears is a pinion B, with an equally
inclined face, and mounted upon the quill G so that it can be moved
longitudinally to permit of its being engaged with any one of the

FIG. 181. — Front Elevation of Quick Change Gear Device,
built by the New Haven Manufacturing Company.

seven gears below it. The quill or sleeve G is splined so that
the pinion B may slide upon it, but must turn with it, in order to
convey motion to the pinion B. The quill G is driven by the
beveled pinion F keyed on the end. The pinion F, in turn, re-
ceives its motion from the beveled pinion E, which is mounted on
the change-gear shaft D, and which carries at its outer end the
change-gear C. The shaft H, supporting the quill G, is mounted

208

MODERN LATHE PRACTICE

in two eccentrics J, J, which give the beveled pinion B an in-and-
out motion relative to the nest of gears when manipulated by the
handle K for changing the gear ratio.

The sliding pinion B is moved longitudinally to the position
indicated by the index plate for the desired thread or feed, by means
of the knob M, and after being engaged with the 'desired gear is
held in position by the pin N. This pin enters a hole marked with
the number of teeth of the gear with which the pinion is engaged,
being, for instance, 48 in the engraving. This provides quick
changes by steps between and including the ratio 32 to 56.

For wider ranges on the lathes of 32-inch swing and larger, a
stud-plate R is mounted on the hub Q at the left end of the gear
box 0, carrying gears so arranged that threads from 2 to 14 may

FIG. 182. — Longitudinal Section of New Haven
Quick Change Gear Device.

be cut, or feeds from 8 to 56 obtained without changing the posi-
tion of the intermediate stud, the gears being so porportioned that
as one is removed from the change-gear shaft E, it is used as the
intermediate gear, and so on.

Open washers are used on the ends of the studs so that no nuts
have to be removed, thus making this portion of the change easily
and quickly effected.

On lathes of 18 to 28-inch swing, inclusive, four additional
changes are provided. This is effected by adjusting gear A longi-
tudinally, permitting it to be meshed with either of the intermediate
gears, the intermediate gear in this case being compound; and by
mounting two gears at C on the change gear shaft.

These gears are of different diameters and both mesh with the

RAPID CHANGE GEAR MECHANISMS

209

compound intermediate gear. A sliding spring key is provided by
which either gear can be thrown into clutch with the shaft, thus
giving the four changes without changing gears, the stud-plate
having to be shifted on its pivot for two of the changes.

FIG. 183. — Front Elevation of Newton's Quick Change Gear Device.

This gives a range from 1 to 15 threads per inch and feeds from
4 to 60 per inch inclusive. By changing gear A, the other changes,
of course, are readily obtained.

It will be noticed that the device is very compact and very simple,
requiring a less number of
gears and other operative LL

parts than almost any de- —
vice adapted to give a like
number of useful changes.

Figure 183 is a front
elevation and Fig. 184 a
partial cross section of the
quick change gear device
invented by Albert E. New-
ton and applied to the
lathes built by the Pren-
tice Brothers Company.

The inventor has directed his efforts to the production of an
improved change speed gearing of suitable form for economical
manufacture and installation and which would be conveniently
handled to actuate the feed rod or the lead screw.

FIG. 184. — Partial Cross Section of Newton's
Quick Change Gear Device.

210 MODERN LATHE PRACTICE

The construction and operation of the device is as fol-
lows :

The lathe carriage may be actuated by the usual feed rod A
or may be driven by the lead screw B when screw cutting. There
is a bearing in the rear end of the head-stock for the shaft C and this
is driven from the spindle through the usual tumbler gears arranged
for the handy reversal of the shaft.

There are three gears fastened to the shaft C and there is a sweep
D having a transverse slot fitting a bolt threaded into the end of the
lathe bed. The sweep or stud-plate can be turned about its sup-
porting hub and fixed in any position to which it is adjusted. By
this means an intermediate gear can be put in mesh with any two
of the six gears shown, and this forms a very convenient arrange-
ment for a three-speed connection and avoids the use of an inter-
changeable set of gears at this point, the change being made with
gears already in position for the purpose.

As will be noticed, the intermediate gear need be no greater in
width than any of the six gears with which it meshes.

A countershaft E carries a series of gears. On the shaft F is a
forked lever G, and between the arms of the latter is a pinion J with
a key engaging the keyway cut in F. An intermediate gear in
mesh with the pinion, is journaled on the stud extending between
the parts of the forked lever G. The end of this lever is turned
upward and is provided with a handle. A pin H is fitted in the
ear extending from the lever and is controlled by a spring-pressed
trigger carried by the handle.

A cover plate is secured to the bed to form a box over the change-
gears, and the front lower edge of the plate, as illustrated in Fig. 183
has a guiding rib supporting the pin H. A series of holes is bored
in the cover plate and in line with the gear-wheels. The forked
lever G and the pinion J can be slid along the shaft F, and opposite
the proper gear the handle may be lifted and locked in place by
means of the pin H.

The end of the countershaft E projects through the right-hand
journal and has a keyway cut in it. A slip pinion K is fitted on this
projecting end and has a key engaging the keyway. A gear N is
on the end of the lead screw B. The gear L has a hub fitted in the
bearing supporting the left-hand end of the feed rod A. The gear

RAPID CHANGE GEAR MECHANISMS

211

L is provided with clutch teeth to match teeth on a clutch M arranged
at the end of the rod A.

A spring normally keeps the toothed parts in contact. An
adjustable collar on the feed rod enables the carriage to be auto-
matically stopped when a predetermined point in the travel is
reached. The slip pinion K on the end of the countershaft E can
be adjusted to engage either the gear N on the lead screw or the
gear L that actuates the feed rod.

The step gearing on the countershaft E permits the same change
speed gearing to drive the feed rod or the lead screw and that when

FIG. 185. — Front Elevation of Flather's Quick Change
Gear Device.

either member is in use the other is idle. The arrangement of the
countershaft E and the shaft F allows them and their gearing to be
assembled on the bench.

The lead screw and the feed rod can be applied to the machine
by bolting the brackets which support the lathe to the bed. Then
the supporting bracket is put in position so that the triple gears will
come in the same plane with their mates, and that the countershaft
E will be in line for the engagement of the slip pinion K with either
gears M or N.

Figure 185 gives a front elevation and Fig. 186 a rear elevation
of the Flather quick change gear device, which is a simple and

212

MODERN LATHE PRACTICE

practical device and apparently well adapted for the purpose, as
most of their devices are and have been for many years.

From here the motion is transmitted by a train of gears, which
will be described later, to the gear D, which drives shaft A in the
feed box. This shaft is cut for a part of its length with teeth to
form a long pinion, and on this portion slides the lever E. The
shaft B carries the cone of gears usual in arrangements of this
kind, and pivoted in the lever E, but not shown in any of these cuts,
is the usual intermediate gear, which meshes with the teeth cut in
the shaft A, and can be brought into mesh with any of the series
of gears on the shaft B.

FIG. 186. — Rear Elevation of Flather's Quick Change Gear Device.

The locking pin F locates the lever in each of its different po-
sitions by entering into the appropriate hole drilled in the face of the
gear box. G is a steel plate fastened to the lower edge of the box,
and provided with a notch to match each locking pin hole. A pro-
jection on the inside of the lever E enters one of these notches, and
prevents the lever from being shifted along the shaft until the inter-
mediate gear has been dropped clear of the gears on the shaft B.

A new feature in this device is the fact that means are provided
in the gear box for giving three different speeds to the feed rod or
lead screw for each position of lever F. The shaft C has turning
loosely upon it two gears, H and J, whose hubs are cut to the form

RAPID CHANGE GEAR MECHANISMS 213

of clutch teeth. Between these two gears is a third one marked I,
which has clutch teeth at both ends of its hub, and is splined to the
shaft, but free to move endwise. An endwise movement is given
to it through the lever K; which projects through the top of the
box.

When in the position shown, the motion is evidently trans-
mitted from shaft B to shaft C through the gear I, and its mating
gear in the series on the shaft B. The gear I may be thrown either
to the right or left, and thus be disengaged from its mate, but con-
nected by the clutch teeth on its hub with either of the gears H or J.
As these are run by their corresponding drivers at different rates of
speed, each position of the lever E, by shifting lever K, will give
three different speeds, or twenty-seven in all. This is the usual
way of changing the turning feeds in the shop of the manufacturer;
the lever E being located at a suitable station, the roughing and
finishing feeds are obtained by the lever K.

The gear I has a spring pin in its hub which engages suitable
depressions in shaft C, and thus prevents the lever K from being
jarred out of position. The shaft C is extended through the gear
box and carries a pinion and clutch L, which may be moved to the
right to engage the clutch on the lead screw, or moved to the left
to mesh with the gear on the feed-shaft.

The 27 feeds and threads mentioned are further increased to
54 by means of a sliding gear which meshes with the wide-faced
gear D and is moved in or out by the projecting hub seen at M.
Suitable gearing in the case N alters the ratio of rotation for these
two positions. While this arrangement gives 54 feeds varying
from 7 to 448 per inch, the threads from 2 to 128, the range is still
further extended to permit the cutting of odd threads, metric
pitches, etc., since the gear D may be removed and one of any
suitable number of teeth inserted in its place.

CHAPTER XI

LATHE TOOLS, HIGH-SPEED STEEL, SPEEDS AND FEEDS, POWER FOR
CUTTING-TOOLS, ETC.

Lathe tools in general. A set of regular tools. Tool angles. Materials and
their characteristics. Their relation to the proper form of tools. Be-
havior of metals when being machined. The four requisites for a tool.
The strength of the tool. The form of the tool. Degree of angles.
Roughing and finishing tools. Spring tools. Tool-holders. Grinding
tools for tool-holders. Dimensions of tools for tool-holders. The Arm-
strong tool-holders. Economy of the use of tool-holders. High-speed
steel. A practical machinist's views on high-speed steel tools. Condi-
tions of its use. Preparing the tool. Testing the tool. Speeds and
feeds. Much difference of opinion. Grinding the tools. Amount of
work accomplished by high-speed steel tools. Average speed for lathes
of different swing. Speeds of high-speed steel drills. Mr. Walter
Brown's observations on high-speed steel. Its brittleness. Its treat-
ment. The secret of its successful treatment. Method of hardening
and tempering. Method of packing. Making successful taps. Speeds
for the use of high-speed steel tools. Economy in the use of high-
speed steel tools. Old speeds for carbon steel tools. Modern speeds.
Relative speeds and feeds. Modern feeds for different materials.
Lubrication of tools. The kind of lubricant. Applying the lubri-
cant. Lubricating oils. Soapy mixtures. Formula for lubricating
compound. Improper lubricants. Various methods of applying lubri-
cants. The gravity feed. Tank for lubricant. Pump for lubricant.
Power for driving machine tools. Calculating the power of a driving-
belt. Impracticability of constructing power tables. Collecting data
relating to these subjects. Flather's " Dynamometers and the Trans-
mission of Power." Pressure on the tool. Method of calculating it.
Flather's formula. Manchester Technology data. Pressure on tools.

WITH comparatively slight exceptions the ordinary lathe tools
are of the same form as those used in the time of the old chain lathe
with a wooden bed. While the modern machinist has found some
new shapes for special work and has been provided with all sorts
and forms of tool-holders, and it is probable that many new and

214

LATHE TOOLS, HIGH-SPEED STEEL, ETC.

215

perhaps improved forms will be brought out in the future, the
same old forms will probably be used for a considerable part of
lathe work as long as there is a lathe to use them on.

/L t\

FIG. 187. — A Set of Ordinary Lathe Tools.

A set of fourteen of these time-honored tools is shown in Fig.
187, which are usually known by the following names, the numbers
given in the engraving being referred to :

1. Right-hand Side Tool.

2. Left-hand Side Tool.

3. Right Bent Side Tool.

4. Right-hand Diamond Point.

5. Left-hand Diamond Point.

6. Round Nose Tool.

7. Cutting-down Tool.

8. Cutting-off Tool.

9. Narrow Round Nose Tool.

10. Wide Round Nose Tool.

11. Inside Boring Tool.

12. Straight Thread Tool.

13. Bent Thread Tool.

14. Inside Thread Tool.

216 MODERN LATHE PRACTICE

In nearly all these tools their names indicate their .uses, which
is quite apparent also from their form.

The question of the proper angles to which lathe tools should be
formed is an important one and there are a good many theories in
relation to the subject. It is a matter of continual discussion
among shop-men who are inclined to disagree very much on the
subject. It is altogether probable that this disagreement is not so
much that the question is one impossible of solution as it is that
each man determines the question for himself from the standpoint
of his own experience and with the range of material with which
he has to work: otherwise, with the conditions which govern the
work under his observation.

These conditions are so varied and so numerous that no fixed
rules for forming tools to meet them all is possible. Some of them
are these:

We have ordinarily to handle such materials as tool steel,
machine steel, steel castings, wrought iron, cast iron, bronze, brass,
copper, aluminum, babbitt metal, hard rubber, vulcanized fiber,
rawhide, and a number of others constantly coming to hand. These
substances as here mentioned give a very wide range to the kind
and shape of the tools that it will be proper to use. But there are
varying degrees and conditions in the same material that still
further complicate the question.

Steel may be hard and brittle, or it may be soft and tough. It
may be of any percentage of carbon up to and perhaps over one
hundred points, and still we must make a tool to cut it.

Wrought iron may have somewhat similar properties as steel,
but, of course, in a much less degree.

The alloys of copper commonly known as hard bronze, nickel
bronze, gun metal, brass, yellow brass, and so on, through an
almost endless variety of mixtures, will require almost as many
different forms as must be used in turning the different grades of
steel.

And so it is to a greater or less extent with all the different
materials with which we have to deal.

In a general way we may say that the quality of the material
we have to cut will influence the results in two ways : first, as to
whether it is hard or soft, and second, whether it is crystalline or

LATHE TOOLS, HIGH-SPEED STEEL, ETC. 217

fibrous. Its varying degrees of hardness or softness determine
whether much or little can be removed in a given time; or, what
amounts to the same thing, whether the speed of the cutting shall
be fast or slow, and whether the feed shall be coarse or fine. Its
crystalline or its fibrous nature will make considerable difference
in the top angles of the tools, and this will be readily seen in the
tendency of the crystalline metal to break up into small chips, while
the fibrous turnings will curl off into spiral or helical shavings.
Therefore the fibrous material will have the sharper angle than that
designed for the crystalline structure of metal.

Of course all tools must be harder than the material they are to
cut; at the same time they must not be so hard as to be brittle, or
be made of a quality of steel that becomes brittle when hardened,
but tough and strong and capable of maintaining their cutting-
edge uninjured during their ordinary use. The fact that they do
this will be best evidence of the correctness of their angles, provided
they have done the proper amount of work, that is, have been run
under satisfactory conditions of speed and feed.

In the proper design of a tool, with angles to suit the work, there
are four points to be remembered, namely: cutting capacity, that
is, as the machinist would say, to "dig in"; the right angle of relief
or clearance; proper strength; and durability or lasting quality of
edge and point.

That these are not simply distinctions without a difference is
seen if we analyze the question a moment. Cutting capacity is the
tendency to dig into the work, to bury itself in the metal. This
is directly opposed by the greater or less angle of clearance or relief.
The tendency to bury itself in the work is due to the "rake " and the
top angle, but principally to the rake in a slide tool and the top
angle in a cutting-down tool.

These points will be clear upon reference to the engraving, in
which Fig. 188 show the angles for a slide tool, and Fig. 189 those
for a cutting-down tool.

As to the proper strength. The tool will be much stronger with
more obtuse angles, yet more obtuse angles will be to the injury
of its other qualities. Again, if the point or the edge is too keen,
that is, at too acute an angle, its strength and durability are both
jeopardized.

218

MODERN LATHE PRACTICE

r-f

FIG. 188. — The Proper Angles for a
Side Tool.

Hence we are forced to the conclusion that the form of the tool
is not only largely governed by the kind and quality of the material
to be acted upon, but is in itself, by reason of the conditions of its
construction and use, very largely a question of compromises on the
one side or the other, and frequently on both.

Referring again to Fig.
188 showing a side tool, and
Fig. 189 showing a cutting-
down tool, both of which
are types of nearly all the
various forms, attention is
called to the various angles
and their designations, which
will apply equally well to
all cutting-tools.

It will be seen that the clearance angle may be anywhere be-
tween a vertical line and 10 degrees from it. The face angle may
have a like variation although we frequently see tools having an
angle as great as 25 degrees. The "rake" or top cutting angle will
be any angle from horizontal to 25 degrees, seldom more.

In a general way it may be said that in cutting steel the softer
the material the more acute may be the angles, and that for very
hard steel the angles must be very obtuse.

For cutting wrought iron the tool with angles too acute is liable
to bury itself in the work and break, on account of the fibrous
nature of the material.

Again, in tools for brass
work the angles will be
very slight, otherwise the
tool will plunge into the
work and spoil it. It is a
common saying in the shop,
when the relative angles of

FIG. 189. — The Proper Angles for a
Cutting-down Tool.

tools for steel and brass are discussed, " Whatever you do for a
steel tool, do the opposite for a brass tool." (The metals mentioned
being those to be machined, of course.) And this is literally true
as far as angles are concerned.

In the general working of steel and cast iron in many shops where

LATHE TOOLS, HIGH-SPEED STEEL, ETC. 219

the workmen get their tools from the tool-room ready ground, the
tool angles are the same for both metals and of all degrees of hard-
ness, unless the foreman has special work to do requiring a special
form of tool. Another set of tool angles are used for brass and
bronze.

When bronze is very tough as well as hard, a special form of
tool will be required, and this will sometimes very nearly approach
the form of a tool for turning steel, including considerable rake and
top angle. Often a diamond-point tool is used. (See Nos. 4 and 5
in Fig. 187.)

Tools are of two general classes according to their use, that is,
for roughing and for finishing. The former must be made mostly
for strength and are intended for deep cuts, coarse feeds, and slower
rates of speed; while the finishing tools are for high speeds, fine
feeds, and shallow cuts. Fine feeds are not, however, always used,
as it is a common condition to use very light, scraping cuts, with a
broad tool and a coarse feed. This is notably the case in finishing
the inside of engine cylinders. The author has seen such a cut of
nearly an inch feed, the tool being very carefully ground and acting
more as a scraper than a cutting-tool. In this case the angles of
the tool were very slight.

On outside work, that is, turning rather than boring, a finishing
tool with a broad cutting edge is frequently made of an inverted
U-shaped form and called a
" spring tool," or a "goose-
neck," which is shown in
Fig. 190, the cutting-edge
A being nearly straight

across, or parallel with the FIG. 190. -A Spring Tool or "Gooseneck."
surface of the work. When there seems to be too much " spring"
in the action of the tool, a small block of wood is inserted at B, to
furnish some support for the cutting edge and prevent chattering.

This form of tool is not nearly as much used as formerly. In
fact the later development of turning tools has been toward more
simple forms, which, under modern conditions, seem better adapted
to the general line of work.

While there are still very many of the ordinary lathe tools such
as has just been described, that are in e very-day use in nearly all

220

MODERN LATHE PRACTICE

shops, the use of tool-holders, designed for holding tools made
from small square or round rods of tool steel, has very much
increased.

This innovation was started before the advent of the now well-
known " self-hardening," or " high-speed" tool steels, that have so
changed machine shop conditions and which followed the intro-
duction of "Mushet" steel a number of years ago.

These tool-holders have been made in great variety and pro-
fusion and much ingenuity has been displayed in producing what
each maker thinks is at once the most convenient, the strongest,
and the best.

Some of these holders use tools made by simply grinding a slight
notch in the bar and breaking off pieces of the proper lengths,
whose ends are ground -to the desired form, while others require a
special form of cutting-tool that is usually drop forged, fitted, and
tempered. It is fair to assume that on general principles and for
general use the tools made from a bar will be the most useful, since

FIG. 191. — A Set of Ten Tools for a Tool-Holder.

it is always the most convenient. The machinist having a bar of tool
steel of the proper size may produce tools of any form, and to fit any
of his different tool-holders, according to which is best suited to
his particular work.

The matter of grinding these tools is a very simple one. The
regular shapes, and about all the shapes that will be needed, are
shown in the engraving, Fig. 191, in which the angle is specified.
Thread tools may, of course, be added to the list, and so also may
some forms of inside boring and threading tools.

The dimensions of the steel used for these tools for light lathe
work is T3B inch and J inch square. For medium lathe work, T56-, f,
T76, and J inch square. For heavy lathe work, f , f , f , 1, 1J' inch
square.

There are many different brands and grades of so-called high-

LATHE TOOLS, HIGH-SPEED STEEL, ETC.

221

speed or self -hardening steel. As between the leading brands there
is very little difference in efficiency; some excelling slightly in one
respect, or upon one class of materials to be machined, while
another brand seems to work better on another.

As to the best form of tool-holder, there will, of course, be
honest differences of opinion, and each machinist will have his
favorite forms.

Probably there are more Armstrong tool-holders used than any
other, and in Fig. 192 is given views of their usual forms. Their
uses are plainly indicted by their names and forms.

STRAIGHT CUT OFF TOOL

BORING TOOL

FIG. 192. — A Set of Armstrong Tool-Holders.

In Fig. 193 is shown at A a good form of tool-holder for regular
straight work. At B is shown a tool-holder and tool for cutting
threads. It will be seen that as this tool is of parallel form through-
out its length, it is only necessary to grind off the top as it becomes
dulled, and raise it to the proper position to compensate for the
amount ground away, in order to always have a fresh surface and
of proper cutting form and angle.

The economy of the use of tool-holders should be apparent to
any one who studies the conditions even superficially.

The one fact that by their use the time and expense of the forging

222

MODERN LATHE PRACTICE

and re-forging of tools is reduced to a minimum, and in fact may be
almost eliminated, the tools to be so treated consisting only of a
very few special tools for special jobs that cannot be conveniently
reached by such tools as may be used in the tool-holders, is amply
sufficient to warrant their use in every shop.

FIG. 193. — The Champion Tool-Holder.

The facility with which tools of different shapes that may be re-
quired can be produced is also an important reason for their use.

Another reason is that when the shop is once equipped with
tool-holders, the cost for the steel for making the tools is very slight
as compared with the heavy forged tools formerly used.

The modern demand for high-speed steel for lathe tools and
its high price makes it necessary, from reasons of economy, to use
small tools; hence tool-holders.

FIG. 194. — The "Three-in-one" Tool-Holder.

In reference to the use of high-speed steel in a very large and
general way, for all classes of work upon which it is possible to use
it, there seems to be no doubt. It has been proven many times, in
many places, under many conditions and on almost every con-
ceivable material that has to be handled in machine tools, that it
has "come to stay" and that any information regarding it is of
practical use.

The following remarks, giving the experience of one practical

LATHE TOOLS, HIGH-SPEED STEEL, ETC. 223

and observing machinist whose name, unfortunately, is not at hand
so that proper credit can be given him, are here introduced as being
valuable in this connection, and practical from the machine shop
point of view:

"The first thing is to make up one's mind as to the quality or
kind of steel to use, which means to be satisfied with the steel which
has been found to work best in one's own shop. This has been a
difficult matter for superintendents and foremen to decide, because
it is so hard to discover the best way to determine which steel will
do the most work, and experience has taught most of us that any
of our high-speed steels, when properly treated, will do considerably
more work than the machine is capable of.

"I do not think it advisable to have too many different kinds of
stock in the works ; results depend entirely upon the way of forging
and treating the tool. If the tool-maker is familiar with one or
two grades of the best high-speed steel, and the quality is found
satisfactory, and bringing about the best results that the machines
can stand up to, these are the steels that should be adopted.

"Each of these steels must be treated differently, and if the tool-
maker succeeds in treating one grade properly and understanding
it thoroughly, it means much time saved and better results in the
shop.

" In introducing the use of high-speed steel in a shop, like every-
thing else that is to be a success, one must start right. That is, the
work should be undertaken by some responsible person — superin-
tendent, foreman or speed boss, in other words, the man who is
responsible for the work turned out in the machine shop. All tools,
of course, have some particular way of treating, which should be
understood by the person in charge. Now it is 'up to the forger/

"The person in charge should see that the tool has its proper
treatment, as success in most cases lies with the treatment. When
the tool is finished, and the superintendent or foreman is satisfied
that it has been properly treated in accordance with directions, it
is ready for grinding and for making a test. It should be ground on
a wet emery wheel, and care taken to heat the tool just so it can
be touched with the fingers.

"The tool once ground and ready to do the work, the question
often arises, 'What lathe, planer, or machine are we going to put

224 MODERN LATHE PRACTICE

it into? ' In most cases when a new tool is tried, it is put in a lathe,
to do turning; so naturally the superintendent or foreman would
pick out the best lathe that was in the shop, i. e., the lathe that was
considered to have the most power.

"Being now ready to make the test, it is generally tried on steel;
that is considered by most superintendents and foremen the sever-
est test to make. Take a piece of steel of almost any diameter,
and of the quality most used in the shop, and prepare to take the
cut. It seems to puzzle most every foreman to know just what to
do and where to start. I speak now of what I have seen, and of
the men who are sometimes sent by the steel makers to demon-
strate the use of their steels.

• "I think the proper way is to get at least one dozen shafts of
a standard size that are used in the regular line of product, and to
first look up the exact time it took to finish or rough off the previ-
ous lot; then to determine about what percentage of time would
be considered a fair gain to warrant adopting the steel, based on
the price per pound of the steel being used. Let it be based at
25 per cent, which I find in most shops can be accomplished, and
the lathe be speeded up faster than when the last lot was turned,
starting with the same feed and about the same cut, which most any
lathe will stand. The superintendent finds, after he has roughed
off about two or three pieces, that the tool seems to stand up all
right.

"The next step is to find out about the speeds and feeds. The
first thing is to increase the feed with the same speed the machine
is running at. In most cases which I have seen, after the tool has
traveled a certain distance the cutting edge would break or crumble,
and the foreman would say, ' Just as I expected. All this high-
speed steel will do the same thing!' forgetting he had just been
doing over 25 per cent more work than ever before, without the
least bit of trouble.

"Now the tool is taken out and looked over, and it is found that
a portion of its cutting edge has been broken off. Here is where
most foremen make a mistake; they take the tool back to the
forger or tool dresser to have it re-dressed and treated over. If
it is only broken off slightly and can be ground, even if it take ten
or fifteen minutes to grind, it should be done by all means. My

LATHE TOOLS, HIGH-SPEED STEEL, ETC. 225

experience has taught me it will prove a better tool than before,
but care must be taken not to overheat in grinding.

"The tool is now put back in the lathe, which is started again;
and generally, to one's astonishment, it will be found that the tool
will stand up all right. One should not be too anxious to break
the tool again (!), but should turn up two or three more pieces with
an increase of feed, keeping a record of the time it takes to turn up
each piece.

"Once convinced that the tool will stay up all right with the
increase of feed, the foreman can increase the speed one step on the
cone. About the time this is done, it is found either that the belt
slips, the lathe is stalled, or the countershaft will not drive. (It is
my opinion that in most all machines which have been built up to a
year or so ago the countershafts are not strong enough in com-
parison with the machine tools.) Now, no doubt if these things had
not occurred the tool would have done better; but in this case,
reduce the speed, and finish the twelve shafts, which it will probably
be found can be done without grinding the tool.

"When the shafts are all roughed off and finished, the foreman
will find to his great astonishment that by actual time the lathe
has produced over 25 to 40 per cent more work than ever before.
I allude to the lathe using most all ordinary tool steels.

"At this point it is up to the superintendent to see just where he
is at, and he finds in looking around his shop that there is hardly a
machine that he can't speed up, but he also finds that the speeds
on the countershafts are all too slow. This means that he has
either got to increase his speed by increasing the main line, or buy
new pulleys to increase his countershafts.

"In most instances it is advisable to increase the speed of the
countershaft, but by doing this he generally finds that the counter-
shaft will not stand the speed. If the machines are not too badly
worn out, and he is satisfied that he can get at least 25 per cent more
work out of the tool by increasing the counter speed, by all means
let him get a new countershaft and treat each machine this way.

"No doubt the reader will know the results that some of us have
arrived at in the last two years. In regard to cutting speeds and
feeds there has been and always will be difference of opinion, and it
is almost impossible to determine the right feeds and speeds, whether

226 MODERN LATHE PRACTICE

it is for steel or cast iron, and for the operations of turning, planing,
or milling; the work varies so in different shops, that is/regarding
the construction of different pieces, the amount of metal there is to
remove from each piece, and how accurately the work has to be
done.

" There is no doubt in my mind that the makers of high-speed
steel have awakened the management of different shops, and it is
surprising the amount of work which can be accomplished even
with the old machines, with very little redesigning. There is no
question but that the machine shops which do very heavy work
have not the necessary power for the use of high-speed steels, as the
power should be used if the machines are old ones.

" Referring again to the question of grinding, I wish to state that
this is a very important factor in the use of high-speed steels. I
have seen much damage done to the tools, in many instances mak-
ing it necessary to treat them over, and, as we all know, this takes
much time. My recommendation for grinding is to let one man
grind all the tools, and be responsible for them. When a lathe
hand or a machine hand wants his tool ground, he simply gives it to
the man who is responsible, and gets another the same size and
shape, these being always kept ground and ready for service. In
this way the tools are kept uniform and ground alike.

"In reference to the amount of work that can be accomplished
on different machine tools, the writer finds that the feeds have been
altogether too fine on most makes of machines up to the time that
they were redesigned for high-speed work. Now it has been
demonstrated that high-speed steel has come to stay, and we all
know that it works better on roughing work than it does on finish-
ing. If most of the product of the machine department is to be
turned, it has come to the point where the majority of work must
be ground; and this is the only way to get good and accurate work,
especially where the strains of the cut spring the work. Moreover,
as it is not necessary to straighten the work to any great extent, it
certainly means a great saving, as many of our readers know. The
writer is not a builder of grinders, but merely speaks of the saving
it has been on his own work.

" Below is a fair average of the speeds that most any good make
of lathe, planer, drill press or radial ought to stand when using

LATHE TOOLS, HIGH-SPEED STEEL, ETC. 227

high-speed steel. Every lathe has a face-plate about the diameter
of the swing or very near that. Take the peripheral speed of same
by feet per minute; the use of a Warner cut-meter will give you
the speeds instantly. This is one of the handiest little tools that
can be obtained, and no machine shop is complete without it. The
speed must be taken with the belt on the largest step of the cone,
with the back gears in. The speed of the following sizes of lathes,
taken from a large face-plate with the slowest speed, I find to work
very well, and considerable saving has been effected even on old
lathes. Of course the feeds will have to be determined by the
amount of power available:

" 14-inch swing lathe; slowest speed with back gears in, 100 feet.

16-inch swing lathe; slowest speed with back gears in, 90 feet.

18-inch swing lathe; slowest speed with back gears in, 85 feet.

20-inch swing lathe; slowest speed with back gears in, 75 feet.

24-inch swing lathe; slowest speed with back gears in, 65 feet.

30-inch swing lathe ; slowest speed with back gears in, 60 feet.

36-inch swing lathe; slowest speed with back gears in, 50 feet.

42-inch swing lathe; slowest speed with back gears in, 30 feet.

" Larger lathes in proportion.

" High-speed twist drills, drilling cast iron, ought to drill the
following, if we have the power and feeds :

diameter, speed 500 r.p.m., 3J inches deep in one minute.

|-inch diameter, speed 400 r.p.m., 2f inches deep in one minute.

f-inch diameter, speed 335 r.p.m., 2J inches deep in one minute.

f-inch diameter, speed 290 r.p.m., 2| inches deep in one minute.
1 -inch diameter, speed 250 r.p.m., 2J inches deep in one minute.
IJ-inch diameter, speed 220 r.p.m., 2J inches deep in one minute.
IJ-mch diameter, speed 200 r.p.m., 2 inches deep in one minute.
If-inch diameter, speed 185 r.p.m., If inches deep in one minute.
IJ-inch diameter, speed 175 r.p.m., If inches deep in one minute.

" Larger ones in proportion.

"These speeds are all based on a peripheral speed of 65 feet per
minute. High-speed drills have done somewhat better than this,
however, but taking into consideration the time of grinding, I find
that this speed is a good average during a day's run."

228 MODERN LATHE PRACTICE

Continuing the discussion of high-speed steel it may not be
amiss to say that it is yet in its infancy, and as far as can now be
judged it has a most brilliant future before it. It has its short-
coming as every comparatively new product has, but when we con-
sider how long it took to develop "machinery steel" to its present
condition, we must admit that high-speed steel has a record that
its friends may be proud of.

One of its good friends, Mr. Walter Brown, has given us in the
columns of " Machinery" some excellent ideas on this subject, in
which he has taken much interest and of which he has made many
valuable observations and suggestions. Among other good things
be says :

"In spite of its shortcomings, however, it is very evidently the
cutting-tool material of the future, both because of its superior
qualities, all things considered, and of the likelihood that most
of its present failings will be overcome as manufacturers get a better
knowledge of its nature and behavior.

"The chief difficulty in the way of its use now is its exceeding
brittleness. Many a user has become discouraged with the result
of a few experiments and has, because of finding that it lacked the
'toughness of other steels, discarded its use entirely. More experience
would, if intelligently obtained, have demonstrated without ques-
tion the great value of this new product of the metallurgist's skill.

"The question of brittleness is largely a question of treatment;
and intelligent experience will very largely obviate the difficulty
so that it will be tough enough to stand up under any proper con-
ditions of work. Every tool-dresser knows how to handle carbon
tool steels, and is guided by his knowledge of their qualities at
different temperatures as indicated by their varying colors. When
he gets a high-speed steel he naturally treatsvit much as he would
carbon steel.

"This is where most of the trouble begins. The smith must
learn an entirely different set of color values and methods of treat-
ment. He thinks that if he has succeeded in getting a hardness
greater than that of his file, he has done his job. That, however,
has nothing to do with the fitness of the tool. I have known cases
(with a certain make of steel) where the tool would do the best
work while still soft enough to take a good Swiss file.

LATHE TOOLS, HIGH-SPEED STEEL, ETC. 229

"In other steels a similar degree of softness, or even a degree
of hardness much greater than that of ordinary steel, would not
work, the tool ' gumming up' and rapidly burning up. The whole
secret lies in getting the tool to such a heat, in the process of hard-
ening, that the constituent molecules are mobile, and then 'draw-
ing' it to the right point.

"When the tool-maker has mastered this secret, he can pro-
duce a tool of high-speed steel as tough as any of carbon steel.
The mastering of it is largely a matter of experience. Our own
experiences have been so interesting and successful that1 I have
thought they might prove of help to others, and I submit them
herewith.

"The tools should be placed in a pipe or box, well surrounded
with small pieces of coke, the packing case then being sealed up
with fire clay. Small holes must be left for the escape of gases,
otherwise the clay will blow out. The heating furnace should
have been previously heated to a white heat. The packing case
is left in the heat from one to three hours, according to size. When
removed from the furnace, the box should be as near the bath of
fish oil as may be, so that there will be no unnecessary delay in
bringing from the gases of the packing case to the bath.

"Exposure to the air not only causes scale, and therefore varia-
tion in size, but tends to affect the precision of the hardening
process. Observance of this caution will prevent a variation of
more than a thousandth of an inch in tools of moderate size. Car-
bon steel usually varies several thousandths as a result of hardening.

"The method of packing will depend somewhat upon the shape
of the tool. It is important to pack in such a way that all tools
packed in one case be so placed as to be handled very quickly, and
at once plunged into the bath, to prevent scaling by reason of con-
tact with the air, as explained above. In case of milling cutters
and key-seat cutters, a good way is to suspend them all from a rod,
each separated from its neighbors by a slight space, sufficient to
allow a free circulation of oil when plunged. Neglect of this caution
will be very likely to cause cracks, from the unequal contraction of
the cutters, the outer edges only being brought into immediate
contact with the bath, and therefore shrinking more rapidly than
the interior parts.

230 MODERN LATHE PRACTICE

"For taps, drills, and similar shaped tools, this hardening leaves
the steel too brittle, and as soon as the tool has become a little dull
it breaks off. To avoid this the tool can be drawn as can a carbon-
steel tool. But here, too, a new set of color scales must be learned.
The blue heat of carbon steel is not enough of the high-speed steel.
The heat must be carried on until the metal reaches a greenish
tinge. It is then allowed to cool in a dry place free from air drafts.

"It is now much tougher and softer than before. In case it
needs still further softening, it can be done by reheating, bringing
it to a faint red, dull enough to be perceptible only in a dark place
(an empty nail keg is convenient for this use) and then cooled as
before. We have made taps as small as -^ inch in diameter to be
used in an automatic nut tapping machine, about the hardest work
to which a tap can be put, with gratifying results.

"In the test three taps cut 92,000 nuts, an average of almost
31,000 nuts per tap; with carbon steel taps we cut 6,000 nuts per
tap. No effort was made to speed up the machine, the test being
one of durability only. The carbon steel taps cost about ten cents,
and the high-speed taps about forty, or four times as much.
The latter, however, cut about five times as many nuts. Besides
this, there is also to be taken into account the more important
saving in the time used formerly for stopping the machine, and re-
moving and grinding taps, which is five times as great when carbon
steel taps are used.

"This is not mentioned as a particularly demonstrative test,
but merely to show that high-speed steel can be profitably used
for small tools, if properly treated. Another place where we are
using high-speed steel with profit and satisfaction in small tools is
in drills. The saving here is very marked; but the statements and
claims of several makers of such drills is not verified by our expe-
rience. We find that we can run such a drill at about double
the speed of the ordinary drill, and at the same time cut more
holes.

"Makers of the new steels are in the habit of making large claims
as to speeds attainable. We have tried about every such steel on
the market, giving each a thorough test. Our experience usually
bears out the moderate statements, and sometimes the extrava-
gant ones, put forth by some makers as to what is possible. For

LATHE TOOLS, HIGH-SPEED STEEL, ETC.

instance, we have cut a y1^ chip, -£% feed, at a rate of 266 feet per
minute peripheral speed, from a rod of machine steel.

"Such speeds are possible for short periods; but whoever buys
a rapid cutting steel with the expectation of maintaining such speed
will be sadly disappointed. With a fine feed, even four hundred
feet per minute can be cut under very favorable circumstances.
But think of the chip that comes off! In case of steel the chip is
no such thing as we are accustomed to, breaking into short pieces
and dropping into the box below.

"At a speed of, say, two hundred feet per minute, the chip
comes writhing and twisting, almost red hot, in a continuous length,
shooting here and there, everywhere but the chip box; and quick
must be the workman that manages to keep well out of the way
of it, for it 'sticketh like a brother' when once he gets tangled in it.

" Possibly, in time, a way will be found to take care of such chips.
Until this is done, however, a moderate speed is most desirable. We
find that on steel, where there is no considerable thickness of metal
to remove, a speed of one hundred feet a minute is very satisfactory.
This allows taking care of chips, and the tools stand up well under
it. In turning gray iron, where the scale is to be removed, about
seventy feet per minute is giving us the best results. Naturally,
however, there being so many different kinds of materials to work
up, and each one of these varying more or less themselves, there can
be no set rule for speed. Each job will work out a rate for itself.
The main thing is to get out the job as fast and as well as possible,
and at the same time to lose as little time as may be in grinding the
tool.

"Another word about the saving to be effected. This will
depend among other things upon the number of machines that are
run. If only one machine runs on a job, there will not be a saving
of two thirds simply because the speed is trebled. It must be
remembered that perhaps 50 per cent of the time for doing a job
on a single machine is used in jigging the piece and setting the tool.

"The high initial cost of the new steels has made it necessary to
devise means for reducing the quantity of metal in the tools used.
The result has been the production of some very ingenious schemes
for holding cutters. The lathe tool holder is, of course, familiar
to all. Milling cutters, hollow mills, and reamers with inserted

232 MODERN LATHE PRACTICE

teeth, are scarcely less familiar. It is now true that we are making
all these tools with inserted cutters of rapid cutting steel at less cost
than the old carbon steel tools. At the same time they are doing
from three to ten times the work, and at a much greater speed."

The question of speeds and feeds is an important one in con-
nection with that of lathe tools, whether the old carbon steel is
used or the new high-speed steel known as self-hardening is that
selected.

As has been said in the observation on the form and qualities of
tools, a great deal depends, not only on the kind of metal worked,
but also on the quality of the particular kind that is to be machined.

With the old form of tools made from the old carbon steels,
cast iron was turned at a speed of from 20 to 25 feet per minute;
soft steel, 25 to 30 feet; wrought iron, 35 to 45 feet; and ordinary
brass at from 50 to 100 feet.

With the present tools and methods such speeds are considered
child's play, and the speeds at which different materials are turned,
assuming a medium grade of metal, will more likely be given as

Soft Cast Iron 50 to 60 feet.

Hard Cast Iron 20 to 40

Hard Cast Steel 30 to 40

Soft Machine Steel 30 to 40

Hard Machine Steel • 20 to 30

Wrought Iron 35 to 45

Tool Steel, Annealed 20 to 30

Tool Steel, not Annealed 15 to 20

Soft Brass 110 to 130

Hard Brass 90 to 110

Bronze 60 to 80

Bronze, Gun Metal 40 to 60

Grey or Red Fiber 40 to 60

The feeds will not vary in the same proportion as the speeds,
or in fact bear any fixed relation to them.

A prominent writer on this subject says that: "An important
point is, that other conditions being equal, the increase of speed
involves a diminution of feed. Hence it is not possible to reduce
the question of speeds and feeds to formulae, or tables."

This is hardly correct as to the fact of the inverse relation of
speeds and feeds under varying circumstances, as the same author
admits further on by saying: "Each class or job must be settled by

LATHE TOOLS, HIGH-SPEED STEEL, ETC. 233

itself in the practice of any given shop." He might have said, with
each different material, and as to whether it is a roughing, sizing,
or finishing cut.

Some practical observations in point may not be amiss, as they
are taken from actual practice and may be held as good mechanical
data, with the use of high-speed steel.

Roughing cuts in soft cast iron may be made with a feed as
coarse as 4 to 5 per inch, with a tool whose leading corner is slightly
rounded.

Roughing cuts on soft machine steel forgings, 5 to 8 per inch.

Sizing cuts on soft cast iron, 12 to 16 per inch.

Sizing cuts on soft machine steel, 16 to 20 per inch.

Finishing cuts on soft cast iron, with a narrow-point tool, may be
from 15 to 25 per inch.

Finishing cuts on soft machine steel, with a narrow-point tool,
20 to 40 per inch.

Finishing cuts on soft cast iron, with a wide point, practically
straight-faced tool with corners slightly rounded, the feed may be,
for soft cast iron, from 1 to 4 per inch.

Under like circumstances, for soft machine steel, the cut may
be from 4 to 8 per inch.

In these different cuts the speeds may be substantially as stated
in the table given above, except the last, in which case the speed
must be very much slower, less than half the speeds there given.

Further than these figures it will be found difficult to set down
a range of speeds and feeds that will be of any practical value. It
must be left for the superintendents, foremen, and mechanical
engineers in charge of work to determine these facts and to adopt
such standards as may be found by actual experiment is most
satisfactory under the circumstances and conditions governing the
work, and which will, of course, include a careful study of the
materials that are to be machined.

The lubrication of tools has a very considerable influence upon
the performance of lathe tools, and when used should materially
increase the output of the machines by permitting faster speeds,
heavier cuts, and greater feeds. Lubrication prevents the friction
that otherwise attends heavy cutting, and therefore prevents heat-
ing to both the work and the tool. A steady stream flowing upon

234 MODERN LATHE PRACTICE

the cutting-tool will tend to carry away such heat as will, to a cer-
tain extent, always take place. Naturally a well lubricated tool
will last longer in proper condition for cutting than one that is
not lubricated, as the friction of the metal across the edge of the
tool will be much less.

As to the kind of lubricant to be used, it will vary with the kind
of metal to be machined and its condition. Cast iron will require no
lubricant. In fact it is probable that any kind of a lubricant would
be a detriment rather than a help when turning cast iron. The
same may be said of ordinary yellow brass castings and the usual
kinds of sheet brass, brass rods and tubes. But for bronze, and
similar alloys containing a considerable portion of copper, it is
always advisable to use a lubricant, and, if very hard and tough,
oil is the proper lubricant. This is also true of the turning of
wrought iron, malleable iron and steel, or steel castings.

As to the kind of oil most appropriate, it is well known that
lard oil leads all others. ,0n account of its high price, this oil is
often replaced by a mixture of lard and other animal oils or fish
oil. Mineral oil should not be used, as it fails to prevent the heat-
ing of the work and the tool. Neither should a mixture of animal
and mineral oils be made for such a purpose.

For reasons of economy certain soapy mixtures are sold for
these purposes. These are mixed with water to a consistency to
flow freely, and often answer the purpose nearly as well as oil. They
are more convenient and cleanly to use around the machine.

While it is convenient to purchase these compounds, a good
one is easily made by boiling for half an hour or more one half pound
of sal soda, one pint lard oil, one pint soft soap, and water sufficient
to make twenty quarts. The soda should first be dissolved in the
water, and the oil and soap added successively while the mixture
is hot. Should the mixture prove too thick to run freely from a
drip can, or to pass through a lubricating pump, hot water should
be added until the desired consistency is obtained.

Any purchased preparation of this kind that has a tendency to
rust the cast iron parts of the machine should be rejected, as it con-
tains either acid or an excess of soda, and sometimes, even potash,
all of which will be detrimental to the work and the machine as well
as to the efficiency of the operations being performed. Trouble

LATHE TOOLS, HIGH-SPEED STEEL, ETC. 235

will also be experienced with the pumps and pipes from becoming
clogged by the undissolved portions of the compound.

As to the means used for applying the lubricant, the first and
most simple is a small, round bristle brush. This will answer well
enough for short jobs and for small parts, but for larger work is
rather a tedious process, requiring the constant attention of the
operator, and thus limiting him to the work of a single machine.
Oil is the lubricant usually applied with a brush.

The gravity feed comes next in order. This is simply a "drip
can," which is supported by a rod attached to the rear of the car-
riage or compound rest. This can, holding a quart or more, is
provided with a bent tube having a faucet, or stop-cock, attached
at or near the bottom. It is kept filled by the operator pouring
from a tray under the work such portions of the lubricant as drip
off the work.

As a constant stream of lubricant is always desirable, however
large or small it may need to be, a small pump is resorted to. A
small tank is located under the machine or near it, from which the
pump draws its supply of the lubricant and forces it up through a
jointed or flexible pipe to the tool. Its flow is regulated by a stop-
cock as in the gravity feed.

The tank is usually made of cast iron, and is divided into two
parts by a vertical plate reaching up to within two or three inches of
the top of the tank. The lubricant, as it flows from the tool, carries
with it many fine chips which flow into one of these compartments,
where the chips fall to the bottom while the lubricant fills the com-
partment, flows over the vertical plate and into the other com-
partment where the clear liquid is drawn off by the pump. This
method is an improvement over the perforated metal plate or the
wire gauze strainer.

Usually these pumps and tanks may be purchased independ-
ently of a machine and attached in any manner desired. As the
pumps are usually of the rotary type, they may be driven from a
small pulley on the countershaft of the lathe if no special provision
for them has been made on the machine itself.

While these lubricating devices are usually more appropriate
for a turret lathe or similar machine than for an ordinary engine
lathe, yet the class of work and the kind of material to be ma-

236 MODERN LATHE PRACTICE

chined will be the deciding factor more often than the type of
machine.

It will be often desirable to know the power which is being con-
sumed in operating a lathe on certain work for which data is required.
For most purposes this can be sufficiently approximated by calcu-
lating the power of the lathe from the width of the belt and its
speed in feet per minute.

For such purposes it is usual among mechanical engineers to
consider that a one-inch belt traveling a thousand feet per minute
will transmit one horse-power. This will give us a key to the entire
calculation.

For instance, if we have a piece of work 6 inches in diameter,
we know that for every revolution it will move through a distance
equal to its circumference, that is, 18.85 inches. If the cutting
speed is 30 feet, or 360 inches, we can easily calculate that it must
make 19.6 revolutions per minute. If the back gear ratio of the
lathe is 12, and we are using the back gears, the cone must make
12 times as many revolutions as the piece of work, or 235.2 revolu-
tions per minute. If the step of the cone on which the belt is
running is 19 inches, it will be practically 60 inches circumference,
or 5 feet, and therefore the belt speed will be 1176.6 feet per minute,
or 1.176 horse-power for every inch in width of belt. Now, assum-
ing that the belt is 4 inches wide, we shall be using 4.7 horse-power,
if we force the cut up to the full capacity of the belt to drive it.

This calculation is for single belts. A double belt is expected
to transmit double the power.

It would be very interesting if we could make a table giving the
power required to drive the lathe on all different diameters, for all
different kinds and qualities of metal, when turned with all differ-
ent forms of tools made from all different kinds of tool steels, and on
all different designs of lathes.

It would, however, be an almost endless task and would be of
very little practical value when it had been accomplished. The
conditions as noted above, and which are all practical, every-day
conditions, are so many and so various that there would be found
very seldom a repetition of them in regular machine shop work.

To construct a table that should give the power required for
different tools and metals worked upon in a certain shop, it would

LATHE TOOLS, HIGH-SPEED STEEL, ETC. 237

be necessary to observe conditions, ^to collect and record data, and
to make calculations from these individual conditions and cir-
cumstances, in this particular shop. And this table, while of con-
siderable value in this shop, and interesting to any mechanical
engineer or shop economist, would not be a safe guide in any other
shop until corrected by the data made by an extended series of
observations, the time and expense of which would be nearly
equal to those necessary to produce the original table.

These remarks are not intended to discourage the desire to
obtain such data. It is always commendable to search, observe,
calculate, and "dig out" all these and similar facts relating to the
performance of machine tools, and such habits should be encouraged
in all who have to do with this work. No labor of this kind is lost,
since every item of such work adds to the sum total of our infor-
mation and enriches the subject for us, and gives us a more secure
and confident hold on the important questions involved in it.

A still further reason for such observation and the recording
of the data thus obtained is the constant changing of the design of
machine tools, the constant changing of material to be worked upon,
the infinite number of forms of the parts to be machined, and the
thousand-and-one differing circumstances of their manufacture.

A recent writer whose name, unfortunately, is not given, in
discussing the question of the power required for taking the cuts
in different metals and the pressure in the tool says:

"The most complete information on this subject is contained
in Flather's 'Dynamometers and the Transmission of Power/ in
which are collected data from many tests upon various kinds of
machine tools. Since the introduction of high-speed steel, however,
conditions have changed so much that the deductions from the
tables mentioned would be to a certain extent incorrect. Probably
the most satisfactory way to determine the pressure on a tool is to
obtain this from the power required to drive the machine when
cutting. Knowing the horse-power, if we multiply this by 33,000
we have the foot pounds per minute; dividing this by the cutting
speed in feet per minute will give the pressure on the tool, neglect-
ing the power lost in overcoming the frictional or other resistances
in the machine itself. In tests upon high-speed cutting steels at
the Manchester Municipal School of Technology, to which we shall

238 MODERN LATHE PRACTICE

presently refer, it was found that the power absorbed by the ma-
chine varied greatly with the temperature of the bearings and also
with the speed. After the bearings become warm, the oil is more
viscous, which makes an appreciable difference; and tests also show
that it sometimes requires more power to run a lathe at high speed
— as would be the case when filing a piece of work — than when
taking a heavy cut at a slow speed. These facts indicate the degree
of care necessary in arriving at reliable information upon the sub-
ject of your inquiry.

Referring to the tests in BLatJ^gr'.8 text-book, we find the follow-
ing formulas deduced from average results, which give the horse-
power required to remove a given weight of cast iron, wrought
iron or steel :

For cast iron, horse-power equals 026 X W.

For wrought iron, horse-power equals 03 X W.

For steel, horse-power equals 044 X W.

"In each of these W is the weight in pounds of the metal re-
moved per hour.

"The most complete information upon power required with
high-speed steels is that obtained by the English tests at the Man-
chester Municipal School of Technology. These are very elaborate
and cannot easily be summarized, but the following statement of
results will answer our purpose and throw some light on the sub-
ject:

CUTTING SOFT STEEL

Weight per Hour Horse-Power

Light cut 105 3

' Heavy cut 445 15

CUTTING CAST IRON

Weight per Hour Horse-Power

Light cut 42 1.7

Heavy cut 198 5.5

"Applying Flather's formulas to these results we find that for
steel the horse-power required would be 4.6, instead of 3, for light
cutting; and 19.6, instead of 15, for heavy cutting. In the case of
cast iron we find the horse-power would be 1.1, instead of 1.7, for
light cutting; and 5.15, in place of 5.5, for heavy cutting. This
would indicate that Flather's formula for steel allows more power
for soft steel than was shown to be actually required by the English
tests, and will probably give ample power for a considerably harder

LATHE TOOLS, HIGH-SPEED STEEL, ETC. 239

grade of steel. In the case of cast iron his formula appears to
apply very closely, but giving results slightly too small.

From these comparisons it would seem that the rule to multiply
the weight of metal removed per hour by .04 would give a safe
value for the horse-power for both steel and iron.

Further examination of the results of the English tests shows
that with the steel more metal was removed per horse-power when
taking a heavy cut than when running at high speed and taking a
light cut; while when cutting cast iron this condition was reversed.

It was found that the cutting force did not vary mucn with the
speed, because at high speed the cuts were light while at low speed
the cuts were deeper and taken with a heavier feed. The pressure
on the tool increased very rapidly as the tool became dull; but
when the tool was in good cutting condition the following pressures
were recorded:

Tons

For soft fluid compressed steel 115

For medium fluid compressed steel 108

For hard fluid compressed steel 150

Tons

For soft cast iron 51

For medium cast iron 84

For hard cast iron 82

"It will be noted in reviewing these pressures that those for
steel appear to be a little irregular, but they are recorded in the
results of the experiments cited."

This interesting subject might, with profit, be pursued much
further and such investigation is earnestly recommended to the
seeker after facts in this respect; but the limits of space will not
permit a more elaborate exposition in this chapter.

CHAPTER XII

TESTING A LATHE

Prime requisites of a good lathe. Importance of correct tests. The author's
plan. Devices for testing alignment. Using the device. Adjustable
straight-edge. Development of the plan. Special tools necessary.
Proper fitting-up operations. Leveling up the lathe for testing. An
inspector's blank. The inspector's duties. Testing lead screws. A
device for the work. A micrometer surface gage. Its use in lathe
testing. Proper paper for use in testing. Test piece for use on the
face-plate. Testing the face-plate. A micrometer straight-edge.
Allowable limits in testing different sized lathes. Inspection report
- on a lathe. Value of a complete and accurate report.

BEFORE entering upon the consideration of the work of the
lathe in all its varied phases and by the different methods that are
appropriate for the many classes of work with which we have to
deal, it would seem proper to discuss the methods of testing the
lathe to ascertain its condition before putting work upon it.

In so doing we shall be able to direct attention to some of the
prime requisites of a good lathe and how to ascertain whether the
particular lathe in question possesses them or not. We should
know whether the main spindle is exactly parallel with the V's or
not, both in a horizontal and a vertical plane; to know whether
the carriage is at exactly right angles to the V's or not; to know
whether the head center and the tail center are exactly in line or
not; and so on through the many requisite features of a good lathe;
•one that will "turn straight, face flat and bore true."

The plan that will be given and the tools and implements used
were devised by the author, who used them in testing hundreds of
lathes and found them accurate and practical, and confidently
recommends them to any mechanic having such duties to perform
and a desire to perform that duty in the best and most accurate

240

TESTING A LATHE

241

manner, and to make the reports on the machines he tests of such
a nature as to command the confidence and respect alike of manu-
facturer, purchaser, and user.

At this time, when such extreme accuracy in machine tools
is demanded, when it may be said that the machine tool that could
be sold as a fairly good tool ten or even five years ago could scarcely
be given away now; when a buyer critically tests every require-
ment of the machine he buys, and oftentimes almost literally dis-
sects it, it becomes necessary to adopt such methods and to provide
such appliances as will insure a practical demonstration of its
accuracy. Although the lathe is the oldest known machine tool
we have, we are far from knowing all its capabilities and possi-
bilities as yet, and each year finds some added good points brought
out by the many workers in the field.

FIG. 195. — Testing Alignment of Lathe Centers.

But whatever may be its special form or construction it becomes
a matter of vital importance to practically test it before it leaves
the hands of the manufacturer.

And that condition or those qualities which are important to
the builders of machine tools are equally important to the purchaser
who "pays good money and expects a good machine." The suc-
cess of the mechanic who runs the machine, and the officials under
whom he works, is a matter that has its important bearing upon the
question, since we cannot expect a high degree of efficiency with-
out good machines.

Therefore the proper appliances for making accurate tests of
lathes are here presented.

Figure 195 shows the general construction of the testing device,
as applied to a lathe, for ascertaining the alignment of the head and

242

MODERN LATHE PRACTICE

tail spindles. An arbor, A, is preferably constructed of thick steel
tubing with hardened steel plugs fitted to and forced into the ends,
which have been previously bored out. This arbor is ground true

and should be from 4 to 6
inches longer than the di-
ameter of the largest face-
plate to be tested.

Upon the arbor is accu-
rately fitted a hardened and
ground collar B. At the end
of the arbor next to the face-
plate the plug has a mortise a,
made square at one end and
at an angle at the other, as
shown in Fig. 196. At the

FIG. 196. — Details of the Testing Bar. angled end is fitted a key 6,

with the usual projections, to

prevent it from dropping out, and controlled by the thumb-screw
c. Passing through the mortise a is a bar C, carrying at its outer
end a micrometer screw device, represented in detail in Fig. 197.
This consists of a bar D, of
a size convenient to hold
in the tool-post of the
lathe as well as in the
slotted end of the bar C,
where it is clamped by the
thumb-screw k.

Pivoted to the bar D is
the curved bar E, having
pivoted to it the block F,
which carries the micro-
meter screw G, operated
in the usual manner. The
knurled thumb-screws d, e, fix these joints in any desired position.
The use of this apparatus is as follows: Place the arbor in the
lathe, slide the collar B up near the mortise a, clamp the micro-
meter device in the tool-post in the position shown in the upper
figure in Fig. 198, and bring the point of the micrometer screw

FIG. 197. — Micrometer in Position to Test.

TESTING A LATHE

243

down upon the collar B, rotating the latter slightly to get the pres-
sure just right. Slide the collar B to near the tail-stock, move the
carriage down opposite to it and
note if the micrometer screw rests
upon the collar as before. If not,
note on the graduations of the mi-
crometer the amount that the tail
spindle is high or low.

It is assumed that the centers
have previously lined fairly well
sidewise. To set them accurately
the same method as above is used,
setting the micrometer device as
shown in the lower figure in Fig.
198.

Supposing that the centers of
the lathe have been found to line
vertically and horizontally correct,
we now desire to know if the back

FIG. 198. — Testing Alignment of
the Tail-Stock Spindle.

box of the head spindle is set in exact prolongation of the line of
centers. Place the bar C in position and clamp the micrometer
device in it, as shown in Fig. 195. Slowly revolve the tram device
thus arranged, setting the micrometer screw to the nearest point in
contact with the face-plate. Continue the revolution and with the
micrometer screw ascertain the exact variations of the face-plate

FIG. 199. — Straight-Edge for Testing the Cross Slide.

from a perfect right angle with the line of centers. Having deter-
mined the accuracy of alignment of the lathe, we now desire to test
its accuracy of facing — whether it will face up a piece concave,
convex, or exactly true, and to note the extent of the variation.
Figure 199 shows an adjustable straight-edge for this purpose.

244 MODERN LATHE PRACTICE

H is a permanent straight-edge used only for adjusting the one
applied to the face-plate. This is shown at K and has its lower
edge formed as shown in the section at the right, and has three
blocks, I, m, and n, sliding upon it and fixed at any point by the
thumb-screw t. These blocks are set at such distances apart as
will accommodate the size of the face-plate to be tested. The
block n carries a fixed point, about -f$ of an inch in diameter at the
point. The block / carries a plain screw point s, used to adjust the
device so that the micrometer screw r of the block m may be ad-
justed at zero. To adjust these set the micrometer screw at zero
and then bring the screw s up or down till all these points rest
properly on the permanent straight-edge.

To apply the device to the face-plate to be tested the surface
w is placed downward on a short arbor, taking the place of the
head center of the lathe and projecting about 6 inches from the
face-plate. This not only furnishes a convenient support, but keeps
the contact points at right angles to the face-plate. Keeping the
points of the block n and the adjusting screw s in contact with the
face-plate, the micrometer screw r may be set to the convexity
or concavity of the plate, and the error read on the micrometer
graduations p, in thousands of an inch, or even much finer.

A subject thus important will necessarily have its developments
and these should be made by actual experience in a practical
manner. In developing these methods of testing a lathe, further
instruments were necessary and are therefore described. In some
cases where there are two methods of test, one of these was used
and in some cases the other. Again, both were used and checked
against each other.

The special tools necessary for determining the accuracy of an
engine lathe must, of course, be accurate and reliable, but they
need not for this reason be elaborate or expensive, as the illustra-
tions accompanying this article will readily show. Their descrip-
tion and use will be fully explained as the process of inspection
is proceeded with in the matter which follows.

It is assumed that the lathe bed, as well as the head-stock, tail-
stock and carriage, have been properly planed, the V's shaped to the
proper angle, and that the V's of the bed have been scraped straight
and true, removing as little of the metal as possible. The head-

TESTING A LATHE 245

stock, tail-stock, and carrriage should now be carefully scraped to
fit the V's of the bed. Their fair bearing may be easily ascertained
by rubbing on a little of a mixture of the dry, red pigment com-
monly known among painters as " princess red," or some similar
dry color, mixed with a small portion of any oil that may be con-
venient. The above color will be found to have this convenience:
it will show almost black where the pressure is very severe and cor-
respondingly lighter where the contact is less perfect. The scrap-
ing should be continued until the contact spots do not exceed f
inch from center to center, and the inspector should assure himself
of this fact before these parts are finally fixed in position.

The carriage should be' run back and forth along the length of
the bed to detect any slight curves that the bed may have taken
since it was planed, and if any are found they should be corrected
by scraping. Of course the bed should be carefully leveled up and
kept so during the time this scraping and fitting is going on.

When the lathe is finally "set up" or erected, great care should
be taken to have it in as firm a foundation as is possible, and this
requirement becomes all the more important as the lathe is larger
and heavier. The bed should be carefully leveled both longitudi-
nally and transversely, applying the level to the tops of the V's at
points not over four feet apart for large and heavy lathes, and
not over three feet for small and medium sized ones. If this
is not carefully attended to it will be difficult to determine with
any reasonable degree of accuracy whether or not the lathe will
bore truly, as a slight change in the tops of the V's, throwing
them out of a true plane, will defeat the test.

Neither can proper tests by means of the carriage be made if
the V's on the bed are not so carefully leveled up as to be correctly
in the same plane.

Before proceeding to further describe this system of lathe test-
ing, attention is called to the accompanying blank report for
properly recording the results of the inspection. It will be noticed
that it is quite thorough, but a long experience in machine tool
work brings us to the conclusion that there is not a superflu-
ous observation or requirement in it. And it is recommended
that lathe builders send a signed copy of this report to the cus-
tomer who purchases the lathe, for his information and guidance

246

MODERN LATHE PRACTICE

in testing the lathe for himself when he has it set up in his own
shop.

There are many items of an inspector's duty not here enumerated
which, in a shop properly arranged and managed, will have been
attended to as the parts are being made and assembled. This
relates only to the performance and outward condition of the lathe
when ready for its final inspection.

Lead screws should be tested before they are put into the lathe
of which they are to become a part. They should be held on centers

GRADUATIONS 50 TO l'

FIG. 200. — Device for Testing Lead Screw Threads.

and may be tested for accuracy of thread by the device shown in
Fig. 200, in which A is the lead screw to be tested, upon which is
applied the main frame B of the device, supported by its capped
bearings C, D, the former just fitting over the top of the thread and
the latter having either a babbitt metal lining cast upon the thread
or being provided with a split sleeve in which this babbitt nut is
cast. The latter arrangement is best, particularly when lead screws
of different pitches or different diameters are to be tested.

In case of different diameters, the bearing C should also be

TESTING A LATHE

247

bored large enough to allow of a suitable bushing being introduced.
The frame B of the device is extended to the right to form a grooved
support for the adjustable arm E, secured by the bolt e and ad-
justed by the screw /. This arm is extended to form a graduated
segment at g. Pivoted in the arm E is the indicating lever F,
whose front end is formed to fit the thread of the lead screw A, and
to whose rear end is fixed the indi-
cating arm G, whose point rests on
the graduations at g.

The leverage and graduations are
so arranged that thousandths of an
inch are indicated by lines, and a
much smaller fraction may be readily
perceived. In using this device that
portion of the frame B between the
bearings C, D, rests on the top of the
compound rest, the lathe being ar-
ranged for the same pitch as the lead
screw to be tested. The screws hold-
ing down the caps of the bearings
C, D, are set up just close enough to
insure a proper fit. The object of
using a babbitted nut in the bearing
D and applying the indicating lever
F at some distance from it is three-
fold. The influence of the lead screw
of the lathe in use is not felt, there is
very little friction on the point of
the indicating lever F, and the rela-
tive inequalities of the thread of the
lead screw to be tested are rendered
more obvious.

Another very important and useful instrument in lathe testing
is the micrometer surface gage, which is shown in Figs. 201 and
202, in which all principal dimensions are given.

The base A is of cast iron, the supporting rod B and the pointer
b are of Crescent steel drill rod, and the other parts (excepting the
spiral spring) are of tool steel. Its construction is readily under-

FIG. 201. — Micrometer Surface
Gage.

248

MODERN LATHE PRACTICE

stood from the drawings, special attention being called to the

arrangement for securing the pointer b, as shown in section in Fig.

202, by means of the conically formed thumb-nut G, its clamping

bolt H, and the conically formed receiver.

The blocks C, D, are connected by the rod K, whose lower

end is fixed in the block D and
whose upper end passes up
through the block C, where it is
cut with a thread 40 to the inch,
and provided with a graduated
thumb-nut L, by means of which
we may read thousandths of an
inch, and even the quarters of
that fraction are readily de-
termined.

C© 1 1 "jji Blocks C and D are forced

F| apart by the spiral spring sur-

rounding the rod K. In the use
of this device the block D is se-
cured by the thumb-screw F.
The pointer b is then brought
down near the work and is se-
cured by the thumb-nut G. The
thumb-nut E is now tightened
just enough to hold it firmly, and
the final adjustment made by
means of the graduated thumb-
nut L.

FIG. 202. — Details of Micrometer
Surface Gage.

The lathe being ready for testing and the face-plate having been
faced off, we begin with the test for alignment, as shown in Fig. 203,
which is a rear elevation of a lathe ready to be tested, and Fig. 204
a plan of the same.

To ascertain the vertical alignment of the head spindle we place
an accurately ground and properly fitted test bar A in the center
hole of the head spindle and place the micrometer surface gage on
the lathe V's as shown in Fig. 203, first applying the pointer b at a
point near the face-plate and then near the outer end of the test
bar, as shown by dotted lines, using the micrometer-adjusting nut

TESTING A LATHE

249

L to ascertain the difference, if any. To render the touch of the
pointer more sensitive a slip of paper should be drawn carefully
between the test bar and the pointer. The best paper for this
purpose is a hard calendered linen typewriter paper, three thou-
sandths of an inch thick, as this paper runs very uniform in thick-
ness.

L T

FIG. 203. — Rear Elevation of Lathe being Tested for Alignment of
Head-Stock and Tail-Stock Spindles.

If the inner and outer V's of the lathe are not of the same height,
a parallel bar should be laid across the V's and the micrometer
surface gage placed upon it. In any event much care should be
exercised to be sure that the gage base sits fairly on its support,
as a slight scratch, or a burr, or the least bit of dirt, will defeat the
object of the test.

lilt

FIG. 204. — Plan of Lathe being Tested for Alignment of Head-Stock
and Tail-Stock Spindles.

The vertical alignment of the tail spindle is tested in the same
manner, as shown in Fig. 203. It may also be tested by bringing
the pointer down on the spindle itself, when it is run back into the
tail-stock, and again when it is run out as far as it will go. It
sometimes happens that we shall get a different result by sliding
the tail-stock to a different position on the bed. In this case we
will probably find some inequality in the V's to account for it.

250

MODERN LATHE PRACTICE

To test the lateral alignment of the head spindle, a bar of the
size of the ordinary lathe tool, with its front end bent to a right
angle, and provided with a micrometer head, is placed in the com-
pound rest as shown in Fig. 204, and the reading made in a manner
similar to the last test. The lateral alignment of the tail spindle
is tested in a similar manner, moving the carriage to the desired
point.

To ascertain the accuracy of the center hole in the head spindle,
we may use our micrometer at the end of the test bar A, as shown
in Fig. 204, and by turning the spindle a quarter of a turn at each
reading we may ascertain its accuracy with certainty.

The foregoing tests would seem to be sufficient to insure the
correct boring of a job on this lathe. But it must not be forgotten
that the error detected by the test, as shown in Fig. 204, will be
doubled in boring a piece of work.

Therefore the best test of ascertaining the boring quality of the
lathe will be by bolting a cast iron test piece to the face-plate, as
shown in Fig. 205. A very light cut is taken off from the raised por-
tions C, C, and measure-
ments taken with the
micrometer. This test for
boring will be much more
conclusive than attempt-
ing to actually bore a piece
of work, owing to the
difficulty of making any
boring tool, held in a com-
pound rest, bore the same
sized hole as both ends of
a piece from 12 to 30 inches

FIG. 205. — Test Piece for ascertaining if
Head-Stock Spindle is Parallel with the Vs.

long. In this connection a diagram and all necessary dimensions
for test pieces for different sized lathes are given in Fig. 207.

To test for the concavity or the convexity of the face-plate it is
usual to use an ordinary straight-edge and three slips of paper.
This may be nearly correct, but we have no means of knowing the
exact amount of the error. For this reason the micrometer straight-
edge shown in Fig. 206 was designed. The stock A is slotted at
each end, and in these slots are secured the outer points B, B, ca-

TESTING A LATHE

251

FIG. 206. — Micrometer Straight-Edge for
Testing Face-Plates.

pable of being adjusted to different diameters of face-plates, and
are secured by the thumb-nuts C, C. The center point D is a microm-
eter head, operated by the usual milled head E.

In using this straight-edge it is first turned up on a fixed straight-
edge and the center point
adjusted so that the three
points are accurately in
line, using slips of paper
to ascertain this correctly.
The test bar is now placed
in the head center hole
and the flat space a of the
straight-edge laid upon it for support.

Slips of paper are now introduced between the points and the
face-plate. The micrometer position is noted, and then adjusted
to hold the center slip of paper, when a second reading will give
convexity or concavity of the face-plate.

The allowable limits of va-
riation of lathes may be about
as follows, viz.: 14 to 20-inch
swing lathes, inclusive, .0005
inch; 22 to 28-inch swing
lathes, inclusive, .001 inch; 30
to 48-inch swing lathes, inclu-
sive, .002 inch; lathes larger
than these, .003 inch.

These limits apply to all
the foregoing tests, the dis-
tances between testing points
to be as given in the table,
Fig. 207. It should be under-
stood that no convexity of a
face-plate is to be allowed.

The various other points of
inspection as given in the re-
port blank will need no special explanation, certainly not to men
accustomed to this class of of ttimes trying and delicate work.

Swing of

Lathes

w'W.ie

is" and 20M

22l!and 2411

32M»nd 36"

42"and.48"

OOrand 72"

24H

275-4

814

FIG. 207. — Table giving Form and
Dimensions for Test Pieces shown in
Fig. 205.

252 MODERN LATHE PRACTICE

INSPECTION REPORT ON LATHE

NAME OF COMPANY

Inspection No Date, inspection commenced

Size of Lathe T Date, inspection completed .

Lathe prepared for inspection by

Special features of Lathe

1. Level longitudinally

2. Level laterally

3. Swing over the V's

4. Swing over the carriage

5. Distance between centers

6. Fitting of head-stock on V's

7. Fitting of tail-stock on V's

8. Fitting of carriage on V's

9. Bores, large at inner end

10. Bores, large at outer end

11. Faces concave

12. Head center, high at outer point.

13. Head center, low at outer point .

14. Head center, to the front at outer

point

15. Head center, to the rear at outer

point

16. Tail center, high at outer point..

17. Tail center, low at outer point...

18. Tail center, to the front, at outer

point

19. Tail center, to the rear at outer

point

20. Center hole in head spindle

21. Back gears, run

22. Second back gears, run

23. Internal gear, runs

24. Feed gears on head, run

25. Compound rest bevel gears, run .

26. Apron gears, run

27. Rack pinion works

28. Lost motion in apron gears

29. Reverse device in apron

30. Lead screw

31. Tail spindle screw fits

32. Cross feed screw fits

33. Comp. rest screw fits

34. Appearance of scraped surfaces..

35. Appearance of polished surfaces .

36. Finished corners properly rounded

37. Width on cone steps

38. Change-gears fit studs properly.

39. Wrenches fit properly

40. Squares for wrenches of uniform

sizes . .

Remarks

Signed.

Inspector,

A critical examination of the above list of questions is invited
in order to fully appreciate the value of such a thorough system of
tests both to the concern who builds the lathe and to he who pur-
chases and uses it. Such a system will give a healthy tone to the
workmanship of the shop, and when fairly met by the conditions of
the machines turned out will be a source of pride to the workmen
employed in it.

TESTING A LATHE 253

On the other hand it will give a feeling of confidence and se-
curity to the purchaser, who will naturally feel that he is getting
full value for the money he has spent in purchasing the machine.
Further, the lathe going into the shop with such prestige will
naturally be looked upon as a good machine, and more than the
usual amount of care will be bestowed upon it and upon the
product which it turns out.

CHAPTER XIII

LATHE WORK

The use of hand tools. Simple lathe work. Lathe centers. Care in reaming
center holes. Locating the center. Use of the center square. Angle of
centers. Lubrication of centers. Centering large pieces of work.
Driving the work. Lathe dogs. The clamp dog. The die dog. The
two-tailed dog. Lathe drivers. Using dogs on finished work. Clamp
dog for taper work. Bolt dog. Methods of holding work that cannot
be centered. Center rest work. Chuck work. Use of face-plate jaws.
Lathe chucks. The Horton chuck. The Sweetland chuck. The
Universal chuck. Face-plate jaws. A Horton four-jaw chuck. The
Horton two-jaw chuck. A Cushman two-jaw chuck. Chucking cylin-
drical work. Inside chucking. Chucking. Chucking work supported
in a center rest. Pipe centers. Mortimer Parker's improved forms
of pipe centers. Spider centers. Ball-thrust pipe centers. Lathe
arbors or mandrels. Kinds of mandrels. Expanding arbors or man-
drels. Making solid arbors. The taper of an arbor. Hardened and
ground arbors. The Greenard arbor press. Its advantages.

IN the chapter on lathe tools the subject of hand tools was
purposely omitted, as their use has greatly diminished during the
past few years, with the possible exception of their employment on
small bench lathe work and on some kinds of brass work, and much
of the work formerly done with hand tools is now done in the
regular operations on the turret lathe, the screw machine, and with
forming tools on ordinary engine lathes.

Such hand tools as are still used in a limited degree will be
referred to in the proper places in the following description of
lathe work.

When the apprentice is first put to work on a lathe it will prob-
ably be the turning of a piece of shafting on centers, and his first
duty will be to center it, that is, to drill and ream proper bearings
for the center. If he is in a modern shop the old method of form-

254

LATHE WORK

255

ing the center hole by means of a prick-punch and a hammer will
not be tolerated. Neither will the practice which succeeded it,
that of drilling a small hole and then spreading it out or counter-
sinking it with the center punch. The hole was once drilled with
a " fiddle-bow 'drill/' which was later replaced by the geared breast
drill, which is very convenient for some jobs but not a tool to drill
a good center hole with.

Lathe centers should be accurately ground to an angle, at the
point, of 60 degrees. Center grinding attachments are provided
for this work (as shown in the chapter on lathe attachments),

FIG. 208. — Centering Lathe Work.

which will give a very perfect angle. Of course the center has been
previously hardened so as to stand the wear of the revolving piece
of work. Nevertheless there should be considerable care exercised
in drilling and reaming the center hole so that it shall really fit the
angle of the center. There are various ways of doing this. The
most convenient way is to use for this purpose a combined drill and
countersink shown at A in Fig. 208, which will drill the center hole
and countersink or ream it to the proper angle. These are made
of various sizes to adapt them to the diameter and weight of the
work to be centered. At B is shown another and older form of
center reamer which is made by turning up the tool to the proper
angle and then cutting away the upper half so as to give a cutting
edge.

The disadvantage of using this form is that two operations must

256 MODERN LATHE PRACTICE

be performed, that of drilling, and afterwards reaming or counter-
sinking.

To center a piece of round material it may be first " scribed" by
the dividers or the hermaphrodite calipers (a caliper having one
regular caliper leg and one pointed one, similar to the leg of dividers),
which are set approximately to the radius of the piece, and three
or four arcs marked across the previously chalked surface, forming
a small triangle or a square, within which the first prick-punch mark
is made. This is followed by the drilling.

This may be more quickly done by a center square shown at
C, Fig. 208, applying it as shown and scratching a line across the
work, then turning the work about a quarter turn and scratching
again in the same way. The intersection of these lines will be the
center, which may then, be marked with the prick-punch as before.

The use of a centering machine will much facilitate the work
on small and medium sized work. In this machine the work is
held in a self-centering chuck, mounted on a short lathe bed and
holding the piece of work exactly in line with and in front of the
center drill and countersink shown at A, and held in a chuck carried
by the spindle of the machine which has a head-stock quite like
that of an ordinary lathe, and the spindle adapted to slide forward
in drilling the hole. By the use of this machine the center drilling
and countersinking will be in accurate alignment with the axis of
the work, and with this drill the angles will be correct, the work
and the center appearing as shown at D, in the above engraving.

Should the form of a center reamer, or countersink, be too obtuse
an angle the effect will be as seen at E, in which it is seen that the
center bears only slightly near its point. It will thus be worn out
of shape and quite naturally the axis of revolution will change.

If the angle of the center hole is too acute the lathe center will
only bear at the edge of the hole, as shown at F, and the tendency
will be to wear a crease around the center at this point, and the
work will finally "run out," that is, the axis of revolution will
change as in the last example.

Should the drill and countersink not be in line with the axis of
the work the result will be as shown at G, and the work will not
only run out of true in a little time, but the lathe center is likely
to be spoiled.

LATHE WORK

257

The proper lubrication of tail centers is important, otherwise
the pressure will create so much friction that the center will heat
and "burn off." To prevent this some centers, particularly large
ones, have an oil hole drilled in the point, which is left large enough
for that purpose. This hole connects with one at right angles with
it and opening beyond or outside of the end of the work, and through
which oil may be introduced while the lathe is running, thus keep-
ing the center always well lubricated. The plan is an excellent one
on heavy work, or in fact on nearly all work in lathes of 24-inch
swing and larger, and the larger the center the more benefit will be
found in its application.

2 3

FIG. 209. — Lathe Dogs.

From these examples and remarks it will be seen that much
depends on making the center holes of the right form if we expect
to produce a good piece of turned work.

In centering large pieces of work it is sometimes the custom to
hold one end of the shaft or forging in a chuck on the main spindle
of the lathe, and the other end in a steady rest, or center rest. The
lathe is started and a pointed tool set in the tool-post is brought
against the work and the center scratched into it as it revolves.
This is quicker and more accurate than the scribing method, par-
ticularly in the case of heavy and rough forgings.

The piece of work having been properly centered, we apply to
it a dog which serves to drive it and suspend it between the centers,
first carefully oiling the tail-stock center and setting it up just
tight enough to hold the work closely and without end motion.

Lathe dogs are of various kinds. The most common kind is
that shown at 1, in Fig. 209, which is fixed to the piece to be turned

258 MODERN LATHE PRACTICE

by the set-screw and the work is driven by the tail of the dog enter-
ing the driving slot in the small face-plate of the lathe. The clamp
dog shown at 2 is useful for driving square or flat pieces, and is also
frequently used for cylindrical work, which it is not so liable to mar
as is the set-screw of the first form.

At 3 is shown another form known as a die dog, the jaws being
movable and closed up by the set-screw. The jaws being threaded
may be applied to threaded work which is of such form that a dog
cannot be placed upon any part but that which is threaded.

At 4 is shown what is called a two-tailed dog, sometimes used on
large work and driven from " drivers" placed against the two tails.
These drivers may be made for the purpose and consist of a piece
of round steel of sufficient length to reach from the front of the face-
plate out to and across the dog, and be secured to the face-plate
by a cap screw, with a washer under its head, and coming through
the face-plate from the back and into the end of the driver. Or it
may have a shoulder and be held by a nut.

More often, however, the driver is a bolt long enough for the
purpose, with a sleeve made of a piece of gas pipe or a block of
cast iron with a hole through it, which keeps the end of the bolt
far enough to reach the dog.

In placing dogs on finished work a piece of brass or copper should
be put under the points of the set-screws to prevent marring the
work. In using the clamp dog at 2 on finished work the pieces of
brass or copper should also be used.

Various other forms of dogs are used for special work and for
very large work ; as, for instance, two more or less curved bars and
fastened together by bolts, somewhat in the form shown at 2, Fig.
209.

But in all cases the principle is the same, to clamp to the piece
of work a device having formed upon it a projecting part, called
the tail, by which the work may be rotated.

In some cases when the clamp dog shown at 2 is much used on
taper work the heads of the clamp screws are made in the form of
eyes, and the upper cross bar or clamp bar has trunnions or bearings
turned on each end which enter into the holes or eyes of the bolts.
By this means the clamp bar may turn in its bearings sufficiently
to have its flat side set fairly on the inclined surface of the taper.

LATHE WORK 259

In driving bolts which are to be threaded and in which the
marks of the center hole in the top of the head are not objectionable,
a "bolt dog" is used. This is simply an offset plate fastened to
the face-plate by a single bolt and its free end slotted so as to em-
brace the head of the bolt. This device is not much used at the
present time as bolts and cap screws are usually made from a bar
in the turret lathe at much less cost than is possible to produce
them in an engine lathe.

Lathe work that is not held suspended between centers must
be held by one of the following methods, namely : bolted or clamped
to the face-plate ; held entirely in a chuck ; one end held in a chuck
and the other in a center rest; or secured to the carriage, or some
part of it, as in boring jobs. One exception is made to these state-
ments. This is that work may be held against the head spindle
center by any convenient means, and the other end supported in
a center rest. This is usually only resorted to for such work as
boring and reaming and, with the exception of the advantage de-
rived from accurate centering by means of the head spindle center,
is not a very advisable method of running work in a lathe, par-
ticularly when a chuck with truly concentric jaws is at hand.

What is ordinarily called center rest work is all kinds in which
one end is supported in a center rest. Of course this does not in-
clude work held on centers and supported in the center or at any
intermediate point by a center rest. In this case many machinists
call it a " steady rest," rather than a center rest, and this function
may be readily performed by a back rest or what is called by some
manufacturers a steady rest, which has the three jaws of the center
rest, although they are not placed equidistant around the circle
and the supporting casting is left open in front instead of being
provided with a hinged top segment.

Chuck work and face-plate work is very closely allied, and in
fact very many face-plate jobs can readily be done in a chuck, and
nearly all chuck jobs can be done if fixed to the face-plate in the
usual manner. It is altogether probable that the first chuck made
was simply a face-plate provided with jaws temporarily attached,
and it is more than likely that these "jaws" consisted merely of
blocks or studs fastened to the face-plate and provided with set-
screws for holding the work.

260

MODERN LATHE PRACTICE

One of the oldest chuck manufacturers was E. Horton, who
established the business in 1851. One of the Horton three-jaw
chucks is shown in Fig. 210.

At A is shown a face view of the finished chuck. It consists of
a front and a back plate shown respectively at D and B. The
jaws are moved in and out simultaneously, by means of the geared
steel screws, the small bevel pinion formed on them engaging the
circular steel rack C, which is enclosed in a deep groove or recess
in the back plate B, as shown. At D is shown the front plate with
the jaws in place, with the projecting portion at the back tapped
to receive the steel screws, which are shown in place. The front

FIG. 210. — The Horton Three-Jaw Chuck.

and back plates fit each other closely, making a perfectly tight
casing for the gearing and screws, so that no dirt, chips, etc., can
possibly get into them and clog and injure the gearing. The jaws
are forged solid, by which great strength is secured to withstand the
strain of heavy work.

At A, Fig. 211, is shown a Sweetland chuck, which in a general
way is similar to the Horton chuck, but possesses some advantages,
in that it may be used as a " universal" chuck, so called, in which
all the jaws move simultaneously to or from the center, or it may be
readily changed so that the jaws work independently of each other,
thus adapting it to a large variety of irregular and eccentric work.

LATHE WORK 261

The design of the improvement is to make the chuck independ-
ent as well as universal, thus combining two chucks in one. In
the recess underneath the rack are the cam blocks, beveled to cor-
respond with the level recess in the rack. The cam blocks are held
in place by the convex spring washers, which allow them to be
moved to or from the center without disturbing the nuts, the friction
being sufficient to hold them in place. When moved to the outer
portion of the rack they connect the gearing, making the chuck
universal, and when moved inward they disconnect the gearing,
thus making each screw independent.

The advantage of making each screw independent, without dis-
connecting the others from the gearing, is a feature not combined
in any other chuck, and is an improvment fully appreciated by the

FIG. 211. — Sweetland Four- Jaw Chuck, and Cushman Face-Plate Jaws.

mechanic when adjusting the jaws for eccentric, concentric, or uni-
versal work. For instance, the chuck having been used independ-
ent, the workman wishes to change to universal, the jaws are moved
inward until the outer end is true with the line on face of chuck;
now each screw can be engaged with the rack separately by sliding
the cam block outward. If one jaw is found to be out of true it
can be disconnected and reset, leaving the others in mesh undis-
turbed.

This chuck has a large hole in center, and will allow a drill or
reamer to pass through work without injury to face of chuck.

The jaws, rack, and pinion screws are made from forged steel,
and all wearing parts properly tempered.

The "bites" on the jaws are ground true after being hardened
and tested thoroughly before coming out of the grinding machine.

262 MODERN LATHE PRACTICE

At Fig. 211 are shown the face-plate jaws heretofore referred to,
and which, when attached to a face-plate, make a very serviceable
and practical substitute for a chuck, and advisable to have from
questions of economy, even on lathes as small as 30-inch swing,
while on lathes above 40-inch swing they are all the more useful,
and on 50-inch swing and larger are almost indispensable, as the
largest chucks usually made are 42-inch and these are very heavy
and very expensive, while a set of four jaws for the face-plate may
be had at a comparatively nominal cost.

Figure 212 shows three forms of chucks. At A is a Horton

FIG. 212. — Horton and Cushman Chucks.

chuck with four jaws. It is built on the same plan as the three-jaw
chuck shown in Fig. 210.

At B is shown a Horton chuck with two jaws, which is very
useful for certain classes of work, and better adapted than those of
three or four jaws.

Not only the Horton chucks but also those of other makers are
built with two, three, four or six jaws, as the nature of the work
may demand.

At C is shown a Cushman two-jaw chuck, with provision for
slip, or "false jaws." By this construction special jaws may be
made with faces of such contour as to fit the irregular form of the
pieces to be machined. This form of chuck is used for the machin-
ing of valve bodies and similar work, and is sometimes fitted with
various indexing devices by means of which the piece may be turned
from side to side and held while various operations are performed.

Special chucks are made of various forms and with a varying
number of jaws, of a variety of different shapes, all of which are
too numerous to illustrate or describe here.

In chucking cylindrical work with a universal chuck of three

LATHE WORK 263

jaws the work is correctly centered by the chuck jaws, provided
there are no uneven places on the work, which by coming under
either of the jaws tend to throw it out of true. Such work is usually
that of boring, reaming, or facing, and similar work on the face or
inside of the casting or forging, and such part of the outside as
extends beyond the chuck jaws.

It should not be forgotten that while we usually grip work upon
the outside, the chuck jaws work equally well by bearing against
the inside of the work; for instance, the inside of the rim of a gear
that is to be faced, bored, and reamed.

When round rods or bars are to be machined or pieces cut from
them, whether to be partly machined or not, a drill chuck, so called,
is used. This is a two-jaw chuck, the jaws being of a variety of
forms, from the shape shown in Fig. 212 to V-shaped jaws with
interlocking teeth, the design of all of them being to hold the bar
or drill firmly, with as little force applied to the right and left screw
that operates them as possible.

Work may be such that one end is held in the chuck and the
other supported by the tail-stock center, or by a center rest whose
jaws furnish a three-point bearing for the cylindrical surface of the
work. While the method of supporting the work by the tail-stock
center is used for work that is to be turned, the second method, that
of supporting the work in a center rest, is better adapted for drilling
and reaming operations. These operations may be wholly done
with the drill and reamer, or by the use of an inside boring tool
held in the tool-post of the compound rest.

It is a common job to have to face up the flanges on the ends of
pipe of various sizes. Sometimes these pipes are of wrought iron or
steel with the flanges screwed on. Sometimes they are cast upon
cast iron pipe. The ordinary method is to hold one end in a chuck
and the other end on a "pipe center," of one form or another. One
form of these centers is called a " spider center," and often con-
sists of any convenient casting, circular in form, that comes handy.
With several set-screws tapped radially into its edges and adapted
to be backed out against the inside of the pipe and firmly held,
while a drilled and countersunk hole in the center affords a good
bearing for the lathe center. Mr. Mortimer Parker suggests some
improved forms which are shown in Fig. 213, in which A shows a

264

MODERN LATHE PRACTICE

new spider center which is quite different from the old style B that
requires, as shown, a block of wood against it to keep it from shov-
ing in or twisting sideways when the center is pressed against it,
or when a heavy cut is started.

This improved center will stand a heavier cut and can be set
quicker than the other style. If the outside is turned true with
the hole the job can be set very readily. C, D, and E show end
views of different forms of this center; and F, G, and H are differ-
ent sizes with bronze bushings in the interior.

At I is illustrated the manner in which a common cone center

FIG. 213. — Pipe Centers and Spiders.

can be turned into a spider center by, drilling three rows of holes
and putting in set-screws and jam-nuts, only one set of screws being
needed, as they can be used in either series of holes.

A spider center allows room for the tool to clear when facing
off the end of a flange, but a cone center does not. When the tool
gets down to the center, as at J, it leaves a shoulder which must
be turned off with a pointed tool.

K is a center with a cone bearing at each end of the hole, which
keeps free from play even if it does wear. Center L is less work to
make, but does not turn around when a heavy cut is taken ; hence a
ball-thrust bearing should be used as at M for heavy work.

LATHE WORK 265

Center N works well in a heavy cut and is easily made. Center
0 is less work to make than any of the others and also works well
with heavy work.

In facing up pipe flanges it is sometimes the practice to hold one
end in the chuck and support the other end in a center rest. The
disadvantage of this method is that the roughness of the out-
side of the pipe is a very poor bearing for the center rest jaws
and poor work in facing is likely to result, while the same pipe
carried on a pipe center, in the same lathe, will be a creditable

Lathe arbors are an important adjunct to lathe work. They
are commonly called arbors although the old English name of
mandrel is the proper word, as an arbor is properly a carrier for a
tool, as a saw arbor, a milling machine arbor, etc., while a mandrel
is used for carrying a piece of work to be turned.

Mandrels are of two kinds, solid and expanding. The solid
mandrel should be made of hard machine steel or a cheap grade of
cast steel capable of being hardened.

In Figure 214 are shown two forms of arbors. That at A is the

FIG. 214. — Lathe Mandrels or Arbors.

common form. The ends are turned down somewhat smaller than
the central body, and on one side, at each end, is a flat space for the
set-screw of the lathe dog to rest upon. The ends are slightly re-
cessed around the center hole so that it will not be bruised if the
end is struck with a hammer. The central body should be ground
with a very slight taper. The entire piece should be hardened,
not simply the ends, as formerly. A J-inch arbor should be 3 J inches
long and a 4-inch arbor 18 inches, all intermediate sizes being of the
same proportion.

At B, Fig. 214, is shown an expanding arbor or mandrel. This
is made in two parts, the arbor proper and an outer shell. The
inner arbor is turned and ground to a considerable taper and the
outer shells accurately fitted to it. It is then split, as shown,

266 MODERN LATHE PRACTICE

by from eight to twelve cuts, alternately beginning at opposite
ends, so that in forcing the inner arbor in on the taper the outer
shell is expanded in very nearly a circular form, at least near enough
for all practical purposes. At the end of each cut is drilled a small
hole to prevent cracking.

A cheap imitation of this really excellent device is made by
splitting the outer shell all the way through at one point only, which
will do as a makeshift when nothing better can be had.

There are various forms of expanding arbors, some of which
have considerable merit and others very little. The one illustrated
above will probably be found to give the best satisfaction.

In making solid arbors it should be remembered that they must
be turned considerably over size, then hardened, which will change
their form somewhat, and then rough ground to nearly the proper
size. They should then be laid aside for some time to give the steel
an opportunity to take on its final changes and attain a permanent
condition as to size, straightness, etc., before it receives its final
finish grinding, which should diminish its diameter very slightly.

The drilling in the ends for the center hole and the countersink-
ing should be carefully done, the angles of the sides of the counter-
sunk hole being exactly 60 degrees.

Arbors are hardened for several reasons, principally to make
them accurately cylindrical, much stiff er and more rigid, and also
less liable to accidental injury, but not to prevent lathe tools from
cutting into them when used by a careless workman.

The taper on an arbor is usually about a hundredth of an inch
per foot with the center of the arbor of the standard diameter. The
fact that the arbor is tapered to this extent makes it necessary to be
careful to force the arbor into the reamed hole from the same side
that the reamer has entered, which should also be the same side
first entered by the piece that is to fit in the hole, provided it is to be
a close fit. This is frequently marked on the drawing and it should
always be so indicated for the guidance of the workman.

Hardened and ground mandrels serve the very excellent pur-
pose of preserving the uniformity of sizes of holes, since if the holes
are not truly sized the pieces will either drop on to the arbor too
loosely or fail to go on sufficiently for good and convenient work.
Again, the arbor being so slightly tapering, the workman will

LATHE WORK

267

notice even a small difference in the diameter of the hole by the
position of his piece on the arbor, and is likely to report the defect
in the work in this respect.

The use of expanding arbors has not these advantages as they
are ground perfectly straight. But they are to be preferred for
this very reason when running fits are desired.

Arbors should not be driven into reamed holes with a hammer.
An arbor press should be used and the author
knows of none better than the Greenard
press, which is made in various sizes, from
the small one to fasten to the tail end of
the lathe bed to the largest sizes which have
a broad floor base. One of the former is
shown in Fig. 215. By the use of these
presses there is no shock in forcing an arbor
into the work, and therefore neither the ar-
bor nor the work is injured. In addition
to this advantage, the arbor maintains a
perfect alignment with the hole as it is
forced in, and therefore there is no unequal
strain or distortion.

The rack and pinion arrangement of this
arbor press is at once simple and effective,
and the rotating table with its various sized recesses in the edge
furnishes an excellent bed for supporting the work as the arbor is
forced into it. A more convenient arrangement could scarcely
be imagined for this work.

FIG. 215 A. — Green-
ard's Arbor Press.

CHAPTER XIV

LATHE WORK CONTINUED

Irregular lathe work. Clamping work to the face-plate. Danger of distort-
ing the work. A notable instance of improper holding of face-plate work.
The turning of tapers. Setting over the tail-stock center. Calculating
the amount of taper. Taper attachments. Graduations on taper attach-
ments. Disadvantages of taper attachments. Fitting tapers to taper
holes. Taper-turning lathes. Turning crank-shafts. Counterbalancing
the work. Angle plate for holding the crank-shaft. Forming work.
Forming lathes. Drilling work on the lathe. Chuck and face-plate
drilling. Holding work on the carriage. Boring a cylinder. The
author's design for boring large cylinders. Holding work by an angle-
plate on the face-plate. Thread cutting. Calculations for change-gears.
Reverse gears. Arrangement of the change-gears. Ratio of change-
gears equal to ratio of lead screw to the thread to be cut. Cutting left-
hand threads. Compound gearing. Calculating compound gears.
Cutting double threads. Triple and quadruple threads. Boring bars.
Varieties of boring bars. Driving boring bars. Boring large and
deep holes. The author's device. The drill, boring bar and cutters
for the work. Flat cutters for boring holes. Boring bar heads or arms.
Hollow boring bars. Milling work on a lathe. Milling and gear cutting
on a speed lathe. Grinding in a lathe. Cam cutting on a lathe. Many
uses for the engine lathe.

THERE is so much irregular work constantly done on the lathe
that no specific description of it can be given. It is the unknown
quantity that the machinist has to deal with and he is expected to
be equal to the occasion and so fertile of resources as to be ready
with a proper method for doing every job that turns up, that he
will not be obliged to hesitate long for means to accomplish the end
sought.

Much of what may properly be called irregular work will be
such as can be handled on the face-plate or in an independent jaw
chuck. Yet these appliances for holding the work will frequently

268

LATHE WORK (CONTINUED)

269

have to be supplemented by the tail-stock center, the center rest,
and the follow rest, as well as the taper attachment.

In clamping work on the face-plate there is danger of springing
the work as it is fastened down. The result will be that it is held
in a distorted position while being machined, and upon being re-
leased by the bolts of other clamping devices it will spring back to
its original position and so show distorted machining. For this rea-
son much care should be exercised to see that it rests fairly on the
face-plate immediately under the clamps or bolts that hold it down.

The same idea applies to rings or similar shapes when held in
the jaws of a chuck or in face-plate jaws. There is always the pos-
sibility of springing them out of shape and that this forcing process
will show in distorted work when the piece is taken out of the lathe.
The author once saw rings of cast iron two inches thick, 6 inches
wide, and about 30 inches inside diameter, pressed out of shape

FIG. 215 B. —Turning Tapers.

by the face-plate jaws attached to a 60-inch face-plate, so much
that several of them were spoiled, and the expedient of strapping
them to the face-plate had to be resorted to in order to produce
work as true as the job called for.

Work may also be distorted when carried in a steady rest, a back
rest or a center rest, by this attachment having been set out of line,
either too high, too low, or to one side. Much more care is needed
in adjusting these attachments than they sometimes receive.

The turning of tapers may be classed as irregular turning work.
• If they are slight the tail-stock center may be set over sufficiently
to give the required inclination, particularly if the work is long.
When the taper is considerable, it will not be proper to set the tail-
stock center over for this purpose as it throws the head-stock and
tail-stock centers too much out of alignment to work properly.
This is shown in Fig. 215. One half the taper shown, on this length

270 MODERN LATHE PRACTICE

of work would be practical. In this engraving A is the head center
and B the tail center.

It will be noticed, however, that if the work is but half as long
and the tail-stock center located at C, the inclination will be twice
as great and consequently the error in the alignment of the centers
double what it would be with the tail-stock center located at B,
and the case more impractical than at first.

The tail-stock is arranged so that the center may be set over to
the rear as well as the front, so that the small end of the taper may
be toward the head-stock when such a position is more convenient.

In setting over the tail-stock center it must be borne in mind
that the difference in diameter between the large and the small end
will be twice the distance which the center is moved from the center
line of the lathe. Therefore, if the work is two feet long, and we want
a taper of one inch in two feet, or half inch per foot, we set the tail
spindle over half an inch. The amount set over at the tail-stock
gives double that taper in the whole length of the work.

Consequently, if we divide the amount of taper on the entire length
of the work by the number of feet in length, we get the taper per foot.
If this simple rule is remembered the mistakes that often occur in
turning tapers will be avoided.

In all taper turning, however, it will not be sufficiently accurate
to measure the amount of tail-stock set over, but the work must
be carefully calipered as the turning process goes on.

When the taper is considerable, it is better to do the work in a
lathe having a taper-turning attachment. Examples of this de-
vice will be found in the chapter on lathe attachments, where it
will be seen that the travel of the compound rest in a transverse
direction is governed by a swiveling bar which may be set at any
desired inclination with the V's of the lathe.

While there are usually graduations on the end of the taper
attachment that are intended as a guide in setting the swivel-bar or
guide, they are frequently misunderstood and consequently useless.
Usually they are marked for so much taper per foot, and when so
designated the length of the work in feet must be considered, if the
diameters at the large and small ends are given on the drawing.

If the taper slide or guide-bar is graduated in degrees, the case
is nearly hopeless with the usual machinist, as the graduations are

LATHE WORK (CONTINUED) 271

of no benefit whatever to him, as his drawing will very seldom be
dimensioned in this manner, but rather the extreme diameters
given, or the taper will be so much per foot.

The use of the taper attachment permits a much wider range of
tapers to be turned than can be successfully accomplished by means
of the set-over feature of the tail-stock. And we have the great
additional advantage of always keeping the centers in line, so that
accurate work can be done, which is not always the case when the
tail-stock is set over, except for very slight tapers.

One of the drawbacks to the use of taper attachments is that
a certain amount of back-lash is liable to exist when many parts
are necessary to the design of the mechanism, from the guide-bar
or swivel-bar to the point of the cutting-tool. These will give a
certain amount of difficulty in making a straight, smooth cut.
Consequently, the gibs should be set' up as close as practicable, all
nuts and adjusting screws set up tight and as much vibration and
back-lash eliminated as possible, and then the back-lash be taken
up by hand before the tool begins to cut.

In all taper turning it is necessary that the point of the tool be
set at exactly the height of the points of the centers, otherwise a
true taper will not be the result but will be slightly concave rather
than in a straight line.

In all cases, in turning tapers to fit a tapering hole, the exact
amount of taper should first be obtained so as to fit the tapering
hole, but to be considerably larger than its final size. Then the
diameter is turned correct, the calipering being usually done at the
small end.

Taper-turning lathes are sometimes made in which the head-
stock and tail-stock are mounted upon a separate bed which is
pivoted at the center so that it practically amounts to the lathe
swiveling while the tool carriage runs straight. In this lathe the
centers are, of course, always in line, the setting for the required
result is quickly done, and as the whole mechanism may be of very
rigid construction, the work done on it is very accurate as well as
economical. The turning of crank-shafts is a frequent trouble to
the inexperienced man who has this work to do. In the present
case it is assumed that the crank-shaft has been properly "laid off"
with a surface gage, on the surface-plate or table, and the centers

272

MODERN LATHE PRACTICE

located, drilled, and reamed, and the shaft proper roughed out to
nearly its finished dimensions.

The operation to be performed is to turn the wrist-pin. This is
shown in Fig. 216. At A is shown the usual method of rigging up
for the job. The shaft is placed in V-blocks on the surface table
and the wrist-pin blocked up to the proper height, as shown by the
surface gage, so that there will be stock enough left on all sides to
finish up to the given dimensions. The "offsets" or " throws,"
C, C, are now put on and the centers accurately located by the

_£>

L _i

— i

— '

FIG. 216. — Turning Crank-Shafts.

surface gage before the set-screws are screwed up tightly to hold
them in place. I

The centers are now measured all around with the surface gage
once more, to make sure that all are in the same plane. The crank-
shaft is now placed in the lathe, the centers in the offsets being
used as they are directly in line with the wrist-pin center. A tool
long enough to reach down between the arms of the crank must be
used. It should be made with a very narrow point, be kept very

LATHE WORK (CONTINUED) 273

sharp, and set either on the center or but a trifle above it. The
idea is to avoid as much as possible any undue strain in the turning,
as the work will not be very rigid and the cuts taken must be light.
The wrist-pin being turned and finished, the offset pieces C, C,
are removed, a block fitted in the space D, between the arms of the
crank, and it is placed on the shaft centers and finished as any other
shaft would be.

One of the precautions that should be taken is to have the work
properly counterbalanced by adding on the face-plate the proper
weight, opposite the crank when turning the shaft, and opposite the
shaft when turning the wrist-pin, so as to prevent undue strain
and vibration.

Another and more rigid arrangement is shown at B, in Fig. 216,
in which, in place of an offset piece at the face-plate end, the bracket
or angle-plate E is used. This is bolted to the face-plate and has
a cap F fitted to it and bolted firmly, with the joint held slightly
apart with paper or thin cardboard. It is then bored out the
exact diameter of the end of the crank-shaft, which is firmly gripped
in it and the shaft much more rigidly held than in the former
example. The offset piece C is used at the tail-stock center the
same as before.

In all these operations great care should be used to lay out all
the centers in the same plane, and to locate the offset arms in the
same manner. The free and careful use of the surface gage will
be necessary to success.

Forming work has been described in another part of this book,
and the reader interested in this class of work is referred to the
chapters in which these matters are considered. The particular
points to be observed in forming work are: to hold the work very
rigid; to have a very rigid cutting or tool carriage; to have a tool
with a very sharp and carefully "stoned-up" cutting edge; to use
a comparatively slow speed and a very fine feed.

When these conditions are obtained the forming lathe works
easily, accurately, and efficiently.

The tools must be so formed that by continually grinding on the
top the form and contour of the cutting edge is not changed.

The forming lathe may have an automatic feed with a stop which
automatically throws out the feed when the proper diameter is

274 MODERN LATHE PRACTICE

reached. This makes the lathe semi-automatic, in that it need only
be set and started, and no further attention given to it until the
cut is completed. Thus one man may run a number of machines,
and the relative efficiency of each will be reckoned, not so much
in the large number of pieces turned out, as in the small cost for
labor, which is usually the most expensive item on this and similar
classes of work.

This is seen very readily in the automatic screw machine, which
turns out much of its work much more slowly than the turret lathe.
But the turret lathe requires the constant attendance of a skilled
operator, while one man may take care of from four to ten automa-
tic screw machines.

In many respects the engine lathe may be made to take the
place of the upright drill, although this class of work is now usually
done in the upright drill, the radial drill, or the boring machine.
However, there are shops which do not possess all these facilities
and still have many jobs that may be properly done in the lathe.

To the ordinary jobs of chucking and reaming it will not be
necessary to refer. The same may be said of ordinary drilling
such as may be done by holding the work in the chuck and using
either a flat drill with a center hole in its rear end for the tail-stock
center, and the drill held from turning by a wrench, or similar
contrivance.

Drills may be held in the tail-stock spindle, in place of the tail
center, if the taper hole is standard as it should be, or when the
drill shank is too small a collet may be used. In this way many
jobs of chuck or face-plate drilling may be done. When the work
is such that it is necessary to revolve the drill instead of the work,
the drill may be transferred to the head spindle and the work held
by bolting or strapping it to the carriage, the compound rest having
been removed for that purpose.

Another method is to strap to the carriage an angle plate, jig,
or other fixture suitable for holding the work to be drilled.

There is a wide range of possibilities in this class of work and the
ingenious machinist is generally very resourceful in this direction.
The following is a case in point;

It is often necessary to bore a hole so large that it is not con-
venient to do it in the ordinary way, by bolting to the face-plate,

LATHE WORK (CONTINUED)

275

and if the casting has no hole through, or one so small as to require
a boring bar too small in diameter to get a steady rest cut, it is
almost impossible of accomplishment on the boring machine. The
casting shown, marked C in Fig. 217, is of such a nature. The pri-
mary factor in the boring of these cylinders is the making of the
bracket A, which forms a solid support for the boring bar B. The
boring bar B is driven in the usual way, or rather in one of the usual
ways. It will be noticed that the taper shank is held from turning
by being screwed into the spindle of the lathe head-stock, and that
it has a conical bearing at the outer end in the bracket A. The
bearing is thus adjustable to take up "back-lash" by sliding the
bracket A to the right along the lathe bed, which in this case is of

^ D Carriage ^

-^pron^i^" ^§^J~~}

Lathe Bed I

FIG. 217. — Cylinder Boring in the Lathe.

the ordinary English pattern, with a flat bed. Of course, by mak-
ing the bottom of the bracket to suit the raised V's, the attachment
is capable of being made to suit the American style of bed.

The cylinder C is bolted upon a slotted plate attached to the
carriage D, upon parallels. In planing the base of the castings,
care was taken to make them in all cases of equal distance from the
face of the base to the center of the casting — not to the core, as
this was liable to be slightly out of true.

Three cutter heads, two roughing and one finishing, were made
like the one shown at F, at the right, in Fig. 217. All had four
cutters slanting to the left at the inner end, in order to bring the
cutting edges outside, or near the end of the block.

At the right of Fig. 217 is shown one of the blocks in detail.

276 MODERN LATHE PRACTICE

E is turned to the angle at which the cutters were required to be
fitted at the point G, and a clamping ring F, turned to fit, was
afterwards clamped on by means of four filister head screws. Four
holes, as at J, in the small view at the right, were drilled in line with
the joint to fit the cutters. After drilling, a small amount was
turned off the inner face of the clamping ring F in order that the
tools would be clamped when the screws were tightened. This
ring when tightened up was found to be sufficient to prevent the
cutters slipping in.

To insure the cutters all having an equal cut, the cutting edges
were ground and also backed off by means of a cutter bar, mounted
on the slide-rest and driven from overhead. The finishing cutter
finished from six to a dozen holes at one grinding and it was then
a simple matter to set them out a little and regrind. It was found
to be advisable to take out and grind the roughing cutters separately
on an emery wheel, as working in the sand they wore rapidly.
Sometimes one broke in cutting out a projecting lump of metal and
they wore generally unevenly.

The hole H, Fig. 217, was bored out (from a cored hole) by two
cutters, as shown (roughing and finishing), fluted similarly to rose
bits or reamers. The roughing cutter was passed through at the
same time as one of the roughing cuts in the large hole; the finish-
ing cut, however, was taken separately to avoid disturbing the
large finishing cut. The carriage was fed up mechanically by means
of the rod feed.

The device for doing this job, when once made, proved to be
useful on other jobs as well.

The author once designed and built a lathe for doing a similar
job to the one here described and illustrated, but on a much larger
scale. In this case it was required to very rapidly bore and finish
large cast iron cylinders about four feet in diameter. As there was
ample power to do the work, and sufficient length of bed was allow-
able to bore a number of these cylinders at a time, and as they were
quite short in proportion to their diameter, the lathe was arranged
to bore two cylinders at once, with three tools for each cylinder,
namely, a roughing tool, a sizing tool, and a finishing tool. Each
of these consisted of a cross bar attached to a boring bar, and carry-
ing a cutting tool on each end.

LATHE WORK (CONTINUED) 277

By this arrangement there were twelve cutting tools in action
most of the time, and as two cylinders were bored during the time
of the travel of the tool across one, the result was that of doubling
the capacity of the former machine which did this work.

Another method by which boring work may be done is to at-
tach it to the face-plate of a lathe by the use of an angle-plate, by
which means various shaped pieces having a finished surface at
right angles to the axis of boring may be conveniently held. El-
bows are well handled by this device and many similar jobs will
readily suggest themselves to the machinist. And not only boring,
but many jobs of turning on such shaped pieces may be conveniently
handled by the use of the angle-plate attached to the face-plate
of a lathe.

Thread cutting in a modern lathe provided with a quick change
gear device for cutting any number of threads per inch, by shifting
one or more levers, is a comparatively simple matter. With a lathe
equipped with removable change-gears for accomplishing the same
purpose it is much more complicated, and its principles frequently
misunderstood. Therefore a clear understanding of these prin-
ciples is necessary to any one who aspires to become an intelligent
machinist.

The spindle or head shaft of the lathe runs at the same speed
as the main spindle; therefore it takes its place in all calculations
for thread cutting. Upon this spindle the first change-gear is
placed. The lead screw carries the second change-gear. , The ratio
of these two gears determines the ratio of the number of revolu-
tions of the main spindle to those of the lead screw. The change-
gear placed between this first and second change-gear is an idler
gear, since it runs loosely on a stud and serves only to communicate
motion, but does not in any way change or modify the ratio.

The reverse gears within the head are used only for reversing
the motion of the head shaft, and are also idler gears, not affecting
the ratio.

The arrangement is shown in Fig. 218, in which a is the head
shaft or spindle; o is the lead screw, and c the adjustable stud in
the adjustable stud-plate, segment, quadrant, or sweep, as it is
variously termed, marked d. A is the first change-gear ; B the second
change-gear, and C the idler gear. As shown, the two gears A and

278

MODERN LATHE PRACTICE

B are of equal diameter and number of teeth, consequently the
lead screw revolves at the same rate of speed as does the main
spindle. It follows, therefore, that if the lead screw is cut with
four threads per inch the lathe carriage will move a quarter of an

inch with each revolution, and the
lathe will cut four threads per inch.

If the change-gear A is only one
half the diameter of the change-gear B,
the lead screw will revolve only one
half as fast as the main spindle, and
the lathe will cut eight threads per
inch; while if the change-gear B is one
half the diameter of the change-gear A,
the lead screw will cut two threads per
inch.

Therefore, whatever is the ratio of
f 1 the two change-gears, A and B, to

accordingly, and produce a thread of
like ratio to the number of threads per inch with which the lead
screw is cut. Otherwise, the ratio of the change-gears A and B
equals the ratio of the thread of the lead screw to the thread to
be cut.

To cut any desired number of threads per inch it is first
necessary to find the ratio which the desired number of threads
bears to the number of threads on the lead screw; then to select
such change-gears as bear this ratio to each other, remembering
that if the desired thread is of a coarser pitch than that of the
lead screw, the change-gear A must be the larger, and if it be a
finer thread than that of the lead screw, the change-gear B must be
the larger.

The gears will revolve in direction of the arrows, by which it is
seen that the lead screw revolves in the same direction as the change-
gear A on the head shaft a, and consequently as the main spindle
of the lathe. This arrangement, with a right-hand thread (as
usual), on the lead screw 6, will cut right-hand threads.

When it is desired to cut left-hand threads the motion of the
lead screw must be reversed. This is done by the addition of the

LATHE WORK (CONTINUED)

279

idle gear E on a second stud e, in the stud-plate d, as shown in Fig.
219.

When the proper ratio cannot be obtained by the use of the
change-gears at hand, or when the
gears of the desired numbers of teeth
would be too small to properly con-
nect, or too large to be put in place,
recourse must be had to what is
termed compound gearing. Refer-
ring to Fig. 221, and the series of
change-gears A, suppose that it is de-
sired to use compound gears, making
the ratio 4 to 1. A 36- tooth gear is
placed on the head-shaft and a 72-
tooth gear on the lead screw. On the
idler stud we place two gears, a 48
and 24, fixed to each other by placing
them on a splined compounding sleeve
which runs loosely on the stud. The 36-gear is engaged with the
48, and the 24 with the 72,. as shown in elevation at A, Fig. 220,
and more clearly seen at A, in the diagram, Fig. 221.

The result of this combination is this: If the 36-gear engaged
the 72, the ratio would be 2; and if the 24-gear engaged the 48,

FIG. 219. — Change-Gears for
Cutting Left-Hand Threads.

FIG. 220.

Compound Change-Gears for Right
and Left-Hand Threads.

the ratio would be 2. These ratios multiplied would be 4. As they
are engaged we have 36 to 48, which is a ratio of 1 J, and 24 to 72
is a ratio of 3, which multiplied by 1 J produces 4.

The effect, then, of introducing the 24 and 48 gears instead of a

280 MODERN LATHE PRACTICE

single idle gear is to double the ratio existing between the gear on
the head-shaft and the one on the lead screw. The combination
as shown would cut 16 threads per inch on a lathe having a lead
screw cut with four threads per inch. (Usually lathes will cut
this number of threads without compounding. The gears here
shown and described are given as a simple example.)

At B, in Figs. 220 and 221, the order of gears is reversed, the

Spindle f~| El O Spindle

stud I f mmu stud

t-ead Screw F IF=IU f? ii=in read Screw

FIG. 221. — Edge View of Compound
Change-Gears .

72-gear is placed on the head shaft and the 36-gear on .the lead
screw. The effect now is, instead of multiplying the pitch of the
lead screw by 4 (4 X 4 = 16 threads per inch on the work cut), the
number of threads of the lead screw is divided by 4 (4-r- 4 = 1),
thus producing in the work a screw of one thread per inch, or one-
inch pitch.

By a thorough and correct understanding of these principles
there should be no difficulty in setting up a lathe for any desired
number of threads per inch. It is usual to have compounding
gears of a ratio of 2 to 1, as 24 and 48, 36 and 72, and so on. But
it may be necessary to use other ratios as H to 1, say 48 and 72,
24 and 36, etc. Or to make the ratio 3 to 1, as 24 and 72, 36 and
108.

It is always advisable to use as large change-gears as possible,
as the motion of the lead screw is more regular and steady, and the
strain on the gear teeth is less, consequently better work can be
done. This should be practised even if compound gears have to
be used more frequently.

LATHE WORK (CONTINUED) 281

In cutting double threads the change-gears are set for double
the pitch, that is, one half the number of threads which the finished
thread is to be. Then proceed to cut one of the threads, leaving
the proper blank space between the convolutions for putting in the
second thread. To locate this properly a tooth in the stud gear
may be marked, and also mark the space in the intermediate gear
into which this marked tooth has meshed. Now lower the inter-
mediate gear out of the mesh, by unscrewing the clamp bolt of the
stud-plate for the purpose, and turn the spindle exactly one half a
revolution, that is, until one half the whole number of teeth have
passed the marked space in the intermediate gear, and the marked
tooth is exactly opposite its former position. Raise the stud-plate,
putting the two gears properly in mesh with each other, and go on
with the cutting of the second thread. This is assuming, of course,
that the stud gear has an even number of teeth and that the ratio
between the lathe spindle and the head shaft or gear spindle is 1
to 1, both conditions being the usual ones.

When this ratio is different, it is readily understood that the
spindle must be rotated a proportional amount which is governed
by this ratio.

Another method of accomplishing the same result is to have
two dog-slots in the small face-plate exactly opposite each other,
and after one of the double threads is finished, to shift the tail of
the dog into the other slot.

Triple and quadruple threads are cut in a similar manner, but
all the details of the work are much more complicated and diffi-
cult, both in making the proper calculations to insure the exact
thickness or pitch of the threads, and in grinding and setting the
tool so as to get the correct cutting angles and clearance.

Boring bars may be used in various ways. They may be sup-
ported on both centers and the work they are to bore strapped to
the carriage. They may have one end fitted to the taper hole in
the head spindle and the other end carried by the tail-stock center
and the work held as before. Or, the boring bar may similarly be
held in the tail-stock spindle and the opposite end supported in a
bushing, in the center hole of the main spindle, while the work may
be carried in one of two ways. That is, it may be strapped to the
face-plate, or held in a chuck; or; if comparatively long, cylindrical

282

MODERN LATHE PRACTICE

work, it may have one end held in a chuck and the other supported
by a center rest.

The author once had a job of this kind to do and it was accom-
plished successfully by the arrangement described and illustrated
as follows:

Given the task of boring a 5J-inch hole endwise through a hard
steel spindle 7J inches in diameter and 5 feet long, with a large and
powerful boring lathe, such as is used on gun work, and the work
would be comparatively easy and rapid. Having only the equip-
ment of an ordinary machine shop, the case becomes more serious.
In the regular course of business such a job was required to be done,

FIG. 222. — Boring Bar for a Long Hole.

and the work was performed perfectly and expeditiously, as will
be described.

Fortunately, a boring lathe was at hand, fitted with a chuck and
provided with a sliding carriage, operated by an automatic feed
and designed to bore a 2J-inch hole, 25 inches deep. One end of
the spindle to be bored was fixed in the chuck and the other run
in the jaws of a center rest, as shown at d, Fig. 222.

An expert blacksmith forged a twist drill 2 inches in diameter
with a twist of 31 inches in length, which was turned up and finished,
and with this a hole was bored a little over 30 inches deep. A soft
brass tube of about iVinch bore, carried oil under pressure to the
point of the drill and on its return brought out the chips. The
spindle was then reversed and the hole was bored from the opposite
end until the two holes met, which they did quite exactly.

LATHE WORK (CONTINUED) 283

Now came the work of enlarging the hole from 2 inches to 5J
inches. It is to this part of the work that particular attention is
called. As the means for holding the drill had proven very rigid
and satisfactory, a boring bar was constructed, as shown in the
upper illustration, Fig. 222. The cutters a and b were of |-inch
round steel, fitted in the usual way, and held by set-screws c, the
bar being placed in a lathe and its ends turned off, so that the cutter
a would measure 3| inches, and b 5| inches. The end of the bar
just fitted the 2-inch hole already bored in the spindle, thereby
furnishing a correct and certain guide and support near the cutters.
The cutting ends of the cutters were formed as shown at A, Fig.
222, i.e., the face of the cutting edges being inclined 5 degrees
and the leading edge 25 degrees, making the angle of the cutting
edge 60 degrees, which proved to be a very effective construction,
the cutter a enlarging the hole to the extent of taking out about
half of the stock and the cutter b removing the remainder.

The spindle was then reversed and the operation continued
from the opposite end until only a small portion of the 2-inch hole
was left to guide the boring bar. The bar was then withdrawn and
a disk e fitted to it. This disk was 5J inches in diameter, so as to
just fit the enlarged hole and furnish a guide for completing the
enlargement of the hole, as shown in the lower illustration.

The work was successfully done, a true, smooth hole bored,
the two sections of which coincided perfectly. It will be noted
that in this job the hole was very large in proportion to the exterior
diameter, and a large amount of stock was taken out; in fact, nearly
350 pounds of hard steel. This was removed at the rate of nearly
30 pounds per hour.

The plan will doubtless commend itself for similar work, and
where there is even a greater difference between the directing hole
and the finished bore three or more cutters might be used to advan-
tage.

It is frequently the custom to fit flat cutters in elongated mortises
made through the bar instead of using a round cutter in a bored
hole. The flat cutters will be proper when the boring bar is com-
paratively small in diameter, as it weakens the bar less than a
round hole of sufficient diameter to carry a cylindrical cutter of
the proper strength. Still the cylindrical cutter should be used

284 MODERN LATHE PRACTICE

whenever possible, both for rigidity and cutting qualities as well as
economy.

When large holes are to be bored a cross arm is used carrying
a cutter on each end. Sometimes two cutters on each end are
used, a roughing and a finishing cutter.

Sometimes a large hollow boring bar is used, carrying a cross-
bar or head with two tools. This cross bar is arranged to slide on
the boring bar and is fed forward by a screw passing through the
center of the bar and having upon it a nut that is connected with
the cross head. Such an arrangement is used for boring engine
cylinders. These boring heads are often driven by the old " star-
feed" arrangement, familiar to nearly all machinists.

These elaborate devices for boring are usually constructed for
special boring machines and may hardly be considered as a part of
the equipment of an engine lathe.

Milling may be successfully performed on a lathe by strapping
the work to the compound rest, to the carriage or to a suitable fix-
ture attached to either. While not so economical or so rapid as
on a regular milling machine, it often proves very advantageous
when a milling machine is not at hand or when the machines of the
shop are crowded with work so as not to be available.

Many light operations of milling may be performed on a speed
lathe, with proper fixtures for the purpose, particularly when the
work is of brass or similar soft metals. In these cases the speed
lathe will often turn out as much work as the plain hand milling
machine.

Gear cutting can frequently be done on the lathe under similar
circumstances to those referred to above. The necessary fixtures
for holding and indexing the work may be comparatively simple
and economical, a change-gear being frequently used as an index,
and many jobs quite satisfactorily done in the absence of a regular
gear-cutting machine.

Grinding is a common operation in the lathe and is referred to
in the chapter on lathe attachments.

In the absence of a suitable machine designed for the purpose,
cam cutting may be successfully done in the lathe, by the use of
proper formers. The milling cutter for such operations is carried
in the center hole of the lathe spindle, and the cam held by a suit-

LATHE WORK (CONTINUED) 285

able fixture attached to the compound rest, or to the carriage, as
may be most convenient.

The work may thus be arranged so as to cut face cams or edge
cams, and to mill the cam slots of irregular contour on either edge
or face cams.

However, the question of cams is one of such great variety, and
the devices necessary to properly handle them are so many, a de-
tailed discussion of ways and means for doing the work does not
seem proper in this place.

The practical and resourceful machinist will find many uses for
the engine lathe that have not been here described, and if he is a
progressive man he will discover many new uses and new devices
for handling the many new kinds of work with which he will be con-
fronted.

Whatever new and improved machines he may have available,
or however well they may be adapted to his many wants, his prin-
cipal dependence will be likely to be, in the future as in the past,
on the engine lathe, "the king of machine shop tools."

CHAPTER XV

ENGINE LATHES

Definition of the word engine. What is meant by an engine lathe. The
plan of this chapter. The Reed lathes. Reed 18-inch engine lathe
The Pratt & Whitney lathes. Their 14-inch engine lathe. Flather
lathes. Flather 18-inch quick change gear lathe. Prentice Brothers'
Company and their 16-inch engine lathe. The Blaisdell 18-inch swing
engine lathe. The New Haven 21-inch engine lathe. Two lathe patents
by the author. The Hendey-Norton lathes. Who were the pioneers
in quick change gear devices? The Hendey-Norton 24-inch engine lathe.
The Lodge & Shipley 20-inch engine lathe.

A LARGE majority of the lathes in use in the machine shop or
manufacturing plant are what have been known for years as engine
lathes. Just why this qualifying designation of engine was applied
to them is not clear, although we know that in former times the
term engine was applied to many machines, particularly those of
the higher class, and very early in the development of the mechanic
arts the word seems to have been used to designate almost any
kind of a machine. Thus we read in the Marquis of Worcester's
"Century of Inventions," published in 1683, of "an engine that
may be carried in one's pocket" for blowing up ships; "a portable
engine in the way of a tobacco tongs"; "an engine whereby one
man may take out of the water a ship of 500 ton," and so on,
showing the strange uses to which the term engine has been put
in times past, while at a comparatively recent period an indexing
machine was called a dividing engine, while Webster says broadly
that an engine is "a machine in which the mechanical powers are
combined."

Recurring to the subject, by the term of engine lathe we mean
that class or type of lathes which is usually so denominated me-
chanically and commercially, and which may be defined as a metal
turning lathe, having a back geared head-stock; a tail-stock capable

286

ENGINE LATHES 287

of being set over for turning tapers; a carriage provided with suit-
able tool-supporting mechanism and having connected with it an
apron carrying the necessary gearing mechanism for producing
power lateral and transverse cutting feeds; and a lead screw, with
suitable gearing for driving it, whereby the usual screw threads may
be cut, through its proper connection with the apron mechanism.

With this conception of the design, construction, and office of
the engine lathe of the present day, the following examples are
presented and their special features discussed, with a view to the
better understanding of this important machine tool. The en-
gravings, the facts stated, and the dimensions, where the same are
given, are derived from the machines themselves or their builders,
or both, and the aim is to make the information as correct and the
estimate of their practical utility as fair as is possible, so that what
is here set down will be of value to the buyer of these machines; to
the machinist who uses them; to the draftsman and designer who
may desire to know of their individual peculiarities; and to the
student who would learn valuable lessons in relation to the design
and development of the Modern American Lathe.

While it is not expected or intended that the lathes of all makers
shall appear in this connection, those of the more prominent builders
will be introduced, and to these will be added such others as may
possess particularly commendable or novel features, in order that
the essential points of the engine lathe may be well and thoroughly
illustrated and described, with a minuteness that their importance
may demand.

Among the many manufacturers of lathes the F. E. Reed
Company may deservedly receive the title of "ancient and honor-
able," not because the product of the concern deserves the name of
ancient, but because of the long and honorable career of the estab-
lishment which has always stood for good materials, good work-
manship, and practical design for every-day tools capable of
standing up to the work, year in and year out, with whatever the
machine tool market affords. While the company have always
built substantial and practical tools, of ample strength and many
conveniencies for the operator, they have not been given to the
exploiting of mechanical fads and fancies or to going to extremes
in any one direction.

288

MODERN LATHE PRACTICE

As an example of the engine lathe built by this company, the
18-inch swing engine lathe shown in Fig. 223 is given. It will be
seen that here is a deep and strong bed supported upon the older
form of legs instead of cabinets. Upon the front leg is a special

FIG. 223. — 18-inch Swing Engine Lathe built by the F. E. Reed Company.

cabinet for holding the change-gears which are of the older form of
change-gears proper, that is, removable. The feed is by means of a
belt upon the well-known three-step cone, with which is arranged
a change of gears making six feeds.

FIG. 224. — Spindle Box of the Reed
Lathe Ready for Babbitting.

FIG. 225. — Spindle Box of the Reed
Lathe after Babbitting.

The head-stock is heavy and strong and carries a spindle made
from a crucible steel forging which runs in cast iron boxes lined
with genuine babbitt metal, as shown in Figs. 224 and 225.

In the first of these illustrations is shown the cast iron box

ENGINE LATHES 289

properly milled out to fit the housings of the head-stock. After this
operation it is bored out and then slotted ready to receive the bab-
bitt metal lining. It will be noticed that these are all " dovetail"
slots, the object of this form being to hold the lining metal securely
in its place. The babbitt metal is cast into the box, after which
it is compressed sufficiently to fill out any shrinkage that may have
occurred upon cooling, and to render it more dense and durable.
It is then re-bored, reamed, and hand scraped, so as to fit the spindle
as perfectly as possible. Constructed in this manner there is nothing
coming in contact with the spindle except the babbitt metal, which,
when finished, has the appearance shown in Fig. 225.

Experience has demonstrated that with proper care on the part
of the operator a box constructed in this manner will last for a
very long time, and, if properly lubricated, that the babbitt metal
will soon " glace" over and form one of the best bearing surfaces
obtainable. The spindle is bored out to If inches. The driving-
cone is of five steps, the largest being 12 inches and is adapted for
a 2|-inch belt. The carriage is of ample strength and has a long
bearing upon the bed, and supports a very substantial compound
rest. The carriage is gibbed to the outside of the bed both back
and front. The apron is of ample dimensions, so as to afford space
for large and strong operating parts, which are few in number and
simple in construction.

The feeds include an independent rod and patent friction feed.
Combined gear and belt feeds are furnished and also an automatic
stop motion in connection with either type of feed. There is also
provided a simple belt tightener device. The belt feeds are from
25 to 95 per inch inclusive. When a geared feed is wanted the
belt can be removed and the feed rod connected with an intermedi-
ate gear. Then by changing the gears upon the feed stud of the
head-stock, feeds may be obtained from 12 to 125 per inch, inclu-
sive. Even this range of feeds seems rather fine for modern methods
of work. The lathe will cut seventeen different threads from 2 to
20 per inch, inclusive. The rack and rack pinion are of steel and
capable of disengagement when regular turning feeds only are
required. An " offset" tail-stock is furnished.

The net weight of one of these lathes with an 8-foot bed is 3,080
pounds, by which it will be seen that ample weight is provided to

290

MODERN LATHE PRACTICE

obtain a strong and rigid machine. The countershaft is furnished
with patent friction pulleys which can be oiled while running, and
with self -oiling boxes which will run six months with one oiling,, and
requiring no further attention.

This company make a variety of different styles and types of
lathes, as well as attachments and accessories, which will be found
described and illustrated further on in these pages and under their
appropriate headings. The reader is referred to them for further
information.

FIG. 226. — 14-inch Swing Engine Lathe built by the
Pratt & Whitney Company.

Another of the old and reliable lathe building establishments
is that of the Pratt & Whitney Company, which has for many years
enjoyed an enviable reputation as makers of fine machine tools.
While they have been progressive, and have brought out many
valuable improvements they have never been prone to exploit
mechanical fads, or to put on the market comparatively untried
devices of the newest kind suggested by enthusiasts who imagined
them capable of marvelous results. They have nearly always pro-
duced machines well and carefully designed, and constructed of
good material and of excellent workmanship.

While the product of the company has been large and varied,
a great deal of attention has been given to producing good lathes,
a sample of which is given in Fig. 226, which is a 14-inch swing
engine lathe of recent design. While rated as a 14-inch lathe it

ENGINE LATHES

291

swings nearly 16 inches over the bed, and, as a lathe of that
capacity, is heavy and strong, with a deep and heavy bed sup-
ported on their well-known design of legs rather than cabinets.
Still the net weight of a 6-foot bed lathe is 2,200, which is very
heavy for a lathe of these dimensions.

The apron is shown in Fig. 227, in which it will be seen that it is
of very strong construction, being made with two plates whereby
the shafts have a support at both ends. The feed rod is carried in
double boxes in which are carried right and left worms, engaging
the two worm-gears which operate the feed mechanism. While the
use of worms and worm-gears in a lathe apron cannot be commended,

FIG. 227. — Apron of the Pratt & Whitney Lathe.

and the difficulties which most builders have found with them, have
caused their use to be discontinued, this company still retain them
and by very good construction render them successful.

The lead screw nut is well supported to stand the strain to which
it is put, and altogether the apron is an excellent specimen of good
material and workmanship. The double plates are a feature that
ought to be adopted in all lathe aprons as it adds much to the
strength of the mechanism, holds the shafts well in line by support-
ing them at both ends, and materially increases the wearing qual-
ities of the various parts.

While the various sizes as have been given for the lathes of other
builders are not at hand, it may be said that all bearings have more
than usual diameter and length and the boxes are accurately scraped
to fit ground journals. The head-stock is massive and well designed
and provided with a five-step cone pulley.

The feed gearing is operated by a two-step cone, but has com-

292

MODERN LATHE PRACTICE

pound gearing by which a large variety of feeds may be produced.
The thread-cutting mechanism provides for cutting from 2 to 92
threads per inch, and by the use of the translating gears will cut
all the usual metric threads.

Other lathes of different dimensions and types will be illus-
trated and described later on in this book and under their appro-
priate headings. , For information of this kind the reader is referred
to the chapters on these subjects.

The name of Flather has been so long and so intimately iden-
tified with the invention and the building of machine tools, that

FIG. 228. — 18-inch Swing Quick Change Gear Engine Lathe,
built by Flather & Co.

in the development of any type of them we naturally look for those
bearing this name. In the improvements of the rapid change gear
devices we find the names of Edward, Joseph, Herbert, and Ernest,
each of whom have added something new to the "state of the art."
In Fig. 228 is given a front elevation of 18-inch swing " quick
change gear lathe/' which seems designed to meet the latest
requirements, and which is powerful, strong and rigid, and com-
bines a reasonable degree of simplicity with accuracy, ease of
operation, good workmanship and material. The head-stock and

ENGINE LATHES 293

tail-stock are fitted to the bed with a V at the rear and a flat
track in front, thus permitting the cross bridge of the carriage to
be deep and strong. As will be seen in the engraving, the head-
stock is heavy and strong with ample housings for the main spindle
bearings, which are lined with genuine babbitt metal, cast solid in
the head-stock, compressed, then bored out and scraped to an
accurate fit for the ground journals of the spindle, which is made
of hammered crucible steel. Its front bearing is 3 inches in
diameter and 4| inches long. The bore of the spindle is 1J
inches.

The spindle cone is of five steps and adapted for a 2f-inch belt,
or made of four steps for a 3J-inch belt, as may be desired.

The carriage is gibbed on the inside and outside and has ample
bearing on the V's, while the tool rests are unusually wide and long,
and are supported the full length by the carriage, even when turning
the largest diameters.

The feed mechanism is of new design and accomplishes in a
simple and durable manner, and with as few gears as may be, all
the results required in the most modern lathe. In a general way
it may be described as attached to the front of the lathe in the
form of a case in which a cone of nine gears is mounted upon a shaft,
any one of which can be instantly engaged by simply moving the
lever in front of the case. Upon another shaft located above the
cone of gears and in line with the lead screw is a double clutch-
gear controlled by the small lever on the top of the gear case.
The shifting of this lever to three different positions increases the
number of changes obtained by the lower lever to twenty-seven.
This number may be doubled by sliding in or out a gear at the end
of the lathe, thus giving fifty-four changes in all. An index
attached to the front of the gear case shows the entire fifty-four
changes, so that the operator may know instantly which lever it is
necessary to move, and to what position to set it in order to obtain
any of the different threads or the different cutting feeds shown
upon the index, the entire mechanism being so simple that the most
inexperienced operator soon understands its construction and its
operation. The standard threads from 2 to 128, including 11J, and
feeds from 7 to 450 per inch, are readily obtained without removing
a gear, while provision is made by which odd threads or feeds may

294

MODERN LATHE PRACTICE

be had at little trouble or expense. All the gears in the gear case
are of coarse pitch, and being cut from the solid are practically
unbreakable.

The rack and pinion are cut from steel, as are also all the gears,
studs and plates in the apron, insuring a great degree of strength
and durability even under the strains incident to very heavy duty.

This company make the usual variety of lathes as built by other
establishments, and all of them are of good workmanship and with
the well-earned reputation for good tools.

FIG. 229. — 16-inch Swing Engine built by the Prentice Bros. Company.

The Prentice Brothers Company have for years built lathes,
good lathes, as must be judged by the fact that many hundreds of
them have been sold and used all over the country. Among the
older and more conservative establishments turning out this class
of work, they have yet endeavored to meet the demands of modern
methods, and in Fig. 229 is shown one of their 16-inch swing engine
lathes, with a quick change gear mechanism and an " offset" tail-
stock.

The head-stock is not as massive as in those of some other
builders, though strong enough for most kinds of work which the
lathe will be called upon to do. The spindle is of high carbon steel,
with 2J-mch by 4J-mch front bearing and a IJ-inch hole in the
spindle. The spindle is driven by a five-step cone, arranged for a

ENGINE LATHES 295

2J-inch belt. The largest diameter of cone-step is 10 inches. The
spindle runs in hard bronze bearings.

The quick change gear device contains the "cone of gears," so
commonly used in these devices, and also a series of multiplying
gears at the end of the head-stock, by means of which fifty-five
changes may be made, from 2 to 60 threads per inch, and feed cuts
from 10 to 320 per inch. All feeds are positive as no feed belts are
used. The carriage and apron do not seem to be of sufficient length
or weight to stand up rigidly to very heavy cuts with the use of
high-speed tool steel. Neither does the bed seem to be as heavy,
at least as deep, as we would expect to find in a modern lathe
adapted to doing the heavy duty now expected of such a lathe.
The lathe with a 6-foot bed weighs when boxed for shipment 1,850
pounds.

The " offset " tail-stock is a very useful feature, which is patented
by the manufacturers and about which there has been much dis-
pute with other builders who have made them from time to time.

Other than this feature and the quick change gear device the
lathe appears to be their regular and well-known product of engine
lathes.

The company make the usual variety of engine lathes of special
design for special work as well as their plain lathes. These special
machines, as well as various attachments and accessories, will be
illustrated and described in future chapters, later on in this book,
and attention called to their special features.

In 1865 P. Blaisdell began the building of lathes and has con-
tinued the business since. While no great efforts seem to have
been made to bring out new and novel inventions, the Blaisdell
lathes have always been known as machine tools, that are well made,
reliable, and practical.

In Fig. 230 is shown an 18-inch swing lathe of their manufacture,
that is a good example of their regujftir line of product.

The head-stock of this lathe has a cone of five steps which take
a 2|-inch belt. The spindle is made from hammered, cast crucible
steel, and is bored out to 1J inches. The boxes are of gun metal or
of cast iron lined with genuine babbitt metal, as may be preferred.
The back gear ratio is 11 to 1, which is high for a lathe of this swing.

The lathe has a power cross feed with micrometer graduations

296

MODERN LATHE PRACTICE

for the cross-feed screw. There is furnished a rapid change gear
device for feeding from 13 to 339 per inch, and a new and powerful
friction warranted not to slip. There is a patented automatic stop
on the feed rod. The lead screw will cut threads from 2 to 23, in-
cluding 11} pipe thread. The net weight of this lathe with an
8-foot bed is 2,400 pounds.

This company make a variety of lathes and lathe attachments
and accessories, some of which are shown later on in this book, and
under the appropriate heading, to which the reader's attention is
directed if interested in this class of the product.

FIG. 230. — 18-inch Swing Engine Lathe, built by P. Blaisdell & Co.

The New Haven Manufacturing Company are among the older
establishments building engine lathes, and for a number of years
have built a line of very strong and substantial tools, notable not
so much for fine finish as for rigidity and for practical utility, special
attention having been given to the quality of the materials entering
into them.

Figure 231 gives a front elevation of their 21 -inch swing lathe,
and Fig. 232 is an end view of the head and bed, showing the feeding
and thread-cutting gears. The arrangement of the former is
peculiar and the subject of a patent granted to the author. In this
case there is fixed upon the outer end of the head-shaft a "cone of

ENGINE LATHES

297

gears," with each of which is engaged an idle gear running loosely
upon a stud fixed to a revolving plate, secured in any desired
position by a spring pin as shown in the end view of the lathe.

FIG. 231. — 21-inch Swing Engine Lathe, built by the
New Haven Manufacturing Company.

When in either of the three operative positions, one of these idle
gears connects the cone of gears on the head-shaft with a reversed
cone of gears running loose upon a stud in an arm of the stud-plate,
and one of them engaging with
the gear running loose upon the
lead screw, which gear in turn
engages with a gear fixed to the
feed rod. By this arrange-
ment the plate carrying the
three (or more) idle gears may,
by revolving it to any one of
its several positions, succes-
sively connect the different size
of gears composing the cone of
gears, and so, at one motion,
changing the rate of feed. By
the changing of a pin passing
through the hub of the feed-rod
gears, another series of feeds may be obtained. The engraving
shows a revolving plate carrying but three idle gears. It is obvious
that any reasonable number of idle gears may be carried and that

FIG. 232. — End Elevation of 21-inch
New Haven Lathe.

298 MODERN LATHE PRACTICE

by the use of multiplying gears these ratios may be had in several
series of numbers. The object of mounting the second cone of
gears upon a stud fixed in an arm cast integral with the main part
of the stud-plate (shown in its inactive position) is so that when
the regular change-gears are mounted upon the head-shaft and
lead screw, and an idler placed upon the idler stud, and the stud-
plate raised to an active position for the purpose of engaging the
three change-gears thus mounted, the second cone of gears will
be thrown out of their active position and the operation of the
feed rod stopped. This same device may be applied to the cut-
ting of threads if desired, by the addition of gears to the cone, and
the use of multiplying gears to get ratios of 2 to 1, 3 to 1, and
4 to 1.

Within the head-stock is a device for handling the reverse
gears, consisting of a horizontal shaft operated by the handle seen
in the front of the head, and having upon it a cylindrical cam cut
with a groove consisting of two movements and three rests, in
which is engaged a hardened steel pin fixed in the yoke-plate, carry-
ing the reversing gears. By this arrangement the yoke-plate is
readily locked in its "forward," "back," and "out" positions, and
held perfectly rigid when moved from one position to the other.
This device was also invented and patented by the author. Either
of these devices can be operated while the lathe is in motion, with-
out danger of breaking the teeth of the gears.

These lathes have hollow spindles and the one shown in the
engraving is made to the following specifications. The beds are
wide, deep and strongly braced and mounted upon cabinets of
liberal dimensions. The width between the V's is such as to form
the base of an equilateral triangle, whose apex is the center line of
the lathe. The heads are very strong and rigid, having a solid
web entirely across under the cone pulley. The spindle is bored
out to ^| inches and runs in nickel bronze boxes. The front bear-
ing is 3i inches in diameter and 5J inches long. The spindles are
powerfully back geared and have hardened steel bushings and check-
nut for taking up the end thrust. Cone pulleys have five steps of 5J
to 13f inches diameter, and adapted for a 3-inch belt. The tail-
stock is very rigid, with a "set-over" for turning tapers and is
secured by two heavy steel bolts. The tail spindle is 2f inches in

ENGINE LATHES 299

diameter and bored for a No. 4 Morse taper. The carriage is heavy
and has a long bearing on the V's, to which it is scraped and fitted
the entire length, and is gibbed at the front and back to the outside
of the bed. It has power cross and lateral feeds, an automatic stop
and a compound rest with a graduated base. The tool is adjusted
as to height by a hardened steel concave ring and washer. The
apron is very heavy, the operative parts simple and very strong.
No worm-gears are used, their usual office being performed by a
large bevel gear and two sliding bevel pinions, by which the motion
is reversed. This sliding movement also operates a simple locking
mechanism by which the thread cutting and feeding operations
become entirely independent of each other, and each, when in opera-
tion, locks the other out automatically. The six regular changes
of feed are 18, 25, 30, 40, 50, and 60 revolutions per inch of, move-
ment for both lateral and cross feed. All feed racks, rack pinion,
studs, rod and lead screw, are made of special steel, and all nuts are
case hardened.

It will be noticed in the engraving of the front of the lathe that
all movements, including those of reversing, are controlled by levers
in the front of the apron, so that the operator need not, necessarily,
leave his place for this purpose.

A 21-inch swing lathe with a 10-foot bed weighs 3,800 pounds.

This company manufacture several other types of lathes and
lathe attachments, which will be illustrated and described later on
in this work and in connection with similar devices built by other
makers.

It is said in a catalogue now on the author's desk that "the
name Hendey-Norton has come to be generally recognized as being
the pioneer in that class of lathes made commercially successful,
having the mounted system of gearing for thread and feed changes."
As to how far this claim is correct, is a proper matter for the me-
chanical public to judge. The phrase " commercially successful"
seems to have been well put in connection with the statement and
may possibly be its "saving grace," for it is well known that as
early as 1868 Humphreys used the much discussed "cone of gears,"
and that he wrote in his patent, "I place my gear-wheels upon a
shaft A, ranging from the smallest to the largest," while in 1892
Norton says in his patent, "on the shaft A, and within the box B,

300

MODERN LATHE PRACTICE

are secured a series of gear-wheels E, of varying diameters, arranged
step-like," etc. As to who was the pioneer may be an open ques-
tion, as are a great many relating to the matter of patented inven-
tions.

In Fig. 233 is shown a front elevation of the Hendey-Norton
lathe of 24-inch swing, and is a late development of this establish-
ment. The head-stock is provided with a "tie" from front to rear
housing, which gives additional rigidity to the head-stock and pre-
vents undue vibration of the spindle and its work. The spindle,
which is bored out to If inches, runs in annular bearings of special

FIG. 233. — 24-inch Swing Engine Lathe built by the Hendey Machine

Company.

metal and having taper bearings for the journals. The front bear-
ing is 3f to 4f inches in diameter and 7^ inches long, while the rear
bearing is 3} to 4 inches in diameter and 5J inches long. Both
these journals are not only self-adjusting, but adjustable, inde-
pendent of each other, and allow for contraction and expansion of
the spindle without disturbing the adjustment. The bearings are
also self-oiling, having automatic oiling rings, running in large
reservoirs of oil, with provision for catching the oil and returning
it to the reservoir for use over again.

The construction of this spindle and its appendages for the
smaller lathes is well shown in the longitudinal section given in
Fig. 234, which shows a very clever piece of mechanical construc-
tion and one well adapted to the purposes for which it is designed.

ENGINE LATHES

301

This view in connection with the end elevation and partial section
given in Fig. 235 shows the internal construction of the feeding

FIG. 234. — Longitudinal Section of the Head-Stock of the
24-inch Hendey-Norton Lathe.

and thread-cutting mechanism and the gearing necessary to accom-
plish the results according to Norton's plan.

The lathe is provided for automatically stopping the carriage

FIG. 235. — End Elevation of the 24-inch Hendey-
Norton Lathe.

in either direction when either feeding or thread cutting, and for
reversing the travel of the carriage by an apron lever.

302 MODERN LATHE PRACTICE

The spindle cone has but four steps instead of five, as is usual
with other makers, their diameters being from 6 to 15 inches and
adapted for a 3|-inch belt. The lathe will cut threads from 1 to
56 per inch and has a turning range of feeds from 5 to 280 per inch.
The 24-inch swing lathe will turn 15J inches over the carriage. The
tool-post takes in tools f by 1J inches. The carriage has a bearing
of 34 inches on the bed and is provided with a strong and well
designed apron, excepting for the fact that worms and worm-
gears are still retained as a part of their construction, notwith-
standing the fact that even the best construction of this type is
liable to injury from the carelessness of the operator and the lack
of a plentiful supply of oil. The tail-stock is strong and rigid, and
carries a 2|-inch spindle bored and reamed for a No. 4 Morse taper.
The weight of a 24-inch swing lathe with a 10-foot bed is 5,450 pounds,
by which it will be seen that it is relatively a heavy lathe, consider-
ably more so than that of many of its competitors.

This firm make other types or modifications of their lathes,
and also some very desirable attachments and accessories for lathes
which are illustrated and described under their appropriate head-
ings further on in this work.

The Lodge & Shipley Machine Tool Company have turned out
some good examples of modern machine tool building, in the recent
types of their engine lathes, showing much consideration and study
of the conditions surrounding the manufacturing problems of the
present day. This is noticeable in their 20-inch swing engine lathe,
a front elevation of which is shown in Fig. 236.

In this lathe the back gear quill and pinion are of forged steel
instead of cast iron, as usual, whereby great strength and durability
may be expected of this part, which in ordinary lathes not infre-
quently fails and has to be renewed. The cone pinion is also
of forged steel. The main spindle is of 55 point carbon-steel and
hammered, and has a If -inch hole through its entire length. The
front bearing is 3J inches in diameter and 5| inches long, and both
bearings are accurately ground and the boxes have an oil reservoir
beneath them from which oil is raised by small buckets attached
to a brass ring located midway on the journal, thus insuring abun-
dant lubrication. Gage glasses at the front of the head-stock
show the level of oil in these reservoirs, which are deep enough to

ENGINE LATHES

303

permit sediment to settle at the bottom out of reach of the oil-
raising buckets, thus keeping the lubricant on the journal clean and
in good condition. The thrust collar is of steel, hardened and
ground.

The general arrangement and construction of the head-stock,
and the gearing contained in the front end of the bed, is well shown
in the longitudinal section in Fig. 237, and the end elevation in
Fig. 238. In these engravings the location of the "cone of gears"
is seen to be in the bed of the lathe instead of in a box or extension

FIG. 236. — 20-inch Swing Engine Lathe built by the Lodge & Shipley

Machine Tool Company.

in front of it, or partially' in the head as is the case of some of the
rapid change gear devices. In Fig. 238 the location of the various
handles and levers for controlling the change gear device is clearly
shown and their use and operation may be readily seen and under-
stood. The movable or sliding connecting or intermediate pinion,
carried by a lever which is held in place by a spring pin entering
any one of the line of holes shown in the front of the head-stock in
Fig. 236, is practically the same as used in the Hendey-Norton
lathe and in others of this type. These changes are very quickly
and certainly made, and the mechanism appears to be substantial
and durable.

The bed is designed with ample depth and width, and is strongly

304

MODERN LATHE PRACTICE

ENGINE LATHES 305

braced internally by cross girts The surfaces to which the lead-
screw bearings are fastened are planed to receive them and the
parts are tongued and grooved to insure perfect alignment. The
V's are rounded on top to prevent bruising. In lathes of 22-inch
swing and larger the beds are additionally strengthened by a cen-
tral longitudinal brace, in the top of which is a rack into which a
pawl pivoted to the bottom of the tail-stock engages, thus affording
a positive brace for holding the latter in position against heavy
strains. The rear end of the bed is cut down low enough to permit
the ready withdrawal of the tail-stock, which is very convenient
when turret slides or similar attachments are to replace the regular
tail-stock.

The carriage is strong and heavy with liberal length of bearing
upon the V's the entire length of the carriage, which is gibbed to
the bed its entire length also. In place of an inside V at the front
of the bed, the surface is flat for the carriage to find an additional
bearing, thus shortening the distance between the supports of the
carriage and so affording additional strength and rigidity immedi-
ately under that portion supporting the compound rest in its usual
position. The V's are kept clean and also lubricated by a specially
designed wiper and oiler fastened to the ends of the carriage.
This not only insures the proper lubrication but prevents grit and
dirt getting between the carriage and the V's, and so destroying
their accurate bearing and smooth surface contact.

The apron is of ample strength and made specially rigid by three
braces through its entire length and a longitudinal brace across
the bottom. It is tongued and grooved into the carriage, and
firmly bolted to it. No worm or worm-gears are used, a compact
arrangement of a large bevel gear and two bevel pinions mounted
in a sliding frame taking the place of the older method of construc-
tion. There are few gears used in this construction, and all of them
are of steel and run on hardened and ground steel studs or shafts.
The lead screw passes through the double bevel pinions, and is
splined to them by a spline reaching the entire length of the gear
sleeve, the edges of the spline being carefully rounded to prevent
the possibility of injuring the split nuts, which are made from
solid metal and then split, instead of being lined with babbitt
metal as usual. These nuts are held in planed grooves in the

306

MODERN LATHE PRACTICE

back of the apron, no clamps or screws being used. This holds
them very rigidly under the heaviest strains. In the larger
lathes it is, of course, necessary to back gear the operative parts
for ease of handling. This is done with few gears, which are
made heavy and strong. The lead screw threads are never in use
except when thread cutting, the locking out of the thread cutting
or the regular feed device being automatically and surely provided

FIG. 239. — Apron of the Lodge & Shipley 20-inch Lathe.

for by a simple device. The rear of this apron is shown in Fig. 239,
by which its compact form and mechanical design is clearly shown.
This establishment builds other types of lathes of very practical
and useful forms and equally good design, as well as various attach-
ments and accessories which will be found illustrated and described
further on in this book under their appropriate headings, and to
which the reader is referred for information of this character.

CHAPTER XVI

ENGINE LATHES CONTINUED

Schumacher & Boye's 20-inch instantaneous change gear engine lathe.
Emmes change gear device. 32-inch swing engine lathe. Le Blond
engine lathes. 24-inch swing lathe. The Le Blond lathe apron. Com-
plete drawing of a front elevation. The Bradford Machine Tool Com-
pany's 16-inch swing engine lathe. The American Tool Works Company's
20-inch. The Springfield Machine Tool Company's 16-inch engine lathe.
The Hamilton Machine Tool Company's 18-inch swing engine lathe. The
W. P. Davis Machine Company's 18-inch swing engine lathe. The Fos-
dick Machine Tool Company's 16-inch swing engine lathe.

THE firm of Schumacher and Boye build a line of well-designed
and practical engine lathes, one of which, called by the makers their
"20-inch instantaneous change gear engine lathe," is shown in
Fig. 240.

FIG. 240. — 28-inch Swing Instantaneous Chan^
Lathe built by Schumacher <

s Gear Engine
Boye.

It will be noticed that the spindle cone has but three steps,
respectively 9, 11, and 13 inches in diameter, and adapted for a
3J-inch belt. As the head is double back geared, the requisite

307

308 MODERN LATHE PRACTICE

number of different speeds is obtained, the back gear ratios being
3i to 1, and 10 to 1. The front bearing of the main spindle is Si-
inches in diameter and 6 inches long. The spindle has a lT9g-inch
hole through its entire length, and reamed for a No. 4 Morse taper.

The change gear device is the one patented by Emmes, in 1902.
and is very effective as a piece of practical mechanism, and is oper-
ated by a front and a top lever, swinging upon centers and carrying
index pins which enter any one of a circle of index holes. Sliding
pinions are also used upon the feed rod to still further enhance the
value of the mechanism by providing for the operating or the dis-
connecting of the feed rod. The reverse for both feeding and thread
cutting is handled at the head, and in the apron, as may be desired.
The cutting feeds are locked "out" while threads are being cut,
and vice versa. Forty changes of feeds and for thread cutting is
provided for. The apron is constructed on simple and strong
lines and is effective in withstanding the strains and shocks to
which it is subjected. All the gears in it are made from drop
forgings. The lathe with an 8-foot bed weighs 3,850 pounds.

This establishment makes lathes up to 48-inch swing, those of
32-inch swing and upward being provided with triple geared head-
stocks which are built very strong, heavy, and rigid. These larger
lathes all have the " instantaneous change gear" device, practically
the same as that provided for the smaller lathes. The aprons of
these lathes are of the box form and of very rigid construction,
avoiding overhang as much as possible, and also the straining of
pinions and studs. These studs are made of tool steel and run in
bronze-lined boxes. The lead screw nuts are also of bronze. The
main spindle, in the head-stock, is of 75-point carbon, crucible steel,
has a 3J-inch hole, and runs in phosphor bronze boxes. It is
reamed for No. 6 Morse taper. The carriage has bearings through
ite entire length on the V's, and is gibbed both back and front. The
compound rest has an angular feed by power with 12 inches travel.
The apron and compound rest have steel gears throughout. The
tail-stock is provided with a pawl which travels in a rack formed
in the bed similar to those shown by Lodge & Shipley. The
48-inch lathe will swing 31 inches over the carriage. The lathe
with a 14-foot bed weighs 17,500 pounds, and is a very strong
and rigid lathe.

ENGINE LATHES (CONTINUED) 309

This lathe has forty changes of feeds and also the same number
for thread cutting.

The company make the usual variety of lathe attachments and
accessories necessary to fitting out their lathes with modern con-
veniences, which will be mentioned later and under headings that
follow this in proper order. Many of these have found their way
into the best machine shops of this country, and are much appre-
ciated.

The LeBlond manufacture of lathes, like their milling machines,
are well known in the market, and are noted for their good and care-
ful design so as to properly meet the requirements which they have
to fulfil. They are made from a good system of standard plugs,
jigs, and templets, by which all the component parts are rendered
interchangeable .

The spindles are all made from hammered crucible steel and
finished by grinding. The boxes on the smaller lathes are com-
posed of phosphor bronze, while those of the larger and heavier
lathes are lined with genuine babbitt metal. The lead screws are
made from 20-point carbon open heart*h steel and are not splined,
whereby the accuracy of the 'screw is maintained for good thread
cutting. Thread-cutting stops are graduated in thousandths of
an inch and right or left hand threads are arranged for by a /
reverse in the head.

The lateral and cross feeds are automatic and are properly
graduated for good work. The aprons are unusually heavy and so
arranged that it is impossible to throw in the rod feed and the lead
screw feed at the same time. The rack pinion can be freed from
engagement with the rack by lowering it out of its engaged position
so that there is no undue resistance when thread cutting is to be
done. It frequently happens that much friction is caused by these
strains upon the moving parts of the apron and cause serious in-
convenience and often damage or breakage to the ports, particu-
larly to the rack pinion.

The tail-stock set-over arrangement is graduated so that tapers
may be readily determined. They are of the overhanging type,
frequently referred to as "the English style," whereby the com-
pound rest may be swung around to a position almost parallel with
the lathe bed.

310

MODERN LATHE PRACTICE

The feed cones on the 12-inch to 24-inch swing lathes are so
arranged that there are tighteners to apply to an improved chain-
feed device so that there is none of the usual troubles from feed
devices driven by belting. On the larger lathes there is provided
an improved chain device, giving three independent feeds on the
feed rod, and which can be changed instantly by a lever in the
front of the head-stock.

While this establishment makes several types of lathes, it will
be sufficient for our purpose here to introduce the regular engine
lathe, and that of 24-inch swing is taken as a good example and
shown in Fig. 241, which gives a front elevation, while Fig. 242

FIG. 241. — 24-inch Swing Engine Lathe built by the
R. K. Le Blond Machine Tool Company.

is an end elevation showing the change gearing. The general
description of this lathe is as follows:

The range of threads that can be cut is from 1 to 16 per inch.
The main spindle is bored with a 2^-inch hole and the front end
bushed for a No. 5 Morse taper. The front bearing is 4| inches in
diameter and 8 inches long. The lathe is driven by a five-step
cone, the steps being from 6 to 17 inches in diameter and adapted
for a 3J-inch belt. While rated as a 24-inch swing lathe, it really
swings 25J inches over the bed and 16 inches over the carriage. As
a 10-foot bed lathe takes in 4 feet 4 inches between centers, it is
seen that the head-stock and tail-stock occupy a space of 5 feet
8 inches on the bed, giving the opportunity to make both of these
important features strong, rigid, and massive. As a 10-foot lathe

ENGINE LATHES (CONTINUED)

311

weighs 5,900 pounds net, it is seen that the weight is 590 pounds
per foot. Countershaft pulleys being 16 inches in diameter, and
for 5-inch belt assures ample driving power, and which, run at 120
and 165 revolutions per minute, give a spindle speed of 2} to 460
revolutions per minute, which is as wide a range as would possibly
be needed in a very large variety of work.

FIG. 242. — End Elevation of 24-inch
Le Blond Lathe.

In the end elevation, shown in Fig. 242, the two stud-plates and
the system of change gearing is clearly shown, and a good idea is
given of the strength and stability of the lathe.

The operative parts of the apron of the smaller sizes of Le Blond
lathes is shown in Fig. 243, by which it will be seen that they are
very simple, and that therefore the parts may be made of sufficient
strength to withstand the hard usage to which a lathe is often sub-
jected. The operation of this mechanism is so simple that a de-
tailed description does not seem necessary, although attention is
called to the very simple manner of locking the rod feed out when
the lead screw feed is in operation, and vice versa.

312

MODERN LATHE PRACTICE

As no engraving of the exterior of a lathe can give a proper and
correct idea of its interior construction, a full and complete draw-
ing of a front elevation of this lathe is given in Fig. 244, particularly
to illustrate this lathe and in a general way to show the construc-
tion of a modern engine lathe of a substantial and practical type
for heavy, e very-day work, and showing its general symmetry and
good proportions.

The Bradford Machine Tool Company have recently developed
a line of lathes which compare very favorably with those of other
builders and possess some excellent features of strength, durability,
and convenience for straight, e very-day machine shop work.

FIG. 243. — Apron of the 24-inch Le Blond Lathe.

In the design and construction of these lathes there are several
noticeable features that may well be mentioned. None of them
have cabinet legs. The old-style belt feed is used in nearly all of
them. One of the exceptions is the 16-inch swing lathe which is
adapted for tool-room work and has the rapid change gear device,
patented by Johnson, which gives a wide range of turning feeds and
thread-cutting pitches.

A front view of one of these lathes is given in Fig. 245.

The reverse in the head-stock of these lathes does not seem to
be particularly effective. A tightening device for the feed belt on
most of these lathes is handy and practical. There are other
special features which will be noticed later on.

The main spindles of these lathes are of hammered crucible
steel with adjustable, taper, bronze boxes; the journals (as well as all
other cylindrical bearings of the lathe) are ground. In the 16-inch
lathe the spindle is bored out to 1J inches.

ENGINE LATHES (CONTINUED)

313

314

MODERN LATHE PRACTICE

The head cone is of five steps and adapted for a 2J-inch belt.
The lathe swings lOf inches over the carriage. The carriage and
apron are of ample dimensions and the requisite strength for all
practical purposes. The lathe is back geared 9J to 1. A 6-foot
lathe weighs 2,000 pounds.

FIG. 245. — 16-inch Swing Engine Lathe, built by the
Bradford Machine Tool Company.

This lathe will cut threads from 3 to 46 to the inch, and has a
ratio of feeds of 4J times the number of threads per inch.

Figure 246 is a longitudinal section of the head-stock, giving a

FIG. 246. — Longitudinal Section of the Head-Stock
of thel6-inch Bradford Lathe.

clear idea of the construction of the spindle, boxes, thrust bearings,
and housings, as well as the form and strength of other parts of the
head-stock. The thrush bearing is upon a fiber washer supported
by a thrust screw and adjusting nut.

ENGINE LATHES (CONTINUED)

315

A rear view of the apron is shown in Fig. 247, by which it will
be seen that worms and worm-gears are avoided and the substantial
arrangement of a large bevel gear and double bevel pinions, mounted
in a sliding form, takes its place. The locking device for preventing
the interference of the thread-cutting and turning feeds with each
other is clearly shown. The smaller pinions and the large rack
gear are of steel and the rack pinion is capable of being withdrawn
when thread cutting is being done.

The carriage is scraped to the full bearing of its entire length
on the V's and is gibbed at both back and front to the outside of
the bed. It is made deep and strong and has power lateral and cross
feeds in all sizes of lathes.

FIG. 247. — Apron of the 16-inch Bradford Lathe.

This company make a variety of different types of lathes and
attachments for them, which will be illustrated and described
under appropriate headings and later on in these chapters.

The American Tool Works Company is a comparatively new
concern and is, therefore, unhampered by old traditions and the
somewhat inconvenient inheritance which burdens some of the
older manufacturers, that is, an accumulation of old designs and
older patterns.

In Fig. 248 is given an illustration of their 20-inch swing engine
lathe, which has a rigid and strong appearance and mechanical
design that speaks well for its builders, who have evidently in-
tended to make a lathe of exceptional productive capacity, and
ability to stand up to the heavy duty now imposed on such tools

316

MODERN LATHE PRACTICE

by the use of high-speed tool steels and coarse feeds for the rapid
reduction of the material.

The head-stock is massive and of a symmetrically rounded form.
The cone has five steps and takes a belt of rather more than the
usual width. The spindle is of high carbon special steel and accu-
rately ground, bored out with a large hole, and runs in a good
quality of anti-friction metal boxes, provided with automatic ring
oilers.

The carriage is proportionately heavy and strong, liberally
provided with T-slots, and has a flat top for convenience of bolting
down work to be bored or otherwise machined. The bearings upon
the V's extend the entire length of the carriage. The compound

FIG. 248. — 20-inch Swing Engine Lathe built by the
American Tool Works Company.

rest is broad and strong and well fitted with hand-scraped surfaces,
as are all the sliding contacts of the lathe.

The bed is of deep box girder section. The webs are well tied
together with cross bars of box form, making the bed very strong
and rigid. It is of the " drop-V " pattern, which gives an additional
swing of about 2J inches. The V's are far apart and the front tail-
stock way is flat, which, in connection with the drop-V construction,
renders it possible to add an unusual amount of metal to the bridge
of the carriage, thus insuring unusual stiffness and rigidity.

The lead screw is located within the bed and imparts motion
to the carriage directly under the cutting- tool. This construction

ENGINE LATHES (CONTINUED) 317

obviates much of the tendency to twist or lift the carriage off its
seat so common in even the best modern lathes where the lead screw
is located on the outside of the bed and pulls the carriage by its
connection with the apron. The apron is tongued and grooved to
the carriage and secured by large and substantial screws. All
studs are of tool steel, hardened and ground. All pinions are of
steel and are bushed with bronze. All gears are of wide face and
coarse pitch. The reverse feeds are not by means of bevel gear and
two bevel pinions, as in most modern lathes, but by tumbler gears,
suitably controlled at the front of the apron. It is well known that
bevel gears and pinions are broken by slipping in and out of engage-
ment when running. In this lathe the bevel gear and pinions are
constantly engaged, and therefore can be cut theoretically correct
and run in close working contact. A separate splined rod is pro-
vided for driving the apron mechanism, thus obviating the necessity
of splining the lead screw, as it is well known that no screw will
remain true after splining. The screw is therefore simply and solely
used for thread cutting and as a further precaution it is placed
inside of the bed and has no connection whatever with the apron or
its mechanism.

The carriage slides, both upper and lower, are fitted with taper
gibs which are tongued and grooved into the sides, so that no amount
of strain will disturb them. These gibs are adjusted by a con-
venient screw at each end. The feed screws are provided with
micrometer dials.

The thread-cutting mechanism is exceptionally well made. All
shafts are of high carbon steel and accurately ground. The four-
speed gear box is mounted on the head end of the bed, and by means
of clutch members, operated by suitable knobs conveniently located,
four changes are instantly obtainable. This, in connection with a
cone of eleven gears, mounted on the inside of the bed, any one pf
which can be engaged instantly by means of a sliding tumbler gear,
makes forty four changes obtainable, without removing a gear.
The index is well arranged and comparatively simple to under-
stand, so that the practical operation of this mechanism is more
simple and easy than many of the rapid change gear devices.

The workmanship on these lathes is unusually good, and this
applies not only to the smoothness and fineness of finished surfaces,

318

MODERN LATHE PRACTICE

but what is of still more importance, to good fits. That the makers
have endeavored to make a particularly good lathe is evident, what-
ever may be our opinion of the design of the "disc of gears " intro-
duced into the rapid change gear design.

The Springfield Machine Tool Company make a variety of engine
lathes and special lathes for various purposes that are unique in
some respects, and very serviceable lathes for a large class of manu-
facturing work.

FIG. 249. — 16-inch Swing Engine Lathe built by the
Springfield Machine Tool Company.

Their 16-inch engine lathe is shown in Fig. 249, which is equipped
with rapid change gear device, reverse motion operated at the apron,
automatic stop for turning and thread cutting, and provided with
a friction-geared head spindle.

In Fig. 250 is given an end elevation of the lathe, principally for
the purpose of showing the rapid change gear device, which is of
the type first patented by Edward Flather in 1895, and since used
to a considerable extent on small lathes built by various makers and
under several later patents, most of which are modifications of
that of Flather.

The main spindle is hollow and of hammered crucible steel, with
large bearings running in self -oiling bronze boxes, and is friction-

ENGINE LATHES (CONTINUED)

319

geared in a similar manner to that of a screw machine or turret
lathe, which is of considerable convenience in many classes of work.

The lead screw has a telescopically arranged extension, con-
trolled by a hand lever. This extension of the lead screw is re-
duced at its end to enter the hole in the change-gear, a distance
equal to its width, before the clutches with which the change-gears
and extensions are fitted come in contact with each other. Thus,
when one of the change-gears is connected with the lead screw it
ceases to depend upon the disc for support, but is mounted on the
lead screw as substantially as if secured
by a nut and washer, although it is at
other times supported by, and practi-
cally journaled in, the circular gear
box. As a sufficient range of feeds or
screw pitches cannot be obtained by
changing gears on the lead screw, only
provision is made at the head-stock for
various ratios of speed. This is ac-
complished by means of three pairs of
gears, contained in cases, and giving
the ratios of 1 to 1, 2 to 1, and 4 to 1;
and when the latter two are reversed,
the ratios become 1 to 2, and 1 to 4,
giving five rates of speed for the fixed
pinion which engages with the inter-
mediate gear, necessary for transmit-
ting the motion to the gear on the lead screw.

As there is only one pair of gears that can be used at a time,
a receptacle is formed in the leg of the lathe to receive the other
pairs, one being suspended from a stud projecting from the rear
of this cabinet, while the other is similarly placed on the inside of
the door, rendering either equally available for use in a moment.

The range of threads which may be cut on this lathe is from 2 to
56 per inch, and the turning feeds from 8 to 224 per inch.

Every change required to cut any of the threads or to produce
any of the feeds above given can be made while the lathe is in
motion.

While the type of device for rapid changes in speeds and for

FIG. 250. — End Elevation of
16-inch Springfield Lathe.

320

MODERN LATHE PRACTICE

thread cutting may not appeal to those machinists who desire a
strongly built and strongly geared mechanism, this lathe is still
very useful on a large variety of small and medium sized work, of
which there is usually a great quantity in the modern factory or
machine shop devoted to this class of work,

The same company make various types of useful lathes, fixtures,
and accessories that will be referred to under the proper headings
later on in this book.

The Hamilton Machine Tool Company build a commendable
line of engine lathes and seem to have aimed to build machines of

FIG. 251. — 18-inch Swing Engine Lathe built by the
Hamilton Machine Tool Company.

good design and construction, combining the later features that
are demanded by modern methods of machine shop and factory
requirements for accurate and rapid work as well as a wide range of
product.

The later designs of this company are heavy and rigid, yet with
proper appreciation of the proportioning of the component parts,
the machine does not have the clumsy or overloaded appearance
sometimes seen in heavy lathes.

As a sample of their modern lathes their 18-inch swing engine
lathe is shown in Fig. 251. The bed is deep and wide and well
braced to resist strains. It is supported upon cabinets of modern

ENGINE LATHES (CONTINUED) 321

design, affording ample cubpoard room for storing tools and small
parts. The pads for the lead screw, feed rod and reversing rod
bearings are grooved and the bearings planed to fit them, thus assur-
ing true and permanent alignment.

The head-stock is massive and of good design, insuring rigidity
and preventing vibration and chatter even on the heaviest work
which the lathe will be called upon to perform. The spindle is of
high carbon steel forging and bored out If inches. It is ground
its entire length and runs in phosphor bronze bearings, hand-
scraped to fit the spindle. Anti-friction thrust bearings are pro-
vided with an adjusting nut for taking up lost motion due to wear.
On this lathe these bearings are provided with hardened and ground
steel washers. On the 22-inch swing and larger lathes these bear-
ings are provided with hardened and ground-steel balls which are
also adjustable and reduce the friction to a minimum, the ball-races
being of tool steel and also hardened and ground.

The spindle cone has five steps, the largest being 12 inches
diameter, and adapted for a 2f-inch belt. Readily removable
gear guards protect the face gear and the back gear from injury
by chips, dirt, etc., and the operator from the danger sometimes
resulting from these exposed parts.

The tail-stock is of the " off set" pattern, that is, cut away in
front so as to permit the compound rest to swing around parallel
to the V's of the lathe. The tail spindle is 2^ inches in diameter,
and is graduated for convenience in drilling. It is of steel and
accurately ground and has an unusually long movement. The
tail-stock has the usual set-over adjustment for turning tapers.

The carriage is massive and strong, and is gibbed at the front,
back and center, and is scraped to a solid bearing upon the bed,
throughout its entire length. It is entirely flat on top and amply
provided with T-slots, so that work to be bored or otherwise ma-
chined can be as readily clamped upon it as upon the table of a
planer or milling machine. The cross-feed screw has a micrometer
attachment, by .means of which, not only can turning and thread
cutting be much facilitated, but the drilling of jigs and fixtures
may be as readily done here as on a milling machine, so far as laying
off accurate distances is concerned, by strapping the work to an
angle-plate bolted down to the carriage.

322 MODERN LATHE PRACTICE

In addition to the above feature, the lathe is provided with a
rotating indicator or chasing dial, located on the top of the carriage,
which enables the operator to catch the thread quickly and properly
without reversing the forward motion of the lathe; and permitting
him to return the carriage quickly to the starting-point by hand.

The compound rest is large and heavy with broad wearing sur-
faces accurately fitted by hand scraping, and provided with taper
gibs. The swivel is graduated in degrees so that it can be quickly
set at any required angle. The tool-post is formed from a solid
steel bar and has a tool steel screw.

The apron is large and strong, and is fitted to the carriage by a
tongue and groove. The operative parts are heavy and strong.
The rod feed and the thread cutting by the lead screw are inde-
pendent, and each, when in use, locks the other out of the possibility
of becoming engaged, thus preventing the liability of breakage
from this source. The feeds are driven by a powerful friction de-
vice and are readily reversible at the apron by a single movement.

An automatic stop is provided by the addition of a rod running
the entire length of the bed, and which operates equally well when
feeding in either direction. It operates with either the turning
feed or with thread cutting, and enables the operator to chase up
to a shoulder, by which feature it is very useful in cutting internal
threads, or in boring to a certain fixed depth. It can also be set
to prevent the carriage running against either the head-stock or
tail-stock, and is therefore a safety device against the serious acci-
dents that sometimes occur from this cause. This device is of great
advantage in duplicating work such as the turning of shafts having
one or several shoulders, as, the cut once fixed, the stop collar may
be set and no further attention paid to the location of the shoulders
than would be necessary in an automatic machine.

The quick change gear device by which a large number of threads
of different pitches are cut, and by which a wide range of turning
feeds are obtained, contains the "disc of gears" or circular case,
containing eight change-gears and constructed upon the plan first
invented and patented by Edward Flather in 1895. In addition
to this device the usual multiplying gears are used, being contained
in another case which properly protects them. This device is
shown in the accompanying illustrations, in which Fig. 252 is an

ENGINE LATHES (CONTINUED)

323

end elevation and Fig. 253, a vertical, longitudinal section, showing
the general design of the mechanism, which appears considerably
complicated and hardly as strong as such a device ought to be in
order to withstand the strains to which it is usually subjected, and
therefore liable to get out of order. The device is well made and
of good material, and will, no doubt, give as good results as may
be expected from this form of rapid change gearing. It will cut
48 different threads from 1 to 56 per inch, and cutting-feeds from
6 to 336, all inclusive, by the use of three removable change-gears.
The method by which the various changes are made is necessarily

FIG. 252. — End Elevation of
the 18-inch Hamilton Lathe.

FIG. 253. — Longitudinal Section of
Gearing of 18-inch Hamilton Lathe.

complicated, and in the hands of an inexperienced operator might
lead to mistakes. This can be said of several of the similar devices
built by other establishments.

The weight of the 18-inch swing by 8-foot bed lathe is 2,580
pounds, by which it will be seen that there has been no stinting of
material in its design.

This company build a variety of lathes and attachments and
accessories for the same, which are illustrated and described under
appropriate headings later on in this book, and to which the reader
is referred for information concerning them.

The W. P. Davis Machine Company make a general line of

324

MODERN LATHE PRACTICE

plain engine lathes, of which a good example is shown of their 18-
inch swing lathe in Fig. 254. The bed is of ample depth and well
proportioned, and is supported on the older design of legs instead
of cabinets.

The head-stock is of ample dimensions and has a crucible steel-
forged spindle with a Ig^-inch hole through its entire length, and
runs in phosphor bronze boxes, reamed and hand scraped. The
front bearing is 3 inches in diameter and 5 inches long. The spindle
cone has five steps, the largest being 11 inches in diameter and
adapted for a 2J-inch belt.

FIG. 254. — 18-inch Swing Engine Lathe, built by the
W. P. Davis Machine Tool Company

The feed is belt-driven by the usual three-step cone, an arrange-
ment for tightening the belt and multiplying gears whereby six
different feeds may be obtained. The change-gears are such as
will cut threads from 2 to 32 per inch inclusive.

The carriage, apron, tool-rests, etc., are of ample dimensions
for the requisite strength. This lathe with an 8-foot bed weighs
2,460 pounds, a fair weight for a manufacturing lathe of these dimen-
sions, which has evidently been the aim of the builders to produce.

The same firm make other types of lathes which are illustrated
and described in future pages and under their appropriate headings.
Some of them have special features to which the attention of the
reader is particularly directed.

ENGINE LATHES (CONTINUED)

325

The Fosdick Machine Tool Company, better known as builders
of radial drills, have recently commenced the construction of lathes
also, and the one shown in Fig. 255 is entitled to special considera-
tion as the aim of the makers evidently is to produce a lathe for
practical use that will meet the demand for a good lathe at a reason-
able price. This lathe is equipped, as illustrated, with feed box and
with compound rest. The bed is made in different lengths from
6 to 12 feet, with cabinet or regular legs, and with or without oil
pan. The spindle bearings are 2J and 2J inches diameter; there is a
l^-inch hole through the spindle, and draw-in chucks are furnished

FIG. 255. — 16-inch Swing Engine Lathe built by the
Fosdick Machine Tool Company.

when required. The bearings are bronze bushed throughout, and
constant lubrication is afforded through an endless chain and large
oil pockets. Owing to the design of the head, a three-step driving
pulley may be used in place of the five-step cone, insuring a more
powerful spindle drive when required for high-speed steel work.

The carriage has bearing surfaces of ample length and width on
the shears, and the apron is of the box-section type, insuring strength
and stiffness. The design of the tail-stock is clearly shown, and
also that of the follow-rest. The compound rest is designed to
receive a heavy tool-post. The compound feed box shown is the
well-known Emmes device, giving forty changes, the screw-cutting

326 MODERN LATHE PRACTICE

feeds ranging from 2 to 56 threads per inch, and the feeds for turning
being just one fourth as coarse.

The taper attachment can be placed on any of the lathes with-
out changing the bed or fitting it with brackets, and a turret of
pentagon form, for the carriage, can be furnished when desired.

All screws on any part of the lathe requiring adjustment are
operated with the tool-post wrench. The friction countershaft has
self-oiling bearings and oil wells are formed in the friction pulleys.

The swing over bed is 16} inches, and over carriage 10} inches.
With the 6-foot bed, the length taken between the centers is 34
inches. The width of the five-step cone pulley face is 2f inches,
and of the three-step 3| inches. The countershaft speed with five-
step cone is 120 revolutions per minute, and with three-step cone
250 revolutions per minute. The weight of the lathe with 6-foot
bed is 2,000 pounds, which is ample for a lathe of these dimensions,
and considerably above the average.

CHAPTER XVII

HEAVY LATHES

The Bradford Tool Company's 42-inch swing triple-geared engine lathe.
The American Tool Works Company's 42-inch swing triple-geared engine
lathe. The New Haven Manufacturing Company's 50-inch swing triple-
geared engine lathe. The Niles Tool Works 72-inch swing triple-geared
engine lathe. The Pond Machine Tool Company's 84-inch swing engine
lathe.

THE 42-inch swing triple-geared lathe, built by the Bradford
Machine Tool Company, is a good example of a well designed and
massive lathe for the heaviest work to which a lathe of this char-
acter will be subjected. With the severe requirements of modern
shop methods and the use of high-speed steels the problem confront-
ing lathe builders has been one to tax their utmost energies in the
way of good design scientifically and practically worked out; good
materials lavishly applied; and good workmanship in every part.
Without all of these in a marked degree a lathe may scarcely be
classed as modern.

As to how well the designers and builders of the Bradford lathe
have succeeded in their conditions is to a considerable extent
manifest by an inspection of the illustration given in Fig. 256 and
a study of the description which follows, as well as to some detailed
engravings illustrating the special features of the machine.

The head-stock is long and massive, occupying over five feet
on the head end of the bed, affording large housings for the spindle
boxes and ample space for broad-faced, heavy back gears, and a
five-step cone of from 10J to 22 inches in diameter and 5| inches
face. The spindle is of crucible steel and is bored out with a 3-inch
hole. It has a front bearing 6 inches in diameter and 10 inches
long, and a rear bearing 5 inches in diameter and 9 inches long.
The bearings are accurately ground and run in heavy bronze boxes,
which are reamed and hand-scraped to a fix,

327

328

MODERN LATHE PRACTICE

It was probably not an Irishman who wrote in the manufac-
turer's catalogue that " the back gears are conveniently located in
front," however much it may sound like it, as it is a mechanical
fact, and being so located applies the power at the proper point.

FIG. 256. — 48-inch Swing Engine Lathe built by the
Bradford Machine Tool Company.

Being triple geared there are fifteen speeds, increasing in proper
geometrical progression, and the lathe is provided with three rapid
changes of feed for each speed.

FIG. 257. — Head-Stock of the 48-inch Swing Bradford Lathe.

The coarse screw-cutting arrangement is shown at the left of
the engraving, Fig. 257, and is a regular device on these lathes. It
consists of a short intermediate shaft in the outer end of the head-
stock, running in a sleeve adapted to be moved longitudinally.
On each end of this shaft is fixed a spur gear, and when the shaft is

HEAVY LATHES

329

shifted to its outward position, the gear on the outer end of the
lathe spindle communicates motion to the screw. When this shaft
is at its inward position, motion is communicated from the cone
gear in a ratio of 8 to 1. So that if the lathe is geared ordinarily
to cut one thread per inch with the outer gears engaged, ft will,
with the inner gears engaged, cut a thread eight times as coarse, or
one thread in 8 inches. In cutting very coarse threads the back
gears are always used. Running in this manner the strain is taken
off the change-gears, and threads or spirals as coarse as one turn in
16 inches can be cut.

In Fig. 258 is shown the nest of gears attached to the front of

FIG. 258. — Lead Screw Gearing for the 48-inch
Swing Bradford Lathe.

the bed. The three upper gears are fast to the lead screw, while
the three lower $ears are engaged consecutively by a sliding key,
controlled by the nut shown at the right of the engraving, and
handled by a wrench. These gears are of steel and may be engaged
and disengaged while in motion.

The apron is massive and well constructed. A rear view of it is
shown in Fig. 259, by which it will be seen that it is very simple,
and therefore the parts may be made of ample strength. All shafts
have bronze-bushed bearings. Independent frictions are used for
both lateral and cross feeds, and are reversed from the front of the
apron.

The lead screw is splined to drive the two bevel pinions, and its
thread is only used when cutting threads. The halves of the lead

330

MODERN LATHE PRACTICE

screw nut are operated by the usual form of cam, controlled by a
lever shown at the right hand of the apron in the front view, as in
Fig. 256. The end of the sliding rod which carries the forks for
moving the bevel pinions is extended to the lead screw nut, where
an attachment is made for locking the lead screw nut open when-
ever either bevel pinion is engaged with the driving bevel gear, and
for locking both of these bevel pinions out of engagement whenever
the lead screw nut is closed, thus preventing the two types of feed
being thrown in at one time. The rack pinion is adapted to be
withdrawn from engagement with the rack when thread cutting
is being done.

The carriage is very long, deep, and massive, and is gibbed both
front and back. It has a bearing of 48 inches on the V's, and is

FIG. 259. — Rear View of Apron of the 48-inch Swing Bradford Lathe.

hand-scraped to an accurate fit. The inside V's of the bed are
lower than the outside V's, by which construction the bridge of the
carriage may be made much thicker and stronger, thus adding
materially to the strength of the carriage at the point where it is
usually the weakest.

The compound rest is large and broad, with an ample tool block
with heavy tool clamping bars, and having an angular power feed
of 12 inches in any direction. The base is graduated and both top
and bottom slides are provided with taper gibs and adjusting
screws.

The tail-stock is of ample dimensions with a bearing 26 inches
long on the bed. The tail-stock spindle is 4J inches in diameter

HEAVY LATHES

331

and has a travel of 16 inches. It has the usual set-over screw for
use in turning taper work, and is provided with a rack and pinion
device for conveniently moving it to any desired point on the bed.

This lathe made with a 12-foot bed weighs 16,500 pounds, by
which its massive design and great strength may be judged and
by which the points stated in the opening sentences of this descrip-
tion may be more readily appreciated.

The American Tool Works Company have recently designed an
excellent 42-inch swing lathe intended for heavy work and having
a number of good features not usually found in lathes of this capac-
ity. An illustration of this lathe is shown in Fig. 260, which gives
a good idea of its massive design and symmetrical outline.

FIG. 260.

42-inch Swing Triple-Geared Engine Lathe built by the American
Tool Works Company.

The head-stock is large and massive with ample housings for
the spindle boxes, which are of phosphor bronze carefully fitted to
the high carbon hammered steel spindle, which is accurately ground
and which carries a five-step cone. As the head is triple geared,
this gives fifteen speeds arranged in correct geometrical progression.

The carriage is very heavy and strong, long bearing on the V's,
and made with a flat top so as to be convenient for bolting down
work to be bored. The compound rest is equally strong and pro-
vided with heavy clamping straps for holding down the tools.

The feed is driven through a quick change gear mechanism which
provides thirty-two changes for feeding and thread cutting, the
range of threads being from 1 thread in 4 inches to 16 threads per
inch, including 11 J pipe thread. The feed range is from 6.4 to 92
cuts per inch.

332

MODERN LATHE PRACTICE

The device is operated while the machine is running, if necessary,
by a revolving nut seen at the right of the gear box beneath the
head, which moves a sliding key engaging two opposite gears, each
being one of a cone of gears which is encased in the gear box. The
feed or screw pitches thus obtained are multiplied by the compound
gears on the quadrant at the end of the head, it being necessary to
change one gear only on the quadrant for each additional thread.

This arrangement gives flexibility to the screw-cutting mechan-
ism, making it possible to cut an unlimited number of sizes of
threads or worms, either finer or coarser than the range indicated
above. An index plate is provided to assist in obtaining the desired
feed or pitch. The feed may be reversed in the apron, a feature
which is valuable on a long lathe where the tool may be working
at some distance from the head-stock.

FIG. 261. — -> 50-inch Swing Triple-Geared Engine Lathe, built by the New
Haven Manufacturing Company.

The New Haven Manufacturing Company build a 50-inch swing
engine lathe that, while it is a comparatively plain and simple lathe,
furnishes as good a tool at the price as any in the market. The
effort has been made to build a very massive and substantial lathe
without unnecessary complication or finish. This lathe is shown in
Fig. 261.

The head-stock is very heavy and well designed, and carries a
forged crucible steel spindle with a front bearing 8 inches in diam-
eter and 12 inches long, and a rear bearing 6 inches in diameter
and 9 inches long, and running in cast iron boxes lined with genu-
ine babbitt metal that is peinned in, bored, reamed, and scraped.
The driving-cone has five steps, ranging from lOf to 19| inches,
and adapted for a 4-inch belt. The head is triple geared, giving

HEAVY LATHES 333

fifteen changes of speed. All the gears are broad and of coarse
pitch, giving ample driving power. The face-plate is heavy and
well ribbed, and keyed to the nose of the spindle, and has a broad-
faced internal gear bolted to its rear side, from which it is driven
by a steel pinion.

The tail-stock is constructed with a double set of holding-down
bolts, by which means the upper bolts may be loosened and the
tail center set over for turning tapers without blocking up the work
or danger of its dropping out of the centers. The tail spindle is 5
inches in diameter and reamed for a No. 6 Morse taper. The opera-
ting hand wheel is directly in front of the operator and is back
geared to the spindle in a ratio of 3 to 1, so as to be easily and con-
veniently operated. A back geared rack and pinion device permits
the tail-stock to be easily moved to any desired position on the bed.

The carriage is very heavy and strong, gibbed front and back,
with an unusually long bearing upon the bed, and carries a massive
compound rest with a long angular feed in all directions^ a gradu-
ated base and large hardened straps, supported by spiral springs
upon studs, for holding the tool. These straps have projecting ends
so that tools may be held outside of the studs, which may be placed
either crosswise or lengthwise of the tool block as may be most
convenient for the work being done.

The apron is built with double plates so as to give shafts and
studs a bearing at each end. All feeds are reversible at the apron.
A large bevel gear with two bevel pinions is provided in the apron,
and an automatic locking mechanism prevents turning feeds and
thread-cutting feed from being engaged at the same time. As an
extra precaution against the frictions binding and refusing to release
properly when a tool gets caught and in danger of breaking or
spoiling work, as is liable to be the case on heavy work, or with very
heavy cuts, an additional friction is provided as safety device, as
the most careless operator is not liable to screw up both frictions
beyond the point of releasing under an abnormally heavy strain,
in case of an accident which might result in serious injury to the
tool, the work, or the feeding mechanism in the apron.

The feed is positive, by a series of gears on the head-stock, with
the usual change-gears for operating the lead screw, which is splined
for "driving the apron mechanism.

334 MODERN LATHE PRACTICE

All sliding surfaces are hand scraped. Taper gibs, with adjust-
ing screws, are used in the carriage and compound rest. The lead
screw is made of special steel rolled for the purpose, 2T7g inches in
diameter, and cut with 2 threads per inch. Pinions are of crucible
steel and all nuts are case hardened. The countershaft has self-
oiling boxes. The weight of the lathe with an 18-foot bed is 20,000
pounds, showing it to be a very massive machine for its capacity.

Prominent among the manufactures of heavy lathes is the Niles
Tool Works who are also builders of heavy machine tools of other
classes which have proven very popular on account of their good
design, ample strength, generous proportions and excellent work-
manship.

In Fig. 262 is shown one of their 72-inch swing lathes adapted

FIG. 262. — 72-inch Swing Triple-Geared Engine Lathe, built by the Niles-
Bement Pond Company (usually called a Niles Lathe).

for heavy work. This lathe is of somewhat similar design to the
50-inch New Haven Lathe shown in Fig. 261, but considerably
heavier, not only in proportion to its larger swing but as generally
considered, a more massive machine.

The head spindle is very large and constructed of cast iron, as
is usual with very large lathes. It is driven by means of the heavy
internal gear on the face-plate only, as the cone runs upon a separate
shaft provided for that purpose. The face-plate, which is very
heavy and strongly braced by ample radial ribs on its rear side, is
keyed to the head spindle and is not ordinarily removable.

The head-stock is triple geared by strong and heavy gears with
wide faces. Thus fifteen speeds are provided for with ample space
on the five-step cone for a wide driving belt.

The feeding and screw-cutting mechanism has three changes

HEAVY LATHES 335

in the head-stock by means of a sliding pin which handles the con-
necting devices of the change gearing. The lead screw drives the
feeding mechanism without using the threads cut upon it, through
the medium of a short feed rod, located in the apron. This method
avoids the use of a long feed rod with its many supports and the
attendant inconvenience which is of much greater moment than in
those used for the much larger and heavier lead screw.

The bed is very broad and massive and furnishes ample support
for the heavy head-stock and its weighty appendages, the long and
broad carriage with its compound rest of ample proportion, and
the massive tail-stock, as well as for the four-jawed center rest
which is furnished with this lathe.

The tail-stock is broad and heavy and carries a large tail spindle,
moved by a system of miter and spur-gearing operated by a large
hand wheel at the front side, and within convenient reach of the
operator. The tail-stock is secured to the bed by four heavy bolts
and a pawl engaging in a rack, cast to the bed on the center line.

While the tail-stock is unusually heavy it can be readily moved
along the bed upon friction wheels, which are easily put in contact
with the bed by means of levers provided for that purpose. The
usual set-over device is provided for turning tapers.

These builders make much larger lathes upon the same design,
and also upon special designs adapted for making large guns, ingot
slicing, machining large forgings such as crank-shafts and the like.
Of this character they build lathes swinging 90, 100, 110, and 120
inches, and of any length of bed that may be required.

An excellent example of heavy lathes for handling large forg-
ings such as crank-shafts and the heavier castings coming within
the capacity of such a machine is the 84-inch swing lathe, built by
the Pond Machine Tool Company, now operating in connection with
the Niles Company. It is shown in Fig. 263. It really swings
86 inches over the V's and 67 inches over the carriage.

The lathe is designed with ample provision for the immense
strains to which such a lathe is subjected. As will be seen by an
examination of the engraving, the head-stock is unusually massive,
with liberal dimensions of the housings for the front and rear boxes
of the main spindle, which is a matter of prime importance in any
lathe, and more particularly in one designed for very heavy work.

336

MODERN LATHE PRACTICE

Attention is also called to the massive construction of the compound
rest, which is much stronger and more rigid proportionally than
that of the 72-inch swing lathe, built by the Niles Works and shown
in Fig. 262.

The carriage has a very long bearing on the bed and is made
deep and heavy, as should be the case with this type of lathe. An
objectionable feature is that of locating apron gears in front of the
apron rather than between the apron plates, out of the way of the
operator and beyond the reach of ordinary accidental injury to
themselves. This should be avoided as far as possible in all lathes.

The tail-stock is of massive and rigid design, and well adapted
for the heavy work expected of the lathe. It is provided with the

FIG. 263. — 82-inch Swing Triple-Geared Engine Lathe, built by the Niles-
Bement-Pond Company (usually called a Pond Lathe).

geared device for moving the spindle, by which the hand wheel is
placed at the front of the tail-stock and within easy reach of the
operator. The base is secured to the bed by four bolts in the usual
manner, while the dividing line between the base and the top cast-
ing carrying the spindle is placed high up and the top secured by
four other bolts. By providing this double set of bolts the spindle
may be set over for turning tapers by loosening the upper set of
bolts only, leaving the main casting or base still firmly secured to
the bed. Thus it is not necessary to block up or to remove the
work from the lathe when setting for tapers, which is of considerable
advantage, particularly on the heavy work which this lathe is
designed to do.

In the builders' description of this lathe they say:

"With a 22-foot bed, this lathe will turn 8 feet 4 inches between

HEAVY LATHES 337

centers. All its spindles are mounted in bronze bearings. The
head spindle has upon it a thick flange of large diameter to which
the face-plate is bolted in addition to being forced on. The cone
has six wide belt steps of large diameter. It is mounted on the
face-plate pinion shaft, is back geared and geared in to an internal
gear on the face-plate, giving twenty-four changes of speed. The
sliding head has a set-over for taper turning, held independently
by four bolts, thus allowing adjustment without unclamping from
the bed. It is provided with a pawl engaging a rack in the bed
and is easily moved by gearing engaging a steel rack.

"The bed has three wide tracks, with the lead screw between
them, bringing the line of strain nearly central, and is sufficiently
wide to support the tool slide without the latter overhanging its
front side when turning the largest diameters. The carriage has
long bearings on the bed, is gibbed to the outside edges, and can
be clamped when cross-feeding. It is provided with a tool slide
having compound and swiveling movements; also with screw-cutting
attachment and automatic friction longitudinal, cross and angular
feeds.

"If either of the feeds, screw-cutting attachment, or rapid
traverse of carriage and tool slides by power is in use, it locks out
all others. The direction of the feeds may be changed at the car-
riage. Screw-cutting attachment and feeds are connected to the
head spindle by three gears and a sliding key, giving three changes
without changing gears. The carriage gearing is driven by a spline
in the steel lead screw. The thread of the lead screw is used only for
screw cutting. The gear engaging the feed rack can be disengaged
when cutting screws, thus preventing uneven motion, caused by
the revolution of the feed gearing."

CHAPTER XVIII

HIGH-SPEED LATHES

Prentice Brothers Company's new high-speed, geared head lathe. A detailed
description of its special features. A roughing lathe built by the R. K.
Le Blond Machine Tool Company. Lodge & Shipley's patent head lathe.
The prime requisities of a good lathe head. Description of the lathe in
detail. The capacity of the lathe. A special turning lathe of 24-inch
swing built by the F. E. Reed Company. A two-part head-stock. The
special rest. Its two methods of operation. Its special countershaft.
The Lo-swing lathe, built by the Fitchburg Machine Tool Works. Its
peculiar design. A single purpose machine. An ideal machine for
small work. Builders who have the courage of their conviction.

THE Prentice Brothers Company have recently brought out a
new high-speed geared head lathe, that possesses some valuable
features and is worthy of careful consideration. It is well designed
to meet all the most rigid demands of modern shop methods that
may be made upon a lathe of this character, and is strongly built to
withstand all the shocks and strains to which it may be subjected.

Apart from its great power, the machine is interesting mechan-
ically in its arrangement for procuring eight spindle speeds from a
single speed countershaft, thus always furnishing an equal belt
power no matter what spindle speed is in use. It is also of much
interest in that it presents a new modification of the quick change
feed device.

The lathe is shown complete in Fig. 264, and the details of the
head-stock, feed gears, and quick change gear mechanisms in Figs.
265, 266, 267, 268, 269, 270, and 271. A careful study of these
details will be interesting as giving a clear insight into the prominent
features of the device. As will be seen by referring to Fig. 265,
four changes of speed are obtained between the pulley shaft and
the spindle through an arrangement of gears and friction clutches,

338

HIGH-SPEED LATHES

339

and that the number of changes are doubled by engaging the back
gears by means of a positive tooth clutch.

FIG. 264. — High-Speed Engine Lathe built by the Prentice Bros. Company.

The back gears never travel fast enough to render it imprac-
ticable to use a positive clutch for this purpose. The result is a
ratio of 6 to 1 between the spindle and any friction while the back

FIG. 265. — Horizontal Section of Head-Stock of
Prentice High-Speed Lathe.

gears are in use. The driving pulley, which is located on a back
shaft, drives the spindle by means of spur gearing. The pulley
carries a 4-inch belt, which runs at a speed sufficient to transmit
15 horse power.

340

MODERN LATHE PRACTICE

The eight changes of speed are obtained by means of the levers
A, B, and C, shown in Figs. 266 and 267, and also at the front of the
head-stock in Fig. 264. This arrangement of the several operative
parts is such that there is no danger of engaging conflicting spindle
speeds at the same time. On the pulley shaft D, in Fig. 265, which
is situated at the back of the head-stock, and revolves at a constant
speed at all times, are two friction clutches E and F, either of which
may be operated by the lever A, which slides the friction spool I
along the shaft D, for the purpose of engaging the clutches at the
right or the left. Between the head spindle and the pulley shaft D
is located a secondary shaft G, which carries two gears of different

FIG. 266. — Front Elevation of Head-Stock
of Prentice High-Speed Lathe.

FIG. 267. — Cross Section
of Head-Stock of Pren-
tice High-Speed Lathe.

diameters, engaging with corresponding gears upon the pulley shaft

D, and also gears which are fixed to the hubs of the friction discs J
and K. These friction discs run loosely upon the quill L, L, which
is itself loosely journaled upon the head spindle and which carries
the friction disc L1 at its end. The friction rings M, N, are keyed
to the quill L. The friction ring 0 is keyed to the head spindle.

The four high-speeds are engaged as follows : With the frictions

E, M, and 0, driving directly; with the frictions F, N, and 0, driving
directly; with the frictions F, M, and 0, driving through the inter-
mediate shaft G; and with frictions E, N, and 0, also through the
intermediate shaft. The back gears and the spindle-driving gear
W run constantly, while the friction spool I is engaged with either
friction E or F. By engaging the friction spool and clutch P, which
is keyed to the lathe spindle, with the spindle driving gear W, the
back gear speeds are obtained. If desired, the lathe is furnished
with a two-speed countershaft, to double the number of speeds to
16.

HIGH-SPEED LATHES

341

The device for changing the feed and for the cutting of screw
threads is a radical change from the swing intermediate gear type,
as it does away with the raising and lowering an intermediate gear
sweep and sliding the intermediate gear laterally to engage with
feed gears on the end of the head and bed. A pull spline and spring
spline in combination replace the older mechanism.

Upon the end of the head-stock and in the position usually
occupied by the regular feed
spindle is a feed shaft, A, in Fig.
268, upon which four gears are
splined. The shaft is supported
at its outer end in a brass bush-
ing mounted upon the gear guard.
This shaft with its gears revolves
at the same speed as the main
head spindle of the lathe. Below
the feed shaft is a hollow stud B,
on which are loosely mounted
four gears meshing with the feed

gears on A. The gears on both FIG. 268. — Vertical Section of Feed

.,! ,-, Gears of Prentice High-Speed Lathe.

A and B run constantly with the

main spindle when not disengaged by the usual rocker device on
the end of the head-stock at 0.

The two groups of gears are of the ratio 2 to 1, 1 to 1, 1 to 2, and

1 to 4, which, in connection with the bank of gears mounted on the

side of the head, gives a range of thread cutting from 2 to 32 per

inch. The feed cuts per inch are 5.7 times the number of threads cut.

The hollow stud B contains a pull rod, C, which has fastened to

its end the spring spline D. The
spring spline allows changes of
feed and thread cutting to be
made instantly while the lathe is
in motion, by sliding the handle

FIG. 269. — Change-Gear Levers of E, Fig. 269, on its guide rod, the
Prentice High-Speed Lathe. handle projecting from the side

of the head-stock and connected with pull rod C, at F, in Fig. 268.
The hollow shaft B contains a slot running the full width of the
four gears.

342

MODERN LATHE PRACTICE

When it is desired to change the rate of feed, the pull spline C
being moved laterally causes the spring spline to be withdrawn
from a slot in the bushing on the feed gear, throwing that gear out
of use. When the spring spline passes the pin E it immediately
engages the next gear. The form of the driving end of the spline
makes this action against the pins possible.

The gears G, G, in Fig. 268, drive the gear H in Fig. 270, which is

fastened to the shaft J, on which
is mounted a yoke carrying a slid-
ing intermediate gear, which en-
gages with the several gears
mounted on shaft K. There being
11 gears in this bank, 44 changes of
feed are obtained. Sliding on the
end of shaft K in Fig. 270 is the
gear L, which by means of a han-
dle on the front of the bed may be
engaged with either gear M on the
feed rod or gear N on the lead
FIG. 270. — End Elevation of Gear- screw. This device is intended
ConnectionsofPrenticeHigh-Speed especially to preserve the lead

screw for screw-cutting purposes,

as a great deal of care is taken in the manufacture of these screws
to have them accurate.

The diagram shown in Fig. 271 is of an end view of the head-

FIG. 271. — Diagram of Gear Connections of Prentice
High-Speed Lathe.

stock, showing the gear connections from the head spindle to the
cone of gears shown in section in Fig. 270, and is useful and inter-

HIGH-SPEED LATHES

343

esting in tracing the line of motion produced by these gears. The
entire scheme of the head-stock and its operative parts is ingenious
and a well-devised piece of mechanism.

A roughing lathe, built by the R. K. Le Blond Machine Tool
Company, is shown in Fig. 272, and is principally interesting from the
strength of its parts in proportion to the dimensions of the work that
it will accommodate. This lathe is built of 18, 21 and 24-inch swing,
and has an extra large spindle which runs in genuine babbitt metal
bearings.

The carriage is much heavier than an ordinary engine lathe, and
is extended out both back and front for additional bearing for tool
rests. Of these there are two, one in front and the other at the

FIG. 272. — 18-inch Swing Roughing Lathe built by the R. K. Le Blond

Machine Tool Company.

rear. The front tool rest has an extra movement in line with the
slide. The back tool rest has an extra movement at right angles to
the slide. Both of these are moved by a single screw moving
towards or away from the center together.

The tail-stock is fastened to the bed with four large bolts, clamp-
ing it as far forward as possible. The feed is positive geared and is
changed by means of lever shown in front of the bed, giving three
changes, and can be stopped automatically at any point desired.
By tripping it with a small handle on the front of the apron the
carriage will proceed without removing the stop, and keep on until
it comes in contact with the next stop.

The lathe is fitted with a geared oil pump for a continuous flow

344 MODERN LATHE PRACTICE

of oil on the work; the pan is large enough to keep all dirt, oil, and
chips from the floor. Countershaft has double friction pulleys.

This lathe is intended for heavy and rough work, as, for instance,
rough turning forgings and heavy pieces of cut-off work that re-
quires to be largely reduced in diameter with a heavy roughing
cut. With the present low price of machine steel there is a good
deal of the latter class of work to be done, and it can be done much
more quickly and economically in a lathe of the class here shown
than in the usual engine lathe, and its use saves the unnecessary
wear when such work is done on the more expensive lathe.

Therefore the heavy roughing lathe is not only a saving in time
and in money for doing the work, but also of the cost of tool equip-
ment.

It was this idea that induced the design and construction of
the so-called " rapid reduction lathes," which have come to be
popular with manufacturers, not only on account of their economical
expenses, but high efficiency.

Turret lathes are sometimes used in a similar manner, cutting
off and roughing out the pieces from the bar stock, and are very
efficient in doing this class of work. The first cost of these ma-
chines, however, is much more than that of the plain roughing
lathe.

The Lodge & Shipley Machine Tool Company build a lathe with
a head-stock that is a radical departure from the usual form of
cone-driven lathes and which is entitled to special consideration. It
is the result of much experimenting and is covered by patents.
Commercially they call it their " Patent Head Lathe." It is an
outcome of the recognition by the builders of tha demand for a
much more powerfully driven lathe for the use of modern high-
speed lathe tools.

The manufacturer of the lathe says: "Our aim in its design has
been to provide this power in such a manner that all the functions
of the regular type would be retained, but the head would have
wearing qualities, in addition, proportionate to the increased service
expected of it. To this end we believe the observance of the follow-
ing conditions to be of the highest importance : First, the spindle
bearings, upon which the accuracy of the lathe is dependent, should
not be subjected to the change of alignment by carrying the pull

HIGH-SPEED LATHES

345

of the belt. Second, more force at the cutting tool should be
secured by the use of wider belts, instead of through higher gear
ratios. Third, the possibility of running the lathe 'out of gear'
should be provided for in cases where finishing cuts are desired.
Fourth, speed changes should be secured without the necessity of
shifting belts. Fifth, the lubrication of the bearings should be
automatic and positive."

Doubtless every thoughtful mechanic will readily assent to
these propositions as being self-evident.

Figure 273 shows the head-stock in place upon the bed and

FIG. 273. — Head-Stock for Lodge & Shipley Patent Head Lathe.

with the main spindle and the gear covers removed in order to
show the construction of the driving mechanism. Power is applied
through a wide-faced pulley of large diameter which is keyed to a
sleeve revolving in the two central bearings of the head-stock. At
one end of this sleeve is a jaw clutch, and at the opposite end two
gears of different diameters. The main spindle passes through this
sleeve without coming in contact with it, having about an eighth of an
inch clearance, and revolves in the two outer bearings, that is, the
extreme front and the extreme rear bearing. It is connected to the

346 MODERN LATHE PRACTICE

driving sleeve for direct belt speeds by the clutch, and for the back
gear speeds through either back gear, according to the speed
desired. A lever, convenient for the operator, engages or dis-
engages the clutch.

As there is no contact between the driving sleeve and the spindle
except through the clutch, the pull of the belt is all carried by the
two central bearings. Sufficient clearance is provided in the clutch
to prevent any of the belt strain being communicated through it
to the spindle. The spindle bearings are thus relieved of all wear
due to belt pull and their life greatly prolonged. By actual experi-
ment with a 20-inch lathe it has been shown that the pressure
exerted by a belt on spindle bearings was 17.6 pounds per square
inch of bearing surface, while the total pressure exerted by the belt
upon a spindle between bearings which effect the alignment of the
spindle was 393 pounds. In the lathe under consideration this was
entirely eliminated.

In the ordinary type of engine lathe the narrowness of the
driving belt compels the use of the back gears for all cuts but the
lightest ones, and on small diameters. To provide sufficient force
at the tool for heavy cuts, this back gear ratio must necessarily be
a high one, and, as the speed at which the cut is taken is reduced
in the same ratio as force is gained, it is apparent that a heavy chip
cannot be removed at a high speed unless the speed of the cone
pulley is increased to an enormous rate. When this is done, the
fact that it revolves directly on the spindle, where it is imprac-
ticable to maintain an adequate supply of oil, soon causes excessive
friction and is liable to stick the cone pulley.

In the lathe we are considering the great width of belt used
delivers sufficient force at the cutting-tool for heavy cuts through a
comparatively low back gear ratio, in consequence of which the
spindle speeds may be proportionately higher. An additional set
of back gears of very low ratio is provided for cuts which are slightly
beyond the capacity of the open belt, but which do not require the
full force afforded by the high ratio. Thus it will be seen that high
speeds can be secured through the back gears without the neces-
sity of revolving the driving pulley at the enormous rate required
of a cone pulley to perform the same work. In addition the con-
struction of its bearings is such as to permit of perfect lubrication,

HIGH-SPEED LATHES 347

which has received a great deal of attention, and the manufacturers
claim that the spindle will run a month with one oiling. Deep oil
wells, holding about a pint each, are formed in the casting under
the centers of the bearings of the spindle and driver sleeve, and
are connected with gage glasses at the front of the head-stock for
the purpose of showing the height of the oil. The oil wells are filled
through these gage glasses, which allows any sediment or dirt
which the oil may contain to settle to the bottom and not be de-
posited on the revolving journals where damage would be liable
from cutting. At the center of each journal is attached a brass
ring with four projections, on the principle of the bucket pump.
As the journal revolves these buckets dip into the oil in the well,
and, passing over the center of the bearing, pour the oil over the
journal. Suitable ducts distribute the oil lengthwise of the bear-
ing and return it to the well to be used again and again. This
method provides a certain system of lubrication without regard to
the speed of the revolving spindle.

The back gearing is designed with ratios to give a uniform pro-
gression of speed from the slowest to the fastest. The two back
gears are connected to the back gear shaft by spline and key, and
are easily moved lengthwise to engage with their respective gears
on the driving sleeve. The back gear shaft and pinion are made of
forged steel, thus insuring the requisite strength and wearing qual-
ities. The journals for the shaft are placed at either end, where
they revolve in bushings provided with oil reservoirs and the same
system of oiling as that for the spindle and driving sleeve.

The end thrust of the spindle is against the rear housing of the
head-stock by means of a large cast iron collar keyed fast to the
spindle, between which and the faced inside of the housing are
interposed two bronze washers placed on either side of a hardened
steel washer of like diameter. This distributes the friction to four
contacts, each composed of two dissimilar metals, and forming a very
efficient device for the purpose.

A variable speed countershaft is provided for the lathe, by which
a wide range of speeds may be obtained.

In Fig. 274 is shown a front elevation of this lathe with the
gear covers removed so as to show the head-stock assembled and
in running condition. The gear covers are of cast iron and cover

348

MODERN LATHE PRACTICE

and protect all portions of the head-stock mechanism, except the
wide-faced driving pulley. This will show the relative importance
which a head-stock built according to this system holds to the other
constituent parts of the machine. It also shows the very consider-
able added length necessary for the head-stock, and therefore the
reduced length between centers when the same length of bed is
considered.

But while the capacity of the lathe, so far as length between
centers is concerned, is relatively much less, the real capacity of
the lathe for producing work, good work, is so vastly increased that
the production of this head may fairly be considered as adding

FIG. 274. — 22-inch Swing Patent Head Lathe, built by the Lodge &
Shipley Machine Tool Company.

very much to the development of the lathe as a modern American
machine shop tool.

A 24-inch special turning lathe is built by the F. E. Reed Com-
pany that is designed for reducing large amounts of metal at one
turning, using the high-speed steel tools, and is an unusually stiff,
strong, and powerful machine.

The head-stock is made in two parts to admit of a cone pulley as
large as the lathe will swing over the bed. It has a large, forged
steel spindle, the front bearing of which is 4J inches diameter by
9} inches long, and runs in babbitt lined bearings. The spindle is
strongly back geared. The cone pulley has five sections, the largest
of which is 20 J inches diameter, driven by a 3i-inch belt; then with
the two friction pulleys on the countershaft this number of speeds
can be doubled, making a total of twenty speeds which can be had

HIGH-SPEED LATHES 349

if desired. This lathe can be furnished with four-step cone for wider
belt if desired.

A special feature of this lathe is the rest. It is provided with
two patented elevating tool-posts, each having a universal tool-
holder, in which any size of steel can be used to advantage, and so
made that they admit of adjustment up and down while the tool
is under cut. Each tool-post is moved from the front by a separate
screw, and the rear tool-post is provided with a screw for adjust-
ment crosswise of the rest. These tools can both be used to turn
to the same diameter by dividing the chip; or, they can be used to
reduce the diameter, removing large amounts of stock, working one
tool in advance of the other, each tool turning to a different diameter.

A positive geared feed is provided, and so arranged that either a
fine or a coarse feed can be obtained by means of the lever shown
at the front of the lathe.

There are two methods of operation :

First. When it is desired to do rapid turning, and where it is
not necessary to largely reduce the diameter, the front tool is
brought up to the work and set so it will reduce the piece to the
required diameter. Then the rear tool is adjusted to a point where
it will turn to the same diameter as the front tool, after which it is
adjusted by means of the cross adjusting screw so that it will divide
the chip. Then by means of the small lever shown at front of
lathe a coarser feed is engaged.

Second. When large reductions in diameter are desired, the
front tool can be set to remove the required amount of stock,
and the rear tool set to follow the front tool for removing a second
large chip from a different or smaller diameter.

Arranged for either of the foregoing operations the lathe will
turn off twice the amount of stock that can be removed at one
turning in the ordinary 24-inch engine lathe, using the high-speed
turning steels.

This lathe is set up with a pan and is provided with a pump and
piping for ample lubrication of the cut ting- tools.

The countershaft is furnished with two patent friction pulleys for
two speeds, 200 and 250 revolutions per minute. These pulleys
are 18 inches diameter and take a 5-inch belt. The pulleys are so
arranged that they can be oiled while running, thereby saving loss of

350

MODERN LATHE PRACTICE

time, danger, and annoyance in running off the belts, which is an
important consideration where a number of lathes are in use. The
countershaft is also furnished with self-oiling boxes.

This lathe is shown in Fig. 275, wherein its ample proportions
and excellent design may be seen and appreciated. It is undoubt-
edly one of the best lathes of its kind, and for this particular and
important use, now on the market. With a 10-foot bed this lathe
weighs 7,390 pounds.

FIG. 275. — 24-inch Swing Special Turning Lathe, built by the
F. E. Reed Company.

A special lathe has been brought out by the Fitchburg Machine
Works at a comparatively recent date that is unique in construction
in a number of ways, and for these reasons, as well as for its claim
to a large production of work within a limited range, it is worthy of
considerable attention.

It is called the "Lo-swing" lathe, and has a capacity from J to
3} inches in diameter and up to 5 feet in length. The builders say:
"We have purposely limited the range of work handled in order
to increase productive capacity — a Lo-swing will do from three
to four times as much work as an ordinary lathe in the same time.

"The extremely low swing and the single slide tool carriages,
all four of which can be employed simultaneously, are distinguish-
ing features of this machine, and the greater driving power, greater
stability, the accurate control of tools and work, made possible
by this construction, result in such rapid and economical produc-
tion of work that the Lo-swing is already an acknowledged cost-
reducer for the shop.

HIGH-SPEED LATHES

351

" The greater driving power, greater stability, the accurate con-
trol of tools and work, the low swing and small carriages, made
possible by thus limiting the range, result in such rapid and eco-
nomical production of work that the Lo-swing stands in the front
rank as a cost reducer."

Figure 276 is a perspective view of this lathe, and gives a good
idea of its general appearance. The aim of the builders is to so
design the lathe as to limit its range of work so narrow as to make
it "a single purpose" machine, that is, to confine its operations to
one single class of work and then produce as much of that one class
as possible.

FIG. 276. — The "Lo-Swing" Lathe, built by the Fitchburg
Machine Works.

Its two distinctive features are first, its very low swing, just
enough to clear a 3J-inch bar; and second, single tool slide carriages,
several of which may be simultaneously employed.

Tfae ideal machine for turning small work, which must be turned
on centers, should have the tool mounted on a low rest with the
guiding rail as close to the work as possible, and with the cross-feed
screw located directly back of the cutting-tool so that a change of
the screw would surely and positively effect a corresponding change
in the position of the tool, .and so that variation under working

352 MODERN LATHE PRACTICE

strain from no load at all to a full load, or from a very light chip
to a very heavy one, would have the least possible effect on the loca-
tion of the tool.

While these conditions have been presented, time out of mind,
by the mechanical engineers who have studied the lathe question
and its relation to the regular lathes built and put on the market,
the lathe builders have been slow to adopt such radical changes as
would properly accomplish the required result.

The builders of the Lo-swing lathe have cut loose from the con-
servative methods of other lathe builders in producing this machine.

While it is yet too early to determine what will be the success
of this venture, and how popular it may become with manufacturers
requiring such a machine, it seems at this writing to have a bright
future before it as a practical manufacturing machine, and its builders
are certainly entitled to considerable credit for having the courage
of their convictions in bringing it out.

CHAPTER XIX

SPECIAL LATHES

The F. E. Reed turret-head chucking lathe. Its special features. A useful
turning rest. The Springfield Machine Tool Company's shaft-turning
lathe. The three-tool shafting rest. The driving mechanism, Lubrica-
tion of the work. The principal dimensions. Fay & Scott's extension
gap lathe. Details of its design. McCabe's double-spindle lathe. Its
general features. Its various sizes. Pulley-turning lathe built by the
New Haven Manufacturing Company. A special crowning device. Its
general design. A defect in design. The omission of a valuable
feature. Pulley-turning lathe built by the Niles Tool Works. A pulley-
turning machine. Its general construction. Turning angular work. Con-
venience of a bench lathe. The Waltham Machine Company's bench
lathe. Its general dimensions and special features. A grinding and a
milling machine attachment. Devising special attachments. Reed's
10-inch swing wood-turning lathe. Special features of design. Popu-
larity and endurance. The countershaft. Inverted Vs.

THE F. E. Reed Company build a number of sizes of turret
head chucking lathes, with both plain and back-geared head-
stocks, and cylindrical turrets placed upon a lateral top slide sup-
ported by a heavy base or bottom slide fitted to the V's of the bed.

In Fig. 277 is shown one of these lathes with a back-geared
head-stock. The spindle, which is of crucible steel, is bored out to 2
inches and has a front bearing 4 inches in diameter. It is fitted
with a three-step cone, the diameters of which are 7f , 11, and 14
inches and carries a 3J-inch belt.

The turret is 12 inches in diameter and has four holes, 2 inches
diameter. It is arranged to be turned by hand, although, of course,
may be made automatic in its action if desired. The turret slide
is 38 inches long and has a movement of 17 inches, with an auto-
matic feed and stop device. The turret shoe or bottom sli^e is
26 inches long.

353

354

MODERN LATHE PRACTICE

The patented rest is a special feature. It is hinged to a slide
which is bolted to the back side of bed, and adjustable for any
length of work. It carries bushing for holding chuck drills, and is
arranged to be turned back out of the way instantly to allow the use
of other tools in the turret. This is a strong, powerful lathe, and
with the Guilders system of three-lip drills and reamers, fully one
third more holes can be made than with ordinary turret chuck
lathes.

The lathe is built heavy and strong and the parts are well fitted
and of good material, so as to stand the hard and continuous service
to which such a machine is subjected, as well as the neglect and the

FIG. 277. — 20-inch Swing Turret Head Chucking Lathe, built by the

F. E. Reed Company.

dirt and sand incidental to chucking work on rough castings. With
a 7J-foot bed the lathe weighs 2,750 pounds.

The turning of shafting requires not only a specially designed
tool carriage, carrying three tools, but there should be a special
arrangement of the feeding mechanism, specially long centers, and
special devices for supporting the long shafts near the cutting-tools
as they are being turned. These conditions have been considered
and provided for in the 24-inch swing shafting lathe, built by the
Springfield Machine Tool Company, which is shown in Fig. 278.

The three-tool shafting rest takes the place of the usual com-
pound rest, and when in place connects the gear upon its oil pump

SPECIAL LATHES

355

shaft to a similar gear on the driving shaft running the entire length
of the bed. In designing the three- tool rest, two of the tools are
placed on the left and one tool on the right of a massive follow rest.
All of these tools are on the front side of the shaft to be turned, in
which position they are convenient to manipulate and their cutting
edges are always in plain sight. Some builders put one of these
tools in a reversed position in the rear of the shaft, to be turned so
as to balance the cutting strains better.

There is a driving mechanism arranged at the tail-stock as well
as the head-stock, which is very convenient when turning shafts
very long in proportion to their diameter, and hence subject to
unusual torsional strains. Either of these drives may be thrown
into gear instantly, Thus in turning a long, slim shaft, that half

FIG. 278. — 24-inch Swing Shaft Turning Lathe, built by the Springfield

Machine Tool Company.

near the tail-stock may be turned with the tail-stock driving
mechanism. As the tools pass the center of the shaft the tail-
stock drive is thrown out of gear and the head-stock drive engaged,
The saving of time by having the drive applied near the point of
resistance to the cutting tools should be considerable on long work.

Attention is called to the substantial manner in which the tail-
stock spindle is clamped in order to render it suitable for support-
ing the driving mechanism, and also for furnishing a large wearing
surface for the supplemental face-plate and face gear upon the
body of the tail-stock.

The method used for guiding the shaft in the follow rest is to
pass it through a split cylindrical collar, one of which is furnished
for each diameter of shaft to be turned. These collars are broad

356 MODERN LATHE PRACTICE

enough to furnish sufficient bearing surface to the shaft to prevent
undue friction or cutting, while they hold the shaft accurately in
place and can be closed up with an adjusting screw to compensate
for any wear that may occur by continued use.

As a copious supply of lubricant is essential in shaft turning,
a duplex single-acting plunger force pump is bolted under the water
reservoir of the shafting rest, from which it receives its supply.
Water is forced up into a tank sufficiently elevated to bring the
supply tubes to the proper height above the cutting- tools. This
tank is arranged with an automatic relief valve susceptible of adjust-
ment so that any desired pressure can be obtained. By this
arrangement the operator need not give any attention to the pump
when he starts up the lathe, inasmuch as it provides auto-
matically for the overflow should no water be required. The water
used may have added to it soda, soap, or any of the usual ingredients
used for such purposes.

On this lathe, when arranged as above, it is only necessary to
remove the shafting rest, replace the compound rest, disconnect
the tumbler gear under the head-stock, and the lathe is ready to
perform any of the ordinary functions of an engine lathe, thus
making it a valuable convertible lathe where there is not shaft-turn-
ing work to keep it going all the time, although that is the primary
object in designing it and that is supposed to be its chief function.

The long centers shown are necessary as they must reach through
the bushing in the shafting rest, which is mainly depended upon to
support the shaft during the process of turning. They are bored
and reamed to the diameter which the shaft is turned by the second
tool (the first tool being a roughing tool), and then split so that by
a little compression, exerted by a set screw provided for that pur-
pose, the bushing is held in position and the shaft is accurately
supported in its proper place.

Some of the principal dimensions of this lathe are as follows:
Front bearing of main spindle, 4 inches in diameter and 7 inches
long. Hole through the spindle, 1J inches. The driving cone has
five steps, the largest of which is 16 inches in diameter and adapted
for a 3J-inch belt. The ratio of the back gearing is 12 to 1. The
feeds are from 4 to 65 per inch. The lathe turns shafting up to
5 inches in diameter. Five feet of the length of the bed is occupied

SPECIAL LATHES

357

by the head-stock and tail-stock. The tail-stock spindle is 2}
inches in diameter and has a travel of 9 inches.

This lathe with a 35-foot bed (to take 30 feet between centers)
weighs, 13,000, pounds, showing its substantial construction and
ability to handle heavy shafting successfully.

Fay & Scott are the builders of an extension gap lathe which
has the advantage over a lathe whose bed is cast with a fixed dis-
tance in the width of the gap, as shown in Fig. 23. In this case there
is a base or lower bed, as shown in Fig. 279, upon which the bed
proper, or upper portion, is mounted and upon which it slides.

FIG. 279. — The Fay & Scott Extension Gap Lathe.

By this arrangement the "gap" can be widened to any distance
desired, or it can be closed up entirely, converting it into an ordi-
nary lathe. This is a great convenience on heavy work, particularly
in a jobbing shop, or in any shop where there is a great variety of
work to be done upon which large diameters occur, as the fly-wheels
on crank shafts, large pulleys, and similar work.

The lathe is triple geared direct to the face-plate, the triple gear
ratio being 34 to 1. The carriage is extended for turning work
the full swing of the lathe, and is supported by an angle bracket
with an adjustable gib on the lower bed. The lathe swings over
the bed 28 inches, and through the gap 52 inches.

The 12-foot lathe takes 6J feet between centers when closed,
and 10 J feet when extended. The gap opens 4 feet, and every
additional foot of bed lengthens the gap 6 inches.

Whatever may be the opinion as to the advisability of building

358

MODERN LATHE PRACTICE

a lathe with two spindles for th& purpose of furnishing a lathe of
large and small capacity, the fact still remains that the two-spindle
lathe, brought out a number of years ago by J. J. McCabe, has
achieved a notable commercial success and many of them are in
use.

An illustration of the 26-48 inch swing lathe of this construction
is shown in Fig. 280, which gives an excellent idea of this machine.

It is impossible in a lathe of this character to so design it
that it shall present a symmetrical contour, however we may view
the matter, yet it seems as if the tail-stock of this lathe might be
somewhat improved in its outlines without detracting from its
strength or usefulness.

FIG. 280. — 26-48 inch Swing Double Spindle Lathe, built by J. J. McCabe.

The lathe has a deep and strong bed and is well supported by
cabinet legs, the one under the tail-stock being arranged to swivel
to fit an uneven floor. The head-stock might be somewhat stronger
to advantage, particularly for the 48-inch swing spindle, but it is
probably a fact that the large swing feature is more in use for boring
and similar work than for heavy work requiring the full swing.
Still we know personally that much large and heavy work is done
on these lathes, and that in shops where such work is an exception
rather than the general rule the lathe proves a valuable addition
to the equipment, saving the expense of a large lathe which, under
ordinary circumstances, would be engaged on useful work only a
fraction of the time.

While the head-stock and tail-stock are ready at all times for

SPECIAL LATHES 359

either the small or large swing, requiring only the necessary chang-
ing of face-plates to suit the work, the compound rest and the
center rest require the use of a building-up or blocking piece when
the change from small to large swing is made, and vice versa.
Naturally the compound rest will not be as stiff and rigid as that
of a regular 48-inch swing lathe, as the compound rest proper is
designed upon lines and with dimensions that appear to be a com-
promise between those of a 26-inch and a 48-inch swing lathe.

The carriage has long bearings upon the bed and is of ample
strength, as is also the apron and its operative parts. The feed is
geared and consequently positive and capable of the necessary
changes expected in a lathe of this character.

The head-stock cone is of five steps and takes a 3J-inch belt.
The head-stock is arranged with four adjusting screws, by means of
which it may be at any time lined up parallel with the ways of the
lathe. The head-stock 'and the tail-stock fit on flat surfaces instead
of V's, thus increasing the normal swing of the lathe without rais-
ing the head spindle, as the inside V's are omitted. The tail-stock
is fitted with a gib on the front side for the purpose of taking up
any wear that will in time take place, and is provided with the
usual set-over screw for turning taper work.

The upper spindle is triple geared and has double the ratio of
back gearing of the lower spindle, while the internal geared face-
plate shown in the engraving is furnished as an extra and gives a
ratio of 72 to 1, giving ample power for large work.

This lathe is also made 24-40 inch, and 26-44 inch swing, while
the one here illustrated and described is also furnished with per-
manent raising blocks or built up solid to swing 32-54 inches. It
is also arranged to run with an electric motor when this method
of driving is preferred.

A pulley turning and boring lathe is shown in Fig. 281, and is
built by the New Haven Manufacturing Company. There are
several features in this lathe which make it of unusual value, not
only for turning and boring pulleys, but for a variety of very useful
work.

Among these are the following: The compound rest has an
unusually long lateral feed. It may be set at any desired angle
and has a power feed, and also a hand feed from either end. The

360

MODERN LATHE PRACTICE

compound rest screw may be disengaged by lifting a latch lever
and the crowning attachment brought into operation.

Ordinarily the crowning of a pulley is effected by making its
two parts with straight lines, leaving the angle of intersection of
these lines in the middle of the face of the pulley. While this answers
the purpose on ordinary pulleys, or pulleys with comparatively
narrow faces, it is manifestly incorrect.

In this lathe the movement of the tool is controlled by a " former "
A, attached to the fixed part of the compound rest and having
a curved slot of proper radius in which the friction roll of a lever
B travels. This lever is pivoted to the compound rest slide and

FIG. 281. — 60-inch Swing Pulley Lathe, built by the New Haven
Manufacturing Company.

its upper end connected to the compound rest tool block by a con-
necting bar which thus controls the movement of the cutting- tool.
Several of these grooved formers, of different radii, are furnished
with the lathe for use with pulleys of different widths of face.

Another feature of this lathe is the automatic feed to the tail-
stock spindle for boring purposes. This feed is of 13 inches travel,
and readily thrown in and out by turning the knob C. In boring
pulleys the proper boring bar is selected, one end placed in the taper
hole in the tail spindle and secured by the clamp dog shown on the
end of the spindle. The opposite end of this boring bar fits in a
bushing in the head spindle, thus assuring a correct and properly

SPECIAL LATHES 361

aligned hole. While this work is being done the pulley may be
held in a chuck, or chuck jaws attached to the face-plate, by the hub
or by the rim. The pulley having been bored is pressed on an
arbor and supported on centers. It is driven by two arms secured
by bolts to the face-plate in the usual manner.

The tail-stock is provided with the usual set-over, the same as in
an ordinary engine lathe, for the purpose of turning tapers. It is
provided with two sets of holding-down bolts so that the top casting
with the spindle may be set over without detaching the tail-stock
from the bed. By this means there is no necessity for removing
the work from the lathe or blocking it up.

The head spindle is driven entirely by means of the internal
gear bolted to the back of the face-plate through a pinion on the
cone shaft. Back gearing is provided by which, with the five-step
driving cone, ten speeds may be produced. A defect in the design
of this back gearing is that the gears are journaled upon a stud
supported at only one end, thus permitting considerable vibration,
which is liable to show by producing chattering of the tool upon the
work.

While the feed is entirely gear driven, provision is made for
accidents to the tool by making the gear upon the end of the cone
shaft with a friction device, by which it will be allowed to slip if
heavy and unusual strain is brought upon it, rather than that the
gear teeth be endangered.

This lathe is not of new design, but has been built in substan-
tially its present form for many years; it is a deservedly popular
machine.

The ordinary length of the bed of this lathe is about 11 feet. It
swings 60 inches over the bed and 50 inches over the carriage and
will take in 50 inches between centers. Its weight is about 10,000
pounds.

The head spindle is bored out so that boring bars of any length
may be used. It will bore and turn pulleys up to 60 inches in
diameter and 19 inches face, and a pulley up to 50 inches in diameter
and 32 inches face.

By throwing out the back gears a fast boring speed is produced,
or the boring and turning may proceed simultanously, if the pulley
is held by the arms on a proper face-plate fixture.

362

MODERN LATHE PRACTICE

There is no arrangement for the employment of a back tool
which might do the roughing work. This fact necessarily limits
needlessly the output of the lathe, as a proper rest for one or more
back tools could be readily and economically provided.

A pulley-turning lathe may be so designed as to become rather
a pulley-turning machine than a lathe proper, and when thus
specialized will usually be a more efficient machine than if designed
strictly on the lines of a lathe. Such a machine is shown in Fig.
282, which is built by the Niles Tool Works, who build these ma-
chines for turning pulleys of 30, 50, and 60 inches diameter.

FIG. 282. — 40-inch Swing Pulley Turning Lathe, built by the
Niles-Bement-Pond Company.

The bed, head-stock and tail-stock are all cast in one piece, and
this casting extends to the floor or foundation and provides a very
rigid support for the operative mechanism of the machine.

The head spindle is driven by spiral or tangent gearing, giving
a very steady movement entirely devoid of the tendency to chatter
as when turning a pulley or other light-rimmed wheel, when the
power is by the usual spur gearing. By this device a much heavier
cut, or a cut at a much coarser feed, may be successfully carried
and consequently the time of performing the operation much re-
duced.

The pulley to be turned is forced on a mandrel or arbor and held
between centers in the usual way for obtaining good concentric
work. As to the method of driving the pulley, there is an equaliz-

SPECIAL LATHES 363

ing face-plate which has arms projecting between the spokes or
arms of the pulley near the rim, and which press equally upon oppo-
site sides of the work so that there is no tendency to spring the pul-
ley out of its proper shape, as is the case when it is held in a chuck.

There are two tool-rests which operate at the same time, one
being in front and provided with an angular feed for crowning the
face of the pulley, and one in the rear carrying an inverted tool and
provided with a hand cross feed. This lathe tool takes the rough-
ing cut while the front tool carries the finishing cut and crowns the
pulley. The angular feed with which the front tool is provided
adapts it for turning bevel gears as well as pulleys. When set to
make a straight cut parallel to the axis of the work it is well adapted
to turning the outside of large gear blanks, balance-wheels, and simi-
lar work.

While the tool at the rear of the machine is often set for a straight
cut, parallel to the axis of the work, it is also provided with an
adjustable slide by which it may be set at an angle for crowning
the face of a pulley or for turning bevel gears and similar work.
This feature is necesary in heavy work particularly, in order to
leave an equal amount of metal to be cut away by the front tool
during its entire cut.

The driving cone is of ample diameter; it is arranged in six steps
and carries a very wide belt. It runs at a proper speed for polish-
ing pulleys, as well as for driving the machine for turning purposes,
and its shaft extends to the front as an arbor or mandrel upon
wiiich the pulley to be polished may be mounted as shown at A,
Fig. 282. A convenient polishing rest is shown at B, which is
used for this purpose.

This machine is not intended for boring the pulleys, this part
of the work being much more expeditiously performed on a chuck-
ing lathe or similar machine, which may be run at a much higher
speed for this purpose.

It frequently happens that small work and that which must be
very true and correct, particularly in tool, model, and experimental
work, a comparatively light bench lathe is much more convenient,
useful and efficient than a floor machine of similar capacity. One
or more of these lathes, of good design and construction, should
form a part of the equipment of every tool room, and of any room

364

MODERN LATHE PRACTICE

in a general machine shop or manufacturing plant where small
work is done.

Such a bench lathe, built by the Waltham Machine Works, is
shown in Fig. 283, and which is a good example of the best grade
of American made bench lathe.

The bed of the lathe is 32 inches long and has a T-groove planed
the entire length of the back side. A bed without this groove will
be furnished, if desired, at a lower price, but such a bed will not
take all the attachments that have been designed for it. The
amount of metal in the bed is distributed so as to give great stability
and rigidity while at the same time pleasing outlines are presented.
These qualities apply equally to other parts of the lathe, beauty
of design being one of its features.

FIG. 283. — 8-inch Swing Bench Lathe built by the
Waltham Watch Tool Company.

The head-stock will swing 8 inches. It has a hardened steel
spindle and bearings, carefully ground and run together. It is very
smooth running and the finest work can be done with it. The
pulley has three steps of 3, 4, and 5 inches in diameter and will take
a belt 1J inches wide. The larger flange has three circles of index
holes, the numbers being 48, 60 and 100. The spindle is adapted
to take split chucks of the most approved pattern, which will
take wire up to f inch in diameter through its entire length.

The spindle of the tail-stock passes entirely through the
casting, so that whatever its position it always has its full bearing
(6f inches). It is graduated to tenths of an inch, while the grada-
tions on the hand wheel read to 1-200 inch. The front side of the
casting is cut away to give more room for the slide-rest. By this
means the lathe can be used closer to the center than would other-

SPECIAL LATHES 365

wise be the case. The back side of the casting is reinforced to give
the necessary stiffness.

The base of the slide-rest rests directly upon the bed of the
lathe, and its squaring device has a bearing on the front of the bed,
below the lowest part of the head-stock and tail-stock. This gives
the opportunity to make a long squaring device, thus insuring
greater accuracy, and also to have the bearing where there is less lia-
bility of trouble from chips, dirt, etc. The builders also make a
swivel squaring device by means of which angles can be turned or
ground with the cross slide, thus enabling one to make two angles
with one setting of the slide-rest. This is a valuable feature in
making special cutters or mills, or in grinding spindles and bearings
having two angles.

The feed screws have hardened bearings, and are provided with
indices that are graduated to read to 1-1000 inch on the swivel
screw, and to 1-2000 inch on the cross-slide screw, the latter division
being adapted so that the movement of one graduation on the
index will make a difference of 1-1000 inch in the diameter of cylin-
drical work which is being turned or ground.

The tool-slide is made flat on top to take various attachments,
and has two T-grooves for the tool-post. Ordinary lathe tools are
used. The slides are carefully scraped together and the whole slide-
rest is neatly ornamented.

For holes and for light outside grinding there is an inside
grinder that is arranged so that the lap can be swung away from
the hole, for testing the size, and then returned instantly to its
original position.

The outside grinder for general work is clamped directly upon
the tool-slide and has a vertical screw adjustment. It is arranged
so that an emery wheel can be used on either end, and there is a
taper hole in the front of the spindle to take arbors for small laps.

Two methods of thread cutting are provided for. The first is on
the Fox lathe principle and is attached to the T-groove on the
back of the bed. Any even multiple of the lead screw thread up
to ten times can be cut, and with a few extra lead screws all ordi-
nary threads can be cut. This method of thread cutting is the
most rapid, but under conditions in which a great variety of threads
must be cut some machinists will prefer to use the slide-rest. By

366 MODERN LATHE PRACTICE

this style of thread-cutting attachments this lathe will cut all
threads from 5 to 100 per inch, and all between 5 and 50 to the
centimeter can be cut.

There is also a special milling attachment, which is a stand
consisting of a base made to take the regular head-stock, and is
provided with a slide which takes the regular slide-rest. The verti-
cal slide has both a screw and lever feed, so arranged that the change
from one to the other can be made instantly. A vise for plain
milling, or an indexing head for gear cutting and cutter making,
can be attached to the tool-slide of the slide-rest. This combination
makes a practical bench milling machine upon which a great variety
of work can be done.

While the descriptions of engine lathes are confined to the lathe
proper, leaving the subject of their attachments and accessories to
be treated in another chapter, it seems advisable to include in the
above description the various attachments of this bench lathe, as
they are essentially different from those used upon or in connection
with an engine lathe, and for different purposes.

In addition to the attachments above described it is frequently
the case that others for special work are frequently devised and
added to the bench lathe equipment, making it a very useful ma-
chine and capable of performing a great many different operations,
among them many which cannot be performed on the regular
engine lathe without the aid of expensive attachments and fixtures.
These qualities make it one of the most useful machines in the shop,
especially where small experimental work and fine tool making, jigs,
and fixtures are to be produced.

A plain 10-inch swing wood-turning lathe for light manufacturing
work or for pattern work is shown in Fig. 284, which possesses some
peculiar features worthy of attention. The lathe is built by the
F. E. Reed Company.

One of the special features of this lathe is the manner of con-
structing the head-stock, a vertical section of which is given in
Fig. 285. The spindle has a single bearing in the head-stock, which
extends over a large proportion of its length, the face-plate being
attached to the front end as usual, and the three-step cone pulley
attached at the opposite end, fitting upon the spindle for a distance
about equal to one of its steps and carried by a flanged collar which

SPECIAL LATHES

367

is fastened to it by screws and resting against a fiber washer with
the wear or end thrust taken up by a suitable adjustable collar at
the end of the spindle.

There is a ^g-inch hole through the spindle, whose bearing in
the head is lysg inches diameter and 7J inches long, while there is
also an outer bearing, formed by the small end of the cone running
on the outside of the head-stock, 2116- inches diameter and 3f inches
long, giving 50 square inches of wearing surface in the head-stock,
which is at least three times more than is obtained in the head-
stock of an ordinary wood-turning lathe of this swing.

FIG. 284. — 10-inch Swing Wood Turning Lathe, built by the
F. E. Reed Company.

The head spindle is a crucible steel forging, and runs in com-
pressed genuine babbitt metal bearings, special care being used to
make the inner and the outer bearings truly cylindrical and con-
centric with each other.

As to the wearing qualities of these head-stocks the manu-
facturers say:

"We have made and sold over six hundred of these lathes
during the last eight years. For over six years we have had one
of them in constant use in our works as a polishing lathe. This

368

MODERN LATHE PRACTICE

is very severe usage for a lathe, but during all this time it has
required absolutely no repairs, and no special attention beyond
seeing that it was kept properly oiled with a good quality of lubri-
cating oil. We have a large number of most excellent testimonials
from schools that have used these wood lathes for a number of
years."

The countershaft is of very simple construction and of similar
design to the head-stock. In place of the usual tight and loose
pulley with the belt operated by a shipper rod and lever, the belt

FIG. 285. — Head-Stock of Reed Wood Turning Lathe.

fork is handled by a vertical rod, the lower end of which hangs in a
position convenient to the operator, who has only to give it a turn
to the right or left by means of a short handle to start and stop the
lathe.

The V's in the bed are inverted, or planed out, and the head
and tail stocks are fitted into them, instead of upon them, which
is the usual way. This allows a perfectly free and level surface
across the top of bed and shelf on back side, without any obstruc-
tion, besides protecting the V's from being jammed. The upper
angle of V is rounded where it meets the surface of the bed, which
also prevents jamming or injury of the bed or V at this place.

The T-rests, instead of being the usual form, are concaved, with
a projecting lip on the bottom which serves as a finger gage for
the operator while using the turning tool. The T-rest holder is

SPECIAL LATHES 369

secured to the bed by a clamping device that is neat, strong, and
quickly operated. There is a shelf on the back side of the lathe,
parallel with the top of the bed, and of the same height; another
shelf is also furnished underneath the bed, as shown in the engrav-
ing. A hook or holder, with proper support for the same is shown.
This is for holding a blue print, or sample of the work, before the
operator, and can be raised or lowered. The form of the lathe bed
in connection with the extra speed of the legs, and the manner of
attaching the lower shelf, all combine to insure steadiness of the
lathe when run at the high speed for which it is designed; and each
lathe is run five hours at 2,600 revolutions per minute before leaving
the works, to see that it is in every respect right.

The workmanship on this lathe is fully up to the standard of the
work usually done by this company, which is sufficient guarrantee
of its quality.

CHAPTER XX

REGULAR TURRET LATHES

Importance of the turret lathe. Its sphere of usefulness. Classification of
turret lathes. Special turret lathes. The monitor lathes. The Jones &
Lamson flat turret lathe. Its general design and construction. Its
special features. Its tools. The Warner & Swasey 24-inch swing uni-
versal turret lathe. Ganeral description. Its capacity. Taper turning
attachment. Its speeds. The Bullard Machine Tool Company's 26-
inch swing complete turret lathe. Its massive form and its general design
and construction. Lubrication of tools. The countershaft. The Pratt &
Whitney 3 by 36 turret lathe. Its special features. Its general desing.
Its capacity. Special chuck construction and operation. The Gisholt
turret lathe. Its massive design and construction. Its large capacity.
Its general and special features. The Pond rigid turret lathe. Its heavy
and symmetrical design. Detailed description. Its operation. Gen-
eral dimensions.

WHILE the regular engine lathe is in almost universal use wher-
ever machine work is done, and while it is the one indispensable
tool in every machine shop, the modifications of it in the various
forms of a turret lathe are becoming second only in the importance
and the range of its work. So great has been the advance in this
respect during recent years that nearly all machine shops, even
small jobbing shops, are not considered as possessing a passably
modern equipment without one or more turret lathes.

Formerly it was not thought worth while to " set up" a job on
a turret lathe unless there were fifty or more pieces of the same kind
to be machined. It is now a common occurrence to use the turret
lathe when only half a dozen pieces of a kind are to be made. The
reasons for this are that formerly special tools had to be made for
many of the jobs attempted, whereas now we have a great many
regular tools furnished with the turret lathe that are of such form
and construction as to be available for nearly all the ordinary turret

370

REGULAR TURRET LATHES 371

lathe jobs, while the addition of an extra tool now and then for
special work, or a special form, will adopt the turret lathe for a very
large variety of work, which may thus be performed with a great
degree of accuracy, with a very good finish and in a very economical
manner.

Where large numbers of pieces of the same kind are to be made,
it is usually the practice to make special tools whenever better
work or a larger output can be thereby secured. This will be
largely a matter of practical judgment of the man in charge of the
work.

We may divide the turret lathe proper, and the engine lathes
when used as turret lathes by the addition of a turret, into five
classes, according to their design and methods of operation, namely :

First, the engine lathe serving as a turret lathe by mounting a
hand-revolved turret upon its carriage, in place of the usual com-
pound rest.

Second, the engine lathe serving as a turret lathe by mounting
a hand-revolved turret upon the bed by means of a shoe or saddle
which supports the turret slide.

Third, a turret lathe proper, built as such, with a turret pivoted
to a slide supported by a shoe or saddle; the turret being revolved
and fed by hand.

Fourth, a turret lathe similar to the last and sometimes called
a " semi-automatic turret lathe," in which there is a power feed on
the cut and the turret is revolved automatically at the end of the
stroke.

Fifth, a complete automatic turret lathe with power feed on the
cut, a quick power return, and the turret automatically revolved
at the end of the stroke.

Those in the third, fourth, and fifth classes are usually provided
with a cut-off slide carrying one tool in front and frequently an
inverted tool at the back.

Various examples of these different classes will be illustrated
and described in the following pages, giving the designs built by
several of the prominent manufacturers of this type of machines.

There are, of course, special machines of this general type of
lathes built for special purposes. There are modifications of the
general class, into the details of which it is impossible to go in these

372 MODERN LATHE PRACTICE

pages, since it is the object to present distinct types or classes, rather
than to expand this work to the dimensions of a cyclopedia on the
subject of lathes.

There is one type that deserves special attention on account of
its valuable service on small work, and that has been known in the
shop for many years as a "monitor" lathe, from the fact, no doubt,
of its resemblance to the turret of a monitor. The slide upon which
the turret is pivoted is run forward and back by a lever which makes
it very rapid in operation. It is usually built for small work only.

The Jones & Lamson flat turret lathe is now so well known that
an extended description of it seems hardly necessary, and yet its
importance in the manufacturing world of to-day, and its many
points of real mechanical interest and importance, demand more
than a passing notice.

A front view of one of these machines is given in Fig. 286, this
particular machine being 3 x 36-inch size, that is, it will work up a
3-inch bar and the turret has a run of 36 inches on the bed.

As will be seen the bed is supported by strong and well designed
legs in a pan nearly the full size of the machine. The head-stock
and its gearing is covered by a protecting case which moves with
it. One of the peculiar features of the machine being the sliding
head which has a transverse movement for the purpose of increasing-
its effective working capacity. The turret is mounted upon a
saddle fitted to broad V's upon which it has a long bearing, insuring
accurate results.

The turret is a flat circular plate and is mounted on a low car-
riage containing controlling mechanism. The connections of the
turret to the carriage, and the carriage to the lathe bed, are the most
direct and rigid, affording absolute control of the cutting-tools.
The turret is accurately surfaced to its seat on the carriage by scrap-
ing, and securely held down on that seat by an annular gib. In the
same manner the carriage is fitted to the V's of the bed; the gibs
passing under the outside edge of the bed. The breadth of this
bridge across from V to V makes an unyielding mass to which the
tools can be affixed.

The indexing mechanism of the turret is of the greatest impor-
tance, and in this particular point the flat turret lathe seems to
have an exceptional advantage. Its index pin is located directly

REGULAR TURRET LATHES

373

under the working tool, and so close to it that there can be no lost
motion between the tool and the locking pin. The turret is turned
automatically to each position the instant the^tool clears the work
on its backward travel, and it is so arranged that by raising and

lowering trip screws near the center of the turret it may be turned
to three, four, or five of the six places without making any other
stops. )

The power feed for the carriage is actuated by a worm-shaft.

374 MODERN LATHE PRACTICE

The worm is held into its wheel by a latch which is disengaged by
the feed stops. There are six feed stops, one for each position of the
turret, and they are independently adjustable. This feature of
an independent stop for each tool will be appreciated by the users
of the other turret lathes, some of which have only one stop for
all turret tools. These feed stops are notched flat bars placed side
by side in the top of the bed. They also serve as a positive stop.

The head-stock is of such great importance that weakness here
would mean a weak link in the chain. Greatest care has been
exercised to make the head-stock equal in stiffness to the turret.

The spindle is ground to size, and its phosphor-bronze bearings
are scraped to give a perfect contact. A 2J-inch hole extends from
end to end, through which the bars of stock pass.

The caps to the spindle bearings are fitted over large hollow
posts which make the top half of the box practically as rigid as the
lower half.

The cone and large gear are loose on the spindle and connected
at will by friction clutches. The large gear is covered with a hood
which protects it from chips and dirt, ensuring smooth running.
The back gear is placed below the cone in the head, and a triple
back gear, when required, is placed beneath the regular back gear.
The regular back gear gives a 4 to 1 proportion, and the triple gear
makes a 16 to 1 speed. The triple gear is required for all standard
screw threads above If inches in diameter, and in chucking work of
large diameter.

The die carriage carries a die of any kind, and a pointer for sha-
ping the end of a shaft or bolt. This carriage is mounted on a
sliding bar and arranged to swing into wrorking position. It is
provided with lugs which take bearing on the top of the cross-
slide, which tool must be in operative position when the die
carriage is used. The pointing tool may be used as a turner for
reducing the stock.

The bed rests on a " three-point " bearing, making it impossible
to twist or vary the deflection of the bed by an unsteady or un-
natural foundation.

A drainage bed and double overflow reservoir with circular
pump are clearly shown in the engraving, and are too simple to
need explanation.

REGULAR TURRET LATHES

375

The head receives its power through a triple friction counter-
shaft of unusual proportions and running speed. The three friction
pulleys are 12 inches in diameter by 4 inches face; two run 300 revolu-
tions per minute, and the remaining, or middle, pulley runs 150
revolutions per minute.

FIG. 287. — Top View of Turret Parts of Jones & Lamson Flat Turret Lathe.

These pulleys have extra long hubs that extend an equal distance
each side of the "pull of the belt" (each side of the rim), and per-
fectly distribute that strain over its entire bearing on the shaft.
The shipper rod is so connected that it will act on any one of the
three clutches at the will of the operator.

The tools used in this machine are of the usual nature but of
improved design in many cases, and are well shown in Fig. 287, as

376

MODERN LATHE PRACTICE

they appear on the machine, in the top view taken from the rear
end, and at the 'front of the machine, looking toward the head-stock.

The machine tools built by Warner & Swasey are known wher-
ever American machines are used as being of good design, good
materials, and good workmanship. In fact, some of the finest ma-
chine work turned out in this country comes from their shop.

Their turret lathes are no exception to this rule, and in Fig. 288
is shown their 24-inch swing universal turret lathe, which is a good
example of a lathe of this type, adapted to a large variety of work
such as iron and brass valves, from 3 to 6 inches, gears, pulleys,
bearings, machine parts of circular contour, and general chucking
work requiring drilling, reaming, and facing.

FIG. 288. — 24-inch Universal Turret Lathe, built by Warner & Swasey.

The bed is 8 feet 7 inches long, and is deep and heavily ribbed
as it should be in a lathe of this kind. The head-stock is cast in
one piece with the bed, rendering it strong and rigid against the
weight of the work and the torsional strain of the machining opera-
tions. The spindle cone is of three steps, the largest of which is
16 inches in diameter and adapted for a 4-inch belt. The spindle
has a 2J-inch hole all the way through. From the end of the spindle
nose to the face of the turret is 36 inches when at its extreme
position.

The friction back gears give two speeds without stopping the
machine, the ratio being 8 to 1.

The turret is hexagonal in form and has a very large bearing
upon the carriage. It is 14 inches across flats and has six 3-inch

REGULAR TURRET LATHES 377

holes, allowing 2J-inch bars to pass through it. The carriage has
a longitudinal travel of 32 inches and a cross travel of 12 inches.

Two sets of independent adjustable stops are provided for each
face of the turret, one operating with the longitudinal and the other
with the cross travel of the carriage. When the general work which
the lathe is expected to do renders these stops superfluous, they may
be omitted from the regular equipment.

The geared feeds, both for the longitudinal and the cross cuts,
give six changes, any one of which is made instantly available by
moving a lever. These feeds are so designed that they will give
respectively 4, 7, 12, 16, 28, and 48 to the inch for every revolution
of the main spindle; that is, the spindle will make these various
number of revolutions while the feeds advance 1 inch.

The lead screw is provided with the proper gears for cutting 2,
3, 4, 5, 6, 7, 8, 9, 10, 11}, 12, and 14 threads per inch. Finer threads
than these are not likely to be required on a lathe of the capacity
of this one.

There is a taper turning attachment for turning tapers up to
3 inches per foot, which is furnished only when specially required.

The machine is driven from a triple friction countershaft which
has 16-inch pulleys adapted for a 4}-inch belt. One of these pulleys
runs at a speed of 100 revolutions per minute and the other at 140,
which gives twelve spindle speeds ranging from 53 to 264 per minute
without the back gears, and from 7 to 30 revolutions per minute
when the back gears are in use. A third pulley is designed to
run the spindle backwards.

The weight of this machine is 4,500 pounds, which shows its
substantial and massive character.

This firm make a variety of styles and sizes of turret lathes
adapted to a large class of products.

The Bullard Machine Tool Company enjoy a reputation for
turning out first-class machines. This applies equally to the
design, the material, and the workmanship.

In Fig. 289 is shown one of their 26-inch swing complete turret
lathes, or as might be more comprehensively termed, turret machines

The machine is of massive design, the bed deep and strongly
braced. It is provided with heavy top members or tracks, carrying
broad V's, and surrounded by a proper pan for catching and carry-

378

MODERN LATHE PRACTICE

ing off whatever lubricating material is used. The bed is well
supported at the head end by a broad cabinet, made long enough
to furnish a solid support under the front box of the main spindle.
At the rear end, where much less support is required, a leg is deemed
sufficient.

The head-stock is of ample length to furnish large housings for
the main spindle boxes, as well as sufficient space for a three-step
cone of liberal dimensions and the necessary back gears, clutches,
etc. The largest section of the cone is 16 inches in diameter and

REGULAR TURRET LATHES 379

adapted for a 4|-mch belt. The spindle is bored out to 3| inches
and is fitted with a chuck of suitable design for taking hexagonal,
square, or round bars. The spindle is driven by triple gearing and
is fitted with a patented friction clutch for instantly changing from
belt speeds to either set of gears without stopping. The change to
back gears is made by moving the clutch lever, and to the triple
gears by means of the lever shown on the back of the front spindle
bearing, thus obtaining three speeds from the cone, three through
the double train of gears, and three through the triple train of gears,
making nine spindle speeds in all. ,

The carriage is designed to be heavy and strong and has a long
bearing upon the bed, to which it is securely gibbed. It is provided
with a taper attachment, reversible cross and lateral feeds, which
are driven by gearing from a splined lead screw, the thread of
which is used only for thread cutting, thus insuring accurate work
of this kind. At the front of the bed and directly below the large
step of the spindle cone are seen the carriage stops, which are ad-
justable in a group upon the bed, and independently as the work
may require.

The cross-slide is unusually wide and is operated by a screw and
a three-ball crank. There are three tool-posts so that forming cuts
may be made as well as the usual cutting-off operation performed.

The turret is hexagonal in form and 14 inches across the flat
surfaces. The tool holes are 3J inches diameter and the center
stud is drilled with a hole of the same diameter so as to allow a bar
to pass entirely through. The tool faces are also drilled with four
holes each for use in bolting on large tool-holders. The turret is
provided with an automatic feed and trip, and with a patented
device for unlocking and revolving it at any point between 8 and
22 inches of its run. It is pivoted upon a long top slide provided
with stops at the rear end and may be operated by the automatic
feed or by the capstan levers in the usual manner. The top slide
is well supported by a long and broad bottom slide or base, firmly
clamped at any point on the bed, and moved along the bed by a
rack and pinion device.

The lubrication of tools is amply provided for, the lubricant being
pumped from a tank on the floor and up through two pipes properly
jointed so as to deliver two streams of lubricating compound at a

380

MODERN LATHE PRACTICE

time at the points desired. Situated over this tank and beneath
the pan surrounding the bed, is a secondary pan supported on wheels
so as to be readily removable when it is desired to clean it out. Into
each end of this, oil and chips drip from the two lips seen at the

right and left. This feature
" ^^^s\ will be duly appreciated by
I . the operator, who has been
/f § accustomed to clean out the
/ & pans of the older style ma-

chines.

The countershaft has three
friction pulleys 20 inches in
diameter, for 4 J-inch belt, and
runs respectively 96 and 144
revolutions per minute for-
ward and 144 revolutions
backward. The weight of
the entire machine is 9,500
pounds, which is a very lib-
eral weight for a machine of
this capacity, and insures
great rigidity and strength of
its principal parts.

Another notable machine
brought out by the Pratt &
Whitney is their 3 x 36 tur-
ret lathe; that is, a lathe ca-
pable of handling a 3-inch
bar of round stock and in
which the turret has a run of
36 inches. The machine is
well shown in perspective in
Fig. 290 and a plan of it is given in Fig. 291.

As may be assumed from its capacity it is a very rigid machine
in which the bed, head-stock and pan are cast in one piece. On
account of the great quantity of oil that is necessary to use upon it
when machining bar stock, the bed is set in a pan of ample propor-
tions and well supported on heavy legs, those under the head-stock

1
i

REGULAR TURRET LATHES 381

being very broad and furnishing a support under the entire length
of the head-stock. The compound casting for bed, head-stock,
and pan is shown in Fig. 291.

One of the new features of the machine is the chuck, which is
arranged to handle bar stock considerably above or below size with
the same gripping force as if the bar were true to size. This is a
feature of much value in machining the larger sizes of rough stock
in which there is usually considerable variation in the diameter even
at different points along the same bar, as well as the frequent occur-
rance of slight bends in the bar that render it difficult to handle in
the ordinary turret lathe chuck.

FIG. 291. — The Single Casting Combining the Bed, Head-Stock and Pan of the

Pratt & Whitney Turret Lathe.

This machine is regularly driven by a three-step cone pulley
adapted for broad, double belts. This cone pulley, in conjunction
with the double friction back gears and a three-speed countershaft
of improved design, gives to the main spindle twenty-seven speeds,
or nine for each step of the cone. These nine different speeds with
an open belt range from 78 to 550 revolutions per minute, and the
eighteen back gear speeds run from O^Q- to 182 revolutions per
minute. This great range of speed adapts the machine to handling
all work, not only from 3 inches in diameter down, but all classes of
materials as well, so that it does its work under a very large range
of conditions and circumstances.

The turret slide has power feed for turning lengths up to 36
inches, and the driving device for the feed mechanism for the turret
and cross-slides is by means of a silent chain which is driven from
a sprocket wheel on the spindle, from whence it leads down to a
gear box containing the variable speed gears for giving the different
rates of feed. The shaft for operating the turret and cross-slide

382

MODERN LATHE PRACTICE

located at the rear of the bed, and the gear box mechanism is oper-
ated by the two short levers in front of the head-stock as seen in
Fig. 290, and by which four rates of feed in either direction are
obtained for either the turret slide or the cross-slide. The turret

feeds range from .007 to 0.23 inches
and those of the cross-slide from .0014
to .004 inches per revolution of the
main spindle.

There are dovetailed upper and
lower edges on the hexagonal turret
faces, to wrhich tools may be rigidly
clamped, and each tool is provided
with an independent stop which is car-
ried in an adjustable bracket fixed to
the front of the bed.

By referring to the plan view of the
machine in Fig. 292, at X, it will be
seen that there are six stops placed side
by side in the bracket above referred to.
Each one of these, when adjusted, is
held by an independent screw. As the
turret is rotated a cam at the bottom
operates an arm carried on a rock-shaft
at the side of the turret slide and
swings it into line with the proper
stop in the bracket. This rocker arm,
or turret stop, is always rigidly sup-
ported, as in all positions the rear
face rests against a machined surface
on the slide.

The cross-slide carries two tool-
posts of good design for holding tools
rigidly, and may be adjusted at any
point along the bed that the work re-
quires by a hand wheel at the front end of the head-stock

The peculiar construction of the chuck referred to above is
worthy of special attention and may be understood by reference to
the sectional engravings and the following description of its mechan-

REGULAR TURRET LATHES

383

ism. In Fig. 293 is shown a section of the chuck and its related
parts, and in Fig. 294 its operative mechanism. In the former en-
graving D is a portion of the
nose of the spindle, and E the cap
screwing on over it. G is the
chuck jaws and H the closing col-
lar. This collar as well as the
jaws of the chuck and the wearing
surfaces of the cap are hardened
and ground, and the rear end of
the latter is made a sliding fit in
the spindle bore, while its front
end is ground to a sliding fit in FIG. 293. — Chuck Construction of the

the ring F, which is hardened and

Pratt & Whitney Turret Lathe.

forced into the nose of the spindle D, and then ground while the
spindle is running in its own journal boxes.

The chuck jaws have square shoulders abutting against the cap
and open and close without end movement, as the spring plugs

FIG. 294. —Chuck and Rod Feed Mechanism of the Pratt & Whitney

Turret Lathe.

keep them in contact with the cap when released by the closer.
The jaws for each nominal size of stock are adapted to hold bars
332 inch over size, or ^ mcn under size, and anywhere within
this range they maintain a parallel grip on the bar. This is due to

384 MODERN LATHE PRACTICE

the fact that the contact between jaws and closer is always a line
contact along the middle of each jaw, the surface at either side of
this line being relieved so as always to clear the conical seat in the
closer.

To give the jaws a uniform gripping pressure upon the work,
regardless of the variation in size from standard, provision is made
for first bringing them into contact with the bar by operating a
lever, after which they are closed tight by means of a second lever,
both levers being mounted at the front of the head and about a
common axis, as shown in Fig. 290.

Referring again to Figs. 292 and 294 it will be seen that the
rear end of the spindle carries two sliding rings actuated by inde-
pendent yoked levers; these latter are connected by links with the
operating levers just mentioned.

The ring C, Fig. 293, is fitted with a pair of racks each of which
engages with a -spiral pinion formed at the center of a right and
left-hand screw; the front ends of the screws fit holes tapped in
collar A, which is secured to the spindle, while the rear ends are
screwed into the sleeve B which carries the chuck-closing fingers J,
whose heels are always in contact with the lugs of the chuck-closing
tube K, the rollers at the outer ends resting against the shoes
carried in the ring I. The yoked lever N, operated through the link
0 by the inner of the two vertical levers in front of the head, is con-
nected also by the slotted link L with the stock-feed mechanism at
the rear.

When the chuck is opened and the stock stop swung down from
the head, the inner lever is thrown over, forcing the link L toward the
rear and clutching the gear M to the feed screw, which is then driven
from the spindle in the right direction to draw the bar forward
against the stock. When the bar is in contact with the stop the
clutch throws to the middle position as shown, stopping the screw;
the lever is then thrown in the opposite direction, sliding the ring C
on its bearing, and by means of the racks, spiral gears and right and
left-hand screws the sleeve B, with fingers J and tube K, is drawn
forward, forcing the chuck jaws into contact with the bar. The
outer lever is then operated to push back the ring I and close the
chuck down hard upon the work.

The manipulation of the levers takes but an instant, and it will

REGULAR TURRET LATHES 385

be noticed that no matter what the position of the closing tube K
may be when the jaws are in contact with the stock, the pressure
exerted through the fingers J and the sliding ring I is always uni-
form and effective.

The upright at the outer end of the stock-feeding apparatus
carries an adjustable rotating support for the bar stock, and the
traversing bracket R actuated by the screw is adapted to receive
various sizes of bushings corresponding to the collars secured to the
stock.

When the feed bracket has reached its extreme forward position
it is run back by moving to the left the short lever shown in Fig.
290, which clutches the reversing gear M to the screw. The clutch
between gears M and S is normally held in mid or inoperative posi-
tion by the spring plungers at the lower end of the arm P. The gears
are driven continuously (so long as the spindle is running ahead), by
the double gear Q on the sleeve above ; the clutch connecting the
driving gear to the spindle end is so formed, however, as to be in-
operative if the spindle is reversed, thus making it impossible to en-
gage the feed accidentally before the spindle is again started ahead.

Taken altogether this mechanism represents the latest and best
development in its line for the purposes intended, and is in keeping
with the usual practice of this company of careful designing and
good, practical construction.

The Gisholt turret lathe occupies, a somewhat different field
than that usually covered by the other manufacturers of turret
machinery, in that the machines are much larger and heavier and
of much greater capacity, handling very large and heavy work.
While there are none of the other builders who make a turret lathe
of much over 30-inch swing, the Gisholt lathe is built as large as
41 J inches, this largest size weighing about eight tons, while there
are very few of those of other builders weighing more than one half
as much.

Figure 295 shows this machine swinging 41 J inches over the
bed. As will be seen, all the parts are very massive and calcu-
lated to withstand the heaviest strains to which a machine of this
type could possibly be subjected.

The bed reaches to the floor (or properly to a well built founda-
tion raised slightly above the floor, upon which a machine of such

386

MODERN LAJHE PRACTICE

weight should always be placed), and has the head-stock cast in
one piece with it so. that the greatest amount of rigidity maybe
preserved. The housings carrying the boxes for the main spindle

are heavy and of ample
width and are three in num-
ber, giving all necessary sup-
port to the spindle. The
back gears are placed over
the spindle and out of the
way, making the machine
considerably narrower at this
point than if they were
placed in the rear, as is
usually the case. They are
of coarse pitch and wide face,
giving ample power for all
occasions.

The wearing surfaces
throughout are made very
large, all sliding surfaces
being scraped to standard
surface plates, and all spin-
dles, arbors, etc., are finished
by grinding on dead centers.
The head-stock is friction
back geared, and is also pro-
vided with an extra power-
ful back gear for doing the
heaviest class of work for
which the machine is
adapted. The spindle is
made of forged steel and
runs in reamed and scraped bronze boxes.

The turret is hexagonal and very large, in order that heavy tools
may be rigidly secured to it. It slides directly on the ways of the
machine and hence has the full traverse of the bed. This permits
of the use of long boring bars, the outer ends of which may be sup-
ported in a bushing in the chuck.

REGULAR TURRET LATHES 387

The carriage is provided with a turret tool-post carrying four
tools, any one of which may be instantly brought into position for
cutting. These tools are independently adjustable as to height.
The cross feed has micrometer index reading 1-1000 of an inch.
Power cross feed and taper attachments are provided if desired.
For each tool in the tool-post and for each face of the turret feed
and dead stops, independently adjustable, are provided, by means
of which the feed may be thrown out automatically at any desired
point. The feed works are entirely novel and permit of four changes
of feed being instantly obtained, either from the end of the machine
or from the turret slide. The feed is also instantly reversible.

The four tools which may be carried in the carriage tool-holder
are held by means of a large square plate, forced down by a heavy
screw in its center. The tools are placed under the edges and parallel
to them and brought into active position by the entire tool-holder
top, swiveling turret-like upon a central pivot, when raised to
the proper position for that purpose. Stops, independently ad-
justable, are arranged for each of these tools, both for lateral and
cross feeds.

Turret stops are arranged at the rear of the machine and may
be severally brought into working position by rotating the cylin-
drical carrier. They are, of course, independently adjustable.

In Fig. 296 is given a view of the top of the machine, which will
serve to show the various operative parts of the turret and its stops,
the revolving tool-holder on the carriage, and the taper attachment,
much more clearly than is shown in the front view in Fig. 295, and
on a much larger scale.

This description might be much more elaborate but the machine
is quite well known among practical shop men and those having
any special connection with this branch of machine business, and
further details do not seem necessary.

Pond tools are considered good tools and are usually designed
heavy enough and strong enough to stand the strain of any work
that the machine may be called upon to do. While this remark
applies to a great extent to all Pond tools, it is particularly applicable
to the Pond rigid turret lathe, represented in Fig. 297, which well
illustrates its massive construction. This is particularly true of
the tool carriage and of the saddle which supports the turret, as

388

MODERN LATHE PRACTICE

well as the bed, which has the supporting legs cast with it. Its
design is such as to furnish the best resistance and support for both
the strain of weight and of torsion.

FIG. 296. — Top View of Gisholt Turret Lathe.

The swing over the carriage is almost as great as that over the
ways, which permits the use of tool-post tools directly behind the

FIG. 297. — The Pond Rigid Turret Lathe.

work, and also allows the carriage to be run behind the chuck so
that the turret may be brought up close to the chuck. Short,
rigid tools with practically no overhang and short boring bars can

REGULAR TURRET LATHES

389

therefore be used. In no other machine is this feature available.
The design of the turret provides for six faces, three of which are
of extra width, permitting the heaviest facing, multiple-turning, and
forming tools to be rigidly attached.

This turret is illustrated in plan in Fig. 298 and in elevation in
Fig. 299, showing the narrow
faces at A, A, A, in both fig-
ures and the wide faces B, B, B.
In the use of a tool held upon
a shank it is obvious that the
width of the face A is ample, as
all that is necessary is sufficient
strength around the tool-hole
D, which is provided for in the
square surface at A. In the
case of large fixtures such as
the inserted blade reamer for
a conical hole shown at the
front of the turret in Fig. 297, the very wide face, provided with a
groove across the center into which a rib on the tool base fits, and
the two T-slots for the four bolts securing it to the turret, are
manifestly very valuable in holding the tool stiff and rigid, and
doubtless suggested the name of " rigid turret," as there is every
reason to assume such condition from the excellent design.

The turret is semi-automatic in its movements, the rapid forward
and return movement and its rotation being controlled by one

lever. It is indexed by worm
and worm-wheel, centered by
taper tool-steel locking pin, and
clamped automatically by wide
clamp rings having bearing a on
its entire diameter, thus insuring
both accuracy and rigidity. It

FIG. 298. — Plan of the Turret of the
Pond Rigid Turret Lathe.

FIG. 299. — Elevation of the Turret of
the Pond Rigid Turret Lathe.

is arranged with hand wheel for operation by hand if desired.

Separate feed-screws are provided for turret and carriage, giving
instantaneously six different feeds with same change-gears. Any
feed available may be used on both the turret and cross carriages
at the same time.

390 MODERN LATHE PRACTICE

The spindle bearings are of very large diameter and the hole
in the spindle is 4J inches in diameter, counterbored to 5J inches
in diameter, 18 inches in depth, so as to permit boring bars with
both roughing and finishing cutters to be used; the roughing cutter
being inside the spindle when the finishing cutter is at work. Head-
stock has self-oiling bronze bearings and a two-step cone, providing
for a very wide belt.

A complete line of standard tools is furnished with these
machines for boring, facing, and turning. The firm has a depart-
ment solely for this purpose, making a specialty of designing and
furnishing box tools and dies for any work that can be handled on
a turret lathe, and adapted to this machine and other machines
of its class.

It will be noticed by reference to Fig. 297 that the changes of
speed in the head-stock are effected by a single lever; the changes
of feed by three levers and two index arms giving a great variety
of feeds and adapting the machine to work on all kinds of metals
and all diameters and forms having a circular cross section.

The general dimensions and capacities of the machine are as
follows: swing over the V's, 28 inches; over the cross-slide, 24 J
inches; hole in spindle, 4J and counterbored to 5J inches for a
depth of 18 inches from the front of the spindle. This machine will
take in a bar 4J inches in diameter. The spindle bearings are:
front bearing, 8x9 inches; rear bearing, 5J x 6 inches. All threads
from \ to 64 per inch can be cut. The spindle speeds are twenty in
number, and from 1J to 182 revolutions per minute in regular geo-
metrical progression. The gearing ratios for the head-stock are
respectively 3i to 1, 8} to 1, 22 to 1, and 57 to 1.

The tool-holding holes in the turret are 3 inches in diameter.
The distance from face of chuck to face of turret when at its ex-
treme position is 5 feet 4 inches. The travel of the turret is 5 feet
and its speed is 25 feet per minute. The cross travel of the car-
riage is 36 inches, which is very liberal. The turret tool-post on
the carriage has four tool positions.

The length of the machine over all is 15 feet 11 J inches, and its
width 5 feet 3 inches. The machine complete weighs 12,500 pounds,
a very liberal weight for a machine of the capacity of this one.

CHAPTER XXI

SPECIAL TURRET LATHES

The R. K. Le Blond triple-geared turret lathe. General description. The
Springfield Machine Tool Company's 24-inch engine lathe with a turret
on the bed. Its special features. Its general dimensions. Its design
and capacity. Turret lathe for brass work built by the Dreses Machine
Tool Company. Its general description. .Special features and con-
struction. A combination turret lathe built by the R. K. Le Blond
Machine Tool Company. A useful machine with many good features.
A 15-inch swing brass forming lathe built by the Dreses Machine Tool
Company. Its distinguishing features. Le Blond Machine Tool Com-
pany's plain turret lathe. Plainness and simplicity its strongest points.
General dimensions. The Springfield Machine Tool Company's hand
turret lathe. A modification of their 18-inch swing engine lathe. The
Pratt & Whitney monitor lathe or turret-head chucking lathe. Its gen-
eral features and construction.

THE R. K. Le Blond Machine Tool Company build a line of
well designed and substantial turret lathes, a representative of
which is shown in Fig. 300, which is of a 31-inch swing, triple-geared
machine with double back gears and a friction device, and is driven

FIG. 300. — 31-inch Triple Geared Turret Lathe, built by the
R. K. Le Blond Machine Tool Company.
391

392 MODERN LATHE PRACTICE

from a triple-speeded friction countershaft, by means of which
fifteen speeds may be had without changing a belt, thus adapting
it to a great range of work requiring different speeds in order to
do the work with the maximum degree of efficiency.

Special attention has evidently been given to the design, so as
to have it very strong and rigid in all parts which support the work-
ing members so as to afford an ample protection against vibrations
when taking heavy cuts. The head-stock is unusually large and
massive.

It is back geared 55 to 1, so that it has enormous power for form-
ing and facing cuts. The turret has a double bearing on the slide,
making it perfectly rigid. It is locked with their patented locking
pin, having a bearing on both sides of the locking ring. All wear
can be taken up between the turret and stem by means of a taper
bushing. The carriage is very heavy, gibbed both back and front,
and the rack pinion is supported on both sides of the rack.

This lathe is especially fitted for box or forming tools, and will
work a nest of roughing tools to good advantage. Changes of
feed can be had instantly by the use of the lever shown on the bed ;
and, with half nuts in the apron, and any tapping work can be done
with positive lead from the screw. A specially strong chuck is fur-
nished having, in addition to the hardened jaws, a set of soft ones to
be used for the second operation, so as to secure perfectly concentric
work, which is frequently difficult, particularly when the limits of
measurement and the exact running of the work are important
conditions.

It will be noticed that the feed gears are of broad face and well
adapted to heavy work and that the lathe carries a very heavy and
strong chuck, which is all-important when heavy cuts are to be
made as well as when the work itself consists of large and heavy
pieces. It is particularly well adapted to machining forging up to
the limits of its swing and of rough outline, which usually prove
very trying to any lathe containing any inherent weakness of con-
struction.

As an example of the second class, the 24-inch swing engine
lathe, built by the Springfield Machine Tool Company, is shown in
Fig. 301. In this case it will be seen that the carriage remains on
the lathe as usual and may be used in conjunction with the turret

SPECIAL TURRET LATHES

393

which is pivoted to a slide, supported by a bed or saddle which rests
upon the V's and is fixed to the bed in the usual manner.

While turrets thus applied to an engine lathe are usually
equipped for hand feed only, there is a device furnished with them
by some builders, by the use of which a power feed is provided.
This is the case with the lathe here shown.

The turret slide is supplied with variable power feed and auto-
matic stop, which in no manner interferes with the usual engine
lathe feeds and screw-cutting mechanism, each being entirely inde-
pendent of the other, and can be used separately or collectively
as the work demands. Therefore, should conditions exist where
the same lathe is to be used for turning work between centers as
well as when held in chuck or face-plate, the tail-stock can be fur-

FIG. 301. — 24-inch Swing Engine Lathe with Turret on the Bed, built
by the Springfield Machine Tool Company.

nished with which the turret interchanges, and either a regular
complete engine lathe is at hand or a modern turret lathe.

The turrets are all furnished with power feed, but are made to
revolve automatically or by hand to suit the user.

The details are constructed with great care. The index ring is
of large diameter and made of tool steel. The locking plunger is
also made of tool steel slides between large bearings, with provision
for adjustment to take up wear.

All the parts pertaining to the automatic revolving mechanism
of turret are also made of tool steel and hardened.

Feeds are engaged and disengaged by levers conveniently placed
in front of the pilot wheel.

394 MODERN LATHE PRACTICE

Although these turrets are of massive proportions, and possess
rigidity to an unusual degree, they are very conveniently handled,
an important factor towards the ends sought.

Some of the dimensions of these turrets are as follows: width
across flats, 12 J inches; diameter of holes for holding tools, 2J inches;
length of the top slide upon which the turret is pivoted, 46 inches;
width of the bearing surface, 11 inches; length of bottom slide, or
saddle, 30 inches; width of bottom slide, 11 inches; extreme dis-
tance between lathe spindle and turret face on a lathe with a 10-foot
bed, 42 inches; weight of turret, 1,200 pounds.

These figures will give a good idea of the substantial design of
this device, which was evidently intended for heavy work and hard
usage. It is very important that all parts of a turret, of whatever
kind of type and for whatever purpose, should be strong, rigid, and
well fitted. If not of sufficient weight to give it the necessary
strength it will fail when put to the actual test of hard work. If
not of sufficient rigidity the tools will " chatter" and either seriously
mar or spoil the work. If all the parts are not well fitted the tools
will not "line up" with the head-stock spindle, and as a consequence
true work cannot be done in the machine. It may be stated as a
practical fact that in turrets built by the best manufacturers it is not
usual to find the entire six holes lining up perfectly with the head-
stock spindle. While the present machines of this type are far
ahead of those built a few years ago, in these respects, the prac-
tical shop man will be fairly well satisfied with a turret if he finds
but two of the holes "dead true," two more near enough true for
the usual class of work, and the remaining two considerably out of
true. And this will generally be the case even though the "finish
boring" of these holes is done with a tool carried by the head-stock
spindle in the lathe that the turret is fitted up for. To the young
machinist this may seem strange, but it is nevertheless true, and
true of probably a large majority of turret machines of the present
day.

A very complete turret lathe for working brass and other similar
metals is built by the Dreses Machine Tool Company. It is shown
in Fig. 302, and is known as a 15-inch friction back geared brass
turret lathe, and is provided with a special chuck, cutting-off slide
and a slide-rest.

SPECIAL TURRET LATHES

395

The bed is of the box pattern with a dovetail top, which pro-
vides the best means for keeping alignment and for quick and firm
gripping of the turret and cut-off rest. It is supported on the
three- point principle to avoid springing and getting out of align-
ment through careless setting up or settling of floors and foun-
dations. The top is provided with holes for the oil and chips to
drop through.

The head-stock on the smaller machines is cast in one piece with
the bed. In this machine it is attached to the bed by gibs and
bolts. The housings are provided for either phosphor bronze or
babbitt metal bearings.

FIG. 302. — 15-inch Friction Back Geared Brass Turret Lathe, with Special
Chuck, Cutting-off Slide and Slide-Rest, built by the Dreses Machine
Tool Company.

The friction clutch back gear is of a new design, very simple in
operation and positive in action. The wear is taken up by a screw
driver from the outside, without even removing the cover.

The spindle is of special hammered crucible steel. The bear-
ings are ground and run in phosphor bronze boxes with special
means for oiling and taking up the wear.

The turret revolves automatically on a ground steel stem with
special device for taking up the wear. It is provided with a set-
over device. The top slide can be operated either by the crank
and screw shown at the rear end, or by the capstan levers in the
usual manner. One of the capstan handles is provided with a short
handle at right angles with it for convenience in quick operations.

396 MODERN LATHE PRACTICE

The entire capstan wheel may be removed and a crank substituted
when quick operations are constantly required.

The longitudinal and cross-feed stop screws are located in easily
accessible places. The base slide is clamped to the bed by a single
handle and the operation of clamping is by a single motion.

The turret locking bolt withdraws by the return stroke of the
top slide, so that the operator needs only to revolve the turret.
This is equally effective as a full automatic turret, but less costly
and complicated.

The index ring and key are of hardened steel and ground. The
square locking bolt is provided with an adjustable taper gib, and
a coil spring for actuating it.

The cutting-off slide is extra heavy and is provided with an
independent stop for both front and rear tools. It has both a screw
and crank wheel feed and a lever feed, either of which may be used
as occasion may require.

The slide-rest is of much better design and construction than
is common in similar work and is a very useful addition to the lathe,
increasing its capacity in handling work of complicated nature,
as by its use another series of cuts may be made without removing
the work from the chuck.

The special chuck is so arranged that the work may be gripped
or released while the machine is running, thus avoiding the neces-
sity of stopping to feed the bar in every time a piece of work is cut
from the bar.

The feed is a positive geared device that should do the work
well and efficiently.

Taken altogether the lathe is well designed and has been pro-
vided with many very useful devices that no doubt prove con-
venient and effective in practical work. The special forming slide
located next to the turret may, of course, be located at any point
in relation to the usual cutting-off slide or the slide-rest that may
be desired in order to properly perform the work in hand. Either
of these adjuncts may be removed when not required for the piece
to be machined, or all may be used upon a long or complicated job
when needed.

A combination turret lathe built by the R. K. Le Blond Machine
Tool Company is shown in Fig. 303. The head-stock and its appen-

SPECIAL TURRET LATHES

397

dages are the same as those shown in Fig. 300, and the bed and
cabinets supporting it are the same. The turret and carriage
arrangements, however, are quite different and adapted to a much
larger range of work.

The carriage is fitted with a turret tool-post which will carry
four tools under the massive top plate shown, and which are securely
fastened by the set-screws through it, thus materially increasing its
capacity for different cuts on the same piece of work. A binding
lever on its top secures the tool clamp in any desired position.

FIG. 303. — Combination Turret Lathe, built by the R. K. Le Blond

Machine Tool Company.

The turret is very heavy and well supported by the turret slide,
upon which it is pivoted, and a long base slide or saddle. It is run
forward and back by a capstan or pilot wheel with long levers giving
ample hand power.

The turret can be connected with the carriage so as to be used
for thread cutting and for tapping, as it thus connects positively
with the lead screw by way of the apron. This feature is valuable
in many respects.

In addition to the above convenience it has its own automatic
feed, which has an unusually long run. As the turret has six large
flat faces, each tapped with four holes in addition to the central hole
for holding tools, it is well adapted for carrying large box tools,
facing tools, or farming tools for special work.

The turret has the usual stops for regulating the length of the
cuts, and a heavy binding nut lever for holding it firmly in any
desired position.

398

MODERN LATHE PRACTICE

It is altogether an exceedingly useful machine, combining many
practical features, great weight, strength and rigidity, and conse-
quently capable of performing very heavy work.

The turret-forming lathe is a machine that is very useful on a
variety of work in which complicated outlines occur in a piece of
circular cross section, and in which a large number of pieces of
exactly the same design and contour are required. In handling
brass work of this variety, what is known as the forming slide, verti-

^ -*

FIG. 304. — 15-inch Forming Turret Lathe with Automatic Chuck, built by
the Dreses Machine Tool Company.

cal forming rest, etc., is found very useful, doing the work upon
soft metals that the very heavy rest with its horizontal forming
tools do for the harder metals, as iron and steel.

In Fig. 304 is shown a 15-inch swing brass forming lathe, with
automatic chuck. It is built by the Dreses Machine Tool Company.

The distinguishing feature of the machine is the forming slide,
which consists of a base securely clamped to the bed and support-
ing a horizontal slide fitted in a dovetail and moved by a feed or
adjusting screw. Upon the top of this slide is secured an upright

SPECIAL TURRET LATHES 399

having formed upon it a dovetail, and being adapted to swivel
within a small arc. Upon the dovetail on this upright is fitted
another slide which is moved by means of a rack, pinion, and
lever. This latter carries the forming tool-holder, which is also
capable of being tilted slightly and properly clamped when it is
adjusted to the right position.

In front of the slide to which the upright is attached is placed
an auxiliary small slide, provided with a tool-post and operated
by the handle shown at the left. This slide is for use in cutting-
off and for other final operations.

For the purpose of adjusting the forming tool to the chucked

casting which is to be machined, the entire mechanism can be

moved longitudinally on the bed by means of the rack and pinion.

A tightening clamp is provided by which the forming rest may be

clamped or released instantly.

An automatic chuck is provided in which work may be gripped
and released without stopping the machine. This is very con-
venient when bar stock is used.

While the machine, as shown, is without back gears, the manu-
facturers build them with this additional means of increasing the
power when such is required.

The countershaft is of the double friction type, whereby six-
spindle speeds are obtained.

The plan of adding the forming slide feature to the turret lathe
is of much interest in manufacture, since it increases very much the
range of the work for which the machine may be used, and with
this forming slide so designed as to make it compound in its action,
and including also the cutting-off tool-post, its usefulness is still
further increased, making the machine as a whole a valuable one
on all light machine operations for any work within its range and
capacity.

One of the plainest types of turret lathes is built by the R. K.
Le Blond Machine Tool Company and is shown in Fig. 305. Its
plainness and simplicity are its strongest points. While its initial
cost is reduced to a minimum, its capacity for handling a variety of
different kinds of work is not correspondingly lessened, as it is well
adapted to the lighter kinds of steel work, to cast iron of consider-
able dimensions, and to work of brass and other softer metals. Not-

400

MODERN LATHE PRACTICE

withstanding the fact that this limits its range of work somewhat,
it is a machine of much practical usefulness as a great variety of
light manufacturing comes well within its range, and it can be done
as well and as rapidly as on a much more complicated and expen-
sive machine.

The head-stock is long and heavy, supporting boxes for the
spindle journals of ample dimensions. The spindle is hollow and
of large size so that bar stock may be worked up. The end thrust
is taken by ball bearings which minimize friction. The driving-
cone has four steps and is adapted for an extra wide belt. The
countershaft is of the double friction type, thus giving eight speeds.

FIG. 305. — 16-inch Plain Turret Lathe, built by the R. K. Le Blond

Machine Tool Company.

The turret is very simple, having as few parts as possible in their
construction. The turret proper revolves automatically, and when
the top slide is flush with the bottom it can be revolved freely by
hand and any desired tool brought quickly into position for work.
The indexing ring is of large diameter and made of tool steel,
hardened and ground, as is also the locking plunger, which auto-
matically adjusts itself for wear. The wear between the turret and
the stem upon which it is pivoted is taken up by an adjustable taper
bushing.

SPECIAL TURRET LATHES

401

The top slide is square gibbed and adjusted by a taper gib. The
turret base is securely clamped in any position on the bed by
two eccentric clamps operated by a wrench from the front of the
turret.

The power feed is driven by a belt upon the four-step feed cones.
It is positive in its action as a belt feed can be, and is engaged by
a lever at the front of the turret and can be tripped to a line in any
position by an adjustable stop.

The lathe shown is of 16-inch swing and has a circular turret
8J inches in diameter. It is drilled with six holes 1} inches in
diameter. The automatic feed is 9 inches. It has a deep and strong
bed and is in its design a very substantial machine.

FIG. 306. — 18-inch Engine Lathe, with Turret on Special Carriage,
built by the Springfield Machine Tool Company.

As an example of the simplest form of a turret lathe with a hand
turret mounted upon the carriage, the one shown in Fig. 306 is
given. It is an 18-inch swing engine lathe built by the Spring-
field Machine Tool Company, and in this particular case a special
carriage is shown, although it is very little different from the reg-
ular carriage upon which the turret may be as readily mounted.

In this case no cutting-off slide is provided, although one may
be readily attached by fitting it to the V's and gibbing it to the
bed in the same manner as the carriage is held to the bed.

402 MODERN LATHE PRACTICE

Some of the special features and dimensions of this turret lathe
are as follows, the information for the same being derived direct
from the manufacturers.

Thjs lathe is a modification of the standard 18-inch engine lathe,
to serve the purpose of a heavy turret lathe, a type which is becom-
ing deservedly popular with the manufacturers of machinery.
With the exception of the turret on the carriage and the turret slide,
the regular design of the engine lathe has been maintained.

The carriage is very heavy, gibbed to the outside of the bed, both
front and back, and is fitted with a turret slide of unusual propor-
tions — 10 inches in width and 16 inches in length, upon which the
turret proper revolves.

The turret is hexagonal in form and 10J inches in width across
the flats. The holes in the same may be as large as 2 inches in
diameter, and the construction is such that a bar may be passed
entirely through the turret. The advantages of this arrangement
are too numerous and well understood to require any further ex-
planation. The index pin and clamping lever are on the right side
of the turret, and, although entirely out of the way, very convenient
for manipulation.

The lathe is provided with power cross feed, as well as longi-
tudinal feed and screw-cutting apparatus, and may be equipped
with taper attachment if desired, and hence can perform on chuck
or face plate work all the functions usually done with the regular
engine lathe, with the advantage of greatly increased production
within the same period of time. As a further convenience a taper
attachment is added.

This taper attachment is designed with a view to strength and
stability, and is attached to the rear of the carriage. It will turn
tapers up to 4 inches to the foot.

Such a lathe is an exceedingly useful machine on a great variety
of jobs continually occurring in the machine shop, particularly
those of which there is a small quantity only to be made. Many of
these jobs may have a portion of the work advantageously done
on this lathe, and the balance on an engine lathe, both working in
conjunction with more efficiency than either would alone.

In Fig. 307 is shown an example of what has been spoken of as
a " monitor" lathe or turret head chucking lathe, although it is

SPECIAL TURRET LATHES

403

used for many k'nds of work beside chucking single pieces. It is
of 10-inch swing and built by the Pratt & Whitney Company.

These machines are used for drilling, boring, and reaming holes
at a much faster rate and with more uniformity than similar work
can be done on lathes formerly used for the purpose. They are
also largely used to finish parts of machinery, cast or forged pieces
of irregular outline and circular cross section, when fitted with
the necessary tools.

FIG. 307. — 10-inch Monitor Lathe, built by the
Pratt & Whitney Company.

They have the same construction as the revolving head screw
machines above the bed, but are not usually furnished with the
wire feed apparatus for feeding wire or rods through the chuck
automatically, or provided with an oil tank, dripping device, etc.,
as the work usually done upon them does not require the use of oil
in cutting. When oil is required these accessories may be readily
attached.

The heads have provision for vertical and horizontal adjust-
ment of the spindle in case its alignment with the turret holes is

404 MODERN LATHE PRACTICE

lost by wear. The spindles are made of hard, crucible steel, and
are provided with cylindrical boxes lined with genuine babbitt
metal.

The larger sizes of these machines are built with back gears,
which render them capable of doing much heavier work than the
machine shown in the engraving.

With this machine, with its quick acting and convenient hand
lever for operating the turret, a very large amount of work can be
turned out in a day; in fact, considering the cost of the machine, it
is, for all work within its capacity, frequently more efficient than
the larger sizes and more elaborate designs of this machine and
others of the same general type.

The lever by which the turret slide is operated also automatically
effects the revolution of the turret at the end of the return stroke
and the beginning of the next forward movement.

There is a cutting-off slide carrying two tool-posts, so that a
front and back tool may be used. One of these may be a cut ting-
off tool and the other a forming tool, if such a tool is needed. Thus
it is adapted to turning to size, or several sizes; threading with a
die in one of the tool-holding holes in the turret; drilling, reaming,
etc., by the turret; and forming and cutting off by the cut-off slide,
making it exceedingly useful considering its simplicity and economy.

CHAPTER XXII

ELECTRICALLY DRIVEN LATHES

System of electric drives. Principal advantages of driving lathes by elec-
tricity. Group drive versus individual motor system. Individual
motor drives preferable for medium and large sized lathes. The Reed
16-inch swing motor-driven lathe. The Lodge & Shipley 24-inch swing
motor-driven lathe. The Prentice Brothers Company's motor-driven
lathes. General description. Crocker-Wheeler motors. Renold silent
chain. The Hendey-Norton lathe with elevated electric motor drive.
Special features. A 50-inch swing lathe with electric motor drive de-
signed by the Author. Detailed description Practical usefulness.
Not strikingly original, but successful.

ONE of the more important developments of the modern ma-
chine shop tools is the electric drive, with which many of them are
equipped. While the system of driving by electric motors has
many phases, and all of them most interesting problems, this chapter
will be more particularly concerned with the question of individual
motors for the machines, leaving out the question of driving a
group of machines from a " jack shaft " operated by a single motor,
and the plan of driving line shafts in the same manner.

There are many advantages in driving machines, particularly
lathes, with individual motors; among them being:

First, the power, and in case of variable speed motors the speed
is directly under the control of the operator;

Second, there is economy in the use of power, as none is used to
drive "jack shafts" or countershafts;

Third, there is also economy in the use of power as none is con-
sumed except when the lathe is in actual operation; and

Fourth, the wear and tear of belting is either reduced to a mini-
mum or eliminated altogether.

While it may be still an open question whether the "group

405

406

MODERN LATHE PRACTICE

drive" system or the individual motor system is the better, par-
ticularly for small lathes, there seems to be no doubt of the indi-
vidual motor system for medium and large lathes, say from
24-inch swing upwards.

In this chapter, therefore, it is proposed to describe and illus-
trate the modern individual motor system as applied to lathes
made by the American up-to-date builder of lathes, and in doing

FIG. 308. — 16-inch Swing Reed Motor-Driven Lathe.

this to show those put on the market by the more representative
concerns engaged in this business.

In Fig. 308 is shown a 16-inch swing Reed motor-driven lathe.
The motor is one-horse power, direct connected, with variable speed.
The motor and its controller are built by the General Electric Com-
pany. The motor has a speed of from 500 to 1500 revolutions per
minute.

As shown in the engraving the motor is geared directly to the
main spindle by suitable gearing so that no belt is required. This

ELECTRICALLY DRIVEN LATHES

407

method seems preferable to the plan of using a short belt. The
noise of fast running gears, in a device of this kind, may be avoided
by introducing a rawhide intermediate gear next to the small steel
pinion on the motor shaft, by which means the gears will run com-
paratively quiet even at a very high rate of speed of the motor
shaft.

The Lodge & Shipley 24-inch swing motor-driven engine lathe
is shown in Fig. 309. This design uses a short belt in driving from

FIG. 309. — 24-inch Swing Lodge & Shipley Motor-Driven Lathe.

a small two-step cone on the motor shaft to the spindle cone. The
motor is of the variable speed type with a speed variation of two to
one.

The motor is mounted on an overhead bracket directly above
the head-stock, pivoted at the rear to two heavy standards bolted
on to the back of the bed, and is connected to the driving pulley by
a short, wide belt, in which sufficient tension for driving is obtained
by means of the adjusting screw with a hand wheel at the front of
the head-stock.

408 MODERN LATHE PRACTICE

When this system is used the cone pulley has two steps, and
two sets of back gears are provided, so that the combination affords
a total of six speed changes, two with the lathe out of gear and two
with each of the back gears in. By varying the speed of the
motor, either through the introduction of field resistance or by
use of one of the multiple voltage systems, intermediate
speeds in each range are obtained, the number of which depends
only on the number of points in the controller. With a 20-point
controller, 120 distinct spindle speeds are thus afforded.

This company also equip their lathes with constant speed
motors, for which purpose they mount the motor at the rear of the
head-stock near the floor. From a small pulley on the motor shaft
a belt runs up to a large pulley on a countershaft located directly
in the rear of the head-stock. This countershaft carries the usual
speed cone, from which a short belt connects with the spindle cone in
the usual manner. The countershaft speed is from 125 to 200 revo-
lutions per minute.

In buying a motor-driven lathe, the purchaser has usually to
decide between a direct-connected and a belt-connected lathe, and
between a constant speed and a variable speed motor. The use
of a constant speed motor direct geared to the lathe is practically
prohibited, on account of the mass of gearing necessary to secure
sufficient speed changes.

This may be obviated by using the countershaft as above
arranged, although it is well known that short belts are objection-
able on account of the high tension that must be maintained to
render them capable of transmitting the required power to properly
operate the lathe.

The Prentice Brothers Company equip their 14, 16, 18, 20, and
22-inch swing engine lathes with a motor drive device which is
shown in Fig 310.

In this case the motor is under the bed and close to the head
cabinet. Eight changes of spindle speed are provided for by means
of a series of gearing located in the head-stock of the lathe. All
of these speeds are available without stopping the lathe. The
gearing is so arranged that it is impossible for the operator to inter-
lock any conflicting ratios of gearing. This is an advantage that
i* greatly appreciated, as it removes all possible danger of break-

ELECTRICALLY DRIVEN LATHES

409

age to the gearing or the clutches in the driving mechanism of the
machine.

A mechanical reverse is provided and may be operated from
the carriage of the lathe so that the operator can start, stop, and
reverse the direction of the spindle without stopping the motor.
This is a great saving of power over the method commonly used,
that is, reversing the motor, stopping and starting the motor when
stopping, starting, and reversing the lathe.

For operating this lathe the manufacturers recommend a con-
stant speed motor with either direct or alternating current, although
a direct-current motor, with a variation allowing an increase of

FIG. 310. — 18-inch Swing Prentice Motor-Driven Lathe.

50 per cent in the speed, can be used to some advantage and would
divide the steps of the mechanical speed variation into five or six
additional changes, giving 40 or 48 changes of speed in all.

In general practice, however, this great number of speeds is
not needed. The advantages of using a constant speed motor are
numerous beyond the matter of efficiency, as in most cases variable
speed motors are of a special nature and it is much more difficult
to secure repair parts than it is with the constant speed motor, as
one can usually have tSe parts needed shipped directly from stock
and without any delays.

Another consideration should be noted. The wear upon the
variable speed reversing controller is considerable when we take

410

MODERN LATHE PRACTICE

into consideration the number of times that the lathe is stopped,
started, and reversed each day

The greatest advantage is that the induction motor is without
commutator troubles, which is the main cause of difficulties with all
direct-current motors.

A lathe capable of doing at one setting the operations that would
require eight or more settings of an ordinary engine lathe is the
24-inch semi-automatic turret lathe, manufactured by the American
Turret Lathe Company and shown in Fig. 311 as a good example
of this class of machines so driven.

FIG. 311. — Heavy Motor-Driven Turret Lathe built by the American Turret

Lathe Company.

Being intended for heavier work than is usually imposed upon a
turret lathe, it has a massive bed construction, a large turret, and is
designed to swing 27 inches for a distance of 12 inches from the
chuck.

Twelve rates of feed and feed reverse and eight speeds of the
spindle are possible with each speed of the motor. The gear com-
binations for all these are protected and may be operated to effect
a change in speed while the machine is running. The levers for
the various gear clutches are shown under the head. The turret
has universal facing heads and provides for thirteen tools, though
seldom more than five are used at a time.

ELECTRICALLY DRIVEN LATHES 411

There is an auxiliary turret which will accommodate four tools
and has power cross feed on one side of the turret. The latter has
power traverse in either direction by a separate motor, and a slower
travel through the feeding mechanism driven from the spindle.
Rotating, indexing, and clamping of the turret hea^d are all auto-
matic, and an independent " knockout" or feed stop serves each
face.

The spindle is driven through a Renold silent chain by a ten
horse-power Crocker- Wheeler semi-enclosed motor mounted above
the head-stock. An M. 12 controller in the current supply allows
the motor twelve speeds, ranging from 876 to 130 revolutions per
minute.

With the combination of electrical and mechanical means the
highest and lowest possible chuck speeds are 90 and 1 1-5 revolu-
tions per minute, respectively. For the operation of the turret a
three horse-power Crocker- Wheeler fully enclosed motor is used.
This runs continuously at a constant speed of 1,000 revolutions per
minute on a two-wire supply, and drives a steep-pitch lead screw
through bevel gearing. A longitudinal shifting of the driven shaft
clutches one or the other of the two bevel gears, producing direct
or reverse rotation, or in the central position releases both.

The Hendey-Norton arrangement of an elevated electric motor
operating a countershaft is shown in Fig. 312.

The electric-motor drive, as illustrated, gives all the advantages
to be had from regular countershaft drive. It will be noticed that
the motor is of the back geared type. Carried on the end of the
commutator shaft are two rawhide pinions of different diameters,
driving two large gears on the countershaft of the motor, the gear-
ing being properly proportioned to give the required driving
speeds to the countershaft.

These large gears run smoothly on the shaft. Their inner for-
mation is that of the friction clutch pulleys used on their shapers,
and carried between them, keyed to but sliding on the shaft, is a
friction clutch, which is thrown into connection with either gear as
desired, being operated by the depending shipper and handle ex-
tended back and supported in a ring at the end of the lathe, as
shown.

The clutch is also fitted with the usual locking spring and point.

412

MODERN LATHE PRACTICE

We thus have two speeds for the countershaft, affording the sixteen
changes for the lathe spindle. These are accomplished with the
motor running at constant speed, thus maintaining its maximum
efficiency at all times.

The reversing device for the carriage is operated at the side of
the apron, which allows the spindle to run in the one direction, and
dispenses with the necessity of wiring the motor for backward drive,
an item of expense and complication which is avoided.

FIG. 312. — Hendey-Norton Motor-Driven Lathe.

The standard carrying the motor is rigidly bolted to the lathe
bed, and, being strongly webbed, is free from any disturbing vibra-
tion. The motor is directly attached to a hinged plate on the top of
the standard.

At the front end of the plate there is carried a short-throw cam
which allows the plate a slight drop and consequent loosening of the
belt when it is desired to shift from one step of the cone to another.
The cam rides upon adjustable posts which afford a means of taking
up any slight stretch occurring in the belt. The motor back gear

ELECTRICALLY DRIVEN LATHES

413

shaft is supported at pulley end with an out-board bearing, which
prevents any springing of the shaft when the belt is used on the
smaller steps of the cone.

The workmanship on the electric motors and their connections,
like the work on the lathes and other product of this company, is
first-class, and the entire outfit is a good example of mechanical
work, although it cannot be said that the design of the device, with
its heavy looking bracket supporting the countershaft and motor, is
altogether pleasing to the eye. It has rather a top-heavy appear-
ance.

The following illustration, in which Fig. 313 is a front elevation

FIG. 313. — Front Elevation — Electric Drive for
50-inch Lathe, designed by the Author.

and Fig. 314 an end elevation and partial section, is of an electric
drive designed by the author for a 50-inch swing lathe.

The advantages of having a machine tool, particularly a large
one, driven by its own individual electric motor are many, however
the electric drive may be arranged. They are greater if the ma-
chine was originally designed to be so driven, and particularly with
a variable speed motor. But it sometimes happens that we are
called upon to arrange an electric drive to a machine already built
and perhaps in use in the shop. We may also be required to drive

414

MODERN LATHE PRACTICE

it with a constant speed motor, and must therefore make proper
provisions for speed changes.

Under these conditions a large lathe had to be arranged for
parties who insisted that the cone pulley in the head-stock should
be replaced by a series of gears of varying diameters and so arranged
as to engage any one of a second series of gears located on a
supplementary shaft in front of them, the gears being placed at
unequal intervals, the smallest somewhat greater than the width
of their faces from each other. The lathe was so arranged and
successfully used, yet the necessary complication of the shifting

FIG. 314. — End Elevation of 50-inch Lathe
with Electric Drive designed by the Author.

apparatus, and the difficulty of readily bringing the proper gear
into engagement with its fellow by sliding the gear longitudinally,
rendered the device somewhat clumsy and inconvenient, and was
the cause of some bad language on the part of the man who ran it.
The next occasion on which a similar problem arose the customer
was not insistent upon any partiular plan, only he " didn't want it
like the other one." The motor to be used was of constant speed
and the following device was adapted in attaching it to the lathe,
as shown by the front elevation in Fig. 313, and the end elevation
in Fig. 314.

ELECTRICALLY DRIVEN LATHES 415

The countershaft cone A is mounted on a shaft journaled in the
brackets B, B, attached to the head-stock, as shown. At the rear
end of this shaft is fixed a gray-iron gear C. The motor D is sup-
ported upon a bracket E attached to the lathe bed and carries on
the end of its shaft the steel pinion F. Between the pinion F and
the gear C, and journaled on the bracket G attached to the head-
stock, is a rawhide gear H engaging both of them. This is intro-
duced to avoid the noise which would otherwise be caused by the
fast-running pinion F on the motor shaft. The gear H is con-
structed with a gray-iron flange on each side, one flange having
formed upon it a hub passing through the rawhide blank and the
opposite flange, and the whole firmly secured together by six flush-
headed screws, the object of this construction being to furnish a
good bearing on the stud upon which it runs and also to furnish
proper support for the ends of the teeth.

Upon the bosses of the brackets B, B, are formed projecting
sleeves upon which are journaled the arms J, J, in the upper ends
of which is journaled the belt- tightening roller K, which is com-
posed of a piece of 5-inch extra thick wrought iron pipe, provided
with gray-iron heads through which its shaft passes. Through the
two end portions of the head-stock, holes are drilled in which is
journaled the rock shaft L, upon which are fixed the two levers M,
M, the upper ends of which are connected to the arms J, J, by the
connecting rods N, N. Upon the front end of the rock-shaft L is
fixed the worm segment P, which engages the worm Q, the shaft R
of which is journaled in the bracket S fixed to the front of the head-
stock, as shown in Fig. 314. Upon the outer end of the shaft R is
fixed the crank T for operating the belt-tightening device.

The belt V is cemented instead of being laced, to facilitate its
smooth running. By a backward turn of the crank T the belt V is
rendered slack enough to be changed from one step of the cone to
the other, and a forward turn of the crank tightens it as much as
may be necessary to drive the lathe.

In practice it was found that the operator preferred to use the
crank for stopping and starting the lathe to examine and caliper
his work rather than to use the electric switch or the rheostat, claim-
ing that it was more convenient to allow the motor to continue to
run and start the lathe gradually by tightening the belt slowly for

416 MODERN LATHE PRACTICE

that purpose, and we must admit that the operator of a machine,
in his daily experience, frequently finds convenient ways to "do
things'.' that the designer or the foreman may entirely overlook.

While the device here shown is simple, and no claim is made
of anything strikingly new or original, it has succeeded admi-
rably and given good satisfaction to the proprietors as well as to
the employees of the shop where it is in use, and will be found an
economical, convenient, and efficient method of applying the elec-
tric drive to existing lathes.

CHAPTER XXIII

PRACTICAL INSTRUCTIONS ON LATHE OPERATION

Setting up a Lathe. Placing the Lathe. Plan of Small Shop. Line Shaft
Size and Speed. Power Needed to Drive Lathes. Leveling Lathe.
Lubrication of Lathe Parts. When to Oil. Attaching Face Plate or
Chuck. Lathe Parts and Their Functions. Headstock. Tail Stock.
Carriage. Automatic Apron. Reverse Gear. Compound Rest.
Starting the Lathe. Operating Levers. Simple Lathe Accessories.
Spur and Screw Centers. Drill Pads. Turning a Steel Shaft. Drill-
ing in the Lathe. Taper Attachment for Lathes. Milling in the Lathe.
South Bend Attachment. Barnes Attachment. Motor Driven At-
tachment. Knurling on the Lathe. Indicators and Their Use. Boring
Bar Construction and Use. Adjustable Boring Bar. Boring Bars for
Heavy Work. Methods of Holding Work. Special Chuck for Gas
Engine Pistons. Increasing Swing of Lathe. Lathes for Heavy Work.
Grinding Attachments, Belt Driven. Machining Concave and Convex
Surfaces. Grooving Oil Ducts. Combination Lathe Dogs and Their
Use. Hacksaw Attachment for Lathes.

IP the Lathe is purchased new, it will undoubtedly come crated
up in a substantial manner with all auxiliary parts wrapped in bur-
lap with excelsior padding. A list of parts included in the pur-
chase price should be carefully checked against the shipment to
insure that all are received. The wrappings should be carefully
removed and inspected to see that no small parts are overlooked.
It will be noticed that all bright parts are covered with vaseline.
This precaution is taken to reduce liability of rusting during ship-
ment. This may be easily removed with a cloth dipped in kero-
sene, after which the parts are wiped dry. The gears should be
cleaned thoroughly and all chips, excelsior shreds or sawdust
removed from each tooth separately. This includes change speed
gears as well as back gears.

417

418

MODERN LATHE PRACTICE

The placing of the lathe in the shop depends upon many con-
ditions such as position of drive shafting, opportunity for counter-
shaft installation, relation to work bench, direction of light, etc.
It is claimed by experienced mechanics that the operator can work
most efficiently with the light coming from a point over the right
shoulder. The floor supporting the lathe should be firm and
level. If there is any vibration after the lathe is started, the
floor should be suitably braced from underneath, if possible. The

GRINDER COUNTERSHAFT^

GRINDER

FIG. 315. — Plan View of Small Shop Showing Arrangement of Shafting and

Location of Lathe.

lathe should be placed so the operator can readily gain access to
all sides as there are many jobs that require the operator to work
at all sides of the machine.

The general arrangement of the lathe, its countershaft and
line shaft to drive it as well as two sources of power that can be
used as recommended by the South Bend Lathe Works are clearly
shown in Figs. 315 and 316. The plan view shows the location of
the machine relative to the bench, as well as the placing of the
line shaft so it can be driven by either an electric motor or small
gas engine, and drive not only the lathe countershaft but an emery

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 419

wheel stand as well. The view at Fig. 317 is a front view of the
lathe and countershaft and is lettered so the principal dimensions
of a lathe may be clearly grasped by the novice machinist. The
swing A is twice the radius R, and indicates the diameter of the
largest piece that can be turned supported by the centers. The
distance between centers B indicates the maximum length that
can be turned between these points of support. The length of the
bed is indicated bv C.

FIG. 316. — View of Small Machine Shop Showing Relation of Lathe to

Workbench.

It is said that the countershaft should be placed at least five
feet above the spindle in order to secure proper belt tension and
that six or seven feet would be even better. The countershaft
may be set either side of the line shaft depending upon position of
the lathe. The shipper rod actuating lever must be conveniently
placed so it may be readily operated by the lathe user. When
the lathe location is settled, the countershaft should be perma-
nently installed. For a light lathe, the countershaft hangers can
be secured to cross pieces, about 2" x 4", which are attached to the
ceiling beams parallel with the lathe ways and sufficiently far apart

420

MODERN LATHE PRACTICE

to make possible the retention of the hanger feet by lag screws.
The countershaft support pieces should be secured to the ceiling
by substantial fastenings, lag screws being the most common.

The usual method of supporting the line shaft is by the joists
which run from the side walls. If the shop is a small one, including
only a lathe, emery grinder and perhaps a drill press, a 1TV

Countershaft

Tail Stock

FIG. 317. — View of Lathe Showing Important Dimensions.

will be ample. The line shaft hangers should be placed eight feet
apart and a shaft speed of 200 to 300 R. P. M. is considered suffi-
ciently fast, the average speed being 250 R. P. M. If electric power
is available, a small motor may be secured to a suitable bracket
attached to the side wall, care being taken to place the motor high
enough so the belt leading from it to the line shaft will not inter-
fere with anyone having occasion to pass under it. If a gas or
gasoline engine is used instead of an electric motor the engine may

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 421

be placed in any convenient location, though usually it is put in a
corner where it will be out of the way.

If the lathe is not larger than 16" swing, a gas engine of 2| to
3 H. P. will be ample, while an electric motor of 1 J to 2 H. P. will
provide sufficient power. The horse power needed to drive a lathe
varies with the size and character of the work. Obviously, the
motor power should be ample so the lathe can work at full capacity.
A 12" swing lathe will take | H. P. under these conditions, a
13" will take } H. P. About 1 H. P. should be allowed for a
15" swing, 2 H. P. for a 16" swing lathe while not less than
1\ H. P. should be supplied to turn an 18" swing machine at maxi-
mum load. The shafting friction in a small shop of the character
indicated at Fig. 315, providing the line shaft is properly aligned
and well oiled, would not be any more than \ H. P. This
figure must be added to the energy necessary to turn the lathe.

When the countershaft is properly fastened in position, move
the lathe over until the driving belt will track properly between
spindle cone pulley and countershaft pulley group. The axis of
the lathe spindle should be parallel with that of the countershaft.
Upon the proper leveling of the lathe much depends, as the way
the lathe is erected has much to do with its accuracy. A car-
penter's level should be placed across the ways near the head
stock. Repeat this operation at various points along the length
of the bed, leveling carefully in every direction. If the lathe bed
is not plumb, put a shim between the low leg and the floor. Shingles
are a favorite shim among millwrights on account of the taper
which makes it possible to level very accurately by driving two
shingles in opposite directions under the lathe leg to raise it grad-
ually. When properly leveled, as can be easily determined by using
the level both parallel to the ways and across them as well, the
pads or feet at the bottom of the legs are securely lagged to the
floor. If the floor is of cement or concrete, it is necessary to drill
out holes and drive in wooden plugs in order to secure anchorage
for the lags. Expanding bolts are also sometimes used for this
purpose.

In belting up the lathe, most mechanics favor leather belts.
The belt nearest the lathe head is usually straight, while the other
is generally a crossed belt to give reverse motion. The counter-

422 MODERN LATHE PRACTICE

shaft belts should be so arranged that when the shipper rod is moved
in the direction of the lathe head, the spindle of the lathe should
revolve so the top of the spindle cone pulley group turns toward
the operator when he is standing in front of the lathe.

LUBRICATION OF LATHE PARTS

To secure proper results from a lathe or other machine tool it
is necessary to keep all working parts properly lubricated as the
neglect of this essential precaution means rapid depreciation of
the various members upon which the maintenance of accuracy
depends. Lubricating oil should be of the best quality and free
from acid. After lathe is properly located, the various revolving
parts of the lathe and the countershaft bearings are well lubri-
cated. The various oil holes are usually clearly indicated by small,
plugs having a knob on the end by which they may be removed
easily. After flushing the bearings liberally with oil, the plugs
are reinserted in the oil holes to keep dust and dirt out. The
main spindle bearings are usually provided with oilers of this type.
The spindle drive cone bearings are oiled by removing small headless
set screws located on both large and small steps of the pulley
group. The back gear quill bearings are oiled through small oil
holes on that member. Use plenty of oil on the lead screw and
half nuts before cutting a thread to prevent cutting the babbit
metal in the half nuts. Oil the head spindle bearings at least every
day and if the lathe is on hard work, it will be well to supply oil
copiously several times every day. The mechanism of the apron,
the lead screw bearings, the change speed or feed gears and all
other parts should be well oiled at all times.

After the lathe is well oiled, run it for a few minutes after it is
first installed to make sure that there is no binding in the bearings,
or that they are not adjusted too tightly. Heating indicates
friction due to lack of oiling, poor bearing alignment or too tight
adjustment. Wipe all surplus oil from the outside of the parts as
it serves no useful purpose and may actually be detrimental be-
cause it will collect chips, dirt, etc. Wipe the ways over with an
oily rag to make sure that tail stock and carriage move back and
forth freely. Before attaching a face plate or chuck on the nose

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 423

of the spindle all dirt should be removed from the threads on spindle
as well as from female threads inside the chuck or in the face plate
boss. The back of face plate or chuck should fit tightly against
the shoulder at the end of the thread spindle nose. Before fitting
the centers, drill pads or taper shank drills in the spindle and
tail stock clean out the tapered holes thoroughly to remove all
chips. A small chip will prevent the center from fitting properly
and inaccurate work will result because centers are not in line.

LATHE PARTS AND THEIR FUNCTIONS

The main parts of a typical screw cutting lathe are clearly
shown in Fig. 318. The view at A is from the end showing screw
cutting and feed gears, that at B is a front view showing the parts
convenient to the operator. While the various important lathe
parts have been outlined in other portions of the book it may be
well to review these so the novice operator can understand the
parts and what they are for. The main portion of any lathe is
the bed which is supported at the right height from the floor by
cast iron legs. The bed supports the head stock at one end, this
in turn carries the spindle to which face plate or chuck is fastened.
The spindle is supported by bearings and is driven by either of two
methods. With the back gears out, the cone pulley group may
be locked to the spindle by a simple clutch pin, which gives the
highest spindle speed. With the clutch pin out, the pulley group
will turn without turning the spindle. With the back gear in and
the clutch pin out, the spindle will be turned at a low speed de-
termined by the back gear reduction. Some work can be done
better with the spindle turning fast, such as wood and brass turning,
filing, finishing, etc., while "hogging" or removing much metal
by taking heavy chips always requires the use of the back gears.
The carriage consists of two parts, a portion resting on the ways
of the lathe bed carrying the cutting tool and an apron attached
to it that carries the mechanism used in moving the carriage back
and forth under the action of the lead screw. The lead screw
determines the lateral feed or movement of the carriage from end
to end of the lathe.

The tail stock of all lathes is adjustable along the ways and
supports one center. The center is mounted in a movable barrel

424

MODERN LATHE PRACTICE

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 425

in the tail stock. This barrel may be moved back and forth by
a screw turned by hand wheel A and locked absolutely in place
at any position by lever C. The tail stock may be locked by a
suitable lever which clamps it to the bed. The lead screw may be
driven at various speeds by varying the gear ratios and may
be turned in either direction by moving lever E. The tool post is
usually carried by a compound rest attached to the carriage. A
compound rest makes it possible to feed the tool in or out in a
direction parallel to the ways by lever A and in a direction at right
angles to the ways by lever B and also to set the tool at any desired
angle with the work. Both levers may be worked simultaneously.
The reverse gear is brought in action by lever E on the end of the
head stock. The carriage may be moved manually when desired
by hand wheel B. The small knob on wheel C actuates a clutch
for the carriage cross feed, while lever D makes the connection
between the half nuts carried by the carriage and the lead screw
in thread cutting.

The parts of the countershaft assembly overhead are easily
identified. The countershaft carries a pulley cone group to drive
that on lathe head stock. The small step of the countershaft
cone is belted to the large step of the spindle drive cone. Two
friction clutches are used, one being driven by a crossed belt to
obtain reverse motion. The shipper handle actuates the clutch
cone and is in turn operated by a shipper bar making it easy to
operate the clutches from any part of the lathe.

An interior view of the usual form of automatic apron furnished
on South Bend lathes is shown at Fig. 319-A. It will be noted
that the lead screw is provided with a spline which drives the
worm operating the power cross feed and the automatic longitu-
dinal feed. The half nuts, which are used in screw cutting, are
clearly shown. The various levers and wheels previously described
are also indicated. The reverse of the South Bend Lathe is shown
at Fig. 319-B. The reverse gear carrier may be rocked so either
gear A or B is in mesh with spindle gear C or it may be left in a
neutral position with both gears out of mesh when it is desired
to run spindle on the direct drive for polishing, etc. The graduated
compound rest is shown at 319- C. In addition to enabling both
cross and longitudinal tool post feed, the rest swivels in a complete

426

MODERN LATHE PRACTICE

Half Nubs

Wheel
B

Reverse Gear
Carrier

Compound Idler
Gear

Lead Screw
Drive
Gear

for Tool Post

Chip Guard

^Compound Rest Swivel Bolt
Compound Rest Top

FIG. 319. — Views of Important Lathe Part Assemblies Making Design and
Location of Components Clear.

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 427

circle and is clamped in any position desired by T head bolts.
The graduation is such that it may be set for any angle.

STARTING THE LATHE

Before starting to do any work on the lathe, it is important to
become familiar with the method of working the various control
levers and wheels and of locking the adjustments to prevent move-
ment when they are set properly. Th,e first thing to do is to try
and run the spindle drive pulley cone free. This is done by making
sure back gears are not in mesh and releasing bull gear clamp or
locking pin that joins the large gear just back of the front spindle
bearing to the pulley group. If the lathe runs freely in this posi-
tion, which is called "in open belt" by some machinists, throw in
the back gears and notice that spindle turns slower than the pulley
group. This is done by rocking the lever F, Fig. 318-A, so the
gears on back gear quill mesh with those on the spindle. The
gears should not mesh deep enough to bottom. To run lathe on
direct drive throw out back gears and lock the bull gear clamp.
The pulley group and lathe spindle speeds are now the same.
Lathe manufacturers caution the operator not to throw back
gears in or out when lathe is running. To connect the reverse
gear, rock the lever E, Fig. 319-B, till either gear A or B is in
mesh with C, depending upon the direction of lead screw rotation
desired. The same caution given about putting back gears in mesh
with lathe running applies just as well in this case.

SIMPLE LATHE ACCESSORIES

The lathe may be used to do almost any work that other ma-
chine tools can do if supplied with the proper attachments. Drill-
ing, grinding, milling and boring may be accurately performed by
using various attachments to be described in proper sequence.
We will first discuss the methods of doing simple jobs and then
will show some methods pertaining to harder work. A number of
lathe accessories that are inexpensive, yet very useful, are shown
at Fig. 320. The spur center at A is used in wood turning, espe-
cially for long work. It is intended for use in the lathe spindle
and not only supports the work but drives it as well when the spurs

428

MODERN LATHE PRACTICE

or lips are forced into the end of the piece to be turned. The
screw center B is for turning large wood pieces that cannot be very
well supported by both head and tail stock centers. The cup
center C is used in connection with either of the others in wood
turning and is generally used in the tail stock. When drilling
with square shank drills and bits the special drill chuck at D will
be found useful. The form shown is provided with a female thread
to fit the lathe spindle nose. The drill or bit is clamped in place

Spur Center

Cup Center

Screw Center

Special Drilling Chuck

Crotch Center

Drill Pad

FIG. 320. — Some Useful Lathe Accessories.

by a set screw. The drilling pad with V groove shown at E, some-
times called a crotch center, is very useful when drilling round bars
as it supports these and centers them automatically. The drill
pad shown at F is used in the tail stock (as is the crotch center E)
as a support for any piece drilled, and is designed for use with
flat stock.

TURNING A STEEL SHAFT

The simplest thing to do on a lathe and one that will give the
apprentice opportunity to become thoroughly familiar with all
levers, etc., is turning a steel shaft. The various forms of lathe
tools available and their method of use are fully described in
Chapter XI, while the forms of lathe dogs and proper use of centers
are fully outlined in Chapter XIII. The first thing to do is to
provide centers in the shaft with a combined drill and center
countersink in order to support it properly on the lathe centers.

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 429

The steps are first, to mark the end of the shaft which is done by
scratching two lines at right angles. The point of intersection of
the lines is where the center should be. To mark the place, a
center punch is used as shown at Fig. 321-A. Place the shaft
between the lathe centers after prick punching both ends and
see if it runs true when revolved by hand. If it runs out hold a
piece of chalk to the shaft while it turns and mark the high spots.
Drive the center hole over in the direction necessary to have the
shaft run true with center punch; in most cases it will mean moving

WORK

CHUCK

SIDE TOOL

.WORK TA1L5TOCK CENTER

' rty

FIG. 321. — Preliminary Steps to Turning and Facing Steel Shaft on the

Lathe.

the center nearer the high spot. The method of countersinking
a shaft is shown at Fig. 321-B. A drill chuck is placed in the
lathe spindle and fitted with a combined drill and countersink.
Place one end of the shaft on the tail center and feed the bar in
by turning the hand wheel at the end of the tail stock. Allow the
countersink to feed in deep enough, then reverse the shaft and
countersink the other end in the same manner. The countersink
should be drilled deep enough so the point of the center will not
be called upon to do any of the work of supporting the shaft. The

430 MODERN LATHE PRACTICE

countersink should have the same taper as the lathe center or 60
degrees, as fully outlined in a previous chapter.

The shaft is then provided with a dog at one end that engages
with a slot in the face plate to drive the piece and is supported by
the tail stock center at the other end. Oil the centers well before
starting to turn the lathe. The shaft should have a slight play
between the centers in order that it turn easily. Select the proper
tool (Chapter XI) for the character of the work and place it in
the tool post, having the cutting point or edge as near the tool
post as possible to prevent the tool springing under a heavy cut.

The position of a turning tool is very important when machining
metal. At Fig. 321- C the usual position is shown. This is about
5 degrees measured on the circumference of the piece to be turned
above the center line. If a tool is placed below center, it is apt
to dig in.

The proper speed and feed to use is only determined by experi-
ence. It is best for the beginner to take light chips at the start.
After the tool has been properly set, move the carriage over to the
tail stock end of the bar and feed in the hand cross feed until
the tool is slightly below the surface of the bar at one end. Set
the lead screw gears for medium speed and feed the tool into the
bar slowly by hand to make sure that the chip taken will not be
too heavy for the lathe. After the chip is started, the automatic
longitudinal feed may be locked in and the tool moved by power.

Before taking the final or finishing chips and polishing the shaft
it will be well to face off the shaft end. This is done with a side
tool as shown at Fig. 321-D. If the end of the shaft is very rough
it may be better to face it off before starting to turn it down in
order to secure an accurate cut. On reaching the countersink
hole, the side tool may be fed in further to face the end of the
shaft clean by slightly withdrawing the tail stock center.

DRILLING IN THE LATHE

A lathe may be used as a horizontal drilling machine and both
sensitive and large drill presses are really developments of the
lathe. The drill press is a vertical lathe without any provision
for mounting turning tools. The use of a horizontal table on a

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 431

drill press makes it more suitable for handling large and heavy
work as the weight of the pieces drilled serve to hold them in place
on the table. A lathe can be used in drilling, only it is more diffi-
cult to support the work when it is bulky or heavy. The simplest
method of drilling is to place the drill in the lathe chuck and hold
the piece to be drilled by hand against the drill pad held in the tail
stock, using the tail stock hand wheel to feed the work against
the drill. In this case, the drill turns as it does in a drilling machine
and the work remains stationary. The lathe chuck or face plate
is often employed to hold the work to be drilled as at Fig. 322-A

Lathe ChucK.

Drill Chuck

Drill

FIG. 322. — Methods of Drilling in the Lathe.

while the drill chuck is supported by the tail stock. The method
of supporting a piece when a long hole is to be drilled by using a
center rest or back rest clamped to the ways of the lathe is clearly
shown at Fig. 322-B. The use of a centering tool which is held
in the tool post is outlined in this view. The drill is held
by the tail stock in the same manner as at A except that in many
cases, when the drill is very long, the tool post may be used to
support the drill after it has entered the bar far enough to center
itself.

432

MODERN LATHE PRACTICE

TAPER ATTACHMENT FOR LATHES

The common method of turning a taper on a piece in a lathe
is described in Chapter XIV and is very easily done. The tail
stock is set off center a sufficient distance to give the required
taper, which may be done on the South Bend lathes as indicated
at Fig. 323-A. The tail stock clamp is loosened and set screw F
is unscrewed the proper distance, then set screw G is turned in
until the tail stock is stopped by set screw F. The tail stock is

Headstock Dqd t Saddle

\ / * Work \

Com
Res
Lathe Bed

RetainincL^

SCREW

Guide Block

FIG. 323. — How to Turn Tapers in a Lathe. A — By Offset Tail Stock.
B — With Taper Attachment.

then clamped to the bed and a chip is taken. Test the piece to
make sure that the taper is correct by trying in tapered hole it is
to fit.

Where a large number of taper pieces are to be turned in dupli-
cate, as in manufacturing, a taper attachment as shown at Fig.
323-B may be employed. This is fitted to the rear V of the lathe
bed by two clamps and the position of the guide bar regulating
the taper is easily altered by changing the angle of the guide. A

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 433

block runs along the guide bar and moves the tool post carriage
in or out by a connecting bar. The desired angle of the guide
bar is set by loosening the retaining screws at each end and setting
it at the inclination desired, after which the screws are again
tightened down.

MILLING IN THE LATHE

A number of milling attachments for use with the lathe have
been offered, some of which are very practical, others that are not
so good. A carefully designed and well constructed attachment
of this nature is clearly shown at Fig. 324 doing various grades of
milling work. This is built by the South Bend Lathe Works and
while made for lathes of their manufacture it is equally valuable
on other lathes of similar design. The attachment is fitted to the
top of the carriage taking the place of the upper portion of the
compound rest. It is located by a dowel pin or centering pin
projecting from the base. The fixture is fastened to the compound
rest with two bolts, in just the same way as the compound rest
upper portion is fastened. The milling attachment is specially
valuable for the small shop as it permits one to use the lathe for
various jobs that ordinarily could be done only with a shaper or
milling machine. As an attachment of this kind swivels all the
way around on a horizontal plane and is graduated in degrees, as
well as permitting it to be swiveled in a vertical plane, many forms
of work can be economically performed. The vertical adjusting
screw has a graduated collar reading in one thousandths of an'
inch thus making the attachment suitable for fine work as well as
a large variety of work.

The illustration at Fig. 324-A shows the use of an angle milling
cutter in forming a piece of cast iron held in the vise of the milling
fixture. The length of the cut is controlled by the cross feed
screw, the depth by the adjustment of the lathe carriage and the
vertical adjustment governed by the vertical screw of the attach-
ment. At B, the attachment is shown holding a steel shaft that
is being keyseated for a Woodruff key. The view at C shows
the method of milling a square on a shaft. The same method can
be used to cut off shafting or tubing by substituting a saw for a
milling cutter. The usual form of milling cutter shown at D

434

MODERN LATHE PRACTICE

is used in connection with the special arbor at E which is made
to fit the taper hole in the head spindle of the lathe. Any milling
cutter may be used, the form depending upon the character of the
piece to be machined.

The Barnes Milling Attachment shown at Fig. 325 can be
conveniently secured to any lathe and is adapted to all classes of

Vertical Teed Control
Clamp^ Screws^

Work
Cross Feed

Woodruff Key
Cutter

Work

Clamp

Screws!

(Lvertical Feed
**** Control
JUT /Milling Cutter

SpinJleNDse

Arbor

5haf

Headstock

Blocks

Collar on Arbor ciampNut

FIG. 324. —The South Bend Milling Attachment and Its Use.

the most accurate milling and gear cutting. It is practically a
universal attachment and can do any work that can be done on a
milling machine of equivalent capacity. It will make milling
cutters, can be used for fluting taps and reamers, for cutting spur
and bevel gears, for surface milling, slotting, etc. The cutter block
is attached to the cross slide of the lathe carriage, can be moved

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 435

in or out and the cutter can be adjusted up and down on the arbor
to accommodate work. The universal head is clamped to the
inside ways of the lathe bed and has longitudinal, cross and vertical
slides. The feed screws are graduated to read in thousandths of
an inch and the vertical and horizontal swivels are graduated 180
degrees, this permitting very accurate adjustments and cuts to be
made at any angle. Either power feed or hand crank on apron

Spur Gear Blank ^ jndex

Driven I ^wr-
Driving Gear Gear j *^\ Milling

HeadstockX ^Attachment

Cutter

•Cross Feed Lever
Cutter Drive Sears

FIG. 325. — The Barnes Milling Attachment.

may be used to feed cutter to work and longitudinal feed of universal
head may be used to increase length of feed. The spindle of the
universal head can be supplied fitted with a draw in chuck attach-
ment. The device will cut gears as large as the lathe will swing.
A complete index is furnished and it is said that all numbers of
teeth can be cut from 1 to 50 and nearly all up to 360. Standard
milling cutters are used. The following specifications give some
idea of the size of the attachment.

436 MODERN LATHE PRACTICE

Longitudinal Feed 4f"

Cross Feed 10£"

Vertical Feed 4f"

Travel of Cutter 3£"

Distance between Centers of Spindle and Over-
hanging Arm . . 9"

Swing on Centers between Overhanging Arm 4^"

Distance between Vise Jaws 2f "

Size of Vise Jaws 4|" X 1

Diameter of Arbor f "

The views at Fig. 326 show the practical application of the de-
vice to a variety of work. Fig. 325 shows the general construction
very clearly. The cutter is driven by spur and spiral gears. A
driving gear is attached to the lathe spindle, this serving to transmit
motion through an idler gear to a small gear mounted .at one end
of the enclosed cutter drive shaft. The shaft carries a spiral gear
at the cutter end of the housing and drives the cutter spindle
through the spiral gear at its lower end. The view at Fig. 326-A
shows the method of milling a bevel pinion. At B the gear cutting
attachment is removed and a vise is supplied to hold work machined
by a facing cutter driven directly from the lathe spindle. The
view at C shows the attachment rigged up for milling flutes in
a reamer. Obviously a device of the character will prove very
valuable in any small machine shop where a regular universal mill-
ing machine is not available.

Another milling attachment for lathes is shown at Fig. 327.
This is made by the Cincinnati Pulley Machine Company and is
capable of using standard cutters and doing such work as Woodruff
keyseats, key ways, surface and end milling, slotting, etc. The
machine is furnished with a J H. P. motor which is geared to a
worm gear driving the cutter spindle so the ratio of 72 to 1 gives
ample power for all average work. The motor is attached to any
lamp socket by cord and is then ready to operate.

They are furnished for either direct or alternating current and
wound for either 110 or 220 volts. The spindle is made of high
carbon steel and runs in bronze bearings. The worm is of steel,
hardened and ground. The worm wheel is made of bronze. The
worm and worm wheel runs in an oil container, the cover of which

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 437

Cutter Bevel Pinion Blank

Tkcin
Cutter

Letthe Bed

Headstoc

Reamer
Drive Gear Work Support

FIG. 32(3. — Outlining Some Practical Applications of the Barnes Milling
Attachment for Lathes.

438 MODERN LATHE PRACTICE

is removed in illustrations to show gearing. Annular ball bearings
are employed on both worm and worm gear shafts to reduce friction.
The illustrations show very clearly the round column on which
the sliding arm is carried. This arm is provided with a vertical
adjustment to raise or lower the cutter according to the work to
be done. The vertical screw connected with the arm permits
micrometer adjustment. Cross and longitudinal adjustment is
taken care of by the carriage and cross feed movements of the
lathe. The cutter in illustration A is milling a squared shaft and
various samples of work that can be done with the device are also
shown here. The desired longitudinal movement of the cutter is
obtained by hand movement of the lathe carriage. The shaft is
supported by the lathe chuck and tail stock center. In the view
B the cutter is shown at work on a male driving clutch member
which is supported by the lathe chuck. The method of using the
attachment is clearly shown in illustrations. An indexing mechan-
ism is also furnished by the makers to permit the device to cut
gears. The driving motor speed is 1700 R. P. M., the cutter
spindle speed is 24 R. P. M.

KNURLING ON THE LATHE

Knurling is very easily accomplished on any lathe if the right
tools are available. The illustration, Fig. 328-A, shows a piece
of steel with three different grades of knurling. The knurling tool
for doing the work is shown at B and is intended to be held in the
tool post in the same manner as a cutting tool. The piece to be
knurled is driven slowly on centers or held in the chuck and the
tool is forced slowly into the revolving work. This revolves the
knurling wheels and produces the desired effect. The knurling
wheels are hardened and it is necessary to use oil plentifully during
the operation. The tool shown at C is a novel one and is very
easily made by any machinist. A pair of cheap pliers with soft
jaws are purchased and milled for the knurling wheels. While
a pair of parallel jar pliers are best, the ordinary forms will do very
well. The pressure for knurling is produced by a wing nut as
indicated. A tool of this nature will be found valuable in knurling
small work where the tool shown at B cannot be used on account
of the spring of the stock.

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 439

440

MODERN LATHE PRACTICE

INDICATORS AND THEIR USE

The old and almost universally used method of trueing up
work in a lathe chuck or when held on centers by using a piece of
chalk to indicate the high spots is only good for the first adjustment
of rough work. For trueing up work where the finish must be
accurate, test indicators have been devised which show minute
variations from truth of running in an unmistakable manner.
Two forms, and the method of using them, are shown at Fig. 329.

Knurl intf
Wheels

Coarse Medium Fine

•Knurling Wheels

Tool Body

Pressure
Screw

FIG. 328. — Tools for Knurling in the Lathe.

The "Last Word" test indicator at A employs a dial gauge and
enclosed multiplying mechanism, the Starrett device at C has a
simple multiplying lever and one end of the lever serves as a pointer
to mark the error on the scale carried on the body of the device.
The gauge at A is shown installed on a ball joint tool post shank.
The auxiliary clamp provided with this instrument to permit of
setting it up on the scriber member of a surface gauge at B is also
shown at A.

The ball joint connection between the tool post shank and the
indicator makes it possible to apply the device to a great variety

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 441

of work. The contact lever has a hardened taper-head stud for
bearing, which provides adjustment for wear. There is a small
tapered hole through the contact ball, and contact points of special
shape can be fitted into this hole to meet the requirements of special
classes of work. In many cases the ordinary contact ball is quite
satisfactory without providing any auxiliary point. The mechan-

ForUse-lnTgplPdst

Scale AuxiliaryCIa

indicator Point Indicator
Fulcrum

FIG. 329. — Indicators and Their Use.

ism of this indicator has been worked out to give the magnifying
power of 100, and at the same time the instrument is of remarkably
small size, which will be appreciated when it is known that the
weight is only 1£ ounce. The dial is graduated to read in 0.001
inch. This instrument can be quickly changed from the tool post
shank to the needle of a surface gauge to adapt it for surface plate

442 MODERN LATHE PRACTICE

work or back to the tool post shank for lathe, shaper, planer, grind-
ing or milling-machine work. It is adaptable for use on a great
variety of tool room and machine-shop operations.

The Starrett indicator is also light and very simple in construc-
tion. The indicating lever is so proportioned that it will multiply
the error about 15 times which is sufficient for all ordinary work.
The method of using the indicator is so clearly outlined at D that
no further description is necessary. Many other uses for a device
of this nature will suggest themselves to the practical workman.

BORING BAR CONSTRUCTION AND USE

The lathe is often used for boring, or internal turning and is as
well adapted for that class of work as it is for the plainer and
easier external work. The simpler operations of boring, such as
holes that are too large to be drilled economically, can be performed
with a simple design boring tool that can be attached directly to
the tool post. A hole is first drilled in the piece of sufficient size
to accommodate the boring tool, the work then going on just as in
external turning as far as control of the tool is concerned. Special
boring tools and supporting fixtures are necessary when the work
demands and while the simple forged tool does good work in the
smaller sizes, it is believed to be more economical to use tool holders
with removable high speed steel tools on the heavier work.

The boring fixture shown at Fig. 330-A is an adjustable design
for light work. The boring tool is supported in a swinging tool
holder held at one end by a fulcrum screw, and the whole is sup-
ported in a frame adapted to be secured to the tail stock spindle.
The amount of stock removed at a cut is regulated by the adjusting
screws passing through the sides of the tool support frame, these
permitting the boring tool to be brought in contact with the work
with varying degrees of pressure. The boring tool is of round
stock and is kept in place in the socket made to receive it in the
tool holder by clamping screws.

Another design in which the cross slide of the lathe is used to
support the boring bar is shown at Fig. 330-B. The tool support
is of round stock, having a hole drilled through one end at an
angle. The cutter is made of high speed steel, round section and

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 443

is a good fit in the hole of the tool holder. A taper pin is provided
to lock the cutter in the holder. The boring bar itself is held by a
cast iron clamp member attached to the cross slide carriage instead
of the usual tool post by bolts. The cutter or boring tool may be

Adjusting 5crew
n

Tool Support Frame

UtheChuck

Boring Toot

Tail5tocK
V 5pindle

Adjusting Screw

Tool Suppoft
Casting

FIG. 330. — Boring Bar Construction and Use.

removed for regrinding by knocking out taper pin which releases
the tool from its socket in the tool holder.

Two designs of boring bars for heavy work are shown at Fig.
331. That at A uses an adjustable boring tool which can be moved
out by loosening the clamping screws and screwing in the adjusting

444

MODERN LATHE PRACTICE

screw. The tool support casting may be attached to the cross-
slide of the lathe as indicated at Fig. 330-B. The boring bar at
B, Fig. 331, is similar in principle to that shown at A as relates to
manner of support. The cutter, however, is of rectangular section
stock, has two cutting edges and is intended to make the desired
hole with one cut. The cutter is held in place in cutter support
by a locking wedge. This form of boring bar is more suitable for
finishing and duplicate boring where it is desirable to have the
bore come to the size determined by the cutter. Cutter supporting
bars or boring bars of the form at A and B, Fig. 331, are used more
in manufacturing than general work. They are also widely used
in boring mills and turret lathes.

rfl

Lathe Chuck

Adjustirg Screw

•Lathe Chuck

Tool Support I f

""TSFL

Tool Support
Casting

Tool Support
Castin

FIG. 331. — Boring Bars for Heavy Work.

SPECIAL METHODS OF HOLDING WORK

While it is not difficult to chuck pieces of regular form or to
secure them to the lathe face plate, there are many machining
operations that call for special methods of holding the work, es-
pecially on machinery used in manufacturing. In a job shop doing
only repair work, each job is different and many extemporized
fixtures are designed and fitted up which are dismantled and
thrown to one side when the work is done. In manufacturing,
which means turning out a number of duplicate pieces, an invest-
ment in accurate fixtures of a permanent character is justified.

Various methods of holding pieces not ordinarily met with in
regular work are shown at Figs. 332 and 333. These will prove

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 445

446

MODERN LATHE PRACTICE

valuable in suggesting ways other pieces of similar form may be
held. The fixture at A is made of cast iron and is bolted to the
lathe face plate. It is designed to support gas engine pistons
when it is desired to bore the hole through the bosses for the wrist
pin. The piston is properly located in the bosses of the fixture
made to receive it and firmly clamped in place. The hole is first
drilled through the bosses, after which a reamer is used to finish
the hole. It is apparent that any body of cylindrical form could
be held by similar means.

It is often desirable to turn the outside diameter of cylindrical
bodies having light section walls. One end is often designed with
a flange so it can be attached to the lathe face plate, but the problem

Chuck Body Plungers 5top Piston Bosses

Tftneac

•Expanding

End View
Gas Engine Piston

FIG. 333. — Special Chuck for Gas Engine Piston Support.

is to supporj; the other end if the piece is long. A revolving spider
for live tail stock center well adapted for work of this character is
shown at B. The main portion of the device or body is of cast
iron and is provided with a bronze bearing which runs on the
taper bearing of the shank adapted to be held by the tail stock
spindle. Provision is made to take the end thrust on a suitably
beveled shoulder on the shank or axle. The spider body is pro-
vided with three holes in which plungers fit. These have their lower
ends beveled to fit the taper on the adjusting screws and are kept
from turning by small set screws working in keyways in the plungers
as indicated. The outer portions of the plungers are rounded off.
To hold the piece securely, it is only necessary to screw in the
adjusting screws and raise the plungers into contact with the inner
periphery of the metal ring. As the screws can be turned inde-

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 447

pendently it is possible to hold the piece firmly, yet accurately.
A fixture of similar design may be made to hold light narrow rings
by having the body of the device threaded to screw on the nose of
the head stock spindle or provided with bolts to fasten it to the
lathe face plate. In this case it is not necessary for the body of
the device to revolve independently of its supporting means.

The automobile steering spindle shown at C is another difficult
piece to machine because of its irregular shape and also because
the holes through the spindle body are not at right angles to the
spindle. The methods of supporting this piece for drilling the holes
and have the spindle at the proper angle as well as supporting the
piece to turn the spindle itself are so clearly detailed that the
process may be readily understood by even the novice machinist.

A special chuck for machining the exterior of a gas engine piston
is clearly shown at Fig. 333. The same wedge operated plunger
principle previously outlined is shown, the novelty being in the
method of operating the expanding wedges or cones simultaneously.

This chuck has two sets of three plungers, one set at the front
and the other at the rear, which true the casting up so that an even
thickness of wall is obtained in the finished piston. The stop
screw serves the double purpose of holding the cover in place and
locating the piston endwise so that an equal thickness of head is
obtained on all pistons. The construction of the chuck, which is
operated through the expanding cone by means of a handwheel at
the back end of the spindle, is clearly shown and needs no further
description. The chuck body may be threaded to be secured to
the head stock spindle nose if desired or held in any other manner.

How SWING OF LATHE MAY BE INCREASED

In a small shop where the possible investment in machinery is
limited, many expedients are followed to fit machines to work for
which they were not primarily intended. One of the conditions
often confronting the small shop owner is to swing larger work than
his lathes are made for, and yet these conditions do not occur often
enough to justify the purchase of a larger lathe. The illustrations
at Fig. 334 show two ways of increasing the swing of a lathe. At
A, the method of using raising blocks to enable a 15-inch lathe to
swing 20 inches over the bed is shown. The raising block equip-

448

MODERN LATHE PRACTICE

ment includes blocks for head stock, tail stock, tool rest and center
rest as well as necessary bolts for attaching blocks to lathe. These
can be procured from the lathe manufacturer in many cases.

The gap bed lathe is a popular machine tool for jobbing and
repair shops, and the combination of the gap bed and lifting blocks

Headstock

Raising Block

Tailstock

Large Flywheel
Raising Block

Raising
Block

FIG. 334. — Methods of Increasing Swing of Lathe Outlined.

as shown at B enables the machinist to do many jobs of repair
work he would ordinarily be obliged to turn away. With a gap
bed lathe, if a job of large diameter comes in, it is a simple matter
to remove the bridge from the bed and swing the work. If opening
the gap does not provide sufficient space, the raising blocks may
be used as well.

In this manner, a lathe capable of swinging but 15 inches
with bridge in place may be able to swing nearly twice that much
with the raising blocks inserted and gap bridge removed.

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 449

LATHES FOR HEAVY WORK

Some of the refinements of detail noted in the Lodge & Shipley
lathes for heavy cuts are shown at Fig. 335 as being of interest to
the student of lathe construction. A light bridge will answer for

Lathe Bed

Clamp
Bolts

FIG. 335. — Lathe Construction for Heavy Cuts.

light cuts on large diameters with the tool point directly above the
front shear. But stresses are of a very different sort when the
lathe is under a heavy cut on a small diameter.

The illustration A shows the position of tool and compound

450 MODERN LATHE PRACTICE

rest on the 24 inch Patent Head lathe when taking a 15 H. P. cut
on work of 5 inches diameter. Heavy arrow indicates direction of
pressure due to cut. Note the large bearing against the top and
inside of bed directly in line with the tool thrust, in addition to
the full length bearing of carriage upon front and rear Vs. This
extra bearing gives a solid support to the bridge just where it is
needed, and positively prevents a deflection or distortion even
under the heaviest cuts.

The sectional illustration at B shows why the tail stock will
not back away from the work, no matter how heavy the cut. A
pawl which engages the rack cast in the center rib of the bed fur-
nishes a positive brace against end thrust. The four bolts for
clamping the tail stock to the bed extend to the top of the barrel,
where the nuts are easily accessible; and because of this construc-
tion the whole tail stock is drawn down solidly and evenly against
the bed. The tail stock is massive in proportions and has long
bearing on the bed. The barrel is large and permits long travel of
the spindle. Floating plug binders lock the tail stock spindle
securely and in correct alignment. The tail stock barrel is not
split, but is always a correct reamed fit for the spindle.

GRINDING ATTACHMENTS FOR LATHE

In the absence of a grinding machine many repair shops com-
plete repairs by boring and turning, when a fine degree of accuracy
would be advisable. Many owners of small shops do not care to
go to tKe expense of installing grinding machines although desiring
their use. In accompanying illustration, Fig. 336, a grinding
attachment is shown, that the designer states may be attached to
any engine lathe of sufficient center capacity.

The grinder itself is carried by a slab and studshaft, the arm
of which is about 1.75 inches in diameter, so as to insure the neces-
sary rigidity. The slab is attached to the face plate of the lathe by
means of two .75 inch bolts, of which the top one is arranged in a
radial slot, to facilitate adjustment of the work in hand. Upon the
arm of the studshaft is mounted a length of solid drawn hydraulic
tubing, which revolves on two brass bushings forced and sweated
into the ends of it, thus leaving an annular space for the lubricant.

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 451

The tube carries a driving pulley on its inner end, the grinding
wheel being attached to the outer end. The driving pulley is
secured to the tube by means of two set screws. This pulley is
fitted with a sufficiently convex face, in order to eliminate lateral
slip of the belt. The outer end of the tube is threaded to receive
a thimble which is screwed and sweated into place.

Owing to the path which the wheel spindle follows the use of
a floating countershaft is necessary. The connecting rod to the
latter is shown broken off in the lower illustration and the ar-

Pulley
Face Plat-

Floating
Countershaft

End View

Emery Wheel

FIG. 336. — Grinding Attachment for Lathe Using Floating Countershaft

rangement of the floating countershaft is depicted in the upper
drawing. As previously mentioned the feed of the grinding wheel
is adjusted by the bolt situated in the radial slot while the travel
is supplied by the lathe slide rest.

Some machinists display considerable ingenuity in building
grinding attachments for the lathe and such a device is shown at
Fig. 337. It will be noted that the design does not employ a
floating countershaft. With it the inventor claims he is able to
grind hardened steel spindles, camshafts, crankpins, valves, cylin-
ders, etc., and states that in planning the attachment considerable

452

MODERN LATHE PRACTICE

thought was given to have the equipment as rigid as possible and
that all parts operated on with it should be ground quite circular.
The maker states that the attachment can be used either for
grinding internal or external work and that it can be fitted easily
to the ordinary lathe. The left hand figure shows the end eleva-
tion and that at the right the grinding spindle and method of
attaching it to the tool clamp of the top portion of a compound
slide rest. The smaller figure shows a plan of the grinding arm it-
self, which is somewhat after the style of a Landis grinder. The
attachment can be made fairly easily, but if desired can be pur-

Drivir^S Drum
Lathe Hcadstock

Driving Drum
Wheel , Wheel.

Wheel
i Support

FIG. 337. — Grinding Attachment for Lathe Using Overhead Drum.

chased. For internal work it is provided with a long arm but for
external work, the latter is only about 3 inches in length.

A small pulley for driving the arm is seen located between two
bearings, so that it will be realized that there is no overhang to
set up vibration. The method of driving the spindle consists of a
countershaft carrying a drum supported by a pair of hangers
placed in front of the ordinary overhead shop shaft and about
central with the lathe, so that the attachment can travel about 6
inches on either side without materially altering the relative
position of the driving belt.

The driving drum consists of two 12-inch diameter pulleys
about 2 inches wide. These are placed about 3 feet apart and

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 453

then lagged with strips of wood one inch in width, these being
placed lengthwise and attached to the pulleys by means of cap
screws. The whole is then skimmed up in a lathe, and it will be
found that this makes quite a nice light overhead drum, which
gives nearly three feet of travel over the grinding wheel. The
small pulley is so arranged that it may be driven off the existing
cone pulley on the overhead shaft which drives the lathe. By this
means a good increase of velocity is given by the emery wheel.

The cut is put on by means of a cross fed screw in the lathe
saddle. If a taper movement is required the top rest is of course
set to taper just as if one were going to machine taper in the ordi-
nary way. The maker of the attachment states that he considers
the rig simple, that it will provide accuracy in grinding, and can be
fitted by any average machinist.

MACHINING CONCAVE AND CONVEX SURFACES

Considerable ingenuity is displayed by automobile repairmen
in overcoming various machining difficulties, and an instance of a
useful lathe attachment is described in a current issue of the Com-
mercial Motor, an English publication. The repairman had
occasion to replace parts of a badly damaged torque tube and
ball universal joint and, when he came to turn the ball and its
seating, was confronted by a problem, inasmuch as the only machine
available was a 12-inch center lathe.

The sketches at Fig. 338 show the attachment constructed and
applied, and demonstrates how the concave and convex surfaces
required were turned. The upper drawing shows the attachment
for turning the concave surface; the lower depicts the ball being
machined. The diagram underneath each lathe illustrates the
path of the cutting tool. The attachment consisted of flat mild
steel strips, the sections being .5 inch by 1 inch. Six lengths
were cut off to obtain the necessary travel, and at the base of the
angle pieces were drilled two .375-inch diameter holes. The plain
ends were drilled out .5 inch.

The swiveling connecting rods, two in number, were drilled
out and tapped .5 inch Whitworth at each end, the centers being
carefully marked out equal to the radius of the ball and spherical

454

MODERN LATHE PRACTICE

seating; that is, four inches. Permitting these to swing at the end
of each angle piece enabled the necessary arc of the cutting tool
to be effected.

It will be noted that for either machining operation, one angle
strip is bolted to the tail stock of the lathe, and another piece to the
top slide under the tool rest. Cross feed only is used, the trans-
verse feed being free altogether so that without touching the hand-

*=${i .M ii

ht'4

FIG. 338. — Device for Machining Concave and Convex Surfaces on Lathe.
A— Path of Cutting Tool for Ball Seating. B — Swivelling Links for
Securing Radii. C — Path of Cutting Tool for Sphere.

wheel the carriage may readily be pushed along the lathe bed.
The cutting tool may then be made to follow the required circular
path.

GROOVING OIL DUCTS ON LATHE

Cutting oil grooves in bearings with a chisel is not always a
satisfactory method and considerable time is lost in the operation.
The proper method is to utilize an oil grooving machine, but these
are not common in repair shops. An attachment for an ordinary

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 455

lathe which the repairman who constructed the device states can
be utilized to groove any size bush or bearing is shown at Fig.
339. The drawing is practically self-explanatory but the chief
points to be considered are that the arrangment should be bolted
firmly to the lathe body and that the adjustable arm connecting
the carriage with the horizontal disc should be parallel with the
lathe bed at each end of its stroke.

t.r-L,

FIG. 339. — Attachment for Grooving Bearings on Lathe. A — Grooved
Brass in section. B — Arrangement of Drive. C — The Work in Chuck.
D — Disc Drilled to Give Various Strokes. E — Adjustable Connect-
ing Rod. F — Screw Which is Removed to Allow for Free Travel of
Tool.

The screw in the carriage holder must be withdrawn before
commencing operations, so as to enable the carriage to slide easily
in either direction. The drive must be so proportioned as to
enable the chuck to make one revolution while the tool is traveling
the whole length of its stroke. An oil groove, after the outline of
that shown in the small sketch, will thus be made to feed oil equally
all over the bearing.

456 MODERN LATHE PRACTICE

For example: Assume that a bush 1.5 inches long is to be
grooved. The pin on the horizontal disc is set .625 inch out of
center; the connecting rod adjusted and the main carriage bed
locked. The transverse screw is then removed from the tool
carriage and the grooving tool set about .125 inch inside the bush,
and the lathe started.

The carriage being free to slide, the connecting rod will cause
the tool to travel just 1.25 inches, and the gearing being so ar-
ranged that the chuck will make one revolution during the complete
travel of the tool, an oil groove of the required length and pitch
will be cut into the bearing.

USE OF COMBINATION LATHE DOGS

Sometimes in the overhaul it is found that the crankpin is worn
oval and will not yield to ordinary methods, and when such is the
case a light cut is taken. The Stras burger Manufacturing Com-
pany is marketing combination lathe dogs, which are shown at
Fig. 340 and these members are adjustable from 2 to 6 inches.
They are designed for holding all kinds of crankshafts, such as
utilized in automobile and marine engines, and other power plants,
and can be employed wherever a common lathe dog can be used.

The design illustrated at D is adapted for turning heavy work
such as motor truck engine crankshafts, and is adjustable from
two to eight inches. It is provided with a screw feed center and
gauge, and each type of dog is constructed of the best malleable
iron with case hardened steel screws.

The company points out that the turning up of a crankshaft
has always been accomplished under certain difficulties except in
shops where they are made in large numbers, and where special
machines are required. As crankshafts are now forged in nearly
all sizes and forms, and may be procured at a reasonable cost in
the rough, it is possible to turn these up in the lathe by the follow-
ing process:

Assuming that a four-throw crankshaft is to be finished, although
single and double ones are more common to the average repairman
of marine engines. The first step is to center the work, either by
laying off and centering in the drill press or in the lathe with the

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 457

use of a steady rest. The driving dog is fastened at one end and
the work placed between centers.

The bearings, front, center and rear, are roughened down to
within .065 inch of the finished size. The straight or tailless dog
is then fastened on the other end and one-half of the stroke is
measured from the center of the crank to the center hole in the

---OH

FIG. 340. — How to Use Combination Lathe Dogs for Turning Up
Crankshaft.

adjustable screws and the nuts securely tightened. The work is
then placed between the adjustable centers and lined up parallel
by running the lathe carriage back and forth.

The second and third pins should be roughened down to within
.0625 inch of the finished size. The dogs should now be loosened
and the crank given half a turn, the first and fourth pins lined up
parallel, and finished to exact size. After this is done the dogs

458 MODERN LATHE PRACTICE

are again loosened and the crank given half a turn back and lined
up parallel to finish the second and third pins to exact size.

The four pins are now finished to size, so the straight dog and
the counter-balance should be taken off, and the crank placed
between centers. The center bearing is then finished to size and
the steady rest applied, while the front and rear bearings are being
finished to size. Care should be taken not to have the tail stock
center too tight during the finishing cuts.

The large face plate should be used for this operation and a
weight clamped to it for a counter-balance. If the crank should
have a flange on one end, it may be chucked and a four-jaw chuck
used instead of the face plate, then only one dog will be necessary.
If a heavy cut is desired or the tool should chatter, the steady rest
can be used on one pin, while the other pin is being turned down.

HACKSAW ATTACHMENT FOR LATHES

A simple power hacksaw attachment that can be used in connec-
tion with this versatile machine tool is shown at Fig. 341 and its
utility in the small shop where such a device does not form part of
the regular equipment can be readily understood.

The attachment consists of the side bar A to which the hacksaw
frame is attached, and the guide bars or supports B and C that
are firmly attached to the base piece F. The bar A is worked back
and forth by a connecting rod E, that is adapted to be attached
to the face plate of the lathe. The small bar D is a guide piece
to keep the saw frame from turning.

The device is simple to build and the materials entering into
its construction are not costly; in fact the design is such that it
may be easily placed on or detached from the shears of the lathe.
The base plate F is composed of a cast iron slab one inch thick,
eight inches wide, and about five feet long. It is possible to form
the guide members B and C integral when the slab is cast if they
are placed on the pattern. The slide is a flat piece of steel .375
inch thick and two inches wide, the length is about four feet, though
this will vary according to the stroke.

A hole is drilled in the center of the bar for a .5-inch bolt, which
is to form the crankpin for the lower end of the connecting rod

PRACTICAL INSTRUCTIONS ON LATHE OPERATION 459

E. The supports B and C may be made of one-inch square ma-
chinery steel. The support B has an end turned and threaded
to suit a .75-inch tapped hole made in the cast iron base F. The
support C may be attached in a similar manner or bolted to the
other end of the base as shown. Each support has a .375-inch
slot cut through the center, this being made just large enough to

12 Inch Bolt

Saw Frame

Couedinf Rod

FIG. 341. — Simple Power Hackshaw Attachment for Lathes.

permit an easy sliding fit to exist between the slide bar and the
sides of the guide members.

The smaller guide D is made of .375-inch by one-inch machin-
ery steel, one end being bolted or riveted to the saw frame, allowing
the other end to slide through the support B, thus eliminating
any tendency of the saw frame to wabble. The connecting rod
E is a strip of .375 steel about two inches, wide and of a length to
suit that of the saw frame, which obviously determines the per-
missible stroke. The connecting rod is drilled at both ends for

460 MODERN LATHE PRACTICE

.5-inch bolts, and is intended to be attached to the face plate of
the lathe at the upper end and the slide bar A at the lower end.
The upper end may be moved to some extent in the slot of the
face plate, making it possible to vary the stroke within the limits
allowed by the slot and the size of the attachment. The saw
frame is forged of machinery steel and the blade is made tight in
the usual manner, by a thumb screw at the outer end of the frame.
An ordinary drill or shaper vise is clamped to the base plate, this
to hold the stock that is to be cut off. The attachment is bolted
to the shears of the lathe by a clamping bar under them, which is
pressed into engagement by a .75-inch bolt as depicted.

INDEX

Adjustable conical front bearing, 115.

straight-edge for lathe testing,

243.

Alignment of centers, testing for, 241.
Allowable limits in lathe testing, 251.
American Tool Works Company's 20-
inch engine lathe, 316.

Tool Works Company's 42-inch

triple-geared lathe, 331.
American Turret Lathe Company's
turret lathe, 410.

Watch Tool tail-stock, 139.
Angles for tools, 216, 218.
Angular work, turning, 359.
Anti-friction metals, 114.
Aprons, 143, 145.

Pratt and Whitney, 291.
Arbors, hardened, 266.

making of, 266.

or mandrels, 265.

press, Greenard's, 267.

taper, 266.

use of, 267.

Armstrong tool-holders, 221.
Asiatic wood turner, 24.
Attaching shaft straighteners, 167.
Attachments, classification of, 52.

for backing off cutters, 185.

for bench lathe, 365.

for grinding, 189.
• for lathes, 176.

for lathes, grinding, 450.

for lathes, hacksaw, 459.

for lathes, milling, 433.

for thread cutting, the Rivett-
Dock, 192.

for turning concave and convex
rolls, 181.

for turning concave surfaces, 183.

for turning convex surfaces, 184.

Author's design of 21-inch engine lathe,

296.

design of fiddle-bow lathe, 26.
reversing gear device, 298.
21-inch lathe, 76.
50-inch lathe, electric drive, 413.

Back gear data, 124.

gear ratios, 124.

geared lathes, 57.

geared lathes, essentials of, 58.

gearing, calculations for, 122.

gearing, faulty design of, 125, 127.

gearing, homely proportions for,
133.

gearing of head-stocks, 120.

gearing of head-stocks, operations
of, 122.

rests, 164.

Backing-off attachment, 185.
Balance-wheel, development of, in
lathes, 28.

Wheel, early used on lathes, 27.
Ball thrust bearing, 112.

turning, 179.

turning attachment, 180.
Bancroft & Seller's change gear device,

59, 194.

Barnes milling attachment, 434.
Bed for lathes, 69, 77.

for lathes, depressed inside V's, 79.
Belt friction in lathe heads, 346.

horse-power transmitted by, 236.

in lathes, 132.

strain on bearings, avoiding, 344.
Bench lathe tail-stock, 139.
Blaisdell carriage, apron, and com-
pound rest, 146.

18-inch engine lathe, 295,

tail-stock, 3.38.

461

462

INDEX

Boring bars, 281.

bars for a long hole, 282.

bars, hollow, 284.

large cylinders, the Author's de-
vice, 276.

tools for lathes, 442.

work on the lathe, 274.
Box form of lathe bed, 80.
Box housings, 113.
Boxes for spindle, Reed form, 288.
Boycott, first in this country, 15.
Braces for beds, 81.
Bradford 16-inch engine lathe, 314.

42-inch triple-geared lathe, 327.

rapid change gear device, 203.

taper attachment, 155.
Brass lathe, Fox, 56.
Bridgford tail-stock, 141.

Cabinet and cupboard, 90.

for lathe beds, 59.

for supporting lathe beds, 87.

future use of, 92.
Calculating amount of taper, 270.

back gearing, 122.
Calculations for change-gears, 277.
Cam cutting on the lathe, 285.
Capillary attraction in lubrication, 118.
Carriages for lathes, 143.

form of, 84.
Carver, Mass., Iron Foundry in, 1735,

18.
Cast iron bed, early form of, 86.

boxes for spindle bearings, 288.
Castings, iron, early history of, in New

England, 17.
Center grinder, Hisey-Wolf, 190.

reaming, 256.

rests, 164.
Centering lathe works, 256.

machine, 256.
Chain lathe, the old, 77.
Champion tool-holders, 222.
Change gear devices, 59.

gear devices, Author's book on,
197.

gear devices, classification of, 195.
Change gear mechanisms, 194.

gears, how listed, 52.

Change-gears, use of, in thread cutting,

278.

Changing speed of lathe spindles, 120.
Chuck work, 258.
Chucking and centering works, 263.

lathes, 54.

Chucks, expanding, 446.
Cincinnati Electric Tool Company's

tool post grinder, 189.
Circular saw attachment for foot lathe,

32.
Clamping work to the face-plate,

269.
Classification of change gear devices,

195.

of lathe attachments, 52.
of lathes, 52.
of lathes, English, 22.
of turret lathes, 371.
Clearance of tools, 218.
Clutch, friction for foot-power ma-
chines, 33.

Combination lathe dogs, 456.
Compound change-gears, 279.
rests, 143, 145.

rests for concaving and convex-
ing attachment, 179.
rests, New Haven, 147.
Concave surfaces, attachment for turn-
ing, 183.
machining, 453.
Conditions of materials to be turned,

216.
Cone diameters, 133.

pulley turning rest, 164.
speeds, 125.
steps, -form of, 108.
Conical front bearing, 115.
Convex and concave rolls, turning of,

181.
and concave surfaces, attachment

for turning, 184.
and concave surfaces, machining,

176.

Countershaft boxes, self-oiling, 172.
speed, 225.

used with foot lathe, 33.
Countershafts, 170.
friction, 170.

INDEX

463

Countershafts, geared, 170, 174.

two-speed, 170.

variable speed, 170, 173.
Crank-shafts, machining methods, 457.

turning of, 271.

Criticism of modern lathes, 148.
Cross-ties for beds, 81.
Crowning device for pulley turning,

360.

Cushman chuck, 261.
Cut-meter, Warner's, 227.
Cutting speeds for high-speed steel
tools, 230, 232.

threads, 277.
Cylindrical cutters for boring bars, 283.

Data, making record of, 237.
Davis 18-inch engine lathe, 324.

tail-stock, 139.

Day's work of the early mechanics, 29.
Definitions of turning, 22.
Design of lathe head-stocks, 346.

of lathe tools, 217.
Designing a lathe head-stock, 133.

lathe carriages, 143.

lathe spindles, 102.

Development of the balance-wheel
idea, 28.

of manufactures, 20.
Devices for machinery concave and

convex surfaces, 176.
Diameters of lathe cones, 133.
Difficulties of lathe design, 70.
Distortion of work, 269.
Double-spindle lathe, McCabe's, 358.

threads, cutting of, 281.
Dreses forming turret lathe, 398.

turret lathe for brass, 395.
DriUing in the lathe, 430.

speeds, 227.

work on the lathe, 274.
Drivers for lathes, 258.

mechanism of a triple-geared lathe,

123.
Driving feeding mechanism, 134.

lathe work, 257.

the lead screw, 135.
Dynamometers and the transmission
of power, 237.

Earliest form of lathe, 23.
Early development of machine tools,
20.

history of the lathe, 21.

lathe rests, 25.

manufactures, 15.

mechanic, tools of the, 17.

New England factories, 16.
Electric drive, advantages of, 405.

simplicity desirable, 416.
Electrically driven lathes, 405
Elementary form of lathe bed, 72.
Engine, definitions of, 286.

lathe, 286.

lathes, complete, 57.
English classification of lathes, 22.

form of lathe bed, 78.

method of determining the swing
of a lathe, 77.

tests of power for cutting tools,

238.

Erecting a lathe, 245.
Essential parts of a back geared lathe,
58.

of a triple-geared mechanism, 131.
Expanding arbors, 265.

chuck design, 446.

Face-plate jaws, 261.

jaws for holding work, 269.

work, 259.

work, improper holding of, 269.
Factories, early New England, 16.
Failures in turning tapers, 150.
False jaws for a chuck, 262.
Faulty designs of back gearing, 125,

127.
Fay & Scott extension gap lathe,

357.

Fay & Scott's extension, 357.
Feeding mechanism, drive for, 134.
"Fiddle-bow" lathe used by the

Author, 26.
Fitchburg machine works "Lo-swing"

lathe, 350.
Fitting tapers, 271.
Fixtures for milling, 433.
Flat cutters for boring bars, 283.

464

INDEX

Flather's quick change gear device, 212.

18-inch quick change gear engine

lathe, 292.
Follow rests, 165.
Foot lathes, 24.

built by the Author, 30.

with countershaft, 32.
Forge lathes, 56.
Forming lathe, 62.

tools, 273.

work, 273.
Forms for pipe centers, 264.

of front bearing, 114.

tools, 218.

Fosdick 16-inch engine lathe, 325.
Foundry, in Lynn, Mass., 1643, 17.
Fox brass lathe, 56.
Freedom, industrial, 16.
Friction clutch for foot-power ma-
chines, 33.

roller follow rest, 167.
Front bearings for spindles, 114.
Full swing rest, 162.
Functions of lathe parts, 423.

of the tail-stock, 135.

Gap lathe, 61.

Gear cutting on the lathe, 284.
Geared countershafts, 170.
Gearing of lathe head-stocks, 120.
Gisholt turret lathe, 385.
Graduations on taper attachments, 270.
Gray's change-gear device, 194.
Greenard's arbor press, 267.
Grinding attachments, 189.

for lathe, 450.

large, 191.
Grinding operations on the lathe, 284.

tools, 220, 223, 226.
Group drive, electric, 405.
Guesswork in lathe design, 132.

Hacksaw attachment for lathe, 458.
Hamilton compound rest, 159.

taper attachment, 152.

18-inch engine lathe, 320.
Hand lathe, 53.

tools, 254.
Hardened arbors, 266.

Head-stock, a favorite form of, 96.

an old design for, 93.

arch form for, 96.

design of, 133.

designing, 93.

development of, 95.

favorite form for, 99.

later form with back gears, 95.

of old form from New Haven, 95.
Heavy lathes, 327.
Height of lathe centers, 86.
Hendey cone pulley turning rest, 164.

follow rest, 165.

open-side tool-post, 159.

proportion for back gearing, 133.

quick elevating tool-rest, 160.
Hendey-Norton cabinets, 91.

carriage, etc., 146.

elevated electric motor drive, 411.

head-stock, 97.

special head-stock, 101.

tail-stock, 138.

taper attachment, 153.

24-inch engine lathe, 298.
High-speed drills, 227.

lathes, 338.

High-speed steel tools, 220, 223, 228,
230.

making of, 228.

use of, 224.

Hisey-Wolf center grinder, 190.
History of the lathe, 21.
Holding work on the carriage, 274.
Homan patent tool-rest, 160.
Horn clutches on countershafts, 170.
Horse-power transmitted by belts, 236.
Horton chucks, 260.

Ideal form of lathe bed, 80.

of lathe spindle, 104.
Importance of proper lubrication, 120.
Indicators and their use, 440.
Industrial freedom, 16.
Inspection blank, 245, 252.
Introduction, 15.
Inverted V's, 368.
Involute bearing for spindle, 114.
Iron castings, early history in New
England, 17.

INDEX

465

Iron Foundry in Lynn, Mass., 1643, 17.
Irregular lathe work, 268.

John Winthrop, his Iron Foundry in

Lynn, 17.

Jones & Lamson flat turret lathe, 372.
Judd's quick change gear device, 206.

Kinds of materials to be turned, 216.
Knurling on the lathe, 438.

Lantern pinions and pin wheels, 194.
Large grinding attachment, 191.
Lathe accessories, 427.

attachments, 176.

attachments, classification of, 52.

bed design, 72.

beds, 77.

carriage, design of, 143.

carriages, 84, 143.

centers, 256.

chucks, 259.

classification of, 52.

control methods, 425.

design, 69.

design at a proper medium, 70.

dogs, 257.

driven by electricity, 405.

earliest form of, 23.

foot-power, 24.

history of, before the introduction
of screw threads, 21.

how to drive, 418.

how to increase swing of, 447.

installation of, 418.

its influence on the mechanical
world, 21.

origin of, 22.

origin of the word, 24.

parts and functions, 423.

requisites of a good, 240.

shaft speed for, 420.

speeds, 227.

spindle, ideal form, 104.

spindles, 102.

spindles, forms of, 102.

testing of, 240.

testing, preparing the lathe, 244.

the fiddle-bow, 26.

Lathe the first machine shop tool, 22

the spring-pole, 24.

tools, 157, 214.
Lathe work, 254.

boring, 442.

drilling in, 430.

grinding, 450.

grooving oil ducts, 454.

how to hold, 444.

indicators for, 440.

knurling, 438.

machining concave surfaces, 453.

machining crankshaft, 457.

milling, 433.

turning a steel shaft, 428.
Lathes for heavy work, 449.

lubrication of, 422.

power needed for, 421.
Lead screw, apparatus for testing, 246.

methods of driving, 135.
Le Blond combination turret lathe,
397.

elevating tool-rest, 160.

full swing rest, 162.

head-stock, 100.

lathe apron, 312, 315.

lathe, general drawing, 313.

lathe head-stock, 314.

lathes, 309.

plain turret lathe, 399.

quick change gear device, 197.

roughing lathe, 343.

tail-stock, 142.

taper attachment, 151.

three-tool rest, 163.

triple-geared turret lathe, 391.

24-inch engine lathe, 310.
Legs for supporting lathe beds, 87.
Lever tail-stock, 142.
Limits of variation in lathe testing,

251.

Line-reaming boxes, 116.
Lipe elevating tool-rest, 161.
Lodge & Shipley cabinets, 90.

compound rest, 159.

foUow rest, 166.

form of bed, 79.

lathe apron, 306.

motor-driven lathe) 407.

466

INDEX

Lodge & Shipley patent head lathe, 348.

patent lathe head-stock, 344.

roller follow rest, 166.

tail-stock, 137.

taper attachment, 151.

thrust bearing, 111.

triple-gear mechanism, 132.

20-inch engine lathe, 302, 304.
Loose chain oiler, 119.

ring oiler, 118.
"Lo-swing" lathe, 350.
Lubricating lathe centers, 257.

the spindle bearings, 117.
Lubrication by capillary attraction,
118.

for tools, 233.

neglect of, 120.

of lathes, 422.

Machine for turning pulley, 362.

tools, importance of, in manufac-
turing, 19.

Machinery convex and concave sur-
faces, 176.

Machines for turning pulleys, 64.
Making tools of high-speed steel, 228.
Mandrels or arbors, 265.
Manufactures, development of, 20.

view of the lathe, 69.
Manufacturing, early New England,
15.

industries, success in, 15.
"Massachusetts Teakettle," 18.
Material for spindle boxes, 112.
Materials to be turned, conditions of,

216.

McCabe's double-spindle lathe, 358.
Mechanics, day's work of the early, 29.

resources of the early, 17.

tools of the early New England, 17.
Methods of holding work, 444.
Micrometer stop, 187.

straight-edge, 251.

surface gage, 247.
Milling in the lathe, 433.

operations on the lathe, 284.
Modern American lathe practice, 21.
Monitor lathe, 372.
Motor-driven lathes, 405.

Multiple spindle lathes, 68.
Mushet steel and its influence on lathe
design, 87.

Neglect of proper oiling, 120.
New Haven follow rest, 165.

head-stock, 100.

lathe carriage, 145.

pulley turning lathe, 362.

quick change gear device, 206.

shaft straightener, 169.

tail-stock, 138, 141.

taper attachment, 154.

three-tool shafting rest, 163.

thrust bearing, 111.

21-inch engine lathe, 296.

50-inch triple-geared lathe, 332.
Newton's quick change gear device,

209.
Niles pulley turning lathe, 362.

tail-stock, 140.

72-inch triple-geared lathe, 334.
Norton's change gear device, 59, 299,
301.

change gear device patent, 299.
Nose of lathe spindle, 105.

Observation and recording of data, 237.
Offset tail-stock, 289, 294.
Oil cups, plain brass, 117.

siphon, 117.
Oil ducts, making, 454.
Oiler, Lodge & Shipley type, 119.

loose chain, 119.

loose ring, 118.
Oiling, neglect of, 120.
Origin of the lathe, 22.

of the word lathe, 24.
Originality in design, 71.

Parabolic form of lathe bed, 72, 75.
Pattern lathes, 53.
Pin wheels and lantern pinions, 194.
Pioneers in quick change gear devices,

299.

Pipe centers, 263.

Pitman or connecting rod on lathes, 28.
Plain engine lathes, 55.
Polishing lathes, 53.

INDEX

467

Pond rigid turret lathe, 387.

82-inch triple-geared lathe, 336.
Potter's wheel, 22.
Power for driving machines, 236, 238.

needed for lathes, 421.

required for cutting tools, 238.
Pratt & Whitney chuck mechanism, 383.

lathe apron, 291.

monitor lathe, 403.

rod feed mechanism, 383.

tail-stock, 137.

3 x 36 turret lathe, 380.

14-inch engine lathe, 290.
Precision lathe, 59.

Prentice Bros. Company's 16-inch
engine lathe, 294.

high-speed lathe, 338.

motor-driven lathes, 409.

quick change gear device, 209.

tail-stock, 139.

Preparing a lathe for testing, 244.
Pressure on bearings due to belt, 346.
Principles of change-gears, 278.
Professor Sweet's design of machine

beds, 73.

Progress of manufacturing due to de-
velopment of machine tools, 19.

of manufacturing in New England,

18.
PuUey lathe, 63.

rest, 162.

turning lathe, 63.

turning machines, 64.
Pump for lubricating liquids, 235.

Quadruple threads, cutting of, 281.
Quick change gear device, Flather's,

212.
change gear device, Le Blond's,

197.
change gear device, New Haven,

206.
change gear device, Newton's, 209.

Rapid change gear devices, 194.

change gear devices, Bradford, 203.
change gear device, Springfield

Machine Tool Co., 200.
reduction lathe, 57, 60.

Reaming center holes, 256.

Rear bearing for small lathe, 113.

Reed compound rest, 158.

follow rest, 165.

motor-driven lathe, 406.

self -oiling countershaft boxes, 172.

slide-rest, 157.

spindle boxes, 288.

tail-stock, 137.

Taper attachment, 150.

The F. E. Company and their
work, 287.

turret head chucking lathe, 353.

two-tool compound rest, 158.

10-inch wood turning lathe, 366.

18-inch engine lathe, 288.

24-inch special turning lathe, 350.
Relieving attachment, 185.
Requisites for a good lathe head, 344.

of a good lathe, 240.
Resources of the early mechanics, 17.
Rests, for early lathes, 25.
Retrospective view of manufacturing

development, 20.
Revolving tool-holder, 161.
Rivett-Dock thread-cutting attach-
ment, 192.
Roughing lathe, 57.

Schumacher & Boye head-stock, 99.

tail-stock, 139, 141.

20-inch instantaneous change

gear lathe, 307.
Screw machines, 67.
Shaft straighteners, 167.

turning lathe, Springfield, 355.
Shafting lathes, 64.

Self-hardening tools, 220, 223, 228, 230.
Set-over mechanism of tail-stocks, 136.
Setting up lathe, 417.
Siphon oil cup, 117.
Sizes of steel for tool-holder tools, 220.
Slide-rest, 157.

South Bend milling fixture, 433.
Special lathes, 62, 353.

tools for lathe testing, 244.

turret lathes, 391.
Speeds and feeds, 224, 232.

of drills, 227.

468

INDEX

Speeds and feeds of lathes, 227.
Spindle bearing for small lathe, 113.

bearings, 110.

boxes, material for, 112.

for lathes, 102.

nose of, 105.

proportions for, 106.
Spindle speeds, graphically illustrated,
125.

with extra large bearings, 107.

with extra long bearings, 107.
Spinning lathes, 54.
Spring tool, 219.

Springfield .engine lathe with turret
on bed, 393.

engine lathe with turret on car-
riage, 401.

rapid change gear device, 200.

shaft straightener, 167.

shaft turning lathe, 355

16-inch engine lathe, 318.
Spring-pole lathe, 24.
Starting the lathe, 427.
Steady rests, 164.
Steel, sizes of, for tool-holder tools,

220.

Steps of a cone, form of, 108.
Stop-micrometer, 187.
Straight-edge for testing lathes, 243.

with micrometer attachment, 251.
Strength of tools, 217.
Success in manufacturing industries, 15.
Successful designing, 71.
Summary of back gear, triple gear,

and cone conditions, 124.
Supports for lathe beds, 59.
Surface gage with micrometer attach-
ment, 247.

Sweet, Prof. John E., design of ma-
chine beds, 73.

opinions on lathe beds, 76.
Sweetland chuck, 260.
Swing of lathe, how to increase, 447.

the English method of determin-
ing, 77.

Tail-stocks, 135.

features of, for different sized
lathes, 136.

Tail-stocks, functions of, 135.

requisites of, 136.
Taper arbors, 266.

attachment for lathes, 432.

attachments, 149.

attachments, disadvantages of, 271.

attachments, graduations on, 270.

turning, 149.

turning, failures in, 150.

turning lathes, 271.
"Teakettle," the Massachusetts, 18.
Temper of tools, 217, 229.
Tempering high-speed steel tools, 229.
Test pieces for use in lathe testing, 251.
Testing a lathe, 240.

a lathe for true boring, 250.

a lead screw, 246.

alignment of head-stock and tail-
stock spindles, 249.

bar for lathe testing, 242.

for alignment of tail spindle, 243.

for parallelism, 250.

micrometer for lathe testing, 242.
Thread-cutting attachment, the Rivett-
Dock, 192.

cutting, and the use of change-
gears, 277.

cutting devices, 59.

cutting on a modern lathe, 277.
Three-in-one tool-holder, 222.
Three-tool shafting rest, 163, 355.

turning rest, 163.
Thrust bearings for spindle, 110.
Tool angles, 216, 218.
Tools, clearance of, 218.

design of, 217.

for the lathe, 214.

for tool-holders, 220.

form of, 218.

holder tools, 220.

holder tools, sizes of steel for, 220.

holders, 221.

lubrication of, 233.

of the early New England me-
chanic, 17.

post grinding attachment, 189.

rests, 158.

set of, for lathe, 215.

strength of, 217.

INDEX

469

Tools, temper of, 217, 229.
Track, for beds, 83.
Treadle, as used on foot lathes, 28.
"Tree lathe," 23.

Triple gear mechanism, essential parts,
131.

gear speeds, 129.

geared lathe, 57.

gearing of head-stocks, 121.

threads, cutting of, 281.
Turning balls, 179.

convex and concave rolls, 181.

crank-shafts, 271.

definitions of, 22.

tapers, 269.
Turret head chucking lathe, 55.

lathe, importance of, 370.

lathes, 65, 370.

lathes, classification of, 371.
Two-speed countershafts, 170.

Use of arbors, 267.

Use of change-gears in thread cutting,

278.

of high-speed steel tools, 224.
of indicators, 440.
of lubricant for tools, 234.

V's, for lathe beds, 84.
Variable speed countershaft, 173.

Waltham bench lathe, 364.

Warner & Swasey complete turret

lathe, 377.

Universal turret lathe, 376.
Watchmakers' early lathes, 27.
Water power mostly used by early

mechanics, 18.
Wing rest, 162.
Wood turning in Asia, 24.

turning lathe, Reed 10-inch, 366.
Wooden beds, 86.
Work, amount of, on machine tools,

226.

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Full text of "Lathe design, construction and operation, with practical examples of the lathe work; a complete practical work on the lathe. Giving its orgin and development. Its design. Its various types as manufactured by different builders, etc"

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