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LATHE BED DESIGN 



A REVIEW OF THE HISTORY, DEVELOPMENT AND 

PRESENT FR/'JYICE IN THE DESIGN 

^ L/-THE 3EDS 



BY JOSEPH G. HORNED 




MACHINERY'S REFERENCE BOOK NO. Ill 
PUBLISHED BY MACHINERY, NEW YORK 



MACHINERY'S REFERENCE SERIES 

EACH NUMBER IS ONE UNIT IN A COMPLETE LIBRARY OF 

MACHINE DESIGN AND SHOP PRACTICE REVISED AND 

REPUBLJSHED FROM MACHINERY 



NUMBER 111 

LATHE BED DESIGN 

BY JOSEPH G. HORNER 



CONTENTS 

The Sections of Lathe Beds - ... 3 

The Longitudinal Forms of Lathe Beds - - - 37 



Copyright. 1913, The Industrial Press, Publishers of MACHINI 
49-55 Lafayette Street, New York City 



A\\ 



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CHAPTER I 



THE SECTIONS OP LATHE BEDS 

All the early lathe beds were made of wood. Engravings showing 
some of these wooden beds may be seen in old works on turning. They 
are to be found now only in some of the lathes used by wood-turners, 
and in some pattern-shops, although in the latter case, lathes with 
iron beds are now almost exclusively used. Fig. 1 shows a wooden 
lathe bed or stand. Different methods were used for attaching the 
bearers or shears to the uprights. At a very early date the wear of 
the top surfaces of the wooden bearers was prevented by screwing thin 
flat iron plates onto them. Strips of wrought iron were also fitted, 
having curved edges chipped and filed to shape, as shown in Fig. 2. 
There was not a great deal of durability in these shears, but the chief 
objection to this construction was that when the timber warped, as 
it was bound to do in the course of time, it pulled the iron strips with 
it, and threw the headstock, tailstock, and rest out of alignment. 

The first all-iron beds were of triangular section, the form prob- 
ably originating with Henry Maudslay. The bed was built of two bars 
of triangular section, secured in brackets bolted onto the legs. There 
was a very good reason for the adoption of this form of bed in pref- 
erence to any other. There were no planing machines at that period 
in the latter part of the eighteenth century so that it was an impor- 
tant consideration to be able to reduce the chipping and filing to a 
minimum on a single bar. Besides, if the two upper faces were true, 
it made no difference whether the bottom one was true or not, because 
there was clearance between it and the tailstock and rest. 

Lathe beds with a single shear of triangular section have often 
been built, although they are seldom seen now, except in the lathes 
used by watch- and clock-makers. These beds are sufficiently rigid for 
light duty, and chips do not lodge on them. The triangular-section 
lathe bed also possesses the virtue of insuring self-alignment of the 
tailstock and rest, which bear on the upper edges only. The essentials 
of the triangular bar section have been revived and perpetuated in the 
Pittler bed referred to later but in a modified and stronger, stiffer, 
and steadier form. The Pittler bed consists of a bar of trapezoidal 
section. The bar is hollow, and the lead-screw, passing through the 
hollow section, is thus protected. In some watchmakers' lathes, the 
essential features of the triangular bed are retained, but the lower side 
is of convex form. Some lathe beds are of cylindrical cross-section, 
either solid or hollow. All these types are simply variations of the 
single bar type, and are illustrated later in this treatise. Mention may 
also be made of square and rectangular beds, the latter being employed 
in a few of the peculiar French lathes used for screw threading. 



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LATHE BED DESIGN 







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LATHE BED DESIGN 



Early Development of Lathe Beds 

Since a single triangular bed was not stiff enough to resist the 
torsional stresses of heavy cuts, which produce vibration and cause 
the bed to spring, an early development was that of using two deep 
parallel bars or beam sections, cast separately and bolted together. In 
the next stage the two bars were cast in one piece with connecting 
ribs. It was still, however, necessary to reduce the labor of chipping 
and filing to the least amount consistent with the practical require- 
ments of the time; hence the form shown in Fig. 6, in which the top 
vees of the triangular bars were still retained, represented standard 
practice, with or without the internal stiffening ribs which were cast 
to increase the rigidity in the lateral direction. Then modifications 
of the design in Pig. 6 were introduced as shown in Pig. 7, where one 
vec is dispensed with, but the other retained for guidance. In Fig. 





Machinery 



Fig. 6. Early Type of Lathe Bed 
with Doable Vee 



Fig. 7. An Early Lathe Bed with a 
Vee and a Flat Way 



8, the width of the flat bearing surface is increased. This type of bed 
also made it easier than with two vees to fit the parts to a nicety. 
This construction is, for the same reason, employed instead of two vees 
in many lathes and grinding machines to-day. At last both bearing 
faces were made flat as shown in Fig. 9, and the longitudinal means 
for guidance offered by the vees was, therefore, abandoned. The lateral 
play was then prevented by making tenons on the heads fit between 
the edges of projecting internal ribs, as shown in Fig. 9. All finished 
surfaces were still kept narrow, however, until, after the invention of 
the planer, they developed into the present forms. 

As the slide-rest developed, the battle of the vees and flats became 
intensified. The older upstanding vees are still retained with modi- 
fications as the only guiding elements in standard American practice. 
At a comparatively recent date slight modifications have been made 
in some forms, in which a flat is combined with the vees; but the 
principal difference which exists even now is that of using either two 
or four distinct vee-ways. In the latter design, Fig. 3, the two inner 



No. Ill LATHE BED DESIGN 



vees guide the sliding tailstock, and the two outer ones, the carriage 
or saddle of the slide-rest. The inner vees are frequently sunk below 
the level of the outer ones to increase the swing of the lathe, and to 
enable a greater thickness of metal to be put into the carriage. Both 
vees are truncated or flattened more or less on the top. The type hav- 





Machinery 



Fig. 8. Another Type of Lathe Bed with 
One Vee and One Broad Flat Shear 



Fig. 9. Lathe Bed with Two 
Flat Ways 



ing two vees only, serving both for the carriage and the tailstock, is 
now chiefly used for the smaller classes of lathes. In England, the 
vee-beds have been long since abandoned, except in a very few cases 
where an Anglo-American design is aimed at. 




Fig. 10. Early Type of the Richard Roberts Lathe Bed with Front Slide 

Some of the early lathes with vees anticipated the modern forms 
of front-slide lathes. Figs. 4 and 10 illustrate beds of this type, as 
constructed by Richard Roberts, of Manchester, from about 1817 to 
1820. They were probably the first of that type, and they do not differ 
essentially from modern lathes of a similar kind. In these illustrations 



LATHE BED DESIGN 



two variations are shown. In one, dependence is placed on the guid- 
ance of one vee only, and the lower edge of the front slide bears against 
a plain face. In the other, a bottom vee is included, with a setting-up 
strip. Note in Fig. 4 that the centers of the heads are brought forward 
in front of the bed center. The remainder of the design is in harmony 
with the practice of that period. 

Fig. 11 illustrates the section of the bed of a large lathe which also 



Machinery 



Fig. 11. Early Type of Bed for Heavy Lathes 

was designed to perform the function of a boring mill; it was built by 
a Dundee firm before 1847. In this case the bed is very shallow, and 
its ways flat, with internal inverted vees. The plate A represents both 
the base of the tailstock and the carriage of the slide-rest. Hook-bolts 
embracing the vees and passing up through the plate, were used for 




Machinery- 



Tig. 12. Type of English Lathe Bed, Standard for a Long Period; Lead- 
screw and Feed-rod in Unsatisfactory Positions 

clamping. In this machine, as in some others of that period, no power 
feed was available to the carriage, but only a hand traverse of the 
tool-holder. The carriage was adjusted by hand through a pinion and 
rack. In this lathe, the movements of the carriages of fifty years 
earlier were thus retained. 

In the usual type of English lathe bed, Fig. 12, the vees are aban- 
doned for ways having broader surfaces, and their place as guides is 
taken by the edges of the ways. The inner edges take care of the 
alignment of the headstock and tailstock, and the outer ones take care 
of the slide-rest or carriage. The outer guides may either both be in 



8 



No. Ill LATHE BED DESIGN 



the form of vees, as in Figs. 5 and 12, or one may be square and one 
vee-shaped, as in Fig. 13. In some cases both edges may be square. 
These types have long been standardized, but there are many varia- 
tions. It is from this starting point that we propose to consider the 
forms of lathe beds as they are designed to-day. 

Flat vs. V- Shaped Lathe Shears 

The transition from the upstanding vees to the flat ways has been 
a gradual one. The adoption of one flat with one vee, which dates a 
century back, has gone through various phases of development, besides 
those shown in previous illustrations. In America, an old type of bed 
by the Brown & Sharpe Mfg. Co. (who do not now make ordinary turn- 




Maohinery 



Fig. 13. Another English Lathe Bed of Standard Design 

ing or "engine" lathes) was substituted for the beds with four vees. 
In this case the vee was employed for guidance, in conjunction with 
a suspended weight. The carriage was also gibbed on the square edge, 
which was situated at the back of the lathe. The Pratt & Whitney 
Co.'s tool-room lathe has a bed of the vee and flat type, as shown in 
Fig. 14. This design is also interesting because of the use made of a 
coiled spring in place of the suspended weight, which, through its 
inertia, is liable to cause vibration. 

The battle between the vees and flats has given occasion to much 
fruitless controversy, since both types are retained tenaciously. There 
is much to be said in favor of the guiding qualities of an upstanding 
vee, and much also for the greater durability of a broad flat surface, 
and of the solidity of the carriage employed in conjunction with the 
latter. That these differences were recognized at an early period is 
evidenced by the frequent combination of a vee with a flat, and also 
by the use of two sets of vees, the outer set being reserved for the 
slide-rest or carriage. This not only divides the wear due to the move- 



LATHE BED DESIGN 



9 



xnents of the tailstock and the carriage between two sets of vees, but 
also affords a broader base for the carriage, with corresponding gain in 
its stability. The self-aligning property of the vees is too obvious to 
require demonstration. In the flat beds self-alignment is absent If 
the tenons of the tailstock wear, a loose fit results. In many lathes, 
however, provision is incorporated for clamping the tongue of the tail- 
stock against the edge of one way only, thus not attempting to make 
a fit against the other. As a rule, the headstocks are then not fitted at 




Machinery 



Fig, 14. Bed of Tool-room Lathe built by the Pratt & Whitney Co., 
Hartford, Conn. 

all, but are adjusted by means of screws passing through the tenons. 
Though the wear on the vee-ways is uniform, they lack the advan- 
tage which the flat ways with vee-edges possess, namely, that of pre- 
venting the saddle of the slide-rest from being lifted during cutting. 
Hence all the early beds were commonly united only at the ends, leav- 
ing the entire length clear for a holding-down device, frequently con- 
sisting of a center-weight suspended from the carriage, and traveling 
with it, as shown in Fig. 15. When increased duty was demanded, 



10 



No. Ill LATHE BED DESIGN 



and the beds were tied together with cross-ribs, the snspended weight 
could not be used. Then clamping or gib-plates were introduced under- 
neath the edges of the bed, as in those English designs which have 
square edges. Sometimes the gib or gibs are fitted underneath the 
internal edges. An example of this, taken from an Italian lathe, is 
shown in Fig. 16, where one gib strip is located on the outer lip of the 
back shear, and another on the inner lip of the front shear, this 
arrangement being adopted because the construction of the carriage 
does not provide room for a strip at the front edge. Gibs bearing 
against both the inner and outer lips are also employed. 

The points in favor of vee-shears may be summarized as follows: 
The wear is uniform, and loose fits cannot develop as in flat ways with 




Machinery 



Fig. 15. Lathe Bed with Weighted Carriage 

square edges; the chips fall off freely; the rapidity of the wear can be 
largely minimized by increasing the length of the carriage; and the 
clamping of the heads on the vees helps to tie the sides of the bed 
together and stiffen them. The risk of damage to the edges of the vees, 
which might be mentioned as an objection to vee-shears, can be lessened 
by rounding them. The arguments in favor of flat ways and against 
vees are briefly: Wear is so long delayed that little account need be 
taken of it; its effects can be counteracted by fitting the tenons of the 
tailstock to the edge of one shear, and as regards the saddle by the 
setting-up of the gibs; the elevation of the vees permits of less swing 
than do the flat ways. 

Location of Lead-screw and Feed-rod 

Inseparable from the design of the bed sections are the problems 
of the location of the lead-screw and feed-rod. It is an interesting fact 



LATHE BED DESIGN 



11 



that the old eighteenth-century lathe of Maudslay's has Che lead-screw 
enclosed within the shears of the bed, thus anticipating the Whitworth 
design of nearly half a century later. The Whitworth bed, with the 
location of the lead-screw, is shown in Fig. 17. In this the divided 
clasp-nut is retained, operated by cam plate and levers through pulling 
or pushing a rod which passes to the front of the saddle. The support- 




Jlachinery 



Fig. 16. Example of Gibbed Vee Bed 

ing bearings for part of the circumference of the lead-screw should 
be noted. The position of the rack is not always as shown; frequently 
it is placed at the front of the bed. Fig. 18 shows a special Whitworth 
bed having the lead-screw placed exactly in the center, supported around 
nearly half its circumference by bearings located at intervals. 




Fig. 17. The Whitworth Bed used in Lathes built by W. G. Armstrong, 
Whitworth & Co., Manchester, England 

Several firms manufacture lathes with lead-screws protected in 
various ways. In standard English practice the lead-screw has long 
been placed outeide at the front, and the feed-rod or "back-shaft" out- 
side at the back. (See Fig. 12.) As a result of the influence of Ameri- 
can practice many lathes are now built with lead-screw and feed-rod 
both in front and close together, and both with the rack traverse 
operated by gears enclosed in an apron. This is in harmony with the 



12 



No. Ill LATHE BED DESIGN 



idea of obtaining the motion required for screw cutting and feed from 
a gear box on the bed in front of the headstock; it also permits a more 
compact arrangement of the carriage. It may be stated as a general 
rule that the best English makers now place the feed-rod in front in 
preference to placing it at the back, and there seems to be no doubt but 
that in a short time the old "back-shaft" will disappear. 

Development of the Sellers Lathe Bed 

The section of a bed used in lathes built by Messrs. William Sellers 
& Co., Inc., as shown in Fig. 19, illustrates the transitional form which 
under different modifications appears in many lathe beds of the present 
day. The vee-sections at the sides in the illustration represent the 
earlier, and the central portion, the later type. The earlier design is 




Machinery 



Fig. 18. A WMtworth Lathe Bed with a Central Lead-screw and Web 

similar to the standard English bed, in so far as the fitting of the 
sliding parts to flat ways and vee-edges at front and back is concerned ; 
but the lead-screw is protected under the front shear in a recess pro- 
vided specially for it. An inverted vee underneath the back shear is 
used to clamp the tenon of the tailstock against the vertical edge of 
the back shear, instead of trying to make its tenon fit between both 
shears permanently, which is not practicable. Messrs. Sellers & Co. 
adopted this method in order to retain the same advantage of align- 
ment (notwithstanding wear of the tenon or tongue of the tailstock) 
as is secured by the use of vee-ways, thereby taking advantage of the 
durability of the flat ways without suffering from the disadvantage due 
to the wear of the tenons. 

The experience with the beds having vee-edges at front and back, 
as shown at the sides in Fig. 19 demonstrated that almost the only 
wear which occurred took place on the top faces, and not on the 



LATHE BED DESIGN 



13 



beveled edges; hence the abandonment of the vees in favor of square 
edges which maintain the traverse of the carriage parallel with the 
axis of the live and tailstock spindles, while the inverted vee main- 
tains the tailstock spindle in alignment with the live spindle. The 





Tig. 19. 



A Type of Bed used in a Lathe built by Wr 
Philadelphia, Pa. 



Sellers ft Co., Inc., 



later type, therefore, provides for the permanent retention of the 
accuracy imparted to the lathe when new, and also provides for the 
protection of the lead-screw. The advantages of this design have been 




Machinery 




Machinery 



Fig. 20. Lathe with Inverted Vee 
for Clamping, built by G. Birch & Co., 

Manchester, England 



Fig. 21. Closed Box Lathe Bed of a 
Type Manufactured by Thomas Ryder 
& Son, Bolton, England 



recognized, and it has been imitated in numerous later lathes. 

The protection afforded to the lead -screw is so important a matter 
that many devices for this purpose have been adopted since the time 
when Whitworth placed it within, instead of outside, the shears. The 



14 



No. Ill LATHE BED DESIGN 



Sellers' design embodies a decided improvement, for in it the lead-screw 
is supported along its entire length by the recess which is provided for 
it, and, therefore, it cannot be deflected. But the half-nut is single, 
and only extends around a rather small arc of the circle. These 
Sellers' beds also were among the first American designs which em- 
bodied the use of cross-ribs. 

Two examples of the employment of the inverted vee are seen in 
Figs. 20 and 22, the first showing the arrangement of the clamping 
plate in relation to the tailstock tongue, and the second a somewhat 
similar construction on a German chucking lathe. The base of the 
turret in this latter case is always pulled over toward the inner edge 




Fig. 22. Inverted Vee Lathe Bed for Clamping: Turret Base, made by 
De Fries & Co., Dusseldorf, Germany 

by the action of the clamping plate, which is pulled upward by means 
of an eccentric bolt and lever. 

Strength of Lathe Beds 

Another development is that of the stiffening and strengthening 
of lathe beds. All the old types were mere skeletons, although some 
of them were stiffened laterally as shown, with ribs placed internally 
or externally. Gradually, the thickness of the metal was increased, 
and the ways widened ; fillets were cast along the bottom edges in addi- 
tion to the cross-ribs. Many of the American beds were of a highly 
molded section, as shown in Pig. 3, with the object of imparting stiff- 
ness chiefly in the lateral direction, and so help to compensate for the 
absence of cross-ribs. 

Lathe beds must always be made much stronger than they would 
have to be in order to merely prevent fracture. The stresses to be 
resisted are in the first place flexure; but it is fully as important that 
the design be stiff enough and heavy enough to resist the tendency to 
torsion and to vibration to chattering. The massing of the metal may 
solve the problem, but it must be done judiciously. Flexure may be 



LATHE BED DESIGN 



15 



met by increasing the depth, because the strength increases as the 
square of the depth. Torsion is more difficult to prevent, while resist- 
ance to vibration demands a mass of metal obtained only by consider- 
ably increasing the dimensions which are required to prevent flexure 
and torsion. Experiments have been undertaken at various times from 
which certain broad deductions have been made; but lathe beds are, 
notwithstanding, mainly evolved from previous practical experience. 
Although the general movement has been going on for a century* this 
evolution has been especially noteworthy since the advent of high- 
speed steel. 

The flexure of a lathe bed is more than allowed for by the propor- 
tions given to it for general strength. A very light bed might possibly 
be bent by the placing of a very heavy piece of work between the 




II i iiiiiiiiiiiiiiiiiuiiiinii in minium iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiifnmrrnnn. 



Machinery 



Fig. 23. The Evolution of the Lang Bed 

centers, or by the stress of heavy cutting near the center of the bed. 
In some American beds the standards or legs have been set a certain 
distance inward from the ends in order to shorten the length of the 
unsupported portion. Sometimes the beds are cambered or fish-bellied; 
long beds have legs in addition to those at the ends ; or in heavy lathes, 
the bed is continuous and rests on foundations located at intervals. 
An unsupported length which will not bend, provided the bed is of box 
section, is given by Mr. Richards as one which is not more than 
twelve times its depth. 

An interesting example of the gradual increase in bed dimensions 
for one size of lathe is shown in Fig. 23. This engraving illustrates 
the evolution of the lathe bed of Messrs. John Lang & Sons, of John- 
stone, Scotland. The ordinary English type is seen in dotted outline; 
this type was employed by the firm previous to 1900. The thin full 
lines show the first narrow guide type of bed of 1900, and the thick 
full lines the present type. 



16 



No. Ill LATHE BED DESIGN 



Torsion can be best avoided, as far as the shape of the bed is con- 
cerned, by making it of a box section. Comparatively few lathe beds 
are, however, constructed in that manner, the general design being 
that of two shears connected by cross-bars or ribs, thus leaving the top 
and bottom edges unconnected. That this is a poor design is admitted, 
but it is one which is more easily molded than a box shape. Long 
ago Prof. Sweet had some castings made for a test, as indicated in Fig. 
24. These castings represent, respectively, the open-frame and the box 



Machinery 



Fig. 24. Experimental Beds investigated by Prof. Sweet 

type of beds, with the same amount of metal in each. The box casting 
proved much stiffer laterally, and thirteen times more rigid against 
torsion. 



J 1 




XaoMnery 



Fig. 25. The Richards Box Bed 

Several firms now construct beds which are wholly or partially 
boxed. It is, of course, necessary to leave some provision in the form 
of openings for the escape of chips and oil. Messrs. George Richards 
& Co., Ltd., of Manchester, England, though they have now given up 
the manufacture of ordinary lathes, were in the field when this depart- 
ure was made. Their first lathe beds were made as shown in Fig. 25. 
The beds were practically encased along the top, and well tied to the 



LATHE BED DESIGN 



17 



cross-ribs along the bottom with broad flanges. Holes cast in the top 
casing permitted the chips to fall through. The holes were surrounded 
by a rib to prevent loss of strength due to the cutting of the holes. 
Otherwise in its general design, the bed is of ordinary English type, 
with flat ways, vee-edges, and a gap. 

In Pig. 21 is shown a section of the beds of the lathes manufactured 
by Messrs. Thos. Ryder & Son, of Bolton, England. These beds are of 
solid box section. In this design the practice of bringing the lathe 
centers considerably behind the center of the bed is adopted, in order to 
afford additional support to the cutting tool when turning large diam- 
eters. The depth of the rear guide strip of the bed is also deepened to 
increase its durability. 

Dr. Nicolson has stated that if the same amount of metal put into 




Machinery 



Fig. 26. Section of the Circular Bed for Lathes made by Drummond 
Bros., Guildford, England 

the ordinary beds were put into the box-shaped or the circular form, 
these types would be from six to ten times as strong to resist twisting. 
This is not so high an estimate as that given many years ago by Prof. 
Sweet, but it is amply high enough to justify that departure from the 
old practice which several lathe makers now have adopted. The solid 
box form is practicable, and easily manufactured ; but the circular form 
is not, except in light lathes, such as those used by watch- and clock- 
makers, amateurs, and scientific workers. For such purposes, several 
examples of this type are built. The circular bed must have a longi- 
tudinal guide or guides for the headstock and slide-rest or carriage, 
and it is here that the difficulty arises in massive designs. In fact, for 
heavy designs, the circular bed may be dismissed as nearly impractica- 
ble, or at least undesirable, in face of the fact that boxed beds of rec- 
tangular section can be and are constructed better and more cheaply, 
and of equal strength. 



18 No. Ill LATHE BED DESIGN 

The circular bed is cheaply made for small lathes of, say, from 6- to 
10-inch swing. It is used for these, not so much because it happens to 
be the stiffest form, but because of the advantage which it offers for 
swivelling the rest to different angles, thus making it a kind of uni- 
versal tool for all kinds of cutting. This design is adopted in the recent 
lathes of that type built by Messrs. Drummond Brothers, Ltd., of Guild- 
ford, England. The bed, of cast iron, 3 inches in diameter, is of hollow 
form, ground on the outside to a limit of 0.0001 inch, and on it the 
heads and saddle fit. As seen in Fig. 26, there is a slot in the under 
side of the bed which receives a tongue or bush secured to the bolt that 
passes up to transmit the motion from the lead-screw. By tightening 




Machinery 



Fig. 27. The Drummond Lathe Bed and Saddle 

the nut on this bolt the swivelling portion A is locked. The range of 
swivel is indicated by the radiating center lines. Fig. 27 shows the 
complete tool-rest, with the upper part held in the split socket of the 
saddle, thus permitting of a horizontal swivel movement which enables 
the tool, or the top of the rest, to be moved in a universal manner. 

This lathe, in its swivel action, resembles the Pittler lathe, although 
the latter is designed in a different way. In the Pittler lathe, the longi- 
tudinal guidance is provided for by a section of trapezoidal shape, with- 
in which the lead-screw passes. The form of this bed is plainly indi- 
cated in Fig. 28. The swivel motion is provided for by making 
the outside of the sliding carriage circular, and fitting the saddle 
of the slide-rest to it. In this way the sliding movement is com- 
bined with a circular movement through a complete circle. The stem 
of the tool-rest can be swiveled in the socket in the split saddle. The 



LATHE BED DESIGN 



19 



greatest swing to which lathes of this model are built is 14 inches. 
Pittler lathes of greater swing are built with approximately rectangular 
beds, having a vee and a flat guide. 

The advantage of the circular form is also recognized in cases where 
it cannot be adopted absolutely. Some of the bench lathes have beds 
of D-section; one made by the Pratt & Whitney Co., of Hartford, Conn., 
is shown in Fig. 29. The headstock, tailstock and slide-rest are clamped 
to the flat top-face and are guided by the two sloping edges, thus pre- 
serving the alignment. The bed being small, is cast in one piece with 
its two feet. 

The "Narrow Guide" Lathe Bed 

We now come to a recent development in lathe bed practice, which 
has already, in the short course of some five or six years, effected a 




Fig. 28. The Pittler Trapezoidal Bed used by the Leipziger Werkzeug- 
maschinenfabrik, Leipzig- Wahren, Germany 

remarkable revolution in lathe construction the application of the 
principle of the narrow guide. This principle, although so lately taken 
up in earnest, is not by any means new. To determine the period of 
its first application would seem impossible, but illustrations showing 
the idea applied to lathe carriages appeared some twenty-five years 
ago. The three illustrations Figs. 30, 31 and 32, are taken from Joshua 
Rose's "Modern Machine Shop Practice," and show how the principle 
was applied many years ago. All three of these illustrations are repre- 
sented in recent practice, and it is noteworthy how the construction 
has been brought into prominence chiefly by the development of high- 
speed lathes. Messrs. John Lang & Sons, when they re-designed their 



20 



No. Ill LATHE BED DESIGN 





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4S * O M 



LATHE BED DESIGN 



21 



on the front shear, or by an underhanging strip, without affecting the 
principle. Sometimes the strip is raised above the general level of the 
bed surfaces, and sometimes it is formed by making a recess or channel 
in the front shear, although this is open to the objection that such a 
recess easily collects and stores the chips. The upstanding ledge, again, 
is more liable to become damaged. 

Fig. 34 illustrates the Lang bed with its saddle. It is possible with 
this design to obtain a length of guide of as much as ten times the 




Machinery 



Fig. 33. The B. K. LeBlond Machine Tool Co.'s Design of Lathe Bed 

width between the guiding surfaces, which has the effect of producing 
a very steady movement, with a much greater amount of freedom from 
twisting than is the case when the saddle fits on the front and rear 
outer edges of the shears. The setting-up of the taper adjusting-strip 
can have no possible tendency to spring the sides of the bed inward, 
as it might possibly have in the ordinary type of lathe bed. 

In conjunction with the narrow guide, it is also the practice to 
bring the lead-screw as close as is practicable to the guide-ways, and 



No. Ill LATHE BED DESIGN 



the twisting tendency and friction caused by the old-style construction 
is minimized. Thus, the location of the lead-screw in Pig. 12 is just 
where it ought not to be with relation to the saddle slides, and this 
example of what was at one time standard English practice contrasts 





Machinery 



Fig. 34. The John Lang & Sons, Johnstone, Scotland, Type of Lathe Bed 




Machinery 



Fig. 36. The Lodge & Shipley Machine Tool Co.'s Lathe Bed with 
Supplementary Bearing Surface 

unfavorably with the location of the lead-screw in Pig. 33 and some 
of the succeeding illustrations, where the force is applied at the correct 
place near to the guide-ways. Experience shows that the narrow 
guide gives more accurate results than the usual design, and that the 
alignment of the saddle movement is preserved for a longer period. 



LATHE BED DESIGN 



23 



American Designs Embodying the Narrow Guide Principle 
Another important advantage, apart from the narrow guide itself, 
is that part of the pressure of the cut is resisted by a vertical face, and 
the forces tending to push the saddle off the bed are acting against this 
face, instead of against the back edge of the rear shear. This feature 
is also embodied in two American designs, by the R. K. LeBlond Ma- 
chine Tool Co., and the Lodge & Shipley Machine Tool Co., both of Cin- 
cinnati, Ohio. In the former company's design a nearly vertical face 
is employed on the front shear, and in the latter's design the vertical 
inner edge of the front shear comes in contact with the carriage. The 
LeBlond lathe, Fig. 33, is not provided with a rear vee, the carriage 
sliding on a flat on the back shear, but in the Lodge & Shipley lathe, 
Fig. 35, the carriage fits on the usual rear vee, and in addition has 
a horizontal bearing on the surface adjacent to the front vee, so that 
the solid metal of the carriage is well supported. 




Machinery 



Tig. 86. Belgian Design of Lathe Bed with Raised Narrow Guide as used 
by Le Progres Industriel Societe Anonyme, Loth near Brussels 

The firm of Le Progres Industriel, Societe Anonyme, of Loth, near 
Brussels, who has been engaged in lathe manufacture for many years, 
utilizes, in its present design, the narrow guiding principle, in con- 
junction with a single vee for the guidance of the tailstock. The car- 
riage, as indicated in Fig. 36, does not touch this rear upstanding vee, 
and there is a clearance at the rear vertical edge of the rear shear. 
The adjustments are made by a wedge strip on the front edge of the 
front shear and by the two gib strips each underneath the lips. This 
design is a sort of compromise between American and English designs, 
and is used on large and small lathes alike. 



24 



No. Ill LATHE BED DESIGN 




'4*- 1 l -t>- 

/. .^=^s '-: 






tfc 



Fig. 37. Lathe Bed supported on Cabinet Standards 





Fig. 38. Gap Bed st 




PT.I 







Fig. 39. Large 



LATHE BED DESIGN 



25 









-=====-- 




Machinery 



Less with Provision for Lubricating the Cutting Tool 



AA, 






u 




>ported on Three Legs 




Gap Bed 



26 



No. Ill LATHE BED DESIGN 




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LATHE BED DESIGN 



27 



way. In this design the proportion of length to width of the narrow 
guide is about 4 to 1, but, as mentioned previously, in some cases 
where a strip is employed, the proportion may be as high as 10 to 1. 
Some firms who retain the front shear for guidance, as in the example 
just referred to, lengthen the wings of the saddle to the right and 
left in order to increase the bearing length. The tailstock slides be- 
tween these wings up to the main body of the saddle. 

Another design of a new 20-inch high-speed lathe, made by Messrs. 
Smith & Coventry, Ltd., of Manchester, England, is shown in Figs. 41 




Machinery 



Fig. 42. Bed for 20-inch Lathe with Strip at Front, designed by 
Smith & Coventry, Ltd. 

and 42. The two views here given illustrate the method of fitting the 
saddle and the tailstock. The front shear constitutes the narrow guide, 
with its take-up strip on the front face. The horizontal bearing is 
amply provided for by three ways; on the two at the rear the tailstock 
slides, as shown by Fig. 41. Gib strips are located under the front and 
rear edges. 

Messrs. Ward, Haggas & Smith, of Keighley, England, fit their lathes 
with a narrow guide of the type shown in Fig. 43. This design is of 
the inverted type, the take-up strip drawing the saddle against the 
inside sloping face of the hanging lip of the front shear. These sur- 
faces are thus out of the way of the chips, and a great proportion of 
length to width of bearing surface is secured. The lead-screw and 
rack are brought very close to the guiding area. Fig. 44 illustrates 
the method of tightening the tailstock by a clamping plate which 
presses against a sloping face on the inside of the rear way, thus draw- 



No. Ill LATHE BED DESIGN 






11 

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LATHE BED DESIGN 



29 



ing the tailstock against the back vertical edge of the shear. As this 
edge is not subjected to wear from the saddle, which clears it, the 
alignment is preserved indefinitely. Another example of an under- 
hanging lip employed as a guide is that of the high-speed lathes built 
by Messrs. George Swift & Sons, of Halifax, England, as shown in Fig. 
55, which shows the saddle without its apron. 

In certain types of lathes one shear is employed alone to guide 
and support the carriage. This design is met with in a certain type 
of boring and turning lathe, where two duplicate carriages are run 
each on its own way, and are entirely independent of each other. A 




JtfocMnery 



Fig. 48. Double.tier Bed with a Raised Narrow Guide on Lathe built 
by Darling & Sellers, Keighley, England 

lower slideway or tier takes the overhang of the carriages. In another 
instance, that of the Libby turret lathe, made by the International 
Machine Tool Co., Indianapolis, Ind., the carriage fits over the front 
shear, as shown in Pig. 45, and a lower vee-guide opposes the tilting 
tendency of the carriage. 

The principle of affording support to the carriage at some point 
situated below the general level of the bed surfaces is met with in 
several designs. One of the most successful examples is that of Messrs. 
Darling & Sellers, Ltd., of Keighley, England. A bed section of one 
of their lathes is shown in Fig. 48. The auxiliary or "lower-tier" 
bed is made in the form of a strong lip, projecting out from the 
front of the bed near the bottom. The saddle has a bearing on this, 
as well as on the top surfaces of the bed. The overhanging weight 
of the saddle is thus supported in a very satisfactory manner, and 
k will be seen that the actual effective width of the bed is increased 



30 



No. Ill LATHE BED DESIGN 






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LATHE BED DESIGN 



31 



ledge, which helps to resist the forces tending to separate the gears 
and rack and pinion, while under heavy duty. With a similar object 
in view, some makers support the rack-pinion by the metal of the 
saddle, in order (see Fig. 5) to prevent the springing away of the 
pinion. Another device is to alter the position of the rack and 
pinion to a vertical location, and support the pinion shaft in bearings 
on both sides of the pinion. A design of this kind is shown in Fig. 
50, showing the construction in a lathe made by Messrs. Joshua Buck- 
ton & Co., Ltd., Leeds, England. 

A different kind of lower-tier bed is made by Messrs. Drummond 
Brothers, Ltd., of Guildford, England. This bed is employed for their 




Fig. 52. Bed with Lower-tier Vee-ways as designed by Schaerer 
& Co., Karlsruhe, Germany 

lathes having 15- and 18-inch swing. The gap is permanently open, 
and the saddle is guided by two lower tiers or slide-rails, so that it 
can be brought along on these past the gap and close up to the 
largest faceplate, with a minimum of tool overhang. 

Another example of a lower-tier bed is that used in a lathe built 
by Schaerer & Co., of Karlsruhe, Germany, in which the advantages 
previously mentioned regarding the support of the carriage below the 
top level of the bed are obtained. There are two lower-tier vee-ways, 
as shown in Fig. 52, set at different heights (by which it is claimed 
that twisting is eliminated), and directly underneath the regular ways, 
so that chips cannot fall into them. The top of the bed is arranged 
with a vee and a flat to carry the headstock. The carriage has no 
bearing on the top, but only in the vee-ways. The position of the 
lead-screw and rack should be noted. 



32 



No. Ill LATHE BED DESIGN 



Methods for Protecting the Ways of Lathe Beds from Chip 

A few instances are met with in which lathe beds are modified 
specifically for the purpose of protection. The bed is either cast of 
such a form that the slides come below the top surface, as in the 
example just noted, or extra covering plates or guards are fitted to 
keep the chips away from the bearing surfaces. A bed made by the 
London firm George Richards, Ltd., Fig. 51, has a top portion A. which 
serves as a cover over the slides, and at the same time guides the 
saddle at the front, forming a narrow guide between its inner face 
and the outer front edge of the main bed. The surfaces B, on which 
the carriage slides are, therefore, absolutely protected from chips, and 




Machinery 



Fig. 53. A German Type of Lathe Bed with Guard Plates over the Slides 

the lubricant does not become dirty. At the top of the portion A. 
the saddle clears this casting. 

Fig. 53 shows a German bed section which has the slideways ar- 
ranged a little below the top surface. Steel covering plates, screwed 
on as guards, prevent chips from falling onto the ways. The tail- 
stock slides on the top part of the bed, between the inner edges of 
the covering plates. 

Messrs. John Lang & Sons build a range of surfacing and boring 
lathes (chucking lathes) without tailstocks, in which curved cast-iron 
guards, supported on short studs at each end, extend from the tail-end 
of the bed up to the chuck, so that chips cannot fall upon the flat ways 
of the bed, but are deflected by the guards and thrown off to one 
side. The section of a bed with its saddle cored to pass the guards, 
is shown in Fig. 54. It will be noticed that the saddle bears against 
the vertical edges of the front shear only, giving a narrow guifle-way 
with a relation of length to width of about 7 to 1. The cross-slide (not 
shown) also fits on the same principle, being gibbed to the two edges 
of one slideway. 



LATHE BED DESIGN 



33 



A rather curious type of bed is shown in Fig. 56. This type re- 
sembles an English bed at the back shear, but has a double "vertical" 
vee at the front edge. This lathe is made by H. Wohlenberg, of 
Hanover, Germany. 

Double- way Type of Lathe Beds 

Among the lathe beds which are made to but a limited extent are 
those of the double-way type, that is, beds with separate ways for 
the carriage and the tailstock. They are useful for work where it is 
required to move the carriage rapidly out of the way, and bring the 
tailstock up to the head without having to remove the carriage each 
time. The illustration Fig. 57 shows an example of this class, con- 
structed by Henry Milnes, of Bradford, England. The tailstock slides 
on a back shear, below the carriage ways. 




Machinery 



Fig. 54. John Lang & Sons' Lathe Bed with Covers over the Ways 

A special type of double-way bed, Fig. 60, the speciality of Messrs. 
Dron & Lawson, Ltd., of Glasgow, Scotland, comprises a flat-topped 
way carrying the tailstock, the tongue of which has a tapered adjust- 
ing strip to maintain the fit in the groove, and a loose bed A, resting 
on two extensions B which project from the main bed. The auxiliary 
bed A can be swivelled on the extensions for taper turning, and can 
be adjusted to and from the centers. The slide-rest is carried on bed 
A, and is fitted by a narrow guide at the front The slide-rest can be 
moved past the tailstock, and the center of the latter need not over- 
hang. Motion is conveyd to the screw of the slide-rest, for feeding, 
through a universal-joint shaft, from the gear box in front of the head- 
stock. Graduations indicate the amount of taper when the bed is 
swivelled. A similar principle is employed in the Niles lathes for 
turning printing-press cylinders, paper-machine rolls, etc., there being 



sequent freedom from vibration. By carrying the webs up between 
the two bearings, as in Fig. 73, the two bearings are firmly tied to- 



No. Ill LATHE BED DESIGN 





It 





Sm 

N 



LATHE BED DESIGN 



36 



carriages both at the back and front, sliding along supplementary 
beds or rails, which are themselves adjustable to and from the center. 

The bed of the Lo-swing lathe (see Fig. 58), built by the Fitchburg 
Machine Works, Fitchburg, Mass., is an example of a special design 
evolved to avoid the built-up design of slide-rest in which the hori- 
zontal tool pressure acts at a point a considerable distance above the 
bed which has to resist it. This lathe, made for turning bar work be- 
tween centers, has the tool-holder situated but slightly above the lip 
of the bed which takes the pressure. 

As a final example of a special type of bed, the double square bar 
design, Fig. 59, is shown. It represents a type employed in France 




Machinery 



Fig. 60. The Dron & Lawson, Ltd., Glasgow, Scotland, Lathe with 
Extensions carrying Supplementary Bed for Carriage 

for screw-cutting lathes, operated by hand, all the principal parts, 
including the bars, being of hardened steel and ground. The slide- 
rest fits on the two bars, and is slid along them by means of a 
lever motion. The headstock is also clamped to the bars. This lathe 
is made by Messrs. Brenot, Buronfosse & Cie, of Paris. 

Beds for Heavy Lathes 

When comparing the sectional forms of beds for large lathes with 
those of the ordinary type for the smaller and medium-sized lathes, 
the principal differences are found in the extra strengthening and 
stiffening of the large beds, in addition to differences in the form 
and number of their slideways, and in the building up and jointing 



36 



No. Ill LATHE BED DESIGN 



of the sections, which for manufacturing reasons sometimes take the 
place of a single large casting. Extra ribbing or webbing is one of 
the first changes introduced as the sizes of beds increase, as shown 
in Fig. 46, where webs are carried down on the inside from the top, 
and in Fig. 47, where the inner ribs completely duplicate the outer 
webs. Many variations of this type exist, which it is impossible to 
illustrate here. It may be mentioned that the bed in Fig. 46 is from 
a large lathe by Messrs. Hulse & Co., Ltd., of Manchester, England, 
provided with the firm's non-rotating twin lead-screws. There is one 
screw on each side of the bed, as shown, so that the saddle is propelled 
in a perfectly even manner, without risk of twisting. 

The number of ways is increased to three, four, and even more, in 
large beds, according to the design of saddles employed, and their 
number. Three ways, as shown in Fig. 61, are frequently employed 





g 


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Mi ^^ 

T 3 


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s 

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^ N- 


Machinery 



Fig. 61. Heavy Type Bed with Three Ways 

when there are independent front and rear saddles, which fit on the 
front and back ways, respectively, and rest partly on the central one 
so that they may pass each other. The edges may be square or of 
vee form as indicated in the illustration. Beds with four slide-ways for 
two or more independent saddles are often used in place of the type 
in Fig. 61, in the larger lathes. The fitting of saddles and rests for 
turning large diameters on faceplate work introduces the use of wing 
or sole-plates, extending from the side of the main bed, or in some cases 
cast with it and provided with a slide-way. For certain functions, 
as in wheel lathes, a long cross-bed passes across in front of the face- 
plate, and is bolted to wings extending from the sides of the main 
bed. In any case, for turning large diameters, it is necessary to 
make the effective width of the bed sufficient to bring the tool-rests 
out to the required radius. 

In some types of lathes for facing only, there is no bed at all, but 
only a stand to carry the headstock, and a T-slotted plate in front 
of this, which has no slide-ways, but which simply supports the tool- 
rest 



CHAPTER II 



THE LONGITUDINAL FORMS OP LATHE BEDS 

The remarks made in the previous chapter relative to the flexure 
and torsion of lathe beds need not he repeated here, but we shall 
consider, with the aid of the representative illustrations, how flexure 
is best resisted, and how the longitudinal shapes are modified to serve 
different functions. The principal differences which are made in the 
forms of beds are those arising from variations in dimensions, while 
subsidiary differences are produced by special designs of lathes, or 
additional functions, or by the particular class of work which is 
done in the lathe. Thus, the shapes of beds of similar dimensions 
for ordinary screw-cutting or engine lathes and those for turret lathes 
are very often radically different. In the one case provision has to be 
included for the screw-cutting and feeding devices, for the carriage 
motions, and for the tailstock, while in many turret lathes these 
features are absent, and the bed is plainer, with provision only for 
clamping the turret base and the cross-slide. On the other hand, the 
arrangements for lubricating the cutting tools and work often intro- 
duce complications into the design of turret lathe beds, and the casting 
is of a more elaborate character below the bed proper around the 
top of the legs or standards. 

The length of a bed has an important influence upon its construction 
and the number of supporting points, and if a gap is included, this 
also modifies the form to a considerable degree. The number of sup- 
ports ranges from the single cabinet standard in some small lathes, 
and the two standards or legs in those of ordinary dimensions, to 
the three or more supports in longer beds. A continuous bed of full 
depth for the whole length is employed in lathes for heavy work and 
large swing, and is supported solidly on concrete foundations. The 
truth and rigidity of a lathe bed depends to a certain extent upon 
how it is fastened down. Ordinarily, beds are bolted rigidly to their 
foundation, which may be a wooden floor or a stone or concrete base. 

Many years ago Prof. Sweet suggested the adoption of a tripod 
support for lathe beds, and this suggestion has been acted upon in 
practice. One end of the lathe is bolted down by the usual means, 
and the other is pivoted on a pin which passes through lugs in the 
bed and in the leg. The only support at that end is the pin on 
which the leg is free to adjust itself. Many firms also adopt the 
three-point support principle without any pivoting device: sometimes 
there are three points of contact with the foundation, and sometimes 
the bed is united to the legs at three points. The effect of an untrue 
foundation is thereby neutralized. Another method of affording good 
support is that of casting the bed with, or bolting it to, a single 
column of box form, which makes the lathe self-contained, and obviates 



38 No. Ill LATHE BED DESIGN 

any risk of distortion or winding. This construction is employed both 
for small ordinary lathes, and for turret lathes up to fairly large 
dimensions. 

Leg-s or Supports for Lathe Beds 

When legs are used to support the bed, it is the custom of some 
makers to spread the legs under the head to a greater extent than 
those under the right-hand end, to resist the vibration, which is more 
pronounced at the headstock end. Other firms do not put ordinary 
ribbed legs at all under the headstock, but prefer a boxed cabinet 
support, even when there are legs at the other end. The principle of 
this seems faulty, since, if it is considered necessary to put a box 
support under the headstock end, the use of a flimsy support at the 
other end of a heavy bed appears unreasonable. Many makers view 
the matter in this light, and place the bed on equally solid and sub- 
stantial supports at both ends; sometimes the supports are of identical 
pattern, but frequently they are a little larger at the headstock end, 
in order to afford more cupboard room for tools and appliances. 

The practice of placing the supports a certain distance inward from 
the ends, mentioned in the previous chapter, is followed in many 
instances, and a further development of this principle is found in the 
case of some lathes, particularly those with gaps, where the metal of 
the boxed bed is carried down to a considerable depth under the head- 
stock, gradually tapering off towards the ends. A great many turret 
lathes have their supports placed some distance inward from the 
ends of the bed, and the under side of the latter is often tapered or 
curved upward from the outside of the legs to the ends of the bed. 

Gap Lathes 

The question of forming a gap in a lathe bed has long been the 
subject of controversy. A gap lathe bed is practically as common in 
England as a straight bed. Theoretical considerations have been urged 
against it, chiefly on the ground that the bed is weakened, because its 
continuity is broken; but an English lathe maker would argue that 
the metal which is removed can be more than compensated for by 
extra metal placed underneath and beyond the gap, and in the heavier 
lathes by metal brought down to the ground in the form of a broad 
foot. The real objection to a gap is its unalterable dimensions it 
is wider than is required for some jobs, and not wide enough for 
others. The fitting of the bridge-piece is also liable to become slightly 
inaccurate when a lathe has done much service, but this can be 
rectified. Thirty or forty years ago such lathes predominated over 
all others, but gradually, with the growth in specialization, they were 
displaced, to some extent, by straight-bed lathes on the one hand, and 
by regular facing lathes, and vertical turning and boring mills, on 
the other. 

The movable gap is used to a moderate extent, in medium and large 
sizes of lathes, and would be adopted more extensively but for the 
fact of the ever-growing specialization. The breadth of gap is adjust- 



LATHE BED DESIGN 



39 






"Mi 





40 



No. Ill LATHE BED DESIGN 



able within a wide range, or it may be closed up entirely, the object 
being, of course, to support the carriage as close as practicable to 
the cutting point of the tool under all conditions. The most serious 
defect in gap lathes, perhaps, is the fact that the lead-screw has to be 
kept low down to be out of the way. In the movable-gap lathes an- 
other difficulty arises in the driving of the lead-screw, which has to 
be done from gears at the right-hand end of the bed. 

Fig. 37 shows the form of a good type of bed, supported on box 
standards at both ends. The bed is equipped for the use of cutting 
lubricant or oil, though not in such a perfect manner as some beds 
shown later. A more elaborate type of bed for a 20-inch high-speed 
lathe, built by Smith & Coventry, Ltd., of Manchester, England, is 







Machinery 



Fig. 64. Bed for Small Lathe 

shown in Pig. 65. The cross-sectional shape of this bed is shown in 
the previous chapter. The details of the boxing and cross-ribbing 
and the joining of the bed to its standards will be observed. The 
right-hand standard is surrounded by an oil rim which conducts the 
lubricant into the trough, and at the top of the bed, close to the 
headstock, a space is left for the oil and chips to drop down into the 
trough. 

The two principal designs of gap lathes are represented in Figs. 38 
and 62, the first having the gap compensated for by the usual deepen- 
ing underneath, and the other having a continuous base, such as is 
adopted for heavier lathes. In each case an intermediate leg is located 
under the bed, owing to its length. It will be noticed that in one case 
the gap-piece entirely fills the opening, while in the other it only 
partially does so, leaving a space for a large face-plate or chuck to 
remain in place, and still providing sufficient length for the support 
of the saddle. 

Fig. 63 shows a French design of gap bed in which the metal is 
carried down in a graceful curve under the gap. The bed is well 



LATHE BED DESIGN 



41 



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No. Ill LATHE BED DESIGN 




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No. Ill LATHE BED DESIGN 



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LATHE BED DESIGN 



45 




at the front and the rear, but also at the ends of the machine. 
The practice of casting the headstock in one piece with the bed is 
becoming more and more common both in ordinary lathes and in those 
of the turret type. It is not always cheaper than to make the head 
separately and bolt it on, but it may be so if quantities of similar 
beds are cast In this case the machining will be cheaper also, pro- 
vided there are proper facilities for dealing with the work. The prin- 
cipal idea, however, is to gain greater rigidity and strength and con- 
sequent freedom from vibration. By carrying the webs up between 
the two bearings, as in Fig. 73, the two bearings are firmly tied to- 



46 



No. Ill LATHE BED DESIGN 




LATHE BED DESIGN ^vK^fF 

A neat design of bed and head for a small lathe is shown in Fig. 69, 
cast with a large tray around it. Fig. 72 shows the bed used in 
some of the German Pittler turret lathes which are supported on a 
single box base arranged as shown with a strainer and trough for the 
lubricant and a receptacle for tools, etc. The cross-sectional view 
shows the jointing of the bed on the standard, and the section of the 
ways, which carry the turret saddle on vees. 

Beds for lathes of large size embody the general principles which 
have been stated, but they are subject to a number of modifications 
which are not met with in those of medium and small size. Supporting 
legs are necessarily absent, the under side of the bed resting on its 




Fig. 73. Turret Lathe Bed with Head cast Solid with it 

foundations for its whole length. Joints in the longitudinal direction 
as well as in the cross direction become necessary on account of con- 
venience in casting, machining or transportation. Gaps or pits are 
used for lathes required for swinging large diameters, and sometimes 
the head is independent of the bed, except that it is mounted on the 
same foundation, that is, the cast-iron bed is not continuous. In some 
facing lathes the bed does not extend in the longitudinal direction, but 
comprises merely a support for the slide-rest. The slide movements 
are obtained only from the rests, and not from the bed. Sometimes the 
longitudinal extension of the bed from the headstock carries only a 
tailstock or a boring head, and the rests are supported on wings extend- 
ing toward front and back. 

Fig. 39 illustrates a built-up bed, with curved ribbing underneath, 
and a slide bed for carrying the tailstock and the saddle. The exten- 
sion plate at the front carries the saddle of the rest for turning 
large work. 



MACHINERY 



12 numbers a year. 
1000 9x13 pages. 
48 6x9 Data Sheets 




MACHINERY is the 
leading journal in 
the machine-build- 
ing field and meets the 
requirements of the me- 
chanical engineer, super- 
intendent, designer, tool- 
maker and machinist, as 
no other journal does. 
MACHINERY is a monthly 
and deals with machine 
design, tool design, ma- 
chine construction, shop 
practice, shop systems 
and shop management. 
The reading matter in 
MACHINERY is written by 
practical men and edited 
by mechanical men of 
long practical training. 
The twelve numbers a 
year contain a thousand 
pages of carefully selected and edited mechanical information. 

Each number of MACHINERY contains a variety of articles on 
machine shop practice. These articles include carefully prepared 
descriptions of manufacturing methods and current mechanical 
developments. Shop systems and shop management are ably 
handled by the foremost writers. Every number contains the 
most extensive and complete monthly record published by any 
journal, or in any form, of new machinery and tools and acces- 
sories for the machine shop. A special department is devoted 
to "Letters on Practical Subjects," to which practical mechanics 
contribute their experiences. There is a department of Shop 
Kinks brief, concise little contributions which contain ideas of 
value to the man in the shop or at the drafting table. 

The mechanical engineer, machine designer and draftsman are 
also well provided for in MACHINERY. Every number contains 
articles on the theory and practice of machine design, on the 
properties of materials, and on labor-saving methods and systems. 
There are reviews of research work in the mechanical field, 
valuable results of carefully made experiments are recorded, and 
the world's progress in every field of mechanical endeavor is 
closely watched. 

One of the most valuable features is the four-page monthly 
Data Sheet Supplement printed on strong manila paper. These 
Data Sheets contain high-grade, condensed mechanical data, 
covering machine design, machine operation and kindred subjects. 
They are the cream of mechanical information. 



RETURN TO the circulation desk of any 
University of California Library 

or to the 

NORTHERN REGIONAL LIBRARY FACILITY 
Bldg. 400, Richmond Field Station 
University of California 
Richmond, CA 94804-4698 

ALL BOOKS MAY BE RECALLED AFTER 7 DAYS 

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books to NRLF 

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MACHINERY'S DATA SHEET SERIES 

Data Sheet Books include the well-known series of Data Sheets 
ongmatea by MACU.KEBI-. and issued monthly as s^piemeiito to the puWicadon 
of these Data Sheets over 500 have been published, -and 6,000,000 copies so dPe 
v.sed and great.y amplified, ,hey are no, present,.! in book form * 

"** 



f VTENTS OP DAT\ fi"EET BOOKS 



No. 1. Scrc.v Threads. 1 .;red Stat. s T\'h<t 
worth, Sharp \- and British Association Tbrea. ": 
Bnggs Plp e Thread: oil Well Casing Gage, 
Mre Hose Connections; Acme, Worm and Metric 
Threads; Machine, WooJ, Lag Screw and i ir 
riage Bolt Threads, etc. 

No. 2. Screws, E.-its and Nuts. -Fillister-head, 
Headless, Collar-head and Hexago,. head Screws' 
Standard and Special Nuts; T-mits. T bolts and 
Washers; Thumb Screws and Nuts; Machine Screw 
Heads; Wood Screws; Tap Drills. 

No. 3. Taps and Dies. Hand, Machine Tapper 
and Machine Screw Taps; Taper Di, Taps Sellers 
Hobs; Screw Machine Taps; Straight and Taper 
Boiler Taps; Stay-bolt, Washout, and Patch-bott 
Taps; Pipe Taps and Hobs; Threading Dies. 

No. 4. Reamers, Sockets, Drills and Milling 
Cutters. Hand Reamers; Shell Reamers and Ar 
bors; Pipe Reamers; Taper Pins and Reamers- 



T, ' U ^;' llln e Machine Indexing, Clamping 

Device, and Planer JacksTables for Milling M" 
chine Indexing; Change Gears for Milling Spirit 
Angles tor setting Indexing Head when Mining 
< lutcnes; Jig Clamping Devices. 

No. 12. Pipe and Pipe Fittings. Pipe Threads 
and Gages; Cast-iron Fittings; Bronze Fittings* 
Hangers ^' " l "' B ' Wl8; PllH> Clan 'P* * 

nn?Rr? 8 ' B f ile S -i and Chira neys--Flue Spacing 
and Bracing tor Boilers: Strength of Boiler Jointa- 
Rivetmg, Boiler Setting; CUlSfleyg. 

No. 14. Locomotive and Railway Data Loc<, 
motive Boilers: IVuring Pressures foi I o *o ' th 
Journals; Locomotive Classittcati.ms: Rail SecUou^ 
Frogs. Switches ,-md Cross-over*; Tire, TraS 
Force; Inertia of Trains; Brake Levers.' 



stem-; , aml Gas En ff>es. sai orat 

Steam, steam Pip,, si/.es; steam Engine 1 -,^!i 
Volume of Cylinders; stuffing Boxes; SettlneC 
iss Engine Valve Gears; Condenser and A 



No. 5. Spur Gearing:. Diametral and Circular 
Pitch; Dimensions of Spur Gears; Tables of Pitch 
Diameters; Odontograph Tables; Rolling Mill Gear- 

mm J h en g n h ,- f S|)Ur (J '' ars ' Hor ^I"> 'er Trans- 
mitted by Cast-iron and RawJr,),- lM..i<,.,s; Design 
of Spur Geaio; Epicyclic Gear ing. 

No. 6. Bevel, Spiral and Worm Gearing.-Rulcs 
and Formulas for Bevel (Jean*; Strength of Bevel 
Gears; Design of BeTel Cears; Rules and formulas 
for Spiral Gears; Diagram for Cutters for Spiral 
Gears; Rules and Formulas for Worm Geantm 

No. 7. Shafting-, Keys and Keyways. -TTorse- 
power of Shafting; Sti ,gth of Shafting; Foi-ch^. 
Driving Shnnkmg ana Running Fits; Woodruff 



fe 



of 



; Tables 



w? t 1 v Mechanics an(1 Strength of Materials __ 
Work; Energy; Centrifugal Force; Center of *rW- 
ity; Motion: Friction; I'einlulnm; Falli-ig p.,. v 
Strength of Mat.-rials; Strength of Flat I'- ' 
Strength of Thi.-b Cylinders, etc 



usses etc 



. 

Rope Drive; Bending Stresses 



in 



: Resistance of Round vi 

; Mim-iit Densities for Various Contacts 
Materials; Centrifugal Fan and Blower 
Hot Water Main Capacities; De-imal 
Metric Conversion Tables, 



uncl ^ vvf ^ a 

pi g8 ; B f" ^"Roller' P-earings^ Clam'l'^Couplhlgs 
flange Couplings; Tootli Clutches: Crab Couplings 
Cone Clutches; Universal Joints; Crane Chain 
Crane Hooks; Drum Scores. 

No. 9. Springs, Slides and Machine Details- 
Formulas and Tables for Spring Calculations; Ma- 
chine Slides: Machine Handjes and Levers: Collars- 
Hand Wheels; Pins and Cotters; Turn-buckles. 

No. 10. Motor Drive, Speeds and Feeds, Change 
fearing, and Boring Bars. Power required for 
Machine Tools; Cutting Speeds and Feeds for 
Carbon and High-speed Steel; Screw Machine 
Speeds and Feeds; Heat Treatment of High-speed 
n T '*! 0ls; T> Taper T rnln; Change Gearing for 
the Lathe; Boring Bars and Tools. 

MAcmNEBT, the leading journal in the machine-building field, the originator of 
the 25-cent Reference and Data Books. Published monthly. Subscription,^ 00 
yearly. Foreign subscription, $3.00. 



und 
. 
': 
d 



The Industrial Press, Publishers of MACHINERY 
9-55 Lafayette Street, New York ' 



Q