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[Arrangements have been made to supply the necessary castings for this lathe, at a low figure, to any who areinterested. This magazine has no financial or other interest in this, beyond that of service to the r eade r. The nameand address of the maker will he furnished, upon request, by the Shop Notes Department, Popular Mechanics Magazine,6 N. Michigan Ave., Chicago.Editor.]

WHILE the turret lathe is essentiallya tool for the production of work inlarge quantities, a 6-in. lathe of the typedescribed in this article will be foundexceedingly useful in the small experi-me nta l shop. With a center held in themain turret, the machine may be used

as a simple engine lathe, and when anumber of similar pieces are to be turnedout in a hurry the work may be per-formed in almost as expeditious a manneras on a commercial turret lathe.

This machine was built and used by the

the spindle first, then re-center and finishthe outside. The nose is taper-bored totake the collets, and threaded eightthread s per inch, U. S. sta nd ard , to fitth e faceplates and chu cks . The tape r seatfor the collets should not be finished un tilthe lathe has been com pletely assembled;

it should then be machined with toolsheld in the toolpost of the lathe itself.The inner races of the ball bearings

should be a good fit on the flat threadson the rear of the spindle, and on the out-side of the spindle at th e fro nt . Bearing-

author in his own work-shop, on fine precisionwork, and many accurate

jobs have been done withit very quickly. Most ofthe work of building canbe done in a workshopequi pped only with a viseand bench d r i l l , wi th thenecessary small tools, asflat cold -rolle d steel isused for the ways, car-riage, and other parts ofthat character; it will benecessary, however, tohave certain things, suchas the machining of theheadstock and the c uttin gof the feed screw, done

Photograph of the Completed Lathe as Used in the Author's Workshop: ItIs Capable of Performing Both Fast and Accurate Work

in a machine shop, but this is a small item.The headstock is made of gray iron, andis fitted with an overarm steadyrest,which allows the carriage to travel thefull length of long work, as the work issup por ted fro m the top and rear. Thespindle is carried, at the rear, by a double-row ball bearing, .75 in. wide, of the com-bined axial and radial-load type, and atthe front by a single-row bearing, .629 in.wide. Bo th of these bearings have anoutside diameter of 2.441 in., and an inside

dia meter of 1.181 in. Care mus t be tak ento bore the bearing housin gs a p ush fitfor the bearings, and to have all facessquare and parallel with each other.

The spindle should be made of a goodgrade of steel, of about .3-per-cent carboncon ten t, and is hollo w. It is best to bore

retaining rings are fitted at the rear,clamping the outer race of the bearingfirmly , and taking up the end thrust.These are fitted with felt dust rings, bear-ing on the collars on the spindle; therings at the front are also fitted with dustrings, running on the spindle, but theserings do not clamp the single-row bear-ing, which is permitted to float.

When the headstock is assembled, thebearing housings should be packed witha good grade of vaseline, which will last

a long time; see that the vaseline supplyis at all times sufficient for good lubrica-tion. Spind les fitted in this ma nn er arefar superior to those fitted with plainbearings, as they consume less power, arefree from vibration, and allow of accurateas well as heavy work. The writer has

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3842 POPULA R M E C HA N I C S

taken a 1/8-in. cut on a piece of 1/2-in.cold-rolled steel at a distance of 5 in.from the collet, the reduced diameterbeing very accurate as to size.

The drawbar for the collets is a tube,the outer diameter of which fi ts the boreof the spindle. It is thread ed at the fr o n tto fit the collets, and is fitted with a hand-wheel at the rear. A tieba r at the top ofthe headstock keeps the two arms stiff and rigid. The cone pulley is fa ste ne d tothe spindle by a setscrew, spotted intothe spin dle ; tw o cone pulleys, of the samesize, should be cast and machined, onebeing used on the cou ntersh aft. The armfor the steadyrest is a length of 1-in.

must be as true and straight as it is pos-sible to make them, as upon their truthdepends the accuracy of the lathe. Whentrued, all surfaces should either be frostedor polished.

The shear anchor bolts should nowbe screwed home, the pipes, leg and rearleadscrew-bearing bolts placed in posi-

tion, and a wood en fo rm mad e to fitclosely around shears and legs, in whichto po ur the cem ent. The ce m en t used isa mixture of one part Portland cementto three parts clean, sharp sand, mixedwith just enough water to enable a hand-ful of the mixture to be picked up andsqueezed and to leave the impression of

c o l d - r o l l e ds t e e l ; i t i sclam ped in posi-

tion by 3/8-in.c a p s c r e w s ,w h i c h c o m -p r e s s t h eslot ted head-s t o c k a r m s .The headstockis fastened tothe bed by two1/2- i n. b o l t s ,r u n n i n g u pthrough pieces

of pipe cast in-to the bed; bythis means nostrains are puton the cement.

T h e c o n -struction of thebed is some-what of a nov-elty, although ithas been thor-oughly t r iedo u t b y t h ewriter in this

the fing ers in it.This cement istamped down

firmly in thefor m , poking i ta r o u n d t h escrews and intot h e c o r n e r swith an ice

pick, or somesimilar tool .When the con-crete has setthoroughly, theb o a r d s a r e r e -

moved and thec e m e n t t h o r -oughly wettedtwice a day forabout a week;this will temp erthe cement, andis a very im-portant part ofthe wo rk. Theresulting bed isas strong asa n y o n e c o u l dwish. Reinforc-

ing rods may be laid down in the cement,as it is bei ng place d, or wir es tw iste dthroughout the bolts, adding further tothe strength of the bed.

The main member of the carriage ism ad e of c old -ro lled steel, 1/2 by 5 by 5 1/4in. in size, machined as shown in thecar riag e-d eta il draw ing. A piece of 1/4by 2-in. cold-rolled steel, 7 in. long, is

fastened to the top of the main memberby 3/16-in. screw s; on this piece the crossslide run s. The cross slide is also madeof steel, machined as shown, and is fittedwith a tur re t toolpost. The cross slideis held to its ways by means of anglepieces, as shown in the front view of thecarriage. The turret is made of steel, andis casehardened; four tools can be

and other machines, and found to be verysat isfa ctory . This me thod of ma king thebed eliminates the hardest work of mak-ing a small lathe, as it does away withthe bed casting and the necessary ma-chining.

A piece of 1/2 by 4-in. cold-rolled steel,30 in. long, is used fo r the shea rs. Thisis first dril led an d tapped fo r a num ber of

3/16-in. stove bolts, of varying lengths,which are used to anchor the shears tothe cement , also dri l led and countersunkfor the leg screws and for the 1/2-in. head-stock bolts. It is next ca refully straight-ened and scraped to a true surface on topand sides, testing the width throughoutwith a micrometer, and using a knife-edge straightedge on the surfaces; these

Method of Making the Bed: The Bolts for the Rear Leadscrew

Bearing are Not Shown, but should be CastIn like the Leg Bolts


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m ou nt ed in thi s at once. On the boss ofthe cross slide is mounted a small indexpost, into the countersunk top of whichthe e levating screw s fit, allo win g each toolto be adjusted to its correct cuttingheight. A spring pushes the turret up-ward when the clamping handle is loos-

ened, allowing the turret to be turned tobring another tool into cutting position.A 1/4-in. square-thread screw operates thecross slide, and the tools are held in thetoolpost by 1/4-in. square-head setscrews.

The apron of the carriage is made ofsteel, 2 in. wide, and is fastened to themain carriage member by flat-head ma-chine screws. The fr on t angle piece of

aga inst the edge of the shears. Brassshim s, or wea ring pieces, 1/32 in. thick , areset in the ends, to take the wear on thefiller piece. The rear ang le is plain , ma-chined as shown in the drawing.

Behind the apron is fitted a bronzenut; this rotates in a bearing fastened to

the apron, and is screwed into one of apair of miter gears, which, in turn, aredriven by 3-to-l spur gears; the largergear is pinned to the handwheel, and thesmaller is pressed onto the hub of thesecond miter gear, which runs in theapron. The han dw hee l run s on a studscrewed into the apron; this stud is fittedwith a knurled friction nut, so that, if

Full Details of the Carriage and Apron Me cha nism : Note the Employm ent of the Small Index Post and Ele-vating Screws in the Toolpost to Secure the Correct Height for Each Tool. The

Post is Set in the Inner Left-Hand Corner of the Turret Base

the carriage is built up, as shown, thefiller piece being slit at each end, so thatwear may be taken up as it develops, bytightening the adjusting screws. Theholes for these screws do not go clearthrough the filler piece, but stop at theslits, so that, by screwing the screws in,the inner ends of the filler are pressed

change gears are fitted to the lathe or itis desired to feed by means of the hand-wheel on the end of the leadscrew, thenut can be tightened and the whole as-sembly of spur and miter gears and nutlocked firmly.

The rear, or main-turret, base and slideare made of cast iron, a dovetailed slide


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Details of the Headstock and Main Turret, and Side Elevation of Completed Lath e: Wh en a Center is Used inthe Tu rret , as Sh own, and the G ib-Loc king Screw Tig htened, the Tool can be Used as an Ordinar y Bench Lathe,for Tu rn in g W ork between Centers. Five Tools can be U sed in the M ain Turret, and Four in the Toolpost

Turret, Making for Speed in Production

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being used, fitted with a 1/8-in. gib. Thefront gib-adjusting screw is fitted with ahandle and is used to lock the turret inposition for plain turning operations.

The turret pivot pin, of cold-rolled steel,casehardened, is 5/8 in. in diameter, witha 5/8-in. U. S. s tandard thread cut on theupper end, and fitted with a clampinghandle. The turret is made of steel, under-cut as shown in the drawings, and has five

equally spaced slots milled around thelower surface for the index finger. Oneside of each slot is radial, the other beingtapered, and the index finger is made tocorrespond. By mak ing the finger andslots of this form, the radial side does theactual locating, and the tapered sidemoves the turret to position; only theradial side need be of great accuracy,while the wear is chiefly on the inclinedside, where it does no harm.

The holes for the tools should not bebored until the indexing mechanism hasbeen assembled and the lathe set up;then, by boring the holes with a tool heldin the chuck, and correctly supported, thegreatest degree of accuracy is obtained.

The details of the indexing device are socomplete that little description is neces-sary; care should be taken, however, tosee that the coil spring is heavy enoughto prevent the index finger from beingwithdrawn from the turret until the stop

pin on the back of the turret base strikesthe pin on the slide; the backward move-ment of the lever will thus move thewhole turret back until the stop pins en-gage; further movement disengaging theindex finger, and allowing the tu rret to berevolved to the next position. The indexfinger slides between beveled strips of3/16-in. steel, and must be a good fit; bothslides and finger should be casehardenedto insure long life.

The speed of the lathe, and the arrange-ment of the countershaft, will be deter-mined by the work to be undertaken andthe shop conditions. A reversing coun-tershaft should be fitted if tap and diework is to be performed on the lathe. A

quadrant and stud can be fitted on thehead end, and a set of change gears pro-vided, if the lathe is to be used for screw-cutting; in this event, no care should bespared to secure an accurate leadscrew.

The builder of this lathe will have avery efficient machine, one that could notbe purchased for many times the cost ofbuilding.

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