[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 reader. 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 in

large quantities, a 6-in. lathe of the typedescribed in this article will be foundexceedingly useful in the small experi-mental shop. With a center held in themain turret, the machine may be usedas 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 eightthreads per inch, U. S. standard, to fitthe faceplates and chucks. The taper seatfor the collets should not be finished untilthe lathe has been completely assembled;it should then be machined with toolsheld in the toolpost of the lathe itself.

The inner races of the ball bearingsshould be a good fit on the flat threadson the rear of the spindle, and on the out-side of the spindle at the front. Bearing-

author in his own work-shop, on fine precisionwork, and many accuratejobs have been done withit very quickly. Most ofthe work of building canbe done in a workshopequipped only with a viseand bench drill, with thenecessary small tools, asflat cold-rolled 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 cuttingof 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, and

is fitted with an overarm steadyrest,which allows the carriage to travel thefull length of long work, as the work issupported from 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. Both of these bearings have anoutside diameter of 2.441 in., and an insidediameter of 1.181 in. Care must be takento bore the bearing housings a push 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 carboncontent, and is hollow. 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 lasta long time; see that the vaseline supplyis at all times sufficient for good lubrica-tion. Spindles fitted in this manner 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 P O P U L A R M E C H A 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 fits the boreof the spindle. It is threaded at the f rontto fit the collets, and is fitted with a hand-wheel at the rear. A tiebar at the top ofthe headstock keeps the two arms stiffand rigid. The cone pulley is fastened tothe spindle by a setscrew, spotted intothe spindle; two cone pulleys, of the samesize, should be cast and machined, onebeing used on the countershaft. 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 wooden form made to fitclosely around shears and legs, in whichto pour the cement. The cement 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 sclamped in posi-tion by 3/8-in.c a p s c r e w s ,w h i c h com-p r e s s t h es lo t 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 piecesof 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 fingers in it.This cement istamped downfirmly in theform, poking ita r o u n d t h escrews and intothe c o r n e r sw i t h an icepick, or somes i m i l a r tool.When the con-crete has setthoroughly, theboards are re-moved and thecemen t thor-oughly wettedtwice a day forabout a week;this will temperthe cement, andis a very im-portant part ofthe work. Theresulting bed isas s t rong asa n y o n e couldwish. Reinforc-

ing rods may be laid down in the cement,as it is being placed, or wires twistedthroughout the bolts, adding further tothe strength of the bed.

The main member of the carriage ismade of cold-rolled steel, 1/2 by 5 by 5 1/4in. in size, machined as shown in thecarriage-detail drawing. A piece of 1/4by 2-in. cold-rolled steel, 7 in. long, isfastened to the top of the main memberby 3/16-in. screws; on this piece the crossslide runs. The cross slide is also madeof steel, machined as shown, and is fittedwith a turret 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 verysatisfactory. This method of making 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 for the shears. Thisis first drilled and tapped for a number of3/16-in. stove bolts, of varying lengths,which are used to anchor the shears tothe cement, also drilled and countersunkfor the leg screws and for the 1/2-in. head-stock bolts. It is next carefully 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 LeadscrewBearing are Not Shown, but should be Cast

In like the Leg Bolts

3844 POPULAR MECHANICS

mounted in this at once. On the boss ofthe cross slide is mounted a small indexpost, into the countersunk top of whichthe elevating screws fit, allowing 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 front angle piece of

against the edge of the shears. Brassshims, or wearing pieces, 1/32 in. thick, areset in the ends, to take the wear on thefiller piece. The rear angle is plain, ma-chined as shown in the drawing.

Behind the apron is fitted a bronzenut; this rotates in a bearing fastened tothe 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 handwheel runs on a studscrewed into the apron; this stud is fittedwith a knurled friction nut, so that, if

Full Details of the Carriage and Apron Mechanism: Note the Employment 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

Details of the Headstock and Main Turret, and Side Elevation of Completed Lathe: When a Center is Used inthe Turret, as Shown, and the Gib-Locking Screw Tightened, the Tool can be Used as an Ordinary Bench Lathe,for Turning Work between Centers. Five Tools can be Used in the Main Turret, and Four in the Toolpost

Turret, Making for Speed in Production

3843

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. standard 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 fiveequally 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 making 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 stoppin 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 turret 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. Aquadrant 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.