April 9 , 1942

Mr. J. W. Pattison

Designs a Lathe and Suggests some Gadgets for it

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TO prevent any misunderstanding, as I donot wish to start any argument on

lathe design, let me state as briefly aspossible just why this article ever came tobe written at all.

First, then, let it be said that, like manyothers, I am very interested in makingaccessories, or gadgets as they are nowcommonly called, to further the scope ofmy lathe.

To facilitate this process, I keep an exactscale drawing of my present lathe, andwhenever any additional part is requiredwhich I intend to make, reference to thedrawing provides all the measurementsnecessary and saves endless time measuringup on the actual lathe itself, which at itsbest can be a dirty job, and dirty hands arenot very helpful on a drawing board.

GadgetsEvidence that many more like myself are

interested in gadget making, or of otherwiseimproving their lathes, will be found byreferring to almost any back number of thisjournal, where a multitude of articles havebeen written, bringing to light manyexcellent ideas for our benefit.

Speaking for myself, I take great interestin these articles, and many of the ideas setforth have been adopted to my own needs ;and as to their success, I have yet to makeone that had to be shelved. Added to this,many original ideas of my own have beencarried out from time to time, with theresult that I now have available quite arespectable accumulation of very interestingand useful gadgets, many of which are inconstant use.

All of these improvements, however, havebeen of a minor character, and in no wayalter the basic design of the lathe ; yet Ihave often thought, had my lathe beenmade of a more plastic material than cast-iron, it would, times without number, havebeen moulded into a variety of differentshapes to further the adoption of gadgets !

A Third HandOne such gadget which, almost of necessity,

requires an alteration of the lathe bed, andone which I had often desired to make,might be described as a sort of third handto the lathe itself. Something where one

could fasten a piece of work and still haveavailable the benefits of the wide range ofmovements of the slide rest on which tomount tools or appliances to carry out thenecessary machining.

Yet another gadget desired was one tosolve the difficulty that often crops up,the devising of some form of auxiliary drive,adaptable to any rotatable tool which hasto travel about in a variety of directions.We all know that difficulty, and the over-head is not always an easy method ofsolving it.

I did get over these two difficulties on myown lathe. be it said in a somewhat nrimativeway ; but it was in the process o f drawingout the design that made me wish for thatmore plastic material already referred to.

A Pictorial VersionIt was then that I decided to kill two

birds with one stone, for, having taken greatinterest in the recent discussions on lathedesign, I decided to mould my lathe into amore convenient design, at least on thedrawing board, thus giving me a pictorialversion of what I wanted.

Having drawn it out for my own amuse-ment, it then occurred to me that it mightprovide interesting entertainment for othersif it was accompanied by. a description. Itis not put forth, of course, as any attemptto solve the ideal lathe question, thatwould take a much more intrepid personthan I, since I am inclined to regard theanswer to that question as somewhatmythical, considering the wide diversity ofopiiiion as to what constitutes an ideallathe. In fact, I wonder if there can be sucha thing as an ultimate ideal, since whenexamining my own drawing there was agreat urge to alter this or that as ideas tookshape. Therefore, to me at any rate, whatwould at one moment appear to be idealsoon disappeared, to an extent dependingupon ones desire to improve on it. All this,however, is quite a different thing fromsaying I would not be content with suchand such a lathe ; indeed, I feel quitesatisfied with the one I own at present ; andalthough it is far from my ideal, I have nointention of changing it for any other. Thatbeing so, the design is put forth only as ofgeneral interest at the present time, though

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April 9, 1942 355 WORKSHOP

I do hope it will induce others to producea scale drawing of similar interest. Nodoubt they will find as many snags as I did,when they come to put their ideas onpaper ; but, above all, let us have theoriginal ideas included and without fixingprice limits, although a measure of sim-plicity will have to be included, otherwisethe design will surely get out of hand, asthere would appear to be no limits whenonce a start is made_ Since no thought ofproduction is being contemplated, there isno need to let price upset ideas. If, however,anyone does hope to see his design produced,no doubt the prospective manufacturer willwhittle down the design until it reaches hisprice limit. Any thought of manufacturenever entered my mind, so price didntinterfere, though much thought was givento simplifying the various parts. Hereshoping, therefore, that any interest takenin this article will form a bait for others t ocome forward with their lathe designs, notnecessarily ideals, though incorporating oneor two original ideas, or should I say ideasoriginally applied in case there is anymisconception as to their origin. To this Ihad better add, that I claim no originalityin my own drawings.

DrawingsNow a word about the drawings. I have

given plan, elevation and end views in pre-ference to a projected view, in case anyonewishes to read off dimensions. Sectionaldrawings of all the parts would take up toomuch space, although, of course, they hadto be made before the outline drawingscould be arrived at. In lieu of sections I haveincluded a description so that readers mayform an idea of what is hidden from view.

General Features of the DesignThe machine was designed to mount on

top of a bench, without cutting away anyof the latter and to operate as a completeunit without any separate motor, belting,countershaft, or overhead gear other thanthat which was part of the machine itself.There had to be no belts to change, and asmuch as possible of the mechanism to beenclosed. Also, there would have been nogear wheels to change, but that was foundto be impracticable unless some limit wasset on the number of threads to be cut.After considering that the amateur uses hislathe to cut worms and spirals, the necessityof very fine feeds at times, and also, at oddtimes, the- driving of the leadscrew indepen-dent of the mandrel, not to mention manyother uses to which loose gear wheels can beput, the adoption of the simple quadrantand standard set of change wheels waspreferred to the quick-change version with

limited uses. Not a convincing argument Iadmit, but it scores in simplicity and in itsuniversal application, and the more universalthe machine can be made the better, at leastfrom the amateurs point of view.

Electricity being available, advantage wasnaturally taken of this as a source of power.Normal accessories such as chucks, face-plate, angle-plates, etc., are assumed to beavailable and are therefore not included inthe drawings.

The BedThis is a box form casting closed at the

top and open at the bottom, well ribbedinside, and with plenty of metal in it, toensure rigidity. Extensions cast with thebed support the motor and columns. Three-point suspension is adopted, with rockersat the headstock end and a sphere at thetail end. This form of anchorage provides aready means of upending the machine to getat the mechanism underneath necessary,since there are no inspection plates. As,however, there is little underneath torequire inspection, that task will only occurat very long intervals and would be simpleenough when it did occur. Besides this, allbolting-down strains are relieved from thebed.

The axis of the mandrel is offset from thecentre line of the bed, the principal objecthere being to get adequate support immedi-atelv underneath the turning tool withoutoverhanging the front edge o f the bed any more than was reasonably necessary. Addedto this, the offsetting allowed for an entirelyseparate way to be formed, along which thesaddle could travel without touching anypart of the bed traversed by the tailstock. Comparatively large wearing surfaces were

provided for a lathe of this size. vet even ifwear did -occur, this could not affect theoriginal alignment of the head- and tail-stock.

No GapNo gap was thought necessary, since the

centres were raised to 4-1/2 in. This height wasadopted for two reasons, first it provides afair maximum turning size for an amateurslathe, although a gap could easily be got byscooping out the bed immediately under-neath the faceplate, whilst still retainingthe desired front way the entire length ofthe bed. The second and most importantreason was to get ample room over thesaddle. The top and vertical faces of thefront shear of the bed take practically allthe pressure of the turning tool, the balancebeing taken on a section of the bed nottouched by the tailstock.

(To be continued)

April 30, 1942 421

Mr. J. W. Pattison

Designs a Lathe -and some Gadgets for it

.a THE lower half of the jig-saw is a casting,enclosine a disc crank which imparts a1-1/4-in. stroke to the saw. Supported by it is

B a table which may be tilted and clamped atany convenient angle. The unit is securedto the lathe bed by a single bolt passingthrough a hole drilled therein. The upperhalf is brought into register with it by some

;B definite marking on the auxiliary bed. In

., * Continued from page 396, M.E., ApriE 23,1942.

this way, the set-up should only be the workof a moment.

For sawing out intricate shapes in sheet metal the jig-saw is idea!, and any materialmay be sawn, if a suitable blade or knife isemployed. Wood, bakelite, fibre, etc., maybe sawn, and such material as cloth, cut witha knife blade. By using the lower half of themachine alone with a sabre saw in its chuck,intricate shapes may be cut in thickermaterials and should be useful in patternmaking.

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4.

JIG SAW ffEAARM TO CARRY

DR/L 1 HEAD.

SPRING FOOT

RISING & FALLING

CIRCULAR SAW

D I A TO FIT AuX SAODLE

!-/II

Universal arm shown carrying jig-sawhead, together with circular saw and

jig filing machine.

WORKSHOP 422 THE MODEL ENGINEER

By removing the saw clamp, the remainingexposed socket becomes available for smallmachine files. With the mechanism set tothe bottom of its stroke. there is plentv ofroom to swing the circular saw into position.Either metal or woodcutting saws may beused and the swing movement of the sawarm is, the equivalent of a rising and fallingtable ; and added to this, there is the tiltingmovement of the table itself. An adiustable

suggesting that it would be amply strongenough to perform this task.

There are numerous other uses to whichthe machine and its gadgets could be put,.

fence is clamped to the front edge of thetable, and two slots are included for use withan angle-gauge. With a gap-piece removedfrom the centre of the table, it would appearpossible to- attempt even surface grinding,although its scope would obviously belimited.

Universal drilling andmilling machine boredto carry any of therotatable tools. Simi-

larly, a small faceplateor slotted table or any-

thing fitted with a 1 in.dia. holding piece

could be mounted.

The other gadget is a universal millingslide and needs little description, except tomention that the gib-piece is adjusted byfour screws and may be locked by a handledclamping-screw. It will, of course, carryany of the rotatable tools, being bored outI in. diameter for that purpose. Besides theuses to which the above gadgets can be put,it would appear possible to do a little planingon anvthing mounted on the boring table,either-by moving the work mounted thereon against a tool held in the auxiliary saddle, orby swinging the auxiliary bed radially. Thislatter experiment suggests, also, that with asuitable clapper-box the tailstock might beused as a shaper for anything within itscapacity, the large dimensions of the ram

as indeed there are-many more gadgetswhich could be added. until the machinebecame a veritable concentrated machine-shop ; but as these appear to be never-ending, imagination must be left to thereader to think them out for himself.

Amateur T o o l m a k i n g(Continued from page 420)

edges just down to the cutting edges, nomore and no less. Painting the lands with plumbers black or red lead facili-tates the accuracy of this filing operation.After heat treatment, touch up the cuttingedge flats and the flutes with Carborundumoil slips, and again you have quite a pro-fessional-looking job.

Twist DrillsAgain flute a piece of silver-steel or reduced

stock of desired diameter with two flutes, asalready described for taps and reamers andfinish bv grinding, but flute a longer lengththan that-required for finishing. Grippmgthe shank of the work tiehtlv in the chuckof the lathe and the other end in the tailstockchuck, form the twist, working back thetailstock to keep the work straight. Removethe damaged fluted part and, after straighten-ing and grinding the point, the drill is-readyfor hardening and tempering. Sizes betweenabout 1/8in. and 5/16 in. can be successfullymade, but the absence of lands makes thesehome-made drills unsuitable for very deepdrilling, as they tend to bind.

Heat TreatmentA muffle furnace is a very useful adjunct

for the amateur toolmaker. Procure half adozen firebricks approximately 4 in. x 6 in.x l in. and secure four together withclamping straps to form a chamber approxi-matelv 4 in. wide, 2 in. deep and 6 in. longand secure another of the bricks to close oneend of the chamber. With an old hacksaw,cut strips from the remaining brick to layacross the bottom of the chamber to supportarticles being treated.

Mount the whole on a suitable standapplicable to your gas burner or blowlamp,as the case mav be. With a half-Dint size ofthe latter, taps, dies, reamers, etc., up to1/2 in. can be satisfactorily hardened andtempered, and, of course, the muffle issuitable for many other heat treatment jobs.The residual heat at the back of the muffleprovides all that is required for temperingsmall tools at a temperature uniformthroughout in their mass.

F376 . THE MODEL ENGINEER

* Mr. J. W. Pattison *

Designs a Lathe -and Suggests some Gadgets for it

WHEN the drawings were completed, thesesurfaces came in for a lot of criticism

from myself. Particularly, they did notachieve one of the objects desired, that beingslides which would remain entirely free fromchips or, even worse, grit if grinding was to beattempted. Any attempt to eliminate thisdisadvantage appeared to bring i n evengreater troubles. An open-top bed would dolittle to relieve the situation, as the slideswould still remain exposed. Transferringthe slides to the front and rear face of thebed was thought of, but this meant no endof troubles, such as leadscrew mounting, tail-stock fixing, etc. On the whole, therefore,it was thought better to leave it alone, andpossibly provide some form of telescopicapron to cover the exposed parts ; butwhether this would be worth the trouble,however, is doubtful.

It is assumed that the bed would beground, and its accuracy would dependupon the parallelism of the vertical faces ofthe front and back shears of the bed, and,of course, the flatness of the top surface.As the head and tailstock are both locatedagainst the rear vertical face, and, as alreadymentioned, the saddle is located against thevertical face of the front shear, alignmentshould be preserved at all times.The Headstock

First in importance is the mandrel. Ithad to be large because I particularlywanted l-in. collet capacity : therefore. theminimum diameter had to be 2 in.

Only when it was drawn out did I fullyrealise why a large mandrel would beexpensive, for almost everything else in theheadstock had to be increased in like propor-tion. Just imagine what diameter pinion isrequired and you will soon realise whatdimensions a 6 to 1 back gear will assume.Also, one cannot mount standard-size changewheels direct on so large a mandrel, assumingit is to be bored out maximum diameter asin this case. Quite a lot of scheming had tobe employed to keep everything withinreasonable dimensions and yet providelarge wearing surfaces.

Everyone appears to be in general

* Continued from page 355, M.E., April 9,1942.

agreement that plain bearings are best forlathe mandrels, and as I have no faultto find with phosphor-bronze carrying ahardened and ground mandrel, that is whatis suggested. No doubt, cast-iron is equallygood. though I have never worked a lathe .tso fitted long enough to form any opinionof my own. Personally, I would favour ball-bearings. but dread the warnings of others.

I have experienced some of the troublesattributed to ball-bearings, but as thesebearings had seen a lot of service I was notconvinced that the faults could not berectified. Whatever the reason, it stillremains a mystery to me why the makersof some of the finest precision lathesemployed on the production of delicatework, such as instrument making, use ball-bearing headstocks and expound theirvirtues as though they were the main reasonfor the accurate work produced. Will some-one with experience of these small modernmachines let us have some facts ? It wouldappear to me that many of the troubles ofthe earlier machines must have been over-come in the modern type. However, hardphosphor - bronze adequately lubricated,

appears satisfactory enough to specify inthis case, These bearings are coned on theoutside for adjustment and are of squaredimensions as regards length to diameter.Both front and rear bearings are of thesame size. A ball-thrust washer takes theend pressure on the mandrel.

The drive enters the headstock by avertical shaft, thence to a two-speed gearthrough a worm and wheel. A 5/8in. face isallowed on all gears in, the headstock. Thegear change is affected bv a lever on theoutside of the head, giving high, neutral andlow, the neutra l pos i t ion a l lowing themotor to be run without turning themandrel.

*

From the top of the vertical shaft theauxiliary drive is taken through a clutch,controlled by a small spring-loaded leverplaced near the rear bearing. A correspond-ing lever near the front bearing works thetumbler gears.

Provision is made for dividing-plates at\the front of the head. The protruding shaft

rries at its rear end a steel worm 1-1/8 in. ineter, which meshes with the mandrel

April 16, 1942 377

gear. This shaft ishoused in an eccen-tric sleeve bearingto allow for theworm being takenin and out of mesh,and for adjustmentof backlash. Thefront end of theshaft carries thequadrant-arm andspr ing p lunge r ,whilst changeabledividing-plates andsectors are carriedon the front end ofthe bearing. It isalso possible to fixa handle in placeof the quadrant andplunger and thusform a hand driveto use in conjunc-tion with the per-manently attachedplate situated at therear end of themandrel. Thislatter plate is 1/2 in.thick and 4 in.diameter, drilledaround its edge with24 holes, 1/4 in.diameter, which areentered at right-angles by an equalnumber of 1/8 in.t apped ho l e slocated around theside face of theplate. Being per-manently fixed, itis always availablefor the direct divid-ing of work intosquares, hexagons,etc., the lockingplunger being a5/16-in. knurled-h e a d e d s c r ew ,turned 1/4 in. to enterthe holes in theplate, and workingin a lug cast in thehead. Check count-ing may be done byinserting set-screwsin the tapped holescorresponding tothose required fo rindexing.

Two adjustablestops, having 1/4-in.turned legs, may be

WORKSHOP

WORKSHOP 378 THE MODEL ENGINEER

entered into any of the holes in the plate and of taking care of all the power likely to befound in an amateurs lathe motor.locked by set-screws. Set tangentially on the

plate, they come up against the cast lug whichacts as a stop. Thus by using the handle onthe other dividing gear to turn the mandrel,end-milling of an arc, or any similar work,may be performed on anything held on thechuck, the positive stops presentmg therotation of the work beyond a predetermineddistance.

This idea is similar to one seen at the M.E. exhibition some years ago, and Itrust the originator of this useful device willpardon my having used it here.

The only other item in the headstock is aclutch which connects the start of the screw-cutting train. Thus, everything is com-pletely enclosed and runs in oil, adequatelubrication being vitally necessary with sucha large mandrel running in plain bearings athigh speeds. A cover-plate is provided forinspection and assemblv. The headstock isbolted down to the lathe bed and occupiesthe full width of the latter.

From the headstock the vertical shaftextends doivnwards into the bed, andexpanding Vee-pulleys connect it to themotor. This form of drive is a similararrangement to that found on the oldZenith and Rudge motor-cycles. The formeremployed an expanding pulley on the engineshaft, and the back wheel with its belt rimwas moved in or out to preserve the tensionon the belt. The Rudge was similar, only

here both pulleys expanded and contractedalternately to get the variable ratio andmaintain the tension on the belt at the sametime. It is this latter arrangement which isused here.

T w o 6-in. pulleys give an infinitelyvariable speed between 30 and 2,200 r.p.m.to the mandrel, the two-speed gear in thehead giving a slight overlap in the middleof this range. Variation of speed is con-trolled by turning the hand-wheel placedconveniently at the front of the bed.

The motor is mounted vertically on anextension of the lathe bed, and thus exposesthe free end of its shaft, which is equippedwith a pulley for use at any time should anextra auxiliary drive be required. Tomention one example, should it b e necessaryto drive the leadscrew independently of themandrel, a belt could be taken from hereto a worm drive, connecting with the geartrain.

The main auxiliary drive is by flexiblecable taken off the top of the vertical shaftin the headstock. Judging from my ownshort experience of a home-made versionof this type of drive, it should be a real boon.It certainly is more adaptable than anyoverhead, and standard cable of no morethan 5/8-in. outside diameter is quite capable

Among other reasons, it was to exploitthis form of drive fully that l-in. colletcapacity was wanted in the mandrel andtailstock, since it was thought that if a well-made head of l-in. diameter carrying screwo n collet chucks was attached to this drive,this head could be slipped into- the mandreland some quite delicate work turned with it.To go a step farther and get down to work ofthe watch-making variety, possibly a furtherhead would be required, together with a barbed, this latter fitting into a hole bored inthe headstock casting. Whether thenecessary accuracy could be attained, how-ever, is quite another matter. In any case,such an arrangement is only mentioned as apossibility, and no provision is made foranything of the sort here.

The speed range available from theflexible shaft is variable between 480 and4,350 r.p.m.

The TailstockIn capacity, this could duplicate the head-

stock, when all accessories would b e inter-changeable. A solid tailstock is to bepreferred to ensure preservation of theoriginal alignment, as it may well be calledupon to perform other jobs than thatusually associated with a tailstock. Slighttaper turning could be accomplished byusing an adjustable offset centre, or bydisengaging the slide nut and using theauxiliary bed, set at an angle, as a saddleguide. The tailstock spindle, is equippedwith the usual screw and hand-wheel, whichmay be disengaged and a lever brought intouse. This lever could be swung out of theway when not in use. Rotation of themandrel is prevented by a block, sliding ina machined slot in the casting. The tailstockassembly is held firmly against the verticalrear face of the bed. being drawn up tight

the top surface at the same

use-w uld be made of this fitment for boringand m ling. The longitudinal motion alongthe lat e bed was of first importance. Noless than 14 in. of sliding surface is used,and as this is onlv 2 in. wide. perfect slidingmotion should be obtained, the rear of thesaddle merely acting as a steady to keep itlevel. Adjustment is by gib-piece along thefront, whilst a stiff gib holds the rear of thesaddle up to its work.

(To be continued)

394 THE MODEL ENGINEER r

*Mr. J. W. Pattison

Designs a Lathe -and Suggests some Gadgets for it

DUE to the exceptional length of the frontslide, the rear of this saddle is not

called upon to take any of the side thrustoccasioned in use ; therefore, binding andchatter should not occur. Long cross-traverse was required to provide for millinglong lengths at one setting. A small table didnot provide facilities for holding long workand traversing past the mandrel, with a fulllength bearing all the way, hence theadoption of an extremely long table.Almost 12 in. of traverse can be obtainedwith full bearing all the way, and to attainthis, the angle of the slides would have tobe reversed so as to retain a reasonable sizedgib strip. For normal turning, this slidewould be well back out of the way, andwould not appear to have any disadvantage,therefore.

A n o t h e r necessity is some form ofrising movement to bring the work tocentre height and put on cuts. To achievethis, the saddle has a false base and thatpart containing the slide can be raised byhand-wheel and securely locked at the rear,to form a variable triangle with the bed. Thebearings which form the axis of this risingand falling movement are 7/8 in. diameterand are adjustable.

The feed screw has a bearing at both endsand a graduated dial at the front end,which can be set at zero. This feedscrew can be instantly disengaged fromits gunmetal nut by giving a few turnsto the set-screw, set in the right-hand sideof the saddle. By releasing this nut, andwith a piece of 1 in. diameter rod boltedvertically on top of the table, to engage acorresponding hole provided in the saddleof the auxiliary bed: then if this latter is setto a predetermined angle, the tool willfollow this angle in taper turning. Anotheraddition to the slide rest which would beuseful when milling would be an adjustablestop. Though not shown in the drawing, itsfitting should be obvious to anyone.

The ApronSimplicity is in evidence here, as no

provision is made for automatic feed, exceptthat normally obtained by change-wheels

* Continued from page 378, M.E., April 16,1942.

and the leadscrew. Rack-and-pinion is addedfor quick traverse along the bed and isassisted by a large hand-wheel. Two half-nuts, each 3 in. long, are used to engage theleadscrew, but they are mounted on rockersinstead of slides. Although this does not givea true up and down movement, the error isso slight, and the advantages so great, thatit was adopted. The difficulty here was toget a long bearing surface, and as the lead-screw was to be tucked away well up under-neath the front shear of the bed, long slideswere impracticable, due to the heightavailable ; thus, rockers with long shaftsappeared to be a much better arrangement.Engagement would be facilitated by theadoption of an Acme threaded leadscrew.A projection cast flush with the forwardedge of the apron engages the automatictrips.

The LeadscrewThis is substantial, being 7/8 in. diameter,

and has an Acme thread, 8 per inch. Theadoption of 8 t.p.i. is open to criticism, butit nevertheless has many advantages. Al lthrust is taken at the headstock end, wherethe plain portion runs in a bronze bush andhas an adjustable thrust-washer. The drivecan be put in and out of engagement by adog clutch, operated by a small knob at thefront which has a snap action so that itremains positively in or out. The shaft onwhich this knob is carried is extended alongthe bed, and thus can be set to operateautomatically. The main purpose of thisclutch is to have the leadscrew entirelyfree from the gear train so that it can beoperated manually by the graduated wheelat its far end without dismantling the geartrain. The single-toothed dog clutch in theheadstock, which works at the beginning ofthe screwcutting train, also has its controlbrought to the front of the lathe andoperated similarly. The more normal methodof screwcutting could be used by disregardingthis last clutch and fitting an indicator atthe end of the saddle apron. Either method,however, requires only a simple fitment.

The Gear TrainThis is a standard arrangement whereby

loose change-wheels are mounted on aquadrant. A single slot is all that is required,

_ ..-. - _- ., _.. ^ __ ,.I , ., .^ , _ .___A-_-~_- 1_

STEADY C O L U M N

REVOL V/NC SADDLF

REVERSIEL E BRACKET _

ZSPEED G E A R CHANGE

C L U T C H C O N T R O L .

Two end views : Left, headstock ; Right, tailstock of the self-contained universal model engineers lathe.

WORKSHOP THE MODEL ENGINEER

due to the long length of the quadrant. Itmight be advantageous to have the studsmilled to slide in this slot, to prevent thetendency to revolve when being tightenedup. Splined sleeves are suggested, and asquare-holed washer and knurled-headedscrew would appear to be as good a methodas any other, to secure the wheels. A ball-handled screw is used to lock the quadrant.

GadgetsThe third hand arrangement, pre-

viously referred to, could take the form of

FL EXIBL E D R I V E

coNNEGr.oNs

BOX

\D R I L L I N G H E A DWITH JAW C H U C K .

TURNING O R M I L L I N G H E A D

WITH COLLET C H O C K . .

Drilling, milling and grinding heads adopted foruniversal mounting on the lathe.

an auxiliary bed mounted at the rear of thelathe and normally parallel to it.

A truncated triangular bar is suggested,clamped in a suitable bracket and mountedon a substantial vertical column, the latterbeing rigidly fixed to the main bed casting.A similar column fixed at the tailend of the bed would act as a steady,keeping the auxiliary bed normally parallelwith the lathe bed, yet allowing it to be setto any angle and clamped in position.

Clamping would be affected bv a locking bolton the main column, assisted by a radius-rod :extending from the remote end of the bed .to the other column. A screw and hand-wheel are provided to assist in raising andlowering the bed on the column. On thistriangular bed slides a saddle, traversed byanother screw and hand-wheel. The outerpart of the saddle is capable of movingaround its base and can be clamped in position. It has a l-in. diameter hole boredin it to take any of the other accessories,including a slotted table. Work may bebolted to this table, or, alternatively, a toolmay be mounted here. It does not requiremuch imagination to realise the amount ofwork that could be accomplished by the aidof the flexible drive and with work mountedin full view.

Little need be said of the flexible drive, asit simply consists of a 3/8-in. diameter multi-stranded steel wire core, enclosed in anouter flexible casing which is oil tight, andhaving suitable solid splined ends to take upthe drive.

Drilling, Milling and Grinding HeadsThree heads for attachment to this drive

are shown in the drawings, one geared forinternal grinding, as this requires anextremely high rate of revolutions ; anotherfor general work, such as drilling up to 1/2 in.capacity, and yet another, this time fittedwith collet chucks, to be used for fineturning or to carry small milling cutters.All are 1 in. outside diameter and theirmounting is almost universal. Like the other gadgets, they will fit into the auxiliarysaddle, the collet chuck in head or tailstock,or the universal milling and drilling attach-ment. Hand drilling, sanding, buffing,polishing, etc., can be done, either on thelathe or at a limited distance from it.

A Metal-cutting Jig-sawAnother gadget is the drill-arm which has

a lever feed, the lever remaining out of theway when the arm is used for other purposes.A further gadget, fitting into this arm is theupper half of a metal-cutting jig-saw, whereit is secured by a set-screw. Adjustable *tension on the saw blade can easily be obtained by raising or lowering the auxiliarybed. This head contains the spring whichpreserves the tension on the saw bladeduring its return stroke. It also has a 1)plunger which provides a blast of air at thepoint of sawing, thus keeping the workclear of cuttings. An adjustable rod,carrying a spring foot and roller saw guide,is inserted in the bracket, immediatelyalongside the head.

,+!

(To be continued)

April 30, 1942 421

* Mr. J. W. Pattison

Designs a Lathe -and some Gadgets for it

.a THE lower half of the jig-saw is a casting,enclosing a disc crank which imparts a1-1/4-in. stroke to the saw. Supported by it is

B a table which may be tilted and clamped ata n y convenient angle. The unit is securedto the lathe bed by a single bolt passingthrough a hole drilled therein. The upperhalf is brought into register with it by some

;B definite marking on the auxiliary bed. In

., * Continued from page 396, M.E., April 23,1942.

this way, the set-up should only be the workof a moment.

For sawing out intricate shapes in sheet metal the jig-saw is idea!, and any materialmay be sawn, if a suitable blade or knife isemployed. Wood, bakelite, fibre, etc., maybe sawn, and such material as cloth, cut witha knife blade. By using the lower half of themachine alone with a sabre saw in its chuck,intricate shapes may be cut in thickermaterials and should be useful in patternmaking.

i

4.

JIG SAW ffEAARM TO CARRY

DR/L 1 HEAD.

SPRING FOOT

RISING & FALLING

CIRCULAR SAW

O/A TO FIT AUX SADDLE

!-/II

Universal arm shown carrying jig-sawhead, together with circular saw and

jig filing machine.

WORKSHOP 422 THE MODEL ENGINEER

By removing the saw clamp, the remainingexposed socket becomes available for smallmachine files. With the mechanism set tothe bottom of its stroke. there is plenty ofroom to swing the circular saw into position.Either metal or woodcutting saws may beused and the swing movement of the sawarm is, the equivalent of a rising and fallingtable ; and added to this, there is the tiltingmovement of the table itself. An adiustable

suggesting that it would be amply strongenough to perform this task.

There are numerous other uses to whichthe machine and its gadgets could be put,.

fence is clamped to the front edge of thetable, and two slots are included for use withan angle-gauge. With a gap-piece removedfrom the centre of the table, it would appearpossible to attempt even surface grinding,although its scope would obviously belimited.

, Universal drilling andmilling machine boredto carry any of therotatable tools. Simi-

larly, a small faceplateor slotted table or any-

thing fitted with a 1 in.dia. holding - piece

could be mounted.

The other gadget is a universal millingslide and needs little description, except tomention that the gib-piece is adjusted byfour screws and may be locked by a handledclamping-screw. It will, of course, carryany of the rotatable tools, being bored outI in. diameter for that purpose. Besides theuses to which the above gadgets can be put,it would appear possible to do a little planingon anvthing mounted on the boring table,either-by moving the work mounted thereon against a tool held in the auxiliary saddle, orby swinging the auxiliary bed radially. Thislatter experiment suggests, also, that with asuitable clapper-box the tailstock might beused as a shaper for anything within itscapacity, the large dimensions of the ram

as indeed there are-many more gadgetswhich could be added. until the machinebecame a veritable concentrated machine-shop ; but as these appear to be never-ending, imagination must be left to thereader to think them out for himself.

Amateur T o o l m a k i n g(Continued from page 420)

edges just down to the cutting edges, nomore and no less. Painting the lands with plumbers black or red lead facili-tates the accuracy of this filing operation.After heat treatment, touch up the cuttingedge flats and the flutes with Carborundumoil slips, and again you have quite a pro-fessional-looking job.

Twist DrillsAgain flute a piece of silver-steel or reduced

stock of desired diameter with two flutes, asalready described for taps and reamers andfinish by grinding, but flute a longer lengththan that-required for finishing. Grippingthe shank of the work tiehtlv in the chuckof the lathe and the other end in the tailstockchuck, form the twist, working back thetailstock to keep the work straight. Removethe damaged fluted part and, after straighten-ing and grinding the point, the drill is-readyfor hardening and tempering. Sizes betweenabout 1/8in. and 5/16 in. can be successfullymade, but the absence of lands makes thesehome-made drills unsuitable for very deepdrilling, as they tend to bind.

Heat TreatmentA muffle furnace is a very useful adjunct

. _ ___.__.__ _.-.

for the amateur toolmaker. Procure half adozen firebricks approximately 4 in. x 6 in.x l in. and secure four together withclamping straps to form a chamber approxi-matelv 4 in. wide, 2 in. deep and 6 in. longand secure another of the bricks to close oneend of the chamber. With an old hacksaw,cut strips from the remaining brick to layacross the bottom of the chamber to supportarticles being treated.

Mount the whole on a suitable standapplicable to your gas burner or blowlamp,as the case mav be. With a half-Dint size ofthe latter, taps, dies, reamers, etc., up to1/2 in. can be satisfactorily hardened andtempered, and, of course, the muffle issuitable for many other heat treatment jobs.The residual heat at the back of the muffleprovides all that is required for temperingsmall tools at a temperature uniformthroughout in their mass.