The Multimachine $150, 12" Swing, MetalLathe/Mill/Drill
Author: Pat Delany
The Lucien Yeomans “secret” that was almost lost.
Metalworking lathes are necessary to the production of almost everything but are very expensive. In1915, special lathes made from concrete were developed to quickly and cheaply produce millionsof cannon shells needed for World War I. Lucien Yeomans, the inventor, won the nation's highestengineering award for it but sadly the technique was almost forgotten after the war. We re-discovered it as a way to quickly make inexpensive but accurate machine tools for use indeveloping countries and in trade schools and shops everywhere.
Step 1 — The Multimachine $150,12" Swing, Metal Lathe/Mill/Drill
Bottom-up development for emergingeconomies: Making machine toolsaccessible to the developing world with aconcrete lathe that can be easily andinexpensively built. The machine tools thatfueled the Industrial Revolution in theWestern World have become too expensiveto be used in the places that most needsmall industries now. This concrete lathecan change that. Based on a proven early20th-century design, it can be made in anysize and the same techniques can be usedto make many different kinds of machinetools.MAKERS NEED METAL LATHES ANDMILLING MACHINES TOO!Easily made from scrap, steel bar andconcrete mix. Built using common handtools, a drill along with a few small welds.Easily converted to drilling and milling.Lathe cost is determined by the kinds ofgood junk you have available. The only"new" stuff needed could be a few sacks ofconcrete mix and some of the non-shrinkinggrout used by tile workers.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 2A metal lathe or metalworking lathe is alarge class of lathes designed for preciselymachining relatively hard materials. Theywere originally designed to machinemetals; however, with the advent of plasticsand other materials, and with their inherentversatility, they are used in a wide range ofapplications and a broad range ofmaterials. This is a 100-year-newer,industrial version of the type shown belowbut this one, ours and the one below allwork in exactly the same way.METAL LATHES ARE THE ESSENTIALTOOL IN PRODUCING ALMOSTEVERYTHING!Ours COULD be made in a size that woulddwarf this one.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 3Our idea started with this. What LucienYeomans did in 1915 (and we also do) isextremely simple. It is well known thatconcrete shrinks as it sets up. This is notimportant when you pour your sidewalk butthis shrinkage would force a concretemachine tool out of alignment as theconcrete casting dried. He solved thisproblem by casting a concrete frame or“bed” with oversize cavities where the partswould normally go and then let the concreteseason and shrink. He would then align themetal parts and hold them in place bypouring a non-shrinking, low-temperaturemetal alloy over them.In our version the component size is similarto a typical 250kg 225mm swing lathe but ithas the capacity to mount a grinder that canbe used to re-surface 300mm diameterclutches and brakes. It was specificallydesigned to be transportable so it could betaken to Maker Faires and could also beused in rural areas of developing countries.A better choice for many would have ways300mm between centers and a 400mmswing. Other parts could be scaled upaccordingly and would add little to the totalcost. A larger lathe would be even easier tobuild since there would be more room forcomponents.The foreman's top hat is the official projecthead gear and logo!
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
We use the long-proven Yeomanstechnique or a small variation of it foralmost every part of our lathe:Fitting the ways to the bed.Fitting the “shoes” to the ways and thecarriage and then grouting them together.Fitting the cross slide to the carriage.Fitting the tail stock to the ways.Fitting the Morse Taper socket in the tailstock.Fitting the spindle cartridge to theheadstock.Fitting the thread follower spindle cartridgein the head stock.
Every part of our lathe can be replaced asparts wear or as improvements are needed.The all-thread type lead screws can bereplaced by Acme type.Spindle bushings can be replaced by ballor roller bearings.The carriage can be a milling or boringtype.A compound slide can be added.CNC or change gear type threading couldreplace the simple “thread follower” type.Steady- and follow-rests can be be added,as can a turret tailstock.The box type cross slide can be replacedby a dovetail type machined on the latheitself.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 6The goal: not the best tool, but one that willwork with reasonable accuracy and thatcan be built by a skilled mechanic usingcommon tools and at the absolute lowestcost.This is my effort to get prototypes built. I am76 and can't walk well anymore so I can'tbuild one to take pictures of. Since I cannotbuild one, I designed the lathe as a simplecombination of long-proven technologies.The machine is based on 5 ideas that havebeen around for nearly a hundred years orare obvious to someone who works withmachines. They are:The Yeomans concrete technique.The cartridge type spindle assembly.Carriage mounting shoes that areconnected only by concrete.Supported round ways.Thread-follower threading with woodenclamp jaws that close on a thread that is tobe duplicated.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 72 pieces of round, straight steel pipe or barfor the "ways" (the round shiny things thatthe carriage slides on).Steel bar for the cross slide.Scrap pieces of angle iron and pipe for thespindle cartridge, carriage frame andsupports for the ways.Junk pistons to be melted and cast intoadapters and bushings or bearinghousings. Casting simple shapes is veryeasy and gives the machine builder theability to make thousands of different,useful devices or products.Concrete mix, re-bar, fiber additive forconcrete and non-shrinking grout.These are the materials needed to build a300mm swing (maximum length that wouldfit on the faceplate) screwcutting lathe thatwould fit on a workbench. A desktop lathehalf this size could also be built. Ouroptimal “shop size” lathe would have ways300mm (centers) apart, swing of 450 mmand would weigh at least a thousandpounds. A lathe the size of a railroad carcould be built using the same basic design.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Steel for the ways will probably require acareful search. Needed are (2) 40mm x 1.5meter (approx) very straight steel rods orpipes (scrap hydraulic cylinder piston rods?) Check them for straightness by putting theround bars or pipe side by side and shininga bright light between them as you firstrotate one, then the other.A known-good lathe could be used to turnthe ways round and straight. If you do haveways turned, be sure to check the waysvery carefully afterwards becausemachining a long piece to an accuratediameter can be difficult.Imperfect ways can (slowly!) be correctedby the "3 rounds" method that can be foundat:http://concretelathe.wikispaces.com/Curr...
The cross slide can be made using 3pieces of steel of different widths or built ina more simple version that requires steel ofonly one width (150mm by 19mm). The 3-piece design is superior because wear iseasily adjusted for but it may require cuttinga piece of heavy plate to a more narrowwidth, a job that would be very difficult formany machine builders.Finding used steel bars may be difficult.Whatever your source of bar, be certain thatthe ends have been sawed and notsheared. Shearing distorts the bar ends.A more simple way of building the slide willbe shown on slide 59.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 10Besides the pipe and bar, shorter pieces ofsteel angle iron and pipe will be needed.The sizes of these shorter pieces dependon the diameter of the ways and thedistance between the ways of the machineyou are going to use.Used pistons will be a source of metal forbushings and adapters because pistonmetal alloy has been proven durable insteel engine cylinders.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 11Building the wooden form and casting theconcrete bed comes first.Next comes installing and aligning theways. A carefully-held spacer can be usedto set the distance between the ways. Apiece of float glass plate can be used to putthe ways in the same plane. A ball bearingon the plate glass can make the ways levelenough for our use here.Making the carriage shoes (the parts thatactually slide on the ways) and firmlyclamping them in place is next because theform for the concrete carriage is builtaround them. Firmly clamping the carriageshoes to the ways before pouring thecarriage concrete will align the carriagewith the ways.Fit the form for the carriage around theshoes and pour concrete. Let it season.If necessary, make a temporary lathe out ofan auto wheel hub assembly mounted onthe headstock and use it to machinespindle bushings or bearing adapters.Later, mount the hub assembly on the rearof the headstock and use it as a spindlebrake.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Make the spindle cartridge assembly,clamp it in place and align it with a dialindicator mounted on the carriage. Groutthe spindle assembly in place. A dialindicator used to measure from the left, rightand center of the carriage can be used toalign the spindleBuild the cross slide, mount it on thecarriage, align it with a dial indicatormounted on the spindle then grout and boltit in place.The tailstock is made in the same way asthe carriage (though in a different shape!).A Morse Taper drill bit held in the spindlecan be used to align the Morse Tapersocket in the tailstock.Add the smaller parts like the lead screwand handwheel mechanism, pulleys, motor,thread follower and tool post.
If you or people you know are interested ininternational development, tell them aboutthis. And please let me know if you do.If you decide to build one, please take lotsof pics for us.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Rule #1 is to PAY INFINITE ATTENTIONTO DETAIL! If you don't, errors willcompound and you will end up with anexpensive boat anchor!Build a mock-up first (especially of thecarriage). Know the source of every bolt,nut and nail. Don't make a stupid mistakewith something that is this big and heavy.
The completed form will look like this.
Materials can be as simple as pallet woodand cardboard or plastic tubing.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Detail of inserted plastic tubes and bolts.The vertical tubes must be large enough topour grout through later.
Pour the concrete, embed the waystabilizer bolts and then add the concreteneeded here. The way stabilizer baseshown here should actually extend the fulllength of the bed except for a gap that willbe used as a coolant drain and to removechips.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The Ways: The ways are the most criticalcomponent of an accurate lathe. Selectionof the steel and accurate alignment are all-important. Yeomans' lathe used speciallyground and hardened round bars thatwould be too expensive for our machines.Pipe should be made more rigid by filling itwith non-shrinking grout. If your budgetallows for machining the ways in anexisting lathe then certainly do it but don'texpect perfect results because many latheswill be too worn to machine the way to theexact size over its entire length.Pipe, round bar and hydraulic piston rodscome in a great variety: Imperial, metric,straight, bent, chrome plated, rusty, etc. Youwill need 2 the same size. Any steel mustbe checked for straightness. A good way todo this is to put the 2 pieces side by side,rotate one while pressed against the otherand use a feeler gauge or bright light frombehind to check for a gap.
The way ends are very tightly wrapped ingreased sheet metal so that the ways canlater be rotated to unworn areas ifnecessary. The sheet metal should betightly kept in place by wire or hose clamps.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Strong support under the ways makes theuse of round ways practical.The angle iron and bar stock should be theheaviest that will fit.
Round ways are used here because theycan be more easily and accurately madethan other possible choices. However, theymust be supported from below to avoid sagand vibration.
Start with a square-edged way support andonce the lathe is running use a flycutter tomachine a heavier (1/2”, 12mm or larger)bar to fit the radius of the way. The inneredge of the support bar should be at thecenter of the way. Heavier supports couldbe especially useful near the chuck wherethe heaviest cuts will most likely be made.If the lathe (and carriage) is large enoughso there is little danger of the carriagebeing lifted by cutting or knurling forces, nocarriage clamp is necessary. This will allowthe use of even thicker (radius-shaped25mm?) way supports in the event they arefound necessary to handle high horizontalcutting forces.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Insert the ways and lightly clamp in place.The supports under the ways are madefrom angle iron and steel bar. A longerlathe (recommended) should have fulllength way support. Round lathe ways willboth sag and vibrate but a rigid support likethis is a simple cure. After the machine iscomplete, the adjustment devices that arebolted to the concrete could be removedand used to build another lathe.
Great care must be taken in aligning theways but the process is actually quitesimple. A machinist-type level will makealignment much easier (this is aGrizzly.com $68 model, a great bargain) butyou can do without one if necessary. Use acarpenter's level to set the ways as level aspossible. Use a spacer between the waysto accurately set the separation betweenthe ways. This spacer must be kept level, atthe center and at exact right angles to theways. Build a bracket to hold the spacer ina consistent position. Use a dial indicator tomeasure the exact distance between theways.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Consider the thickness of a thin piece ofpaper as an accuracy goal. Use a thick,square piece of plate glass (float glass isbest) laid across the ways to check (with afeeler gauge) for even contact on all 4corners. Rotate the glass and check again(the glass plate may not be perfectly flat).Move the glass plate from one end of theways to the other to make certaineverything is correct. Adjust the waysupports for even contact under the ways.
The cross slide can be made in severaldifferent ways. The method shown requiressteel plate in 3 different widths which maybe hard to find in the developing world. Analternate way would be to invert theclamping device. Only 2 pieces of the steelthe same width would then be needed butcare would have to be taken to keep theexposed sliding parts free of steel cuttings.An accurately built carriage is critical tolathe accuracy and will take thought andcare in construction. I suggest you studythis section extremely carefully so that youwill be able to adapt components to thesizes of low cost materials that areavailable.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Using a pre-cast, seasoned concrete bed iscritical to the project and SO is the steelframe for the carriage. Most machinebuilders would find it difficult to build awelded or bolted carriage frame that wouldhave the vital even contact on the ways.We avoid the problem by making the framein 2 pieces, clamping them to the ways, andthen using concrete to fix the 2 sides inplace permanently.When the carriage is cast, the concretelinks the 2 pre-aligned sides together.
Another view.The cross slide lead screw could be eitheron the leading or trailing edge of the crossslide. If on the leading edge it is closer tothe center of cutting forces (good) and moresusceptible to chips from machining (bad).If used in the leading edge position, itshould have some kind of a plastic cover.
How everything goes together.Every fit is critical, however if things turn outpoorly you can just make a better carriageand swap it out.As long as the ways are accurately madeand aligned, everything else is made to beimproved upon once the machine runs andhas been well tested.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Top view.Actual dimensions are better seen in thehttp://concretelathe.wikispaces.com/Curr...Multimachine Concrete Lathe 11.27.11 ver.1.10.pdf
The bolts that hold the top slide down mustbe very strong (use cylinder head studs?)and should be welded to bars embeddeddeeper in the concrete than is shown.
The round ways are supported by a bar thatis slightly off center so that there will beroom for a carriage clamping device. Sincea flat surface can only contact a roundsurface in a very small area, we takeadvantage of this fact by using just theedges of two flat surfaces to support theways and to hold the carriage in place.Normally, cutting forces tend to press thecarriage downwards but occasionally theclamps will be very necessary.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
On a carriage for a lathe with shorterways.space saving techniques must beused. These clamp bolts fit into notchescast into the carriage. A longer carriage willbe easier to make because the clamps canbe external and the inner parts not socrowded together.
The way support bars and the carriageclamps meet at the center of the ways. Theway support bar should actually be shownas a heavy vertical support bolted to apiece of angle iron.The carriage is, in effect, pre-aligned. Thetwo shoes are first leveled and then firmlyclamped to the ways. They are notmechanically connected until concrete ispoured into the form so that it connects theshoes on each side. Any slight distortionfrom concrete shrinkage can be adjustedfor by putting shims between the shoe andthe bushings. The bushings should then belightly epoxied in place.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The width of the carriage is determined bythe space between the shoes and that isdetermined by the diameter of the pipeused for the shoes and the distancebetween the ways. The pipe can be splitwith a hacksaw or an angle grinder with acutoff disk. It is very important that length ofthe shoe should be between 1.5 and 2times the distance between the waycenters.The headstock has oversize cavities so thatlong shoes can slide inside if this provesnecessary to keep the optimal carriagelength/width ratio. Just extend the shoespast the clamp mounting tabs and adjustthe length of the grouted areas in theheadstock so that the longer shoes willslide inside the headstock.
These replaceable bushings are lightlyheld in place by a small spot of epoxy.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The carriage frame and shoes. The shoesare split pieces of heavy-wall pipe. Theinside diameter of the pipe should be about12mm to 25mm larger than the outsidediameter of the way. The bushings will takeup this space and could be made from castiron, bronze or piston metal alloy. Theholes in the tabs are used to mount theclamps that contact the bottom of the ways.These holes should be at least 12mm(1/2”). The welded-on cross bars (madefrom re-bar?) should be large enough tohave enough contact area so that they willnot flex.The placement of the drilled tabs andpieces of re-bar depend on the size oflathe. Adding a foot to the bed length willallow both a longer carriage and a longertail stock base. A longer carriage andtailstock will let you spread out the tabs andre-bar. The re-bar should be covered by atleast an inch of concrete at the side. Theconcrete should have a fiber additive mixedin. The larger carriage will makeconstruction easier and the carriageheavier and less likely to vibrate and causetool chatter.
Tab placement again. The safest way todetermine tab placement is to actuallymodel the shoes on the ways. The rear tabswill probably be much closer to the end ofthe shoes than is shown in the drawing.because they will probably have to extendpast the handwheel mechanism. (model it!)
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Where the welded re-bar pieces fit into theconcrete.You can see here that the internal clamps(needed on a short bed lathe) cause a littlecrowding.
Build the wooden form for the carriagebefore the way clamps are attached. Usethe clamp mounting tabs to support thecarriage (and tailstock) form.
Cast the concrete over the surface of theshoe in this area.Start the sides of the form at the bottomedge of the "shoe" that slides on the way.The tabs that are welded to the shoes makegood attachment points for wooden blocksused to hold the form in place.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 52Close in the edge of the form here. Use thewidest possible carriage width to supportthe base of the cross slide.Maximum cross slide support area isnecessary because the cross slidemounting bolts are closer together thanthey really should be. Every design is aseries of trade-offs, in this case the trade offis caused by having to surround the crossslide bolts with enough concrete so that itwill not crack if the cross sllde hold downbolts are over tightened.A fiber additive should be added to theconcrete mix and the concrete mixed formaximum strength.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 53For clarity, the concrete casting is shownwithout the embedded re-bar pieces thatare welded to the shoes. This particularcarriage design can be dropped over thelead screw so that it would be easy toreplace it with a different or specialized(milling, for example) carriage. Fourthreaded rods are used to mount the baseof the cross slide. These must be of verygood quality steel that is firmly anchored inthe concrete. Engine head studs would bea good choice here. They should be cut tothe proper length and welded to bars thatwill anchor them in the concrete below theembedded re-bar.On a small lathe, great care will have to betaken to fit the steel parts that come from 3directions! This was the only big problem Inscaling the Yeomans lathe down 95%!This "cut out" will not be necessary for along bed lathe that has externally-mountedclamps.The inverted "U" shaped cutout is usedonly if an easily-removed carriage isdesired.Cored holes should be placed so that themilling attachment and the base of thehandwheel mechanism can be connectedby pieces of all-thread.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
An overhead view of an externally-mountedway clamp.
The main lead screw is a piece of threadedrod that does not rotate. The carriage andthe tailstock are moved forward by turningnuts that move along the screw. The leadscrew is secured by nuts at the foot (end) ofthe lathe. The carriage and tail stock can bethe “drop on” type that is easily removedand replaced. The size of the lead screwcould be anything between 18mm and25mm for this 300mm swing version of thelathe.Backlash can be compensated for byadding 2 opposed spring (Belleville)washers and an extra nut. The mostcommon lead screw source is the all-threadrods found in metal shops and hardwarestores. Commercial all-thread screws with ablack finish seem to be of a higher quality.Cross slide lead screws can also comefrom auto seat adjusters and auto jacks.The quality of the leadscrews are vital tolathe accuracy. Replace the all-thread typewith higher quality screws if possible.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
This carriage mechanism is quite simple.Unlike most lathes that have complex"aprons" with many parts, this one just has5 simple parts that can be built using just adrill, hacksaw and file. The handwheel canbe replaced by a bicycle sprocket that latercan be linked to another sprocket in aneasier-to-reach location. Or, to get the latheup and running in a hurry (so it can make itsown parts), just make the mounting plate,add a nut that can be turned by a wrench tomove the carriage forward and heavysprings to pull it back.The clamp parts, grooved nut andhandwheel adapter could be easily madeat this stage. One side of the clamps(above) can be shimmed to reducebacklash in the carriage hand wheel clampdevice. The coupling nut could have alarger grooved hub pressed over It to makea larger clamp contact area. If a millingattachment is going to be added, the basecan be made longer so that a bolt can gobelow the leadscrew and connect to it tothe milling adapter.
The base plate of a 3-piece cross slide. It ismade at least 25mm more narrow than thepart above so that there will be clearancefor the slide clamps.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 58When grinding an optical flat (or other kindof flat), three disks are used. Let's call them"A", "B" and "C". Put A on B with some finegrinding compound. Grind until a frostedfinish is seen on both surfaces. Now do thesame with B on C. Now repeat with C on Auntil the surfaces have 100% contact.Repeat this process until it takes little (orno) work to get 100% surface contact in allthree combinations. The surfaces will thenbe very flat. It works on steel as well as onglass.How does it work? A on B results in aspherical surface, B on C results in a lessspherical (closer to flat) surface, C on Aresults in an even closer to flat surface aftergrinding. Each pass results in flatterspheres. If A is concave, B is convex and Cis concave. When A and C are ground toeach other, they hit the high points first.Now either A or C is concave and the otheris convex. Grinding both against B resultsin the flats being averaged. Eventually theyare flat enough. Gravestones andmonuments are often VERY flat. Theymake good layout tables!The plate edges are also important sincethe clamps are screwed to them. Edges ofhot-rolled steel plate are not flat and thishas to be corrected since clamp parts arescrewed to them. Carefully file the edgesflat while constantly checking with asquare. Keep flipping plates over and end-for-end while checking them side by sideuntil you get them filed to identical widths,with parallel sides and flat edges. Thanksto Dave LeVine for this.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Mounting holes are counter bored 25mm forthe nuts that hold it down.
The top slide should be at least 1.5 timesas long as it is wide in order for it not to jamwhen it is advanced under pressure.
An easily made slide adjuster. The arrowpoints to a cut in the steel bar. The outerpart of the bar is threaded and as the screwis tightened it bends the thinner part of thebar in toward the cross slide. The brass baris optional.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Another way to build machine slides is toinvert the clamp. This lets you build thecross slide assembly using just two piecesof steel of the same width. This may bemore economical and in some areas mightbe the only way practical. Thedisadvantage is that metal particles frommachining may get between the clamp andthe slide. Leather wipers attached to theedges of the top pieces of the clamp shouldhelp with this. Wear could be adjusted forby judicious filing or adding a thin shim.A common way to build something like thisis to fit it a little too tight and add very thinshims to make things move smoothly. Theshims can be removed as the parts wear inand play develops. Another difficulty withinverted clamps is that an additional“compound” slide is made harder to mountbecause of the more narrow mountingsurface. A temporary, light-duty clampcould be made from carefully fitted angleiron.
Cross slide alignment: Use the dial testindicator to measure from the end of thespindle to the top and the edge of the crossslide is it is moved from one end to theother. Be certain that the spindle does notturn as you do this.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 64Building any kind of a low cost machinetool takes a lathe of some kind. Thealuminum or zinc/aluminum alloy castingscould be turned on a good wood lathe but itwould be much easier to use your concretelathe bed and carriage as a "temporary"lathe. Huge savings are possible by castingand turning your own bushings andadapters.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 65A great many front wheel drive and fourwheel drive vehicles (but not all), use acomplete spindle assembly which includeswheel bearings, wheel mounting studs, andmounting structures.Be aware that some are held together by acenter bolt; often the end of a stub axlewhich is splined. The splines do not matter.The mount can go into the concrete (if thebolts are put in place first), and thefaceplate can mount where the brake andwheel did. The old stub axle can completethe drive system.While this will not make a hollow spindle(one with a through hole for longworkpieces), it is a fine spindle for makingthe relatively short pieces for a goodspindle capsule and for pulleys.Using cast aluminum pulley blanks, youcan make drive and reduction pulleys for"serpentine" belts (multi-groove type Kbelts are common in automobiles) whichhave lower losses and less slippage thanmore common "V" belts. The pulleys aresimple if you can grind a 40-degree tooland the belts can be run "inside out" forinitial machining of the final drive parts.While building a lathe to make a lathe is notthe only way to make a good lathe, it isoften beneficial and the less-desirable lathecan still be used to do maintenance whenthe better lathe is finished. While it lacks alot of utility (like the ability to turn longworkpieces), it is much better then no lathe.If the spindle used a disk brake, reversingthe disk makes a good faceplate and, if the"hat" is deep enough, a cup chuck.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
This is typical of a drum brake setup usedon many vehicles. The drum will come offthe spindle without too much trouble inmany cases. Reverse the drum, add screws(for jaws) and a simple 3- or 4-jaw "cupchuck" can be made. As with the priorspindle design, while it is far from perfect itwill work to make parts and train operators.Machining pressure plates, brake rotors,etc. does not need a hollow spindle.
Many kindle of lathe spindles can be usedbut for our purposes they should all beenclosed in an outer pipe "cartridge" thatcould be embedded in concrete after it isaligned.
The outer part of the spindle cartridge canbe made from a piece of pipe (like the outerpart of a hydraulic cylinder), bushings youcast yourself out of piston metal, a thrustdevice to keep the spindle from movingback and forth and a hollow or solid spindle(like the piston rod of a hydraulic cylinder).The whole assembly is first aligned in theheadstock and then (naturally) locked inplace by pouring in non-shrinking grout.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The outer tube protects the spindle andbushings from the concrete. If the outer tubeis large enough, the bushings can later bereplaced with ball or roller bearing adaptersso that a higher speed spindle can replacethe initial slower speed bushing typespindle. Adjusters are shown here but thefront adjuster could be replaced with a steelwasher between the bushing and the chuckbackplate, and the rear adjuster replacedwith a simple steel collar that could bemoved in order to eliminate end play.
Spindle lubrication: On the main and on thethread follower spindle bushings, cut an “O”ring groove here. Drill and tap the outerbody of the cartridges for a 90-degree fittingfor an oil line and grout the oil line in placewith the spindle.
The "universal" shape for for every castingused on the lathe. It can be used for spindlebushings, ball or roller bearing housings,adjusters and a chuck back plate. It is verysimple and easily cast.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The chuck back plate (mount) is seeminglysimple, but if you have to buy one it couldcost more than the lathe itself! If you makeyour own, the two most common choicesmay be either a piece of cast iron that couldbe turned down to size or to make one froman aluminum casting. A cast aluminumback plate should have two clamp boltsand nuts (not tapped) on each side and anadded steel safety collar. The hub will haveto have a large enough diameter so thatthere will be clearance for the nuts.
Use an old flywheel as a combinationfaceplate and chuck.A slow speed lathe drive could be a shaftwith a starter pinion gear and the flywheelring gear.
A simple clamp like this can be used on theflywheel/faceplate.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
A scrapped hydraulic cylinder couldprovide both the spindle and the outer partpf the spindle cartridge.The piston rod should be at least 37mm (50to 100mm is much better) in diameter. Itshould be 200mm longer than theheadstock.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
An original Multimachine spindle designthat is heavy duty and very accurate. Youmay recognize it as the common bicyclefront axle type. Spindle size could be basedaround the sizes of inexpensive automotivetapered roller bearings.This type of spindle will require moremachine work but, if this spacer was boredon the ends to accept the outer part of theroller bearings and then used as the outerpart of the bushing-type spindle cartridge,the simple bushing-type spindle could bemade to "bootstrap" this more complex,high-speed spindle at very low cost.A bushing type spindle should be replacedby a ball or roller type if the lathe is to getmuch use as a milling machine sincemilling speeds are higher than normal(home-made) lathe spindle speeds.
An accurate home-built chuck. Plans are athttp://concretelathe.wikispaces.com/Curr...
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Temporarily, the adjuster could be replacedby the sprocket hub if a steel washer wasused between them.
Spindle alignment. Slide the spindle so atleast 8” sticks out the front of the headstock,then use a dial test indicator to measure tothe spindle to both sides and the center ofthe carriage as the carriage is movedforward and backward. After the spindlehas been accurately aligned, pour in thegrout to lock it in place. This makes thespindle parallel to the ways, which is all-important.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The headstock, spindle andflywheel/faceplate assembly can be assimple as an inverted engine block, crankand flywheel that has had the main bearinginserts carefully drilled and the mainbearing caps drilled and tapped for greasefittings. A lathe with a 600mm to 900mm (orlarger) swing could be easily made thisway. Just remember that the largestYeomans shell-making lathe weighed 9000Kg, so scale accordingly!An engine block headstock shouldprobably kept at under 200 rpm since thebearing inserts were meant to be used witha pressurized oil system. Grease every fewhours at first until you make sure thatnothing overheats.
The thread follower chuck rotates at thespindle speed and is driven by bicyclesprockets and chain. An idler should beadded so that the chain can be adjusted orremoved when not needed. There is a limitto bicycle chain speeds so use amotorcycle chain for speeds much over 70RPM (which is 3 times the speed youshould start threading with anyway).To cut a thread, a sample piece of threadedrod is held by the follower chuck and ismanually clamped in the wooden or plasticblock clamp that is attached to the carriage.This pulls the carriage at the proper speedfor cutting a duplicate of the sample thread.The follower spindle cartridge is firstaligned and then grouted into theheadstock.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The thread that is cut could be unusuallyaccurate because the wooden block shouldaverage out imperfections in the sampledthread. Special note: Threading on a lathealways requires practice even if you usethe best equipment. Threading usuallytakes multiple passes with the threadingtool. Our device will require extra practiceto learn how to “pick up” the existing threadon subsequent passes but this should notbe too difficult because the wooden clampcan be “eased on” instead of suddenlyengaged.You won't find a device like this describedanywhere else but I have built and usedone on the original Multimachine. Thefollower spindle should have an oil line runto it as was described for the main spindle.Half-inch water pipe is about 5/8” ID so this,2 bushings and a piece of 12mm rod eitherthreaded or epoxied into a discarded drillchuck should work well.Compressed air help will be needed if thisis to be used on a large lathe. An aircylinder could be used the clamp the threadfollower and a carefully regulated aircylinder used to add a little push to theother side of the other side of the carriage
The tailstock has a frame that is exactly likethe carriage. Except for the difference inshape, construction is similar.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
An all-thread coupling nut can be cut in thisway and then be pressed slightly closed inorder to reduce backlash to a minimum.
If you use a Morse Taper socket, a slotshould be cast into the tailstock concrete sothat a wedge can be used to knock loose aMorse Taper tool. Naturally, the slotsshould line up! Something should bewelded to the back of the MT socket orgrooves cut into it so it will not turn or pullloose from the grout.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
A J.V. Romig milling cross slide design. Wemount it vertically instead of horizontally .Original plans for this design are bench-mill.pdfat:http://concretelathe.wikispaces.com/Curr...
Dimensioned plans;Chucks and clamping devices;Cutting tools and fluids;And more are at:http://groups.yahoo.com/group/multimachi...
Several lathes are about to be built but arenot yet at the photo stage.Be careful; work safely!
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Really study everything at the wiki sitebefore you start this!
The goal is to make a workpiece like thisusing the Multimachine lathe, an accessorypowered spindle and no extra (veryexpensive) vises or chucks.See the part being made by a half milliondollar machine at:http://www.youtube.com/watch?v=139z62o6O...Why would you need something thiscomplex? An otherwise unobtainable partor an experimental device that would be tooexpensive to have made.
You could almost do it with this Versa-mil.This $10,000 device used to be availableand could have done many of the neededoperations. The manual for this wonderfulmachine is in the Multimachine newsgroup"files" section.Our job is to do it for 50 bucks.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
For full access to the workpiece, thecarriage should be low enough to fit belowit and be wide enough to mount a 12"powered auxiliary tool so that it can reachthe the side of the workpiece.
The cross slide mount for the poweredspindle.
Rear view.The base is simply clamped in place.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The front end of the piston-metal castingthat is used for the spindle housing. Oilholes will have to be added. This end isbored to fit a solid Morse Taper socketadapter.As the housing wears it can be replaced orbored out so a bronze bushing could befitted.
The back end of the spindle housingshould be bored to the size of shaft that ispinned in the back of the Morse Tapersocket.These sockets are usually hardened so therear of the socket will have to be annealedso that it can be drilled for the cross pin.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 103The spindle could be a solid Morse tapersocket that has been drilled to accept apinned shaft that has been turned down onthe end to fit the drill chuck.The MT socket could be replaced by asimple steel cylinder if necessary. It couldbe made longer and a drill chuck or millingcutter could be retained by a large setscrew. The common Weldon flat is used forthis purpose in many tooling schemes.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 104The spindle must be able to move in everydirection to reach the front and side of theworkpiece, The spindle needs at least75mm of vertical travel, to tilt up and downat least 45 degrees and move in and out atleast 75mm. It also needs at least 1/2 hp topower larger mills and drills. The onlyeconomical solutions are air-powered drillmotors that can run at both high and lowspeeds.These drill motors will require a LARGEvolume of compressed air for many kinds ofwork and especially with a steel workpiece.A good choice for some may be a relativelysmall air compressor and a very large airtank bought as scrap. However, with thissetup it may take a long time to getsufficient air pressure for a big cutting job.Another choice could be a variable speedelectric motor but this would be bothexpensive and hard to mount. A frame 48,3600 rpm motor and a VFD would be agood choice for a larger lathe and auxiliaryspindle combination but could easily costmore than the lathe itself.The most common solution will be avariable speed drill motor.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
It is my personal (only) opinion that lessthan expert machinists are likely to loseworkpiece accuracy if they have to move itbetween different kinds of machine tools. Ifyou have watched the MAZAK video youhave seen the power of doing many kindsof operations with just one machine tool.The MAZAK machine uses two chucks todo this. Our machine would require that thepart be reversed in the chuck and "dialedin" just once.If a four (independent) jaw chuck was used,the workpiece could be almost any shapeand could have almost any machiningoperation performed on it without much lossof accuracy.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
