The Multimachine $150, 12" Swing, MetalLathe/Mill/Drill
Author: Pat Delany
Tools used in this project$10 dial test indicator (1)A hand or electric drill (we have plans for a $5 drill that will work) (1)Mechanic's hand tools (1)
Parts relevant to this projectScrap, pipe, concrete mix and a very small amount of welding. (1)
The Lucien Yeomans “secret” that was almost lost.
Metalworking lathes are necessary to the production of almost everything but are very expensive. In 1915, special lathesmade from concrete were developed to quickly and cheaply produce millions of cannon shells needed for World War I.Lucien Yeomans, the inventor, won the nation's highest engineering award for it but sadly the technique was almost forgottenafter the war. We re-discovered it as a way to quickly make inexpensive but accurate machine tools for use in developingcountries and in trade schools and shops everywhere.
Step 1 — The Multimachine $150, 12" Swing,Metal Lathe/Mill/Drill
Step 2
Bottom-up development for emerging economies.Making machine tools accessible to the developingworld with a concrete lathe that can be easily andinexpensively built. The machine tools that fueledthe Industrial Revolution in the Western World havebecome too expensive to be used in the places thatmost need small industries now. This concrete lathedesign can change that. Based on a proven early20th-century design, it can be made in any size andthe same techniques can be used to make manydifferent kinds of machine tools.Easily made by a good mechanic using scrap, steelbar and concrete mix. Built using common handtools, a drill along with a few small welds. Easilyconverted to drilling and horizontal and end milling.Lathe cost is determined by the size of the machineyou build and the kinds of good junk you haveavailable.
Many people will not know what this machine isso...A metal lathe or metalworking lathe is a largeclass of lathes designed for precisely machiningrelatively hard materials. They were originallydesigned to machine metals; however, with theadvent of plastics and other materials, and with theirinherent versatility, they are used in a wide range ofapplications and a broad range of materials. This is a100-year-newer, industrial version of the type shownin the step below but this one, the one below andours all work in exactly the same way.METAL LATHES ARE THE ESSENTIAL TOOL INPRODUCING ALMOST EVERYTHING IN OURLIVES. Simply put, they are used to make almosteverything that is round and they also are used tomake the rollers that are used to make almosteverything that is flatOurs COULD be made in a size that would dwarf this1500 kg. machine.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Our idea started with this. What Lucien Yeomans didin 1915 (and we also do) is extremely simple. It iswell known that concrete shrinks as it sets up. Thisis not important when you pour your sidewalk but thisshrinkage would force a concrete machine tool out ofalignment as the concrete casting dried. Yeomanssolved this problem by casting a concrete frame or“bed” with oversize cavities where the parts wouldnormally go and then let the concrete season andshrink. He would then align the metal parts and holdthem in place by pouring a non-shrinking, low-temperature metal alloy over them.Our lathe design is similar to a typical 250kg 225mmswing (chuck capacity) lathe. Our lathe also has thecapacity to mount a common 100mm grinder thatcan be used to re-surface vehicle clutches andbrakes. Ours was specifically designed to betransportable so it could be taken to Maker Fairesand yet would also be highly useful in shops. Abetter choice for many would have ways 300mmbetween centers and a 400mm swing. Other partscould be scaled up accordingly and would add littleto the total cost. A larger lathe would be even easierto build because there would be more room forcomponents.Also, on this larger version, the head and tailstocksshould be enlarged and the lathe bed (base) shouldbe made at least 150mm thick.
We use the Yeomans technique or a related use ofconcrete or non-shrinking grout for almost every partof our lathe:Fitting the ways to the bed.Fitting the “shoes” to the ways and the carriage andthen grouting them together.Fitting the cross slide to the carriage.Fitting the tail stock to the ways.Fitting the Morse Taper socket in the tail stock.Fitting the spindle cartridge to the headstock.Fitting the thread follower spindle cartridge in thehead stock.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Every part of our lathe can be replaced as parts wearor as improvements are needed.The all-thread type lead screws can be replaced bythe Acme type.Spindle bushings can be replaced by ball or rollerbearings.The carriage can be replaced with special milling orboring typesA compound slide can (and should) be added.Electronic lead screw or change gear type threadingcould replace the simple “thread follower” type.Steady and follow-rests can be be added, as can aturret or powered tailstock.The box type cross slide can be replaced by adovetail type machined on the lathe itself.
The goal: not the best tool, but one that will workwith reasonable accuracy and that can be built by askilled mechanic using common tools and at theabsolute lowest cost.This is my effort to get prototypes built. I am 76 andcan't walk well anymore so I can't build one to takepictures of. Since I cannot build one, I designed thelathe as a simple combination of long-proventechnologies. The machine is based on 5 ideas thathave been around for nearly a hundred years or areobvious to someone who works with machines. Theyare:The Yeomans concrete technique.The cartridge type spindle assembly.Carriage mounting shoes that are connected only byconcrete.Supported round ways.Thread-follower threading with wooden clamp jawsthat close on a thread that is to be duplicated.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Step 72 pieces of round, straight steel pipe or bar for the"ways" (the round shiny things that the carriageslides on). THE WAYS ARE THE MOSTIMPORTANT PART OF THE LATHE so be verycareful as you select them. Good pieces of carefullyaligned railroad track could be used on larger lathes.Steel bar for the cross slide.Scrap pieces of angle iron and pipe for the spindlecartridge, carriage frame and supports for the ways.Junked pistons to be melted and cast into adapters,bushings or bearing housings. Casting simpleshapes is very easy and gives the machine builderthe ability to make thousands of different, usefuldevices and products.Concrete mix, re-bar, fiber additive for concrete andnon-shrinking grout.These are the kinds of materials needed to build a300mm swing (maximum length that would fit on thefaceplate) screwcutting lathe that would fit on aworkbench. A desktop lathe half this size could alsobe built. Our optimal “shop size” lathe would haveways 300mm (centers) apart, swing of 450 mm andwould weigh at least a thousand pounds. A lathe thesize of a railroad car could be built using the samebasic design.The length, diameter and width of the ways are thedetermining factor in the size of the lathe you build.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Steel for the ways will probably require a carefulsearch. Needed are (2) 40mm x 1.5 meter (approx)very straight steel rods or pipes (scrap hydrauliccylinder piston rods?) Check them for straightnessby putting the round bars or pipe side by side andshining a bright light between them as you first rotateone, then the other.A known-good lathe could be used to turn the waysround and straight. If you do have ways turned, besure to check the ways very carefully afterwardsbecause machining a long piece to an accuratediameter can be difficult.Imperfect ways probably could be slowly correctedby the "3 rounds" method that can be found athttp://concretelathe.wikispaces.com/Curr.... Themethod has not been tested on pipe this large. The 3rounds method is similar to the centuries old 3 flatsmethod of truing flat surfaces.
The cross slide can be made using 3 pieces of steelof different widths or built in a more simple versionthat requires steel of only one width (150mm by19mm). The 3-piece design is superior because wearis easily adjusted for but it may require cutting apiece of heavy plate to a more narrow width, a jobthat would be very difficult for many machinebuilders.Finding used steel bars may be difficult. Whateveryour source of bar, be certain that the ends havebeen sawed and not sheared. Shearing distorts thebar ends.A more simple way of building the slide will be shownon slide 66.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Besides the pipe and bar, a few shorter pieces ofsteel angle iron and pipe will be needed. The sizes ofthese shorter pieces depend on the diameter of theways and the distance between the ways of themachine you are going to build.Used pistons are a source of castable metal forbushings and adapters. Piston metal is an easilyavailable alloy has been proven durable running iniron engine cylinders.
Building the wooden form and casting the concretebed comes first. This is not complicated and a goodtutorial for this the "Make a concrete counter top"type of book available in home improvement stores.Next select, install and align the ways. A carefullyheld spacer can be used to set the distance betweenthe ways. A piece of float glass plate can be used toput the ways in the same plane. A ball bearingplaced on the plate glass can be used to determine ifthe ways level enough for our use since what isreally important is to insure that the ways parallelwith the spindle.Making the carriage "shoes" (the parts of thecarriage that actually slide on the ways) and firmlyclamping them over the ways comes next becausethe wooden form for the concrete carriage is boltedto and then built around them. Firmly clamping thecarriage shoes to the ways before pouring thecarriage concrete will align the carriage with theways, a task that will be very difficult otherwise.Fit the form for the carriage around the shoes andpour the concrete and let it season.If no wood or metal lathe is available, make atemporary lathe out of an auto wheel hub assemblymounted on the headstock and use it to machinespindle bushings, ball or roller bearing adapters.Later, mount the hub and brake assembly on the rearof the headstock and use it as a spindle brake.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Make the spindle cartridge assembly from 2 piecesof pipe with simple cast bushings used betweenthem, clamp it in place and align it with a dialindicator mounted on the carriage. Measure from theleft, right and center of the carriage. Pour groutthrough the holes in the top of the headstock to lockthe spindle assembly in place.Mount a square or a dial test indicator on the spindleand use it to align the cross slide.The tailstock is made in the same way as thecarriage (though in a different shape!). A MorseTaper drill bit held in the spindle can be used to alignthe Morse Taper socket in the tailstock.Add the smaller parts like the lead screw andhandwheel mechanism, pulleys, motor, threadfollower and tool post.
If you or people you know are interested ininternational development, tell them about this. Andplease let me know if you do.If you decide to build one, please take lots of pics forus.
http://bit.ly/Ht8vuiThe era of high speed steel cutting tools but beforethe time of tool stores, silicon carbide andcommercially available coolants.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Rule #1 is to PAY INFINITE ATTENTION TODETAIL!. If you don't, errors will compound and youwill end up with an expensive boat anchor!Build a mock-up first (especially of the carriage).Know the source of every bolt, nut and nail. Don'tmake a stupid mistake with something that is thisbig and heavy.THINK THROUGH EVERY STEP.
The completed form will look like this.
Materials can be as simple as pallet wood andcardboard or plastic tubing.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Detail of inserted plastic tubes and bolts. Thevertical tubes must be large enough to pour groutthrough later.
Pour the concrete, embed the way stabilizer boltsand then add the concrete needed here. The waystabilizer base shown here should actually extendthe full length of the bed except for a gap that will beused as a coolant drain and to remove chips.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Attach on the way adjusters. They can be cut fromscrap angle iron that could be tapped for adjustingbolts. locknuts should be added. If necessary, theadjusters could be replaced with hardwood wedgesbut accurate way adjustments would be much moredifficult.After the non-shrinking grout is poured in the waycavities and has a time to set up, the adjusters canbe removed and used to make other machines.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The Ways: The ways are the most criticalcomponent of an accurate lathe. Selection of thesteel and accurate alignment are all-important.Yeomans' lathe used specially ground and hardenedround bars that would probably be too expensive forour lathe. If you use pipe it should be made morerigid by filling it with non-shrinking grout. If yourbudget allows for machining the ways in an existinglathe then certainly do it but don't expect perfectresults because many lathes will be too worn tomachine the way to the exact size over its entirelength.Pipe, round bar and hydraulic piston rods come in agreat variety: Imperial, metric, straight, bent, chromeplated, rusty, etc. You will need 2 the same size.Any steel must be checked for straightness. A goodway to do this is to put the 2 pieces side by side,rotate one while pressed against the other and use afeeler gauge or bright light from behind to check for agap.
The way ends are very tightly wrapped in greasedsheet metal so that the ways can later be rotated tounworn areas if necessary. The sheet metal shouldbe tightly kept in place by wire or hose clamps.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Strong support under the ways makes the use ofround ways practical.The angle iron and bar stock should be the heaviestthat will fit.
Round ways are used here because they can bemore easily and accurately made than other possiblechoices. However, they must be supported frombelow to avoid sag and vibration.
Insert the ways and lightly clamp in place. Thesupports under the ways are made from angle ironand steel bar. A longer lathe (recommended) shouldhave full length way support. Round lathe ways willboth sag and vibrate but a rigid support like this is asimple cure. After the machine is complete, the 16adjustment devices that are bolted to the concretecould be removed and used to build another lathe.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Start with a square-edged way support and once thelathe is running use a flycutter to machine a heavier(1/2”, 12mm or larger) bar to fit the radius of the way.The inner edge of the support bar should be at thecenter of the way. Heavier supports could beespecially useful near the chuck where the heaviestcuts will most likely be made.If the carriage is is heavy enough (75kg ?), there isless danger of the carriage being lifted by knurlingoperations or a improperly adjusted cutting tool and acarriage clamp may not be even needed.A thicker (radius-shaped 25mm?) way support maybe needed to handle high horizontal cutting forces inthe area close to the chuck. The vertical way supportbolts should be laid out with this in mind. Save
Great care must be taken in aligning the ways butthe process is actually quite simple. A machinist-type level will make alignment much easier (this is aGrizzly.com $68 model, a great bargain) but you cando without one if necessary. Use a carpenter's levelto set the ways as level as possible. Use a spacerbetween the ways to accurately set the separationbetween the ways. This spacer must be kept level,at the center and at exact right angles to the ways.Make a bracket to hold the spacer in a consistentposition.If possible use a dial indicator mounted on thisbracket to measure way separation instead of relyingon the "feel" of how the spacer fits between theways.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Consider the thickness of a thin piece of paper as anaccuracy goal. Use a thick, square piece of plateglass (float glass is best) laid across the ways tocheck (with a feeler gauge) for even contact on all 4corners. Rotate the glass and check again (the glassplate may not be perfectly flat). Move the glass platefrom one end of the ways to the other to makecertain everything is correct. Adjust the waysupports for even contact under the ways.After the under the way supports are adjusted andtightened, repeat the alignment tests.
The cross slide can be made in several differentways. The method shown requires steel plate in 3different widths which may be hard to find in thedeveloping world. An alternate way would be to invertthe clamping device. Only 2 pieces of the steel thesame width would then be needed but care wouldhave to be taken to keep the exposed sliding partsfree of steel cuttings. This 2 plate method is shownin step 66.An accurately built carriage is critical to latheaccuracy and will take thought and care inconstruction. I suggest you study this sectionextremely carefully so that you will be able to adaptcomponents to the sizes of low cost materials thatare available.
Using a pre-cast, seasoned concrete bed is criticalto the project and SO is the steel frame for thecarriage. Most machine builders would find it difficultto build a welded or bolted carriage frame that wouldhave the vital even way contact on all 4 corners. Weavoid the problem by making the frame in 2 pieces,clamping them to the ways, and then using concreteto fix the 2 sides in place permanently.When the carriage is cast, the concrete links the 2pre-aligned sides together. A simple solution to anextremely difficult problem
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Another view.The cross slide lead screw could be either on theleading or trailing edge of the cross slide. If on theleading edge it is closer to the center of cuttingforces (good) and more susceptible to chips frommachining (bad). If used in the leading edge position,it should have some kind of a plastic cover.
How everything goes together.Every fit is critical, however if things turn out poorlyyou can just make a better carriage and swap it out.As long as the ways are accurately made andaligned, everything else is made to be improvedupon once the machine runs and has been welltested.
A commercial, dovetail type, compound slide thatcould be a model for yours.
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 must be verystrong (use cylinder head studs?) and should bewelded to bars embedded deeper in the concretethan is shown.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The round ways are supported by a bar that isslightly off center so that there will be room for acarriage clamping device. Since a flat surface canonly contact a round surface in a very small area, wetake advantage of this fact by using just the edgesof two flat surfaces to support the ways and to holdthe carriage in place. Normally, cutting forces tend topress the carriage downwards but occasionally theclamps will be very necessary.
On a carriage for a lathe with shorter ways.spacesaving techniques must be used. These clamp boltsfit into notches cast into the carriage. A longercarriage will be easier to make because the clampscan be external and the inner parts not so crowdedtogether.
The way support bars and the carriage clamps meetat the center of the ways. The way support barshould actually be shown as a heavy vertical supportbolted to a piece of angle iron.The carriage is, in effect, pre-aligned. The two shoesare first leveled and then firmly clamped to the ways.They are not mechanically connected until concreteis poured into the form so that it connects the shoeson each side. Any slight distortion from concreteshrinkage can be adjusted for by putting shimsbetween the shoe and the bushings. The bushingsshould then be lightly epoxied in place.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The width of the carriage is determined by the spacebetween the shoes and that is determined by thediameter of the pipe used for the shoes and thedistance between the ways. The pipe can be splitwith a hacksaw or an angle grinder with a cutoff disk.It is very important that length of the shoe should bebetween 1.5 and 2 times the distance between theway centers.The headstock has oversize cavities so that longshoes can slide inside if this proves necessary tokeep the optimal carriage length/width ratio. Justextend the shoes past the clamp mounting tabs andadjust the length of the grouted areas in theheadstock so that the longer shoes will slide insidethe headstock.
These replaceable bushings are lightly held in placeby a small spot of epoxy.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The carriage frame and shoes. The shoes are splitpieces of heavy-wall pipe. The inside diameter of thepipe should be about 12mm to 25mm larger than theoutside diameter of the way. The bushings will takeup this space and could be made from cast iron,bronze or piston metal alloy. The holes in the tabsare used to mount the clamps that contact thebottom of the ways. These holes should be at least12mm (1/2”). The welded-on cross bars (made fromre-bar?) should be large enough to have enoughcontact area so that they will not flex.The placement of the drilled tabs and pieces of re-bar depend on the size of lathe. Adding a foot to thebed length will allow both a longer carriage and alonger tail stock base. A longer carriage and tailstockwill let you spread out the tabs and re-bar. The re-barshould be covered by at least an inch of concrete atthe side. The concrete should have a fiber additivemixed in. The larger carriage will make constructioneasier and the carriage heavier and less likely tovibrate and cause tool chatter.
Tab placement again. The safest way to determinetab placement is to actually model the shoes on theways. The rear tabs will probably be much closer tothe end of the shoes than is shown in the drawing.because they will probably have to extend past thehandwheel mechanism. (model it!)
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Where the welded re-bar pieces fit into the concrete.You can see here that the internal clamps (neededon a short bed lathe) cause a little crowding.
Build the wooden form for the carriage before theway clamps are attached. Use the clamp mountingtabs to support the carriage (and tailstock) form.
Cast the concrete over the surface of the shoe inthis area.Start the sides of the form at the bottom edge of the"shoe" that slides on the way.The tabs that are welded to the shoes make goodattachment points for wooden blocks used to holdthe form in place.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Close in the edge of the form here. Use the widestpossible carriage width to support the base of thecross slide.Maximum cross slide support area is necessarybecause the cross slide mounting bolts are closertogether than they really should be. Every design isa series of trade-offs, in this case the trade off iscaused by having to surround the cross slide boltswith enough concrete so that it will not crack if thecross sllde hold down bolts are over tightened.A fiber additive should be added to the concrete mixand the concrete mixed for maximum strength.
For clarity, the concrete casting is shown without theembedded re-bar pieces that are welded to theshoes. This particular carriage design can bedropped over the lead screw so that it would be easyto replace it with a different or specialized (milling,for example) carriage. Four threaded rods are used tomount the base of the cross slide. These must be ofvery good quality steel that is firmly anchored in theconcrete. Engine head studs would be a good choicehere. They should be cut to the proper length andwelded to bars that will anchor them in the concretebelow the embedded re-bar.On a small lathe, great care will have to be taken tofit the steel parts that come from 3 directions! Thiswas the only big problem In scaling the Yeomanslathe down 95%!This "cut out" will not be necessary for a long bedlathe that has externally-mounted clamps.The inverted "U" shaped cutout is used only if aneasily-removed carriage is desired.Cored holes should be placed so that the millingattachment and the base of the handwheelmechanism can be connected by pieces of all-thread.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
An overhead view of an externally-mounted wayclamp.
The main lead screw is a piece of threaded rod thatdoes not rotate. The carriage and the tailstock aremoved forward by turning nuts that move along thescrew. The lead screw is secured by nuts at the foot(end) of the lathe. The carriage and tail stock can bethe “drop on” type that is easily removed andreplaced. The size of the lead screw could beanything between 18mm and 25mm for this 300mmswing version of the lathe.Backlash can be compensated for by adding 2opposed spring (Belleville) washers and an extra nut.The most common lead screw source is the all-thread rods found in metal shops and hardwarestores. Commercial all-thread screws with a blackfinish seem to be of a higher quality. Cross slide leadscrews can also come from auto seat adjusters andauto jacks.The quality of the leadscrews are vital to latheaccuracy. Replace the all-thread type with higherquality screws if possible.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
This carriage mechanism is quite simple. Unlikemost lathes that have complex "aprons" with manyparts, this one just has 5 simple parts that can bebuilt using just a drill, hacksaw and file. Thehandwheel can be replaced by a bicycle sprocketthat later can be linked to another sprocket in aneasier-to-reach location. Or, to get the lathe up andrunning in a hurry (so it can make its own parts), justmake the mounting plate, add a nut that can beturned by a wrench to move the carriage forward andheavy springs to pull it back.The clamp parts, grooved nut and handwheel adaptercould be easily made at this stage. One side of theclamps (above) can be shimmed to reduce backlashin the carriage hand wheel clamp device. Thecoupling nut could have a larger grooved hubpressed over It to make a larger clamp contact area.If a milling attachment is going to be added, the basecan be made longer so that a bolt can go below theleadscrew and connect to it to the milling adapter.
The base plate of a 3-piece cross slide. It is made atleast 25mm more narrow than the part above so thatthere will be clearance for the slide clamps.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
An angle iron alternative to the split pipe shoe. Thebrass wear strips could be eliminated if necessary.
When grinding an optical flat (or other kind of flat),three disks are used. Let's call them "A", "B" and"C". Put A on B with some fine grinding compound.Grind until a frosted finish is seen on both surfaces.Now do the same with B on C. Now repeat with C onA until the surfaces have 100% contact. Repeat thisprocess until it takes little (or no) work to get 100%surface contact in all three combinations. Thesurfaces will then be very flat. It works on steel aswell as on glass.How does it work? A on B results in a sphericalsurface, B on C results in a less spherical (closer toflat) surface, C on A results in an even closer to flatsurface after grinding. Each pass results in flatterspheres. If A is concave, B is convex and C isconcave. When A and C are ground to each other,they hit the high points first. Now either A or C isconcave and the other is convex. Grinding bothagainst B results in the flats being averaged.Eventually they are flat enough. Gravestones andmonuments are often VERY flat. They make goodlayout tables!The plate edges are also important since the clampsare screwed to them. Edges of hot-rolled steel plateare not flat and this has to be corrected since clampparts are screwed to them. Carefully file the edgesflat while constantly checking with a square. Keepflipping plates over and end-for-end while checkingthem side by side until you get them filed to identicalwidths, with parallel sides and flat edges. Thanks toDave LeVine for this.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The cross slide lead screw could be a piece ofthreaded rod but parts from an old gear puller couldwork well since they usually have a fine thread andthe screw is hardened. Later you could make a nutwith a similar thread and use it with cupped washersto eliminate most end play.
Mounting holes are counter bored 25mm for the nutsthat hold it down.
Like this
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
use transfer screws to accurately align the baseplate and the 4 studs that are sticking up through theconcrete carriage. Screw these transfer screws partway into nuts and screw the nuts onto the ends ofthe studs. Align the base plate over the transferscrew pointed ends and tap with a hammer. Heavilypunch the first hole position, fit and align the plateand mark the remaining holes one by one. Deepenthese light marks with a regular center punch anddrill with a small pilot drill.Make your own transfer screws by epoxying short,sharpened pieces of an old Allen wrench into setscrews the same size and thread as the carriagestuds.If you use an endmill as a counter bore tool, do itafter each hole is bored and before the plate ismoved, otherwise the hole center will be hard tolocate.
The top slide should be at least 1.5 times as long asit is wide in order for it not to jam when it isadvanced under pressure.
An easily made slide adjuster. The arrow points to acut in the steel bar. The outer part of the bar isthreaded and as the screw is tightened it bends thethinner part of the bar in toward the cross slide. Thebrass bar is optional.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Another way to build machine slides is to invert theclamp. This lets you build the cross slide assemblyusing just two pieces of steel of the same width.This may be more economical and in some areasmight be the only way practical. The disadvantage isthat metal particles from machining may get betweenthe clamp and the slide. Leather wipers attached tothe edges of the top pieces of the clamp should helpwith this. Wear could be adjusted for by judiciousfiling or adding a thin shim.A common way to build something like this is to fit ita little too tight and add very thin shims to makethings move smoothly. The shims can be removedas the parts wear in and play develops. Anotherdifficulty with inverted clamps is that an additional“compound” slide is made harder to mount becauseof the more narrow mounting surface. A temporary,light-duty clamp could be made from carefully fittedangle iron.
Cross slide alignment: Use the dial test indicator tomeasure from the end of the spindle to the top andthe edge of the cross slide is it is moved from oneend to the other. Be certain that the spindle does notturn as you do this.
An alternative way of aligning the cross slide is touse a square.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
Building any kind of a low cost machine tool takes alathe of some kind. The aluminum or zinc/aluminumalloy castings could be turned on a good wood lathebut it would be much easier to use your concretelathe bed and carriage as a "temporary" lathe. Hugesavings are possible by casting and turning your ownbushings and adapters.
A great many front wheel drive and four wheel drivevehicles (but not all), use a complete spindleassembly which includes wheel bearings, wheelmounting studs, and mounting structures.Be aware that some are held together by a centerbolt; often the end of a stub axle which is splined.The splines do not matter. The mount can go into theconcrete (if the bolts are put in place first), and thefaceplate can mount where the brake and wheel did.The old stub axle can complete the drive system.While this will not make a hollow spindle (one with athrough hole for long workpieces), it is a fine spindlefor making the relatively short pieces for a goodspindle capsule and for pulleys.Using cast aluminum pulley blanks, you can makedrive and reduction pulleys for "serpentine" belts(multi-groove type K belts are common inautomobiles) which have lower losses and lessslippage than more common "V" belts. The pulleysare simple if you can grind a 40-degree tool and thebelts can be run "inside out" for initial machining ofthe final drive parts.While building a lathe to make a lathe is not the onlyway to make a good lathe, it is often beneficial andthe less-desirable lathe can still be used to domaintenance when the better lathe is finished. Whileit lacks a lot of utility (like the ability to turn longworkpieces), it is much better then no lathe.If the spindle used a disk brake, reversing the diskmakes a good faceplate and, if the "hat" is deepenough, a cup chuck.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
This is typical of a drum brake setup used on manyvehicles. The drum will come off the spindle withouttoo much trouble in many cases. Reverse the drum,add screws (for jaws) and a simple 3- or 4-jaw "cupchuck" can be made. As with the prior spindledesign, while it is far from perfect it will work to makeparts and train operators.Machining pressure plates, brake rotors, etc. doesnot need a hollow spindle.
Many kindle of lathe spindles can be used but for ourpurposes they should all be enclosed in an outer pipe"cartridge" that could be embedded in concrete afterit is aligned.
The outer part of the spindle cartridge can be madefrom a piece of pipe (like the outer part of a hydrauliccylinder), bushings you cast yourself out of pistonmetal, a thrust device to keep the spindle frommoving back and forth and a hollow or solid spindle(like the piston rod of a hydraulic cylinder). Thewhole assembly is first aligned in the headstock andthen (naturally) locked in place by pouring in non-shrinking grout.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The outer tube protects the spindle and bushingsfrom the concrete. If the outer tube is large enough,the bushings can later be replaced with ball or rollerbearing adapters so that a higher speed spindle canreplace the initial slower speed bushing type spindle.Adjusters are shown here but the front adjuster couldbe replaced with a steel washer between the bushingand the chuck backplate, and the rear adjusterreplaced with a simple steel collar that could bemoved in order to eliminate end play.
Spindle lubrication: On the main and on the threadfollower spindle bushings, cut an “O” ring groovehere. Drill and tap the outer body of the cartridges fora 90-degree fitting for an oil line and grout the oil linein place with the spindle.
The "universal" shape for for every casting used onthe lathe. It can be used for spindle bushings, ball orroller bearing housings, adjusters and a chuck backplate. It is very simple and easily cast.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The chuck back plate (mount) is seemingly simple,but if you have to buy one it could cost more thanthe lathe itself! If you make your own, the two mostcommon choices may be either a piece of cast ironthat could be turned down to size or to make onefrom an aluminum casting. A cast aluminum backplate should have two clamp bolts and nuts (nottapped) on each side and an added steel safetycollar. The hub will have to have a large enoughdiameter so that there will be clearance for the nuts.
Use an old flywheel as a combination faceplate andchuck.A slow speed lathe drive could be a shaft with astarter pinion gear and the flywheel ring 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 could provide both thespindle and the outer part pf the spindle cartridge.The piston rod should be at least 37mm (50 to100mm is much better) in diameter. It should be200mm longer than the headstock.
An original Multimachine spindle design that is heavyduty and very accurate. You may recognize it as thecommon bicycle front axle type. Spindle size couldbe based around the sizes of inexpensiveautomotive tapered roller bearings.This type of spindle will require more machine workbut, if this spacer was bored on the ends to acceptthe outer part of the roller bearings and then used asthe outer part of the bushing-type spindle cartridge,the simple bushing-type spindle could be made to"bootstrap" this more complex, high-speed spindle atvery low cost.A bushing type spindle should be replaced by a ballor roller type if the lathe is to get much use as amilling machine since milling speeds are higher thannormal (home-made) lathe spindle speeds.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
An accurate home-built chuck. Plans are athttp://concretelathe.wikispaces.com/Curr...
Temporarily, the adjuster could be replaced by thesprocket hub if a steel washer was used betweenthem.
Spindle alignment. Slide the spindle so at least 8”sticks out the front of the headstock, then use a dialtest indicator to measure to the spindle to both sidesand the center of the carriage as the carriage ismoved forward and backward. After the spindle hasbeen accurately aligned, pour in the grout to lock it inplace. This makes the spindle parallel to the ways,which is all-important.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The headstock, spindle and flywheel/faceplateassembly can be as simple as an inverted engineblock, crank and flywheel that has had the mainbearing inserts carefully drilled and the main bearingcaps drilled and tapped for grease fittings. A lathewith a 600mm to 900mm (or larger) swing could beeasily made this way. Just remember that the largestYeomans shell-making lathe weighed 9000 Kg, soscale accordingly!An engine block headstock should probably kept atunder 200 rpm since the bearing inserts were meantto be used with a pressurized oil system. Greaseevery few hours at first until you make sure thatnothing overheats.
The thread follower chuck rotates at the spindlespeed and is driven by bicycle sprockets and chain.An idler should be added so that the chain can beadjusted or removed when not needed. There is alimit to bicycle chain speeds so use a motorcyclechain for speeds much over 70 RPM (which is 3times the speed you should start threading withanyway).To cut a thread, a sample piece of threaded rod isheld by the follower chuck and is manually clampedin the wooden or plastic block clamp that is attachedto the carriage. This pulls the carriage at the properspeed for cutting a duplicate of the sample thread.The follower spindle cartridge is first aligned and thengrouted into the headstock.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
The thread that is cut could be unusually accuratebecause the wooden block should average outimperfections in the sampled thread. Special note:Threading on a lathe always requires practice even ifyou use the best equipment. Threading usually takesmultiple passes with the threading tool. Our devicewill require extra practice to learn how to “pick up”the existing thread on subsequent passes but thisshould not be too difficult because the wooden clampcan be “eased on” instead of suddenly engaged.You won't find a device like this described anywhereelse but I have built and used one on the originalMultimachine. The follower spindle should have anoil line run to it as was described for the mainspindle. Half-inch water pipe is about 5/8” ID so this,2 bushings and a piece of 12mm rod either threadedor epoxied into a discarded drill chuck should workwell.For a large lathe, the length of the clamp should beincreased and larger diameter sample screws made.Compressed air "help" could also be added to a largelathe. An air cylinder could be used to close theclamp on the thread and carefully regulated airpressure supplied to an air cylinder used to add alittle push to the other side of the carriage. Thiswould help overcome inertia.
The tailstock has a frame that is exactly like thecarriage. Except for the difference in shape,construction is similar.
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
An all-thread coupling nut can be cut in this way andthen be pressed slightly closed in order to reducebacklash to a minimum.
If you use a Morse Taper socket, a slot should becast into the tailstock concrete so that a wedge canbe used to knock loose a Morse Taper tool.Naturally, the slots should line up!
Something should be welded to the back of the MTsocket or grooves 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. We mount itvertically 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...
The Multimachine $150, 12" Swing, Metal Lathe/Mill/Drill
