A No-Cost, Heavy Metal Lathe From Junkyard Parts

We have to admit that our first thought on seeing a Frankenlathe made from old engine blocks was that it was a set piece from a movie like The Road Warrior. And when you think about it, the ability to cobble together such a machine tool would probably make you pretty handy to have around in an apocalypse.

Sadly, surviving the zombie mutant biker uprising seemed not to be the incentive for [Paul Kuphaldt]’s version of the [Pat Delany] “Multimachine”. He seemed to be in it for the money, or more precisely from the lack of it. He was shooting for a zero-dollar build, and although he doesn’t state how close he came, we’re going to guess it was pretty close. The trick is to find big castings for the bed and headstock – Mopar slant 6 blocks in this case. The blocks are already precision machined dead flat and square, and the cylinder bores provide ample opportunities for stitching the castings together. The drivetrain comes from a 3-speed manual transmission, a 3/4-ton Chevy truck axle donated the spindle, and a V8 cylinder head was used for the cross slide. The tailstock seems to be the only non-automotive part on the machine.

We’d love to see a video of it in action, but there are ample pictures on [Paul]’s website to suggest that the heavy castings really make a difference in keeping vibration down. Don’t get us wrong – we love cast aluminum Gingery lathes too. But there’s something substantial about this build that makes us feel like a trip to the boneyard.

[via r/homemadetools]

28 thoughts on “A No-Cost, Heavy Metal Lathe From Junkyard Parts

    1. I was thinking the same, but I did buy a 4-jaw chuck for a wood lathe at Sears (remember them) years ago.
      It had to be cheap, or I wouldn’t have bought it.
      Mine doesn’t look much different than that one (mine has less rust).

    2. There are pictures of a diy 4 jaw chuck also. I dont like the chain holding the blocks together, all chains should be replaced with brackets. Im also not sure bolting the tailstock to a rotating flywheel is smart, better to remove it and bolt to the bellhousing.

      1. It doesn’t look like the brake drum that he used for the tail shaft support is rotating at all, but you have to dig a good bit to find the pictures of the support.
        It looks to be attached by tabs welded to the drum, and then drilled to allow bolts to pass and be threaded into the bell-housing bolt holes on the block.

      2. I’m not a fan of the chain either. Personally, I’d weld the blocks together. I know cast iron is tough to weld, but still, the chains are a little janky looking.

    1. I think it’s a work in progress, too. OP posted this back in 2018, so I figure he’s made some progress since then. Hopefully he figured out how to thread with it. The Pat Delany link mentions that the lack of threading can be fixed with a stepper motor drive for the cross slide.

      1. Well, there’s one way to thread stuff on a lathe: you weld a piece of threaded rod with the right thread pitch at the end of your workpiece and fix the whole thing between the centers. Then free the slide and weld a lever with a half-nut on the end on the slide. You press the nut against the threaded rod and spin the motor up – it pulls the slide in, and you yank the nut off the rod to stop it. Rinse and repeat until you’ve cut your thread.

        1. You are my kinda guy.

          I always liked the thread chase option.

          Turn down a bolt to press fit into the headstock tube backwards- behind the headstock, a 1.5x longer than you need threads. Weld a mating nut onto a flat bar, bend 90 degrees so bar with nut can spin on this bolt while most of bar can be bolted to lathe saddle.

          Bolt bent bar to lathe saddle, bending wherever needed to affix. A very good idea to weld or bolt a brace in the corner of the bar where you bent it to go around the headstock.

          Put a 60 degree threading bit on your saddle, start lathe at low speed- 20 rpm or hand turn. Bolt in back becomes a copy attachment to your lathe saddle in sync with your spindle (good idea for a tight fit- use a setscrew!)- and you can now cut any thread on any non threadcutting lathe, via the copy principal.

          Its an old trick- but I’ve done it for one off stuff when I had no screwcutting lathe available, and it works.

    1. Dude, I’m a machinist, a toolmaker, and just plain maker- and this has every part of me stoked.

      This is the kind of thing you always think should be possible and hear stories about but you never see and then when you see it you just stand in awe, smile really wide, ask to see it cut, and buy the guy a beer!

      If someone I meet does this kind of thing they are instantly my friend

  1. Hmm, now I have a problem since I have a cheap Chinese lathe which needs work and a couple of engine blocks too in that I’m now gathering cognitive momentum visualising up some hybrid (can only lathe while driving) – eek !

    1. I’m picturing a plate that covers wheel nuts, plus a shaft going to a universal joint.
      Jack up the car and you have a power drive. Cruise control gives you constant rotating speed.

    1. I think a lot more store is being put in the flatness and squareness of these blocks than deserved – just because two big lumps are flat & square doesn’t mean that lathe is true in any direction. Even assuming the bores are round to any sort of tolerance is quite a leap of faith tbh.

  2. I,m Paul I built this “engine” lathe plus a homemade 4 jaw chuck plus a milling “head” which goes with it. I have all this and more on “homemade tools”

    I sure appreciate the positive feed back.

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