Tiny Pneumatic Tool Made From A Single(-ish) Bolt

We’ve noticed a couple of things about the “Widget from a Single Bolt” genre of metalworking videos. The first thing is that almost all of them need to use a freakishly large bolt, and many of them also rely on other materials to complete the build. And secondly, these builds all pretty much depend on a lathe to transform the bolt into the intended widget.

While this single-bolt pneumatic graving tool build is guilty on that first count, it somehow manages to avoid needing a lathe. Not that [AMbros Custom] wouldn’t have greatly benefited from a lathe to make this somewhat specialized and unusual tool a reality. A graving tool or graver is used during metal engraving, the art of making controlled cuts into flat metal surfaces to render complicated designs. A powered graver like this can make engraving faster and more precise than a traditional manual graver, which is typically powered by light taps with a special hammer.

The lathe-less build [AMbros] undertook was quite ambitious given the number of moving parts and the tight tolerances needed for a pneumatic tool. The real hero here is the hand drill pressed into service as an impromptu lathe; teamed with various tools from files to emery cloth to even a Dremel and an angle grinder, it did a respectable job turning down the various parts. The entire build is shown in the video below, and it’s worth a watch just to see what ingenuity can accomplish when coupled with sheer persistence.

Hats off to [AMbros] for sticking with what was admittedly a problematic build, and here’s hoping a lathe is in his future. With that, he may be able to pull off other impressive “single-bolt” builds, like this combination padlock. Or throw another bolt or two in and pull off this cryptex-like safe.

[via Instructables]

17 thoughts on “Tiny Pneumatic Tool Made From A Single(-ish) Bolt

      1. Then why not just say “used a hand drill as a makeshift lathe” rather than stressing several times “he didn’t use a lathe” when he clearly used a device to turn metal which is a lathe. Turning something like that using a drill is impressive and that is what they should have stressed. I’m not criticizing the build or the results, but the writing of the article is wonky.

          1. I am in that bracket, nearly took my left arm off “in the blink of an eye” trying to do this free hand before bothering to finish the article :-D

            /s because although words do have meaning, it is also true that a bit of temporary poetic licence is forgivable in making a subject readable for the layperson.

    1. Using a rock as a hammer, do drive a nail in, doesn’t make it a ‘hammer’. There are countless other examples. You can’t really make something like this out of a bolt without using a drill of some sort. Kind of assumed.

  1. Kudos to accomplishing the project with what you have on hand. But I don’t get why you would use a hand drill in a vise when you have a drill press on hand. I saw nothing that couldn’t be done vertically.

    Anyway, now I know how tools from H.F. are made.

    1. i’ve been warned here that the chuck from a drill press is just friction fit and will go flying if you put a sustained sideways load on it

      i have no idea if the hand drill is really different, or what the real limits are for that kind of silliness

      1. I believe there is a difference. The drill press is a tapered bore so the chuck to motor connection is held by friction. In a hand drill the chuck to motor connection is typically a geared arrangement with bearings preventing the spindle and gear from contacting the surface of the casr. That doesn’t mean that it prevents contact or gear misalignment or other issues if too much lateral force is applied, but it may provide more than a drill press depending on the quality of those inside bits. The trouble with a hand drill is probably both constant speed and torque, but that is just a hunch on my part.

      2. Yes. A drill press nearly always uses a jacobs taper to attach the chuck, and a hand drill chuck is threaded on. Hand drills also (nowadays) always have a left-handed screw inside the chuck to retain it – because hand drills are operated in both directions. If you put side force on a drill press chuck you’ll soon find yourself dodging about 3 lbs of spinning metal flying at you.

      1. Yes, /but/: the earlier video- and he alludes to this in his Instructables text- used a modified compressor so that the piston in the graver was alternately sucked and blown. The current video uses an unmodified compressor with the tool oscillating from positive pressure only.

        He definitely gets a 9 for trying and- mostly- succeeding. I did have to cringe however at some of his working methods: for example marking a centre using multiple lines which didn’t intersect, punching a centre which was visibly out, and then ploughing on regardless to drill the inevitable out-of-centre bore.

        Apropos the discussion above about lathes, drills and chucks, the original Jacobs chucks were mounted to an arbor with a taper (“Jacobs Taper”) separate from the Morse Taper used to fit the arbor to the drill itself. I haven’t a clue whether that applies to any hand drills which seem to have a threaded shaft, but not trusting a side-loaded drill would probably be good advise.

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