Impressive Hack Turns Bolt Into Pneumatic Engraver

Master craftsperson turns a huge bolt into a pneumatic engraving tool.

Did you ever see one of those videos that causes you to look at an everyday object in a new light? This is one of those videos (embedded below). And fortunately for us, there’s a write-up to go along with it in case you don’t always understand what’s going on.

In this case, what’s going on is that [AMbros Custom] is masterfully turning a stainless steel M20 bolt into a pneumatic engraving tool. Yeah, you read that correctly. But the most amazing thing about this hack is the minimum of tools used to do it. For one thing, there’s not a lathe in sight — [AMbros Custom] just chucked it into the drill or added a few nuts and clamped it in a vise.

So, how does it work? [AMbros Custom] hooks it up to a compressor, which causes the piston inside to go up and down, agitating the engraving bit. If you don’t want to watch the video, there are a ton of build pictures in the write-up.

What else can you do with a bolt? If you have the tools, you can do plenty. You could even turn one into a secret cash stash for buying more large bolts.

24 thoughts on “Impressive Hack Turns Bolt Into Pneumatic Engraver

  1. Well it’s great manufacturing and I’m happy to see it here, but at this point is it really a “hack”? Just like turning steel tunes into a bike… I’m personally happy when I hack a bolt into a bottle opener.

    1. Not a hack? he uses makeshift hand tools to transform a bolt into another tool and he hacks a compressor to better fit its new use case.

      Not sure which part is not a hack, maybe if you share your hacks I could understand where are you coming from.

    2. The problem is there is no one definition of what a hack is. It means different things to different people. It could mean a little known secret to doing something easier, gaining illegal access into something, someone is not good at a skill, and more… So in my definition of hack, this isn’t a hack. to me this is tool making or fabricating its just that the steel is a reused bolt instead of round stock. And calling it a hack devalues what the makers skills and what they have accomplished.

  2. Wow, Patience and dedication.

    An that drill press! You couldn’t fined a dial micrometer with enough range to measure its run-out! And the lath … eh em file and cutting grinder.

    Beautifully crafted, a one off for sure.

    The last time I spent that much time with a file was at the start of an apprenticeship in the 70’s. We were given a lump of steel, a file and three months to make a complex structure that was blue-printed. If you didn’t give up and leave during that three months and your work passed blue-printing then you got the apprenticeship.

  3. I liked that he showed the failed attempts near the end. Given my time is worth something, this wouldn’t be something I would do, however, if it is an exercise in fabrication that you can learn from – those are always beneficial. The only thing I thought was weird is that he used the file for things like the threads when he had a grinding wheel he used in other parts of the fab.

      1. If you used it upside down like he did. I usually use that tool with the guard protecting me, including wearing gloves and safety glasses. I also use a grinding wheel as opposed to a cutting disk if I’m grinding. Maybe it’s just me.

        1. No it’s not just you. To grind you use a grinding disk, it’s safer that way. To cut you use a cutting disk, it’s safer that way. To use a cutting disk on it’s side to grind is a good way to kill yourself. There nothing slow about the RPM of a grinder. A bit of math can tell you that the angular velocity of the cutting disk when converted to a linear velocity when the the cutting disk fractures is going to send it right through your dermis and possibly even your skull.

          1. Well as a metal worker, I would hope you don’t see the worst accidents.

            Some people remove the guard, because it gets in their way.

            My last grinder was in the range 18000 to 20000 RPM.

            Cheap cutting disks are only 1mm thick, it doesn’t take much to wear them even thinner using the side of a cutting disk for grinding.

            When it’s so thin that it disintegrates then those pieces are going to go somewhere. At 18000+ RPM they will go somewhere FAST and with no guard that could well be your abdomen.

          2. My work is easily compared to a carnivore zoo, everything is big and will try to kill or eat you.

            Most(if not all) pieces of disk will bounce off an apron and face shield with barely leaving a mark, Sleeves will prevent arms getting marked and don’t forget the proper gloves. About removing the guard… yeah, i can see my hand slipping and mark a finger or 2 that’s why “i” never do it.

          3. Just a quick calculation and the linear speed of my last (abrasive) cutting disk, diameter 125mm (about 5″) (the small one) is 471 km/h or 292 MPH. I also had a 400mm (14″) (abrasive) cutting disk, girth 3mm (about 1/8″) but I can’t remember the RPM to calculate the speed. I also had a 14″ TCT cutting blade that should scare the living shit out of any non-psychotic person. I used to stand more “beside” the cutter rather than inline with the blade. The metal to be cut was always bolted down. Anything that can make an effortless, perfectly clean cut through metal should go anywhere near soft things like humans.

  4. I watched it to figure out how they did the valving in the tool, like a jackhammer. I assumed wrong. There’s no valving. The other hack is on the compressor: It’s modified to supply push-pull air to the tool.

    But I really like the faux-burl carbon-reinforced plastic handle!

    1. Same here. I don’t understand how nobody else noticed this. He could have just attached the engraving tool directly to the compresor motor using bowden line or linkage, kinda like diy tattoo machines work. because that compressor is mosty useless anyway after this modification. I was hoping that the design will be compatible with pressurized air lines in my shop, but this makes it tied to that very compressor, which is cheap and not built for prolonger periods of use.

  5. Filing down stainless… what a job it is!
    Small correction: stainless work hardens, not heat hardens. Therefore, keeping it cool does not prevent work hardening but may help tool life. The way around work hardening is to take a deep enough cut that the tool gets below the hardened surface.
    In the case of drilling, it requires feeding into the work faster than you’d think while keeping the RPM lower than for mild steel. There are plenty of recommendations out there regarding surface speed.

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