Homesmithing News: Printed Revolver, Easy Home Rifling

Here’s the Imura Works’ latest Zig-Zag Revolver, the Flying Swallow. Imura Works is named for the Japanese martyr to the cause of home gunsmithing.

It has quick-change cylinders for rapid reloads.

Of course, this wouldn’t be that interesting if files weren’t available. But files are available — how ’bout that. The file pack includes not only the .stls that you need to print it out, but also assembly drawings that show how it all goes together.

Happy printing!

Beyond Printing: The Steel Rifled Barrel

Of course, a printed pistol has its limits; we’ve seen a lot of better examples of homemade guns made from steel. In an austere or denied environment, raw steel will always be available, but one stumbling block many small and home machinists have encountered has been rifling a barrel. But it turns out, there is a high-throughput, benchtop way to do it: electro-chemical machining (ECM). You don’t need a big ECM machine: you can improvise with innocuous parts and chemicals (table salt!). This is the whole setup:

Yep, the el cheapo battery charger is all the power supply you need. They used 33 AWG copper wire.

Here’s some results from an early series of experiments.

HERE it is! Rifling a barrel using the ECM (electrochemical machining) process by the one and only Jeffrod. This fosscad project is still in its early infancy so expect more to come! ECM is like reverse-electroplating where you are removing material instead of adding it. ECM is a very precise method and is more suitable for mass production. The ECM process can be used on hard materials that cannot be machined by other more traditional processes. Unlike the EDM (Electrical discharge machining) process, no sparks are generated with ECM between the cathode and anode.

That particular barrel used a pentagonal 3D-printed mandrel, copper wires, and three rounds of 5 minutes in a saline solution with 6 volts and 6 amps running through the wires. The rifling is 5-thousandths deep. It’s not a target barrel, but it’s a process that will produce a legal and likely functioning rifled barrel. And you can experiment with it with just some steel tubing, a bucket, wires and a mandrel. This is the mandrel, with the copper machining wires attached.

The whole process is recounted on this imgur thread, including several earlier experiments before this last barrel was produced. These barrels are a proof of concept, not in any particular caliber or chambering at this time. So we’re a long way from making, say, AR barrels, but a Sten barrel is close.

¬†You can’t ban guns. Make one problem difficult, and the community reacts to the damage by detouring around it. Short of lobotomizing the whole community, this is only going to grow from here.

26 thoughts on “Homesmithing News: Printed Revolver, Easy Home Rifling

  1. LFMayor

    That ECM is brilliant! I followed online plans to make a homebuilt electrolysis anode style bore cleaner a while back and it uses the same concept, it just applies a broadcast approach to the removal instead of this targeted concept. Worked really well to clean up a Turk Mauser that I got on the cheap.
    On these rifled barrels, would you use a very, very fine lapping compound to hone it out of the rough? A ceramic lapping tool on a rod…. or maybe porous hard rubber to hold the compound?

    1. Bert

      Fire lapping- Cast lead bullets rolled in a small ammount of fine abrasives between a couple of steel plate to embed with the desired grit, then loaded and fired at low velocity through a barrel are a simple method.

  2. James

    These are great additions to determined home builder,would say download as I suppose what happened with Cody and his Lego pistol(mean that in a good way)feds might try and take off the net,as with Cody’s plans/download and mirror across the net.

    I have used electrolysis for cleaning gas tanks and other parts,now,those same tools used in a new way for rifling?!The world gets more interesting daily.

    As always,want the plans/home build for Q-37 Explosive Space Modulator,and someone here keeps looking for plans for a 4000 watt(?)plasma rifle,any help appreciated!

    1. Mr. 308

      “feds might try and take off the net”

      I think it was Dennis Miller who said it, taking something off the internet is like getting pee out of the pool.

      1. James

        I believe this is why Cody did,in that he knew was mirrored all over net and was applying for a manufacturing license.These actions were never gone thru/taken to a court to enforce,just a decree but understand with the net and license app why Cody did what he did.That said,can’t count on net always being up and any info one gets from net should be on a stick/printed ect.

  3. Tom Stone

    This is deplorable and quite possibly misogynistic.
    It’s time to impose background checks and a waiting period for anyone who buys batteries, copper wire or table salt.
    Think of the children!

  4. CoolHand


    The best materials to use for laps are soft-ish metals like brass or aluminum (unless you are lapping aluminum, the materials must be of differing hardnesses, the lap always being the softer of the two).

    I’ve seen wood used to good effect for polishing, but it doesn’t hold size very well, so it is difficult to lap to a specific dia with a wooden lap. Brass is best for lapping to a precise size, with dead soft copper coming in a close second. Alum will work, but it is a lot harder than most brass, so it doesn’t charge with abrasive as readily.

    Interesting times, indeed.

    You can’t stop the signal.

  5. Clarence Chen

    Hey, the absolute uselessness of all the other laws haven’t fazed them, but one can hope, I guess.

  6. Clarence Chen

    Pretty soon, we’ll all be printing our own guns, thus making obscure one-off prototype reproductions viable……. I want a Scwartzlose 1898 so bad………

      1. 11B-Mailclerk

        Swallow approx equal “Shu-Sway!” The sound of a sword draw and cut. (Or am I mistaken?)

        I believe that is the approximate translation of the “swallow” name of a fighter jet they were developing in 1945.

        I may have mis-remembered the name, but if I am right, “flying swallow” is pretty apt for a defensive sidearm.

  7. SiGraybeard

    The thing that’s most interesting here to me is rifling a barrel with no moving parts. People have obviously been doing rifling for a long time. To my knowledge, nobody has ever done it with no moving parts. As it is, their system would work with pistol length barrels. For rifle length, it turns into a long, narrow plastic container.

    This is one of those technologies to keep an eye on. Even if it doesn’t make match grade barrels, if it can make “service grade”, that’s an incredible step up. I would guess it could be tweaked to continually get better, just like every new battery technology gets better as the engineers gather experience with it. It could also lead someone else to develop an even better approach based on this method. For example, what about masking off the areas in the barrel you want to stay unetched, and then putting the whole barrel in an etchant tank? No 3D printed tool like these guys use, just something like a silkscreen in the barrel.

    1. whomever

      “No 3D printed tool like these guys use, just something like a silkscreen in the barrel.”

      If I’m reading the imgur thread right, the tool is the ‘silkscreen’ – where the tool is a tight fit no salt water flows and no erosion takes place, and no metal is removed. The cross section of the grooves doesn’t matter. That means you could machine the tool in lots of fun ways – with something like a conventional rifling machine but now you can work on the OD, not the ID, which is easier, or with a geared down dividing head as is used for say drill flutes, etc, etc. I’d wager you could print out a pattern on paper and wrap the tool and use an xacto knife if you have good hands.

      But what I thought was interesting was the speed – they’re talking 10 minutes per barrel. That’s a lot faster than any pull through single point cutter is going to be, and it doesn’t take any skill once the tool is made.

  8. Pingback: SHOT Show 2017 and New Gun Tech |

Comments are closed.