Flail

Posted: 12th July 2026

Recently I found myself with a short length of stainless steel chain and nothing to use it for, so I tried to think of something that a chain would be good for. What's the first thing that comes to mind when you think of uses for chain? A flail of course, so that's what I made. I also wanted to try getting something CNC-machined, since I had never done that before.

Head

While historical flails would mostly have just been plain round balls, some of them had spikes, and that's how they tend to be portrayed in modern media. Since spikes look cool I made mine spiky too. I didn't think machining a spiky ball in one piece would be a good idea, so instead I opted to get commercially available speaker spikes (sometimes used as feet to reduce coupling of vibrations from the speaker to the floor) and then screw them into the head. To give the spikes a flat surface to sit on, I made it a dodecahedron rather than a sphere. I used FreeCAD to design it, since it'a open-source and can output the .step files that CNC machining services want. I also used the "Pyramids-and-Polyhedrons" workbench, as it would be more complicated to construct a dodecahedron with only FreeCAD's built-in primitives.

A CAD drawing of a dodecahedron, with a hole in the centre of each face. — You can make holes threaded in FreeCAD, but the threads don't end up in the exported `.step` file, so you still have to tell the CNC machining service that you want the holes threaded (or tap them yourself).

The available literature indicates that a real mediæval flail would have had a head of just a few hundred grams at most, becoming too slow to swing beyond that. Given the density of steel, that would only allow for a pretty small head. Since I'm not actually going to be swinging it around, I made the head about 50mm across, which ends up heavier than would likely be ideal, but it looks better than a more realistically small one. Also humans (like me) are taller now than they were when flails were in use, so heavier ones are likely to be less of a hindrance now.

A dodecahedron machined out of stainless steel. Each face has a threaded hole in it. There's a ruler next to it for scale, showing it to be about 50mm across. — Draw some numbers on it and it could be used as a D12, albeit a table-top-destroying one.

Stainless steel spikes with threads on the end. — These are quite easily available off-the-shelf.

The same machined dodecahedron as before, this time with the spikes screwed into eleven of the holes, plus an eye bolt screwed into the twelfth hole. — To allow for attachment to a chain, I screwed an eye bolt into one of the holes.

The complete assembly weighs 542 grams. You really, really do not want to drop it on your foot.

Handle

I reckoned that it would be nice to have a handle of a length that could be held in either one or two hands - about 30cm, like a longsword or katana would have. The easiest way to construct one would have been just a piece of wood with an eye bolt screwed into one end for the chain, but I made something a little fancier, using a hollow tube with a threaded rod running inside the whole length and screwed down at each end to clamp against the tube. I cut some larger diameter end-caps out of oak to help stop the user's hands from slipping off the ends of the tube.

A carbon-fibre tube about 300mm long, a threaded rod the same length, two threaded spacers, one eye bolt, one speaker spike (the same as used for the head), a few washers, and two circular pieces of wood. — The washers should be larger, but I couldn't get any larger ones by the time I put it all together.

The same parts as the last photo, but the wood parts are fitted to the end of the tube, and all the metal parts are screwed together to form one long part which is laid next to the tube. — Here the metal parts are screwed together outside the tube, so you can see how they are supposed to clamp the end caps to the tube.

The same parts as the last photo, but now the metal parts are inside the tube, leaving the eye bolt and spike sticking out of the ends of the tube. — Now it just needs to be wrapped in something to make it more comfortable and grippy.

Complete Flail

Since I'm quite good at crafting, this turned out to be a +1 flail.

I wrapped the handle in bicycle handlebar tape, since that's available in a variety of interesting colours and patterns, and is comfortable and durable. With everything assembled it weighs a hair over 1kg, so the head is about half the total weight. In order for it to not come apart over time when swung around, I would probably need to apply threadlocker to all the threaded parts, but for now it's just screwed together by hand. Regardless, I'm not sure if I would be able to wield it effectively, but that's fine because it's a decoration to hang on my wall, not a weapon to be used.