How to make a Bike spoke Brooch

Being a bit of a fantasy nerd, I'm irresistibly drawn to old-fashioned garb such as cloaks and robes. I recently acquired a cloak from my friend Dylan who moved away, but it was lacking a closure for the neck, so I set about researching traditional methods of joining the halves of such a garment. The so-called penannular brooch is an elegant solution that apparently was ubiquitous in antiquity. It is simply a pin that passes through fabric to be joined, and an attached ring that captivates the ends of the pin. A gap in the ring allows the pin to be passed through before rotating the gap away.

Bike spokes are a great material to make a lot of things out of:
-  They are abundant, about a dollar apiece at a bike shop, or free if you have a dead wheel you can salvage from. Ask your local bike shop; they will probably give you a dead wheel for free if you tell them what you're doing and aren't too obnoxious about it.
-  They are often (ideally) polished stainless steel, which makes for a pin that slides through fabric easily and doesn't corrode.
-  They are quite stiff and strong for their diameter, which is good, because an incomplete circle is a much weaker structure, mechanically speaking, than an equivalent solid ring. They are more than stiff enough to make even a large brooch, maybe up to 100mm in diameter, though that's bordering on absurdly-large-belt-buckle territory. A 100mm brooch is likely an attempt to shatter fashion conventions in a dramatic statement.

2mm spokes (the most common size you're likely to find) are great for the ring part, and can be used for the pin as well, but a skinnier pin, made from a 1.7, or 1.8mm spoke would pass through the tight weave of a modern fabric better.

For tools, all you really need are a pair of decent needlenose pliers and some sturdy wirecutters. Most consumer needlenose pliers come with mono-buttocked integral cutting blades on their jaws, which worked just fine for me, though a person of limited hand strength may wish to use cutters better suited to the task. Longer-handled needlenose pliers would be nice if you are lacking in hand strength, as 2mm spokes take a fair bit of force to bend, especially when bending the tight loop in the pin. I have a pair that I got from a free box that I can loan out if needed.

I also used:
-  A hammer and the small anvil on the back of my crappy vise.
- A bench grinder to sharpen the pin. You could conceivably use a fine file or a whetstone to sharpen it, but I suspect that would be rather tedious. If you're joining loosely-woven fabric, or something like a hand-knitted garment, you may not need to sharpen it at all, though you still may wish to soften the sharp edges left by the wire cutters.

My favorite palindromes are faintly legible on the plywood backdrop: "Dog, no poop on God!" and, "No son, onanism's a gross orgasm-sin, a no-no, son."

The first step is to trim off the elbow of the spoke and the threaded end. Then cut the remainder into two pieces, one about twice as long as the other. Doesn't have to be exact. I ended up cutting off extra length later anyway.

I started with the shorter piece, bending a tight loop onto one end with the tip of the pliers:

Play around with it. You'll get a feel for how to work the wire into the shape you want.

Then to sharpen the point. I used a bench grinder to put a fine point on it, dipping it in a pot of water every few seconds to keep the heat from building up and discoloring the stainless steel (and from burning my poor little fingers).

Stainless doesn't usually spark much, so don't expect this shower of sparks.
Definitely wear safety glasses when grinding. I'm practically religious about it, and sometimes I still get irritated eyes at the end of a day of heavy grinding. Plus, stainless is non-magnetic, so the doctor won't be able to suck it out of your eyes with a magnet like they do for regular steel objects in the eye.

I also hammered the loop flat on the back of my crappy vise. Don't hammer on a nice vise please.

Then on to the ring part, or "penannulus" (heh heh, penis-anus).
Bend the longer piece of wire into a near-circle:

Cut off the extra length:

And ta-dah!

I also hammered the ends of the ring flat in an attempt to make it look a little nicer:

Then just slip the loop of the pin onto the ring and you're done!
To use the brooch, push the pin through the pieces of fabric you want to join, pass the gap in the ring over the end of the pin, and then rotate the ring to keep the pin from going back through the gap.

This picture is of version 1, which had a dangerously long, sharp pin. I cut the pin shorter and resharpened it.
Another improvement that can be made is to recurve the ends of the ring so that the pin is captivated on the ring. It also makes it look a little fancier, though my wire-work could use some refinement:

Ultimately, in the couple of hours that I have worn the cloak, I have drawn blood gouging myself on the pin multiple times. Maybe I'm doing it wrong, but I suspect that the issue is that I had to sharpen the pin really sharp to make it work with the tightly-woven fabric of the cloak. It is likely that most ancient fabrics were of a much looser weave. If you look at pictures of old brooches, they often have somewhat blunt pins.
The pin also leaves a hole in the fabric, which may massage out with time, but I suspect that repeated piercings of the fabric will eventually wear it out.
The penannular brooch is an elegant mechanism, but a more sophisticated clasp that has mating halves attached to each lapel of the cloak seems more convenient to operate, less damaging to the fabric, and safer than fumbling with a sharp pin near the neck.

Nerdmode: Engage!