Most recently, since it is cyclocross season, I decided to make a set of shoe spikes, I used some 6061 aluminum I had and machined four matching spikes. They have 7mm long M5x0.8 threads on one end and a chamfered point at the other. I used my lathe as a 2-axis mill to cut 10mm wrench flats onto them.
Below is the front hub I made from a round bar of 6061 aluminum. pressed cartridge bearings into the shell and made threaded end caps to fit on a M10x1 axle. I drilled 32 holes with a drill press using a drawing from my 3D model of the spoke holes.