It's nice to have a milling machine, and even nicer to have a specific task for which it is well suited!
The flaps in the original Subsonex were manual, with a lever on the left side of the cockpit. A recent change added an electric option, and I went with that in my jet - which meant I needed a place for a flap switch. I managed to shoehorn a DPDT toggle switch into the only available space on the left side of the cockpit, but the old human factors and cockpit design engineer in me just wasn't happy with a simple toggle bat for an important switch.
So into the scrap bin I went, and came out with a 3/8" thick chunk of aluminum. I sketched out a design, drilled some holes, milled it to shape, tapped holes for set screws and voilà! A regulation flap-handle-shaped switch that fits - and in my opinion, looks good doing it.
The tricky part was the shape of the toggle switch bat. It is, in fact, shaped like a baseball bat, with a taper that makes it hard to fit into a cylindrical hole. I solved this by using two set screws - one from either side, with tapered points, so that they can be fiddled with to center the handle and then give a firm grip on the switch.