A while back I was going to make some custom reupholster nails for a chair. The nail heads were going to be .45cal shell casings. Looks sick with black or dark brown leather. However I couldn’t get enough shell casings. So for a year or so they have been stashed away in a plastic bag in my storage room.
Today I got a cool idea on using them as knobs for potentiometers. They can be cut to desired length with a pipe cutter. You could use a hacksaw but you might damage the shell casing. A cutting wheel with a rotary tool would work however you would probably get tons of burs and a uneven cut.
To attach the shell casing to the pot you can go a few routes. You could take a existing knob and mold the inside so it can slide on a D type or spline. That’s if you plan to do a huge run of them. You could use a cardboard shim and some glue but if you have to remove the knob you’ll have to break the glue joint. From my trial and error simple hot glue works fine as a shim. Fill the casing and drill it out with a bit that is slightly smaller so you get a nice friction fit.
To overall look is awesome and the feel is a bit different since they’re not a typical knob size. I might try this on one of my guitars however as a inlay from one of these knobs.