This 1947 Gretsch floor tom came to me with these leg supports.The part that the thumbscrew fits to - the leg support - has stripped. Has anyone here had experience with plugging a metal (I think it's Aluminum) hole and then redrilling - tapping?I could go to a machine shop and have them plug the hole and then redrill it but that is going to cost me $100 or so I just know it.
I'm always into stuff like this----not just on drums. -----and always trying to avoid , paying a fortune to fix a 10.00 part. Here is what I would do.
Drill and tap the hole to accept the smallest size plug, that you can freely drill and tap for your intended thumbscrew size. You can get the tap drill sizes online. Get a compatible piece of aluminum rod, about 1 inch longer than you need. File about 1/2"" of one end into a square, standard size, that will take an open end wrench. and thread it to the same thread. Put the piece in a drill press or lathe(might need a machine shop ,to do this but it won't be that expensive) and drill and tap it to your intended ,thumbscrew size. Clamp the squared end in a vice and cut the outside thread, the same as your hole.
Take your mount and very lightly chamfer the inside and outside of the hole, with a drill, being carefull not to go too deep---1/16" should do.. Clean up the threads with your tap.Turn your stub into the hole,about 1/16" past the inside of the hole. Cut the stub off,with a hacksaw leaving about 1/16" excess on the outside. Put the outside 1/16" on the anvil part of the vice. Using an appropriate size socket, on the inside edge of the stub, you can gently hammer it ,to mushroom the inside, into the chamfered relief. The outside will mushroom as well. Once the edges are tight the plug is locked. You will have to gently file and polish the outside edge of the plug. Clean up the thread, with your tap.
Taps and dies need lots of oil. Don't worry about expensive thread cutting oil. The stuff you put in your car will do on aluminum ,just fine.