My favorite option, by far, is to install a stainless steel insert into the hole that will give me EXACTLY the same size thread as the original, damaged thread. I can the use precisely the same machine screw as I had used originally. The inserts, tiny coils of stainless steel, can also be used right from the get go to add strong threads to parts made of softer materials like aluminum or even plastic.
I'll show you how to properly install one of these inserts in the main workshop at TechShop Detroit. You buy a thread repair insert kit or use the basic tools available at TechShop. In either case the drill press in the Metal Shop at TechShop is very useful for accurately drilling/enlarging the holes you need to make in your part to install these inserts.