Since you are asking I will assume you don't have much experience in this area. You need to use a steel cutting drill bit, and a drill press with a vise is recommended. If you use a hand drill, be aware that the drill will catch, and try to injure your wrists. So if you tackle this brace yourself and go slow. It's easy if you know how, if you don't go slow and be careful. If you want to come to Hamilton, I'll do them for you.