Yes, you may want to start small if your useing say, a hand drill because it will tend to wobble and drill over size. If your mounting a bike part I would not worry about it too much. Heli coils in a loose hole can still have threads that are "in print" so to speak. If your original threads were 10 - 1. metric then just run the right size drill through the existing hole. It should follow right on through. Then counter sink the hole and tap with an M10 - 1. STI tap. Piece of cake. My reference chart only shows M10 - 1.5. Tomorrow I will check my heli coil spec. book and search for M10-1. By the way, people seem to have a bit of an attitude here. Whats up with that? I am just trying to be helpful not Mr. Know it all. later, in difficulty