I recently bought a couple of wa handles with pre-drilled tang holes. I want to use these as temporary handles for trying out blades before I get them permanently rehandled. Thus I want to be able to friction-fit the tang in the hole (no epoxy, no burning in). I've been using needle files to enlarge the holes and it's going extremely slowly. Does anyone have a suggestion as to a better method for enlarging them toward the bottom? Thanks---