| HI
Years and years ago i got a set of counter bores from a ME show for a pound or so. When i need one that i dont have I go the Bunker route but grind the drill to a stub length to avoid wander. The big advantage with true counterbores is the guide that fits into the drilled hole. Milling cutters and slot drills can chatter when entering a bored hole like that, but keeping the speed down prevents it.
Cheers Kevin
Cheers kevin |