For those of you that have drilled your rotors. Are you chamfering with a countersink, or leaving the hole edges sharp? I know the holes serve to not only cool but remove embedded debris/material from the pads so chamfering seems counter productive. I'm getting really clean holes to begin with, no breakthrough or tear out. Just not sure if I need to kiss em with a countersink to deburr. I'll probably swirl finish the rotor with a 2" roloc pad after sandblasting so that will do a lot of deburring.