Originally posted by floodo1
you really shouldnt buy a countersink for use on graphite unless its carbide.
its pretty expensive, something like 30+ but a carbide countersink basically never wears out on graphite.
pretty much everything cheaper wears out after just a few holes.
carbide really is the ticket for tooling when working with graphite, its stays so sharp, it works so well 
The $5 bit I bought a year ago still works fine after 1 Yok SD topdeck, 1 pro4 lower deck (holes not deep enough from the 1st batch), and some holes here and there. I'm sure the $30 bit will last longer, but do I need it for what I use it for....nah.