benchmark tri-bores cobalt drill bits 33% more cutting action and material removal for more holes 33% less edge stress and heat build-up for faster drilling cutting drills rounder burr-free holes especially in thin materials patented geometry with tris standard bore 2-flute stainless inox structural steel angle iron steel stud steel plate steel tube cast iron threaded rod save tri-bores benchmark 17pc set mae holes pale de trous benchmark pcs cobalt drill bit set more holes 13pc set drills longer drills better drills faster tri-bores cobalt drill bit set