Drill Bits Cobalt. No Center Punch Needed: Century 135 Degree Quick-Cut Points Are Self-Centering And Penetrate Faster With Less Pressure, Will Not Walk Or Wander At The Starting Surface. Cobalt Drill Bit 3/16" Overall Length 3-1/2" 12X Life Rating, Comparison To The Average 118 Degree Point High Speed Steel Drill.
Black Oxide Drill Bit 25/64" Manufactured To Aerospace Naps 907-B Specifications..Drill Bits Black Oxide. Black Oxide Drill Bits Are Manufactured From Industrial High Speed Steel, Surfaced Treated For High Performance And Long Life.