Drill Bits Black Oxide. Black Oxide Drill Bits Are Manufactured From Industrial High Speed Steel, Surfaced Treated For High Performance And Long Life. Designed To Drill Common Steel (Flat Bar, Single Iron, Tubing), Wood And Plastic. No Center Punch Needed: Century Quick-Cut Points Are Self Centering And Penetrate Faster With Less Pressure, Will Not Walk Or Wander At The Starting Surface. Manufactured To Aerospace Naps 907-B Specifications. 29pc Set Includes: 1/16″ to 1/2″ By 64ths.