Black Oxide Drill Bits. Black oxide drill bits are manufactured from industrial high-speed steel, surface treated for high performance and long life. Designed for drilling common steel flat bar, plain iron, pipe, wood, and plastic. No center punch is needed. Century Quick Cut points are self-centering and penetrate faster with less pressure, will not walk or wander on the starting surface. Features. 0.15-inch black oxide drill bit. Specifications: Dimension 1 x 4 x 10 inches. Hub 40. Weight: 0.05 lbs