Drill America D/AN series high speed drill bit is a dependable, general purpose drill designed to perform in a broad range of materials in the iron and steel families. Ideal for production, maintenance or portable drilling jobs. Surface treated with abrasion-resistant black oxide. High-speed steel tools are good for most general purpose applications, offering a combination of hardness and toughness for wear resistance. Black oxide treatment adds lubricity and creates small pockets on the surface of the tool that act to hold coolant near the cutting edge. Round shanks allow use with a wide variety of toolholding systems. When run in a counterclockwise direction (right-hand cut) spiral fluted tools evacuate chips up and out of the cut to reduce clogging.