Westward Taper Shank Drill Bit: 1 3/8 in Drill Bit Size, 8 7/8 in Flute Lg, #4 Taper Shank

These drill bits have a black-oxide finish that retains lubricants to improve the bits' wear resistance and chip flow. Black-oxide bits should only be used for drilling ferrous metals. High-speed steel drill bits provide more flexibility and absorb more shock and vibration than cobalt and carbide drill bits, making them suitable for use in manual drilling machines and handheld power tools. They may leave a rough finish on the hole. These bits have spiral flutes that evacuate chips as the bits drill into a workpiece.