Drill bit shank from 0 to 7. The Morse taper allows the bit to be mounted directly into the spindle of a drill, lathe tailstock, or (with the use of adapters) into the spindle of milling machines. It is a self-locking (or "self holding") taper of approximately 5/8" per foot that allows the torque to be transferred to the drill bit by the friction between the taper shank and the socket. The tang at the end of the taper is only for ejecting the drill bit from the spindle, with the aid of a drift. The arbor of a drill chuck is often
Drill bit metric and imperial sized drill bits alongside the required screw tap sizes. There are also certain specialized drill bits that can create holes with a non-circular cross-section. While the term "drill" may refer to either a drilling machine or a drill bit for use in a drilling machine, in this article, for clarity, "drill bit" or "bit" is used throughout to refer to a bit for use in a drilling machine, and "drill" refers always to a drilling machine. Drill bit geometry has several characteristics: Most drill bits for consumer use have straight shanks. For heavy duty drilling in industry,