Drill bit shank The name comes from the German "Stecken – Drehen – Sichern" (Insert – Twist – Secure). In German-speaking countries the back-formation "Spannen durch System" (Clamping System) is used, though Bosch uses "Special Direct System" for international purposes. The triangle shank is almost always made by machining three flats on round bar stock. It is intended as a minor modification of a straight shank, still allowing it to be held in a 3-jaw drill chuck, but allowing higher torque transmission and limited slipping. The Morse taper twist drill bits pictured right are used in metalworking. The full range of tapers is
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,