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 the Boring and Trepanning Association), is a drill bit that cuts an annulus and leaves a center core. Trepans usually have multiple carbide inserts and rely on water to cool the cutting tips and to flush chips out of the hole. Trepans are often used to cut large diameters and deep holes. Typical bit diameters are and hole depth from up to . The lip and spur drill bit is a variation of the twist drill bit which is optimized for drilling in wood. It is also called the brad point bit or dowelling bit. Conventional twist drill bits tend