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 (well) of the bit by scraping, grinding or localized compressive fracturing. The cuttings produced by the bit are most typically removed from the wellbore and continuously returned to the surface by the method of direct circulation. Drill bits are broadly classified into two main types according to their primary cutting mechanism. Rolling cutter bits drill largely by fracturing or crushing the formation with "tooth"-shaped cutting elements on two or more cone-shaped elements that roll across the face of the borehole as the bit is rotated. Fixed cutter bits employ a set of blades with very hard cutting elements, most commonly natural