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 the surrounding material. (By comparison, a counterbore makes a flat-bottomed hole that might be used with a hex-headed capscrew.) A countersink may also be used to remove the burr left from a drilling or tapping operation. Used almost exclusively for deep hole drilling of medium to large diameter holes (approximately diameter). An ejector drill bit uses a specially designed carbide cutter at the point. The bit body is essentially a tube within a tube. Flushing water travels down between the two tubes. Chip removal is back through the center of the bit. Gun drills are straight fluted drills which allow