Drill bit shank shaft and shank, is usually of the same diameter. It is held usually in a three-jaw drill chuck. Bits of diameter too small to grip firmly can have straight shanks of larger diameter than the drill, which can be held firmly in a standard size collet or chuck. Large drill bits can have straight shanks narrower than the drill diameter so that they can be fitted in chucks not able to chuck the full diameter. Such a drill bit is called a reduced-shank or blacksmith's drill. For example, this allows a bit to be used in a pistol-grip drill's chuck.
Drill string compensator Drill string compensator A drill string compensator decreases the influence of the heave of a drilling vessel on the drill bit. Drill string compensators are also known under the more general name: heave compensator. Drill string compensators are used onboard drill ships and semi-submersible drill rigs. There are two major types of drill string compensators: Drill string compensators are just giant springs between the drill bit and rig. These consist of one or more hydraulic cylinders and air bottles. In between, a medium separator is sometimes used. If there is no spring element, movement of the drill rig would immediately