Drill bit shank A hex shank can be grasped by a 3-jaw drill chuck or held in a chuck specifically for hex shanks. Quarter-inch hex shanks are common for machine screwdriver bits and have spread from that application to be used for drill bits that are compatible with screwdriver machinery. The diameter of an SDS and SDS Plus shank is 10 millimeters. (The SDS Max is 18 millimeters.) The SDS shank has the advantage of fitting into a simple spring-loaded chuck, so that bits are simply pushed into the chuck without tightening. This shank and chucks made for it are especially suited to
Drill bit (well) primary goals. Most rolling cutter and fixed cutter drill bits have internal passages to direct drilling fluid, conveyed by the drill pipe from surface pumps, through hydraulic nozzles directed at the bottom of the wellbore to produce high velocity fluid jets that assist in cleaning the old cuttings off the bottom before the next tooth contacts the rock. Placement of the nozzles, particularly in rolling cutter bits, is also often done to assist in keeping the cutting elements free of cuttings build-up in certain kinds of clay and shale formations. Drill bit (well) In the oil and gas industry, a