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
Down-the-hole drill introduction of high air pressures (25 bar plus) has meant that the DTH system can compete easily and efficiently with other drilling systems. DTH tools were used to locate the trapped miners in Chile and enabled food, water, and medicine to be passed to them and communication systems to be set up that eventually led to their safe rescue. DTH is short for “down-the-hole”. Since the DTH method was originally developed to drill large-diameter holes downwards in surface-drilling applications, its name originated from the fact that the percussion mechanism followed the bit down into the hole. Applications were later found