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
Tightening key Tightening key A corner key or tightening key is a small wedge or block of board, timber or plastic, inserted into the slotted inside corners of a canvas stretcher frame to prevent or adjust sagging. The piece is tapped in to expand the stretcher bars slightly, tensioning the canvas. The keys can be used to re-tighten the canvas as it relaxes naturally over time. Tightening keys are commonly made in plastic or wood, and are commonly known as corner keys or corner wedges. Corner keys or wedges come in various forms. Most are available for a single size stretcher bar,