Drill bits are but one of the many tools used in industry. Regardless of the shape or design of the bit, they are designed to perform a single function and that is to drill a round hole in a given material. The drill bits are fitted into a rotating drilling machine, the drill can either be a hand held device or a rigid machine tool such as a drill press or lathe. There are many different drills, extra long drills for drill either very deep holes or penetrating thick material as well as reduced shank drills, double end drills, etc. Depending on the material to be drilled, the drill can be made from carbide tips or plain heat treated steel.
Depending on the type of drilling machine, drill bits can have a straight shank, a reduced diameter shank or a tapered shank. Straight and reduced diameter shanks are used in both hand held and stationary drilling machines, tapered shank drills are used exclusively in stationary drill presses and other rotating machine tools; extra long drills are usually straight shank. Drills which have a fixed diameter shank are held from rotating by a chuck, a device which closes down on the drill bit and locks it securely in position. In the case of tapered shaft drill bits, the bit has a tang machined on one end; it in turn fits into a corresponding slot in the rotating drill socket. The taper is held in place by friction and the tang.
In many home workshops and industrial machine shops drill bits are often bought in sets. The drill bits that are sold for home use are simple hardened steel, as the bits are subjected to much harder work in an industrial environment, they are usually carbide tipped.
Extra long drills have their place in industry; they are used to drill very deep holes or to drill straight through a thick slab of material. There are also applications where the surface which is to be drilled is deep set in a machine or component and the additional length is not used for the depth of the hole but for the distance the surface to be drilled is away from the drilling machine. These drills are often seen in the aircraft industry.
