Drill (tool)

A drill is a cutting tool for making holes in solid material, although especially handheld power drills can be used as a general-purpose power source for rotating tools such as screwdriver bits and sanding disks. Its most common implementation is a means to rotate and press a drill bit against, and into, the material to be drilled. Some drills do not rotate the bit, but hammer it against the piece being worked.

Primitive drills, which might be no more than a sharpened rock hammered against the work, are among the earliest human tools. Drills for some applications are still muscle-powered, but the majority of industrial drills are driven by an electrical motor or compressed air. Very large drills, such as those used to make oil wells, may be powered by a gasoline or diesel motor. Some hammer drills use an explosive charge to drive the bit.

Drill bits are usually replaceable, since they wear out faster than the drill motor. For many hand and industrial processes, the drill accepts different sizes, point types, and materials of drill bits, for different applications.

Waste or core removal

Many drills grind the material removed into small waste. Some drills, however, keep the removed material as intact as possible. One type is called a core drill, which is used in geology to take soil samples. Hole saws also produce intact cores,