n.
Tool to make holes, usually by revolving.
Drills, gimlets, and augers have cutting edges that detach material to leave a hole. Drilling usually requires high speed and low torque , with little material being removed during each revolution of the tool. The earliest (perhaps Bronze Age ) drill points had sharp edges that ultimately developed into arrow shapes with two distinct cutting edges. This shape was effective and remained popular until the late 19th century, when factory-made, spiral-fluted twist drills became available at reasonable cost to displace the blacksmith-made articles. Rotating drill bits containing diamonds or other hard materials are used for drilling rock, as for tunnels or oil wells. See also drill press .