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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 alsodrill press.
This entry comes from Encyclopædia Britannica Concise. For the full entry on drill, visit Britannica.com.