Countersinks

Countersinks are used to drill a tapered hole in a flat steel surface. The overall cut diameter is the wide end of the tapered hole. For example, a 1/2″ countersink is tapers from 1/2″ to zero. There are four types of countersinks, single flute, three flute, four flute, and six flute. They are available in 60, 82, 90, 100, and 120 degrees. A countersink is used to allow a screw or bolt to tighten down flush to the surface it is securing.