Taps and dies are metal threading tools, tap and die sets are used to cut and restore internal and external threads precisely. A tap is used to form the female component of the assembly, as in the case of a nut or socket, a die is used on the male component, as in a screw or bolt. In other words, a Tap is used to create the internal threads in a hole and a die is used to make or repair external threading on a round rod, screw, or bolt. T handle wrenches are used with a tap to create or repair an internal thread. T Handles hold the end of a tap to provide extra leverage for hand tapping.