Taps, dies and threaders are cutting tools used to create screw threads. Taps are used to cut the female portions of the mating pair (e.g., a nut). Dies are used to cut the male portion of the mating pair (e.g., a screw). The process of cutting threads using a tap is called tapping, whereas the process using a die is called threading. Both tools can be used to clean up a thread, which is called chasing.