DIES are usually round and are used for cutting external threads. They can be held in a Die Stock for hand operation or in a Die Holder for use by machine. Dies are usually split which enables adjustment for precision, and also to extend the life of the die as it wears. They can also be solid which makes them fixed. Taper thread dies (NPT, BSPT) are usually solid. The lead at the front (etched) face is normally 3 pitches, for standard threading, and 2 pitches at the back face for closer threading, or soft materials. DIE NUTS are hexagonal, for turning with a wrench or spanner, and are usually used for repairing damaged threads.

DIE NUTS are hexagonal, for turning with a wrench or spanner, and are usually used for repairing damaged threads.