a machine for working metal (mainly steel) pipes by chip removal or threading.
Pipe-working machines are of three main types. Cutting machines are used to obtain accurate end surfaces. Pipe-threading and pipe-roll-threading machines are used to obtain cylindrical and tapered threads; the roll-threading method usually provides a stronger threaded joint. In the manufacture of pipes and tubing for critical applications, special machines are used to remove the imperfect external layer of pipes prior to cold rolling.