Threading Dies Information

Threading die Threading dies are used to form or cut a male thread on the outside of rods or bars. Threading dies provide precision in cutting and extend the life of a die by reducing wear. Taps and dies are the tools used for cutting threads. A male thread (bolt) is fed between rollers that have the full thread form grounded into their outer diameter. The lobes mold the material into the required thread form and shape. Threading dies are used for either thread cutting or thread forming. Thread cutting can be internal or external. For large volume productions or for greater strength, threads are rolled for thread forming. Threading dies use rolled thread that has greater strength than a cut thread, though it usually requires more energy to roll a thread than cutting the thread.


Threading dies have several variations, including:

  • top adjusting screws
  • side adjusting screws
  • non adjustable screws


There are a variety of ways in which threading dies function. Threading dies cut a male thread and are used with taps that cut the mating female threads. A metric threading die represents thread by pitch instead of inch, which is the method of thread designation in the United States. In metric thread dies, the thread pitch is specified in millimeters. A metric threading die is fundamentally different because the thread pitch is specified instead of threads per inch, or threads per millimeter. There are generally three types of taps: taper, plug, and bottoming. A tap cuts a female thread on the inside surface of a pre-drilled hole. A tap is lobed and does not have any cutting edges. It is forced into a hole and the material is changed into the required thread form by the lobes. Die head tap threading is used in the high-volume production of threaded components. A chaser is inserted into the die head and the die head is closed bringing the chasers down to a cutting position. When a sufficient length of thread has been cut, the head of the threading dies opens to allow the head to retract rapidly without interfering with the new thread formed. Threading dies are designed and manufactured to meet most industry specifications.


Threading dies are used in a variety of applications. Threading dies are commonly used in industrial metal working. Threading dies are used for repairing threads in stripped holes or bolts. Rolled threading dies have an increased advantage of strength, longer life, and reduced material cost. Taps are used in motorcycles, cars, and industrial machinery. Threading dies are also used for rethreading jammed pipes.

Related Information

CR4 Community—Threading and Galvanized Pipes

Image credit:

Glenn McKechnie / CC BY-SA 3.0