Threading

Tapping machine

Hole after tapping

Threaded rod

Threading is a process that creates threads on cylindrical shapes by, in the case of internal threads (e.g. a nut), rotating a cutting tool into a hole; or in the case of external threads (e.g. a screw) rotating a cutting tool onto a shaft. Alternatively single point threading applies a tool to a rotating part to form threads. Internal threading is also often referred to as tapping.

Threading is often intended to prepare a feature to accept a screw, nut or mating threaded part. Threading is a low cost method of securely fastening parts together. Motion conversion systems also use threading, for example when a lead screw is used to convert the rotary motion of a conventional or stepper motor into a precise linear motion.

Most hard materials can be used for threading. Usually the tooling required is a stock item.

Threading Design Considerations

• Avoid very hard materials such as many stainless steels.
  
• Minimize number of types of threads.
  
• Reduce depth of threading.
• Consider requesting to re-tap after powder coating or plating or to plug threaded holes before finishing.
• Try to use standard thread sizes.