Manufacturing Screw Threads
How are threads made?
Internal Threads:
- First a tap drill hole is cut with a twist drill.
- Then the threads are cut using a tap.
- Chamfers are sometimes cut to allow for easy engagement.
External Threads:
- You start with a shaft the same size as the major diameter.
- The threads are then cut using a die or on a lathe.
Why is the tap drill diameter a little bigger than the minor diameter of the mating thread?
Why is the tap drill hole longer than the length of the threads that you specify?