Making a pipe thread is easier than people believe, but it is important to perfect a few details. The way they are manufactured is very similar to that of a standard thread.
We have found that the easiest way to make pipe threads is through a CAD software. This will allow you to make slight adjustments to the pitch, various depths and diameter of the part. We use CAMWorks but there are many other options available. Within CAMWorks we can adjust nearly every detail of an NPT thread to bring a part within spec. It is important to know the tolerance of your NPT thread and to have the proper inspection equipment (thread gauge or ring gauge)
Manufacturing a Pipe Thread
How to Manufacture a Pipe Thread
- Profile the Part
Cut the OD of the part to have the desired taper
- Tool Selection
Select a NPT threading insert or a standard threading insert. Some NPT threads have roots which may require a special NPT insert. Otherwise a standard insert should be fine.
- Threading the Part
Run the insert across the OD of the part in accordance to the pitch, taper, major and minor diameter.
Inspecting a Pipe Thread
Pipe threads are typically inspected with a ring gauge or a thread gauge. The general rule of thumb is the gauge has to be within 1 revolution of depth. In other words, the gauge can be one revolution short or one revolution past the desired depth.
For information on any threads we like to use the Threadcheck software tool. It has a plethora of information on threads and we highly recommend it. You can try it for free or purchase licenses directly from their website here.