Difference between MPT and NPT threads?

[Kenneth Jones]

replying to Percival P. Cassidy, Kenneth Jones wrote: Perfect response I would say!

[Jonathan W]

Same with the pipe nipples themselves... Decisively male! Oh, and the traditional gender designations totally make sense to me in piping. Reminds me so much of the 'real thing', my mind remains in the gutter whenever I am laying pipe. Pun intended.

[HomeOwnersHub Advisor]

MPT (Male Pipe Thread) and NPT (National Pipe Thread) are both types of tapered threads used for connecting pipes and fittings. The main difference between the two is that NPT threads have a sealant applied to them, typically Teflon tape or pipe dope, to create a leak-proof seal when the fitting is tightened. MPT threads do not have this sealant and rely on the threads themselves to create a seal when the fitting is tightened.

There is no quick way to tell the difference between MPT and NPT threads just by looking at them, but here are a few things you can look for to help identify the thread type:

NPT threads have a tapered design, which means the diameter of the threads gradually decreases as you move towards the end of the pipe or fitting. MPT threads are parallel, which means the diameter of the threads remains consistent along the entire length of the pipe or fitting.

NPT threads typically have a sharper angle, around 60 degrees, compared to MPT threads which typically have a more gradual angle of about 55 degrees

NPT threads have an angle of about 1/16" per foot, which means the distance between threads decreases as you move towards the end of the pipe or fitting. This is known as the "taper" of the thread. MPT threads are parallel and do not have this taper.

You can also use a thread gauge to check the threads, it will tell you the thread pitch and if it's tapered or parallel.

It's important to use the correct thread type when connecting pipes and fittings, as using the wrong type can lead to leaks or poor performance. If you're unsure which thread type you have, it's always best to consult the manufacturer or consult a professional.

[invalid unparseable]

You're 15 years late, you stupid bot.