NPT threads

Underburden · Jan 18, 2016

Are the threads on a male PVC fitting the same as the threads on a short shank female coupling like those you'd have on layflat hose? (see image)
I want to mate the 1½" short shank to a 1½" PVC fitting but I'm not sure if the threads are compatible.
Thx for the help

Bob

motohed · Jan 18, 2016

They should be I've used simular fitting with no problem , generally always NPT .

SpecJet · Jan 18, 2016

The brass fitting on the lay-flat is a NST straight thread, the NPT pipe fitting is tapered.
They are both the same pitch (threads per inch) and same diameter.

They do work together but the joint will not be full strength because of the tapered pipe thread.

Underburden · Jan 18, 2016

Thank you
Bob

SpecJet · Jan 18, 2016

Forgot to add.
The plastic pipe fittings suck, they will eventually crack between the threads.
Metal fittings are worth their price.

Reed Lukens · Jan 18, 2016

Cam-locks are a lot easier if you are transporting your equipment every day, any plumbing or rubber shop has either type you are looking for. You can get them in hose thread or pipe thread and there is a difference in the thread pitch. The pvc is npt and when looking at them, you can't see the difference until... you try to match the hose thread to the pipe thread, so be sure that you get the same thread for both or just go cam-lock's forever like I did decades ago

- 2" Aluminum Part C Female Coupler x Hose Shank - AL-C200

Underburden · Jan 18, 2016

At the link Reed posted, looks like Part A and Part C would work provided Part A's threads mate to the PVC fitting's thread.

Bob

Reed Lukens · Jan 18, 2016

Underburden said:
At the link Reed posted, looks like Part A and Part C would work provided Part A's threads mate to the PVC fitting's thread.

Bob

Yes part a matches up but why the pvc? If you can - stay away from pvc

Hoser John · Jan 19, 2016

Never use pvc if humanly possible. 1 rock-1 slip-1 misstep and crunch days over-John

ebuyc · Jan 20, 2016

I like the plastic cam locks better

Bob you can screw the NST brass hose fitting onto the PVC no problem as the seal is the rubber washer between them. I personally threw those connectors away because I was ALWAYS loosing that stupid rubber washer!

Ok so ABS does not get brittle like PVC and the ABS plastic cam lock quick connects are super strong. I think the plastic cam locks are actually better then the cast aluminum ones. The interior diameter of the aluminum cam locks is seriously restricted and has a rough texture, not consistent from one cast to the next. BUT the plastic ones have a much larger I.D. and are nice and smooth on the inside. The plastic ABS is not going to break either. When I was building my 2", 2.5" and 3" dredges the I.D. of the couplers really came into play. Feeding a Highbanker it is probably mute.