Polysulfone Qc Npt & Bsp

[markws]

I am considering using 1/2" full port bsp valves on my AG set-up.

I know the rule of thumb is that BSP and NPT are not compatible althought there are minor differences between the two thread types - such as thread pitch. However many comments via google indicate that you will not truely notice this difference until you get to around 2 to 3 ".

Therefore are 1/2" npt polysulfone QC's compatible with 1/2" bsp ball valves.

Groups such as B3 only offer this type of combination - My assumption is that my comment is correct.

Any replies would be appreciated.

MWS

 

[Rex]

Therefore are 1/2" npt polysulfone QC's compatible with 1/2" bsp ball valves.

[post="101777"][/post]​

Well I've got various 1/2" bits and pieces (inc polysulfone QCs) and everthing seems to screw in and not leak. Sometimes you can't always screw things as far as you'd like, but that's generally fixed with the right amount to teflon tape.

Good luck

 

[Prof. Pils]

As long as it does'nt leak. Sounds good to me.
Cheers Glenn

 

[Stagger]

YES

Both have 14 threads per inch however the NPT screwing into a BSP fitting will be a little loose (not to bad through) just use more thread tape. The two difference are the thread angle NPT is 60 deg and BSP is 55 deg and there are some small differences in the major and minor dia sizes.


The problem is in the size range 1 2 in NPT the TIP (threads per inch) is 111/2 Threads and BSP is 11 Threads.

The same problem in Whitworth (BSW) and Unified Coarse (UNC) at BSW is 12 TPI and UNC is 13 TPI, BSW are interchangeable with UNC apart from . BSW is 55 deg and UND is 60 deg this only a problem when using high pressure and alike.


So the answer to your question is yes will be fine it is one is American and one is British thread.


Stagger

 

[markws]

thanks for the response stagger - just wanted to be 100% sure prior to ordering a batch of them from the US

regards

MWS