SpudFiles

Ok guys is it ok to use BSPP and NPT fittings together? There is a 5 degree pitch different but ive heard that this is not a problem, but im not sure at pressues of about 8bar?

The sizes i would be using would be 3/4" and 1/4". Any knowladge would be helpfull.

Thanks

NH

Officially: no.
But you could. They are semi-compatible. Some sizes have the same pitch and work better together then others. Main difference is the shape of the threads.
Crossing them over does not guarantee a leak-free joint. It may also differ per manufacturer.

Here is a link with some nice information:
http://www.colder.com/Portals/0/pdfs/NPT.pdf

I would say if your dealing with pvc and Teflon tape it COULD work. But if your dealing with metal I would say it's a no go.

What are you threading together. If you haven't (or even have) already bought it, we might be able to suggest an alternative.

I found my alternative, the page before in the catologue was stuck to this page and has all the bspp fittings

Thanks though!

Theoretically, you can buy converting fittings for the threads if you want to be really sure.
Airlines do them up to 1/2" size here, you might be able to find 3/4" somewhere else.

NPT male/BSPT male
NPT male/BSPP female
BSP male/NPT female

Then again, I've run sizes that really aren't supposed to be mixed before. A common one is mixing 1/2" BSPP and 15mm compression threads - with healthy amounts of PTFE tape.

Cheers but yeah i found all bsp threads on the previous page i feel so silly.

possibly you will be with leak problem