Does BSPT R 3 1/2" exist?

[emonje]

I see here a drawing saying 'BSPT thread, 3 1/2"'. As far I know BSPT jumps straight from 3" to 4". Can anyone please clarify?
Thanks.

 

[desertfox]

Hi emoje

I think your correct, have a look at this site:-

http://www.roymech.co.uk/Useful_Tables/Flanges/Pipe_Threads.html#tt

However any thread can be turned once you have the geometric relationship. If you look through this site you will see under the tapered thread info relating to the thread geometry.
Maybe its a drawing error buts its worth asking the question.

regards

desertfox

 

[unclesyd]

If you can find someone who has this type pipe threading device for BSPT threads you should be able to get the thread required. Your best bet would be to find someone who installs fire sprinkler piping as they use a lot of 3 1/2" pipe.
Also some rental companies have these type machines for rent.

http://www.drillspot.com/products/63299/Ridgid_141_Geared_Pipe_Thread_Ratchet