Pipe thread designation

[engtobe]

Hi,

We order 1" NPT here at the company I work for. We have had several batch, sometime the are cut thread, sometime it's a rolled thread.

We assemble different pieces of pipe, elbow and valves together, all of this while trying to keep the length within tolerance. I noticed that the assembly is easier as well as consistent when we have rolled thread.

My Question is the following; Is there a standard designation that I can ask for when ordering the pipes and fittings to ensure that I am getting a rolled thread, not a cut one?

I have looked in handbooks, several other related books and the web, without succes. If someone can help me, it would be appreciated.

Thank for your time
Alain

 

[nackra]

http://www.engineeringtoolbox.com/npt-national-pipe-taper-threads-16_750.html

http://www.tflx.com/pdf/nptsizes.pdf

http://www.colder.com/Downloads/NPT.pdf

try the posted links. I believe that they will help.

 

[Cockroach]

No, there is no standard. You are getting an industrial practice preference between one company and another.



Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada