crystalltiice
Aluminum
- Joined
- Jul 31, 2015
Hi,
So as the title suggests, I would like to cut a "universal thread" for 1/4 NPT/BSP fittings. I did not know this existed until I recently discovered some official fittings stating that they are "universal". The first time I came across something similar was on a Chinese hydraulic ram port. When measured the thread pitch gauge for 18 and 19 TPI both rock slightly so not a perfect fit.. Can't remember what fitting I ended up using but recall that it fitted fine. I just assumed it is bad Chinese tolerance but now it seems it might be a "universal thread/pitch".
Here is an example of the thread: https://www.industrialspec.com/shop/media/catalog/pdf/universal_thread_spec.PDF
I think the other reference was from a George + Fischer catalog, they claimed it was a patented thread form even though I can't seem to find any patent.
Edit: Might have been John Guest:STRAIGHT ADAPTOR - SUPERTHREAD | John Guest
and here (page 3 of the pdf): http://www.cameco-tubings.be/sites/default/files/Push-In Speedfit Fittings -Guide-En.pdf
So the question is what is the official pitch/ thread form for this "universal thread/pitch"? I have both 18 and 19 TPI 1/4 pipe thread taps and the thought was to just use both in the same hole, probably not the most elegant way but worth a shot.
So as the title suggests, I would like to cut a "universal thread" for 1/4 NPT/BSP fittings. I did not know this existed until I recently discovered some official fittings stating that they are "universal". The first time I came across something similar was on a Chinese hydraulic ram port. When measured the thread pitch gauge for 18 and 19 TPI both rock slightly so not a perfect fit.. Can't remember what fitting I ended up using but recall that it fitted fine. I just assumed it is bad Chinese tolerance but now it seems it might be a "universal thread/pitch".
Here is an example of the thread: https://www.industrialspec.com/shop/media/catalog/pdf/universal_thread_spec.PDF
I think the other reference was from a George + Fischer catalog, they claimed it was a patented thread form even though I can't seem to find any patent.
Edit: Might have been John Guest:STRAIGHT ADAPTOR - SUPERTHREAD | John Guest
and here (page 3 of the pdf): http://www.cameco-tubings.be/sites/default/files/Push-In Speedfit Fittings -Guide-En.pdf
So the question is what is the official pitch/ thread form for this "universal thread/pitch"? I have both 18 and 19 TPI 1/4 pipe thread taps and the thought was to just use both in the same hole, probably not the most elegant way but worth a shot.