I was wondering if anyone could tell me how to quickly and easily size the threads on a NON-FIRST pneumatic coupling. Is this done the same as sizing threads on a standard screw?
Thanks,
indieFan
There are many types of pipe threads used here in the USA. The most common and easily found at the local hardware store is NPT. This is a tapered thread and is most easily checked by measuring the outside of the pipe or inside of the inernal thread and then checking against the following:
NPT – OD of pipe
1/16- 27 – 0.3125
1/8-27 – 0.405
1/4-18 – 0.540
3/8-18 – 0.675
1/2-14 – 0.840
Size would be the closest/next largest.
More info can be found at http://www.mcmaster.com/ and searching ‘pipe threads’ , click on ‘pipe measurement’.
If all fails take the fitting to the hardware store and they can tell you by matching. If you have a straight thread then this is another can of worms and they will not match with anything you have from FIRST.