Hi Guys, My friend is asking me to do the calculation for NPT thread. He is asking if 1 1/4 NPT thread is able to hold 10 000Psi pressure acting on it. In my opinion there is no need to do the calculation for the thread. Of course it will hold it. Don't quote me on this but I think that there is no difference in the way how low and high pressure npt threads are cut. High pressure fittings are more bulky due to pressure. What are your thoughts?