NPSM Hose Ends: Straight Threads, Swivel Seats, and Correct Mating Parts
May 25th 2023
National Pipe Straight Mechanical describes a parallel pipe thread used in a mechanically seated connection. In common hydraulic hose-end arrangements, the straight threads pull a swivel nut onto a compatible male nose while the mating seats form the seal. The threads retain the parts; they are not normally the primary fluid boundary.
This distinction explains two frequent service problems. A stra