NPSM straight pipe thread ring gages are manufactured per ANSI/ASME B1.20.1. NPSM threads are designed for free fitting mechanical joints. This pipe is often used for special applications where there is no internal pressures and is often found to be more suitable to use. All straight pipe thread ring gages are of Unified screw thread form and are supplied in a class 2A for external threads. The minimum pitch diameter of internal threads is basic and equal to E1 of NPT threads. Thread Check offers gages for a complete range for hose coupling screw threads covered under ASME B1.20.7. Other straight pipe thread gages include NPSF, NPSC, NPSL, NPSI, NPSH, and NH sizes. Thread Check’s expert sales engineers can assist you with selecting the correct gages for your application.