1-11.5 NPT vs 1-1/2-9NH: specs compared
Updated 05 September 2026.
50.55 mm
1-1/2-9NH wins on major diameter
On major diameter, 1-1/2-9NH leads: 50.55 mm versus 33.4 mm.
| Spec | 1-11.5 NPT | 1-1/2-9NH |
|---|---|---|
| Designation | 1-11.5 NPT | 1-1/2-9NH |
| Major diameter | 33.4 mm | 50.55 mm |
| Threads per inch / pitch | 11.5 | 9 |
| Thread form | tapered, 60 degree | straight (parallel), 60 degree |
| Seals on | on the thread flanks with PTFE tape | rubber gasket in the female swivel |
Questions and answers
Which has the higher major diameter, 1-11.5 NPT or 1-1/2-9NH?
On major diameter, 1-1/2-9NH leads: 50.55 mm versus 33.4 mm.
How do 1-11.5 NPT and 1-1/2-9NH compare?
On major diameter, 1-1/2-9NH leads: 50.55 mm versus 33.4 mm.