1-1/2-9NH vs 1-1/4-11.5 NPT: 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 42.16 mm.
| Spec | 1-1/2-9NH | 1-1/4-11.5 NPT |
|---|---|---|
| Designation | 1-1/2-9NH | 1-1/4-11.5 NPT |
| Major diameter | 50.55 mm | 42.16 mm |
| Threads per inch / pitch | 9 | 11.5 |
| Thread form | straight (parallel), 60 degree | tapered, 60 degree |
| Seals on | rubber gasket in the female swivel | on the thread flanks with PTFE tape |
Questions and answers
Which has the higher major diameter, 1-1/2-9NH or 1-1/4-11.5 NPT?
On major diameter, 1-1/2-9NH leads: 50.55 mm versus 42.16 mm.
How do 1-1/2-9NH and 1-1/4-11.5 NPT compare?
On major diameter, 1-1/2-9NH leads: 50.55 mm versus 42.16 mm.