R2-1/2 vs 2-1/2-8NPSH: specs compared
Updated 05 September 2026.
75.184 mm
R2-1/2 wins on major diameter
On major diameter, R2-1/2 leads: 75.184 mm versus 72.16 mm.
| Spec | R2-1/2 | 2-1/2-8NPSH |
|---|---|---|
| Designation | R2-1/2 | 2-1/2-8NPSH |
| Major diameter | 75.184 mm | 72.16 mm |
| Threads per inch / pitch | 11 | 8 |
| Thread form | tapered, 55 degree | straight (parallel), 60 degree |
| Seals on | on the thread flanks with PTFE tape or paste | gasket in the coupling |
Questions and answers
Which has the higher major diameter, R2-1/2 or 2-1/2-8NPSH?
On major diameter, R2-1/2 leads: 75.184 mm versus 72.16 mm.
How do R2-1/2 and 2-1/2-8NPSH compare?
On major diameter, R2-1/2 leads: 75.184 mm versus 72.16 mm.