2-1/2-8NPSH vs R3: specs compared
Updated 05 September 2026.
87.884 mm
R3 wins on major diameter
On major diameter, R3 leads: 87.884 mm versus 72.16 mm.
| Spec | 2-1/2-8NPSH | R3 |
|---|---|---|
| Designation | 2-1/2-8NPSH | R3 |
| Major diameter | 72.16 mm | 87.884 mm |
| Threads per inch / pitch | 8 | 11 |
| Thread form | straight (parallel), 60 degree | tapered, 55 degree |
| Seals on | gasket in the coupling | on the thread flanks with PTFE tape or paste |
Questions and answers
Which has the higher major diameter, 2-1/2-8NPSH or R3?
On major diameter, R3 leads: 87.884 mm versus 72.16 mm.
How do 2-1/2-8NPSH and R3 compare?
On major diameter, R3 leads: 87.884 mm versus 72.16 mm.