R3/8 vs 4-1/2-4NH: specs compared
Updated 05 September 2026.
146.3 mm
4-1/2-4NH wins on major diameter
On major diameter, 4-1/2-4NH leads: 146.3 mm versus 16.662 mm.
| Spec | R3/8 | 4-1/2-4NH |
|---|---|---|
| Designation | R3/8 | 4-1/2-4NH |
| Major diameter | 16.662 mm | 146.3 mm |
| Threads per inch / pitch | 19 | 4 |
| Thread form | tapered, 55 degree | straight (parallel), 60 degree |
| Seals on | on the thread flanks with PTFE tape or paste | rubber gasket in the female swivel |
Questions and answers
Which has the higher major diameter, R3/8 or 4-1/2-4NH?
On major diameter, 4-1/2-4NH leads: 146.3 mm versus 16.662 mm.
How do R3/8 and 4-1/2-4NH compare?
On major diameter, 4-1/2-4NH leads: 146.3 mm versus 16.662 mm.