G1/8 vs R1/8: specs compared
Updated 05 September 2026.
3
specs differ
G1/8 and R1/8 differ on 3 specs: designation, thread form, seals on.
| Spec | G1/8 | R1/8 |
|---|---|---|
| Designation | G1/8 | R1/8 |
| Major diameter | 9.728 mm | 9.728 mm |
| Threads per inch / pitch | 28 | 28 |
| Thread form | parallel, 55 degree | tapered, 55 degree |
| Seals on | flat washer or bonded seal on the face | on the thread flanks with PTFE tape or paste |
Questions and answers
How do G1/8 and R1/8 compare?
G1/8 and R1/8 differ on 3 specs: designation, thread form, seals on.