1/4" NPT (1/4-18 NPT) vs Bsp58: specs compared
Updated 05 September 2026.
5
specs differ
1/4" NPT (1/4-18 NPT) and Bsp58 differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.
| Spec | 1/4" NPT (1/4-18 NPT) | Bsp58 |
|---|---|---|
| Designation | 1/4-18 NPT | 5/8" BSP (7/8"-14 nut) |
| Size / thread | 1/4-18 NPT tapered | 5/8" BSP female, carried on a 7/8"-14 coupling nut |
| Fitting form | tapered, 60 degree | parallel beer thread |
| Seals on | on the thread flanks with PTFE tape or paste | flat nylon or fibre washer on the face of the thread |
| Rating / role | US pipe thread on some regulators, gauges and check valves | the US and UK draft shank and Sanke coupler beer thread |
Questions and answers
How do 1/4" NPT (1/4-18 NPT) and Bsp58 compare?
1/4" NPT (1/4-18 NPT) and Bsp58 differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.