1/4" NPT (1/4-18 NPT) vs Bsp38: specs compared
Updated 05 September 2026.
5
specs differ
1/4" NPT (1/4-18 NPT) and Bsp38 differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.
| Spec | 1/4" NPT (1/4-18 NPT) | Bsp38 |
|---|---|---|
| Designation | 1/4-18 NPT | 3/8" BSP (G3/8) |
| Size / thread | 1/4-18 NPT tapered | 3/8" BSP (G3/8) parallel |
| Fitting form | tapered, 60 degree | parallel pipe thread |
| Seals on | on the thread flanks with PTFE tape or paste | flat washer on the thread face |
| Rating / role | US pipe thread on some regulators, gauges and check valves | the smaller UK dispense thread on some shanks, John Guest stem adapters and inline taps |
Questions and answers
How do 1/4" NPT (1/4-18 NPT) and Bsp38 compare?
1/4" NPT (1/4-18 NPT) and Bsp38 differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.