Hydraulic fittings
NPT Thread Chart
Reference geometry rows for NPT thread identification. Use with physical pitch and sealing checks.
Last updated 2026-05-12Confidence: reference-derived4 rows
| Nominal | Dash | Thread type | Pitch / TPI | Major diameter | Seal |
|---|---|---|---|---|---|
| 1/8 | tapered | 27 TPI | 0.405 in / 10.287 mm | thread | |
| 1/4 | tapered | 18 TPI | 0.540 in / 13.716 mm | thread | |
| 3/8 | tapered | 18 TPI | 0.675 in / 17.145 mm | thread | |
| 1/2 | tapered | 14 TPI | 0.840 in / 21.336 mm | thread |