Pipe Threads (BSP / NPT)
NPSM Straight Pipe Thread (Mechanical)
Straight pipe thread for free-fitting mechanical joints sealed by a gasket, such as hose couplings.
- Standard
- ANSI B1.20.1
- Flank angle
- 60°
- Sizes listed
- 15
- Range
- 1/8" - 27 NPSM – 6" - 8 NPSM
| Nominal Diameter | Major Diameter mm | Major Diameter Inch | Tapping Drill Size mm | TPI | Pitch mm |
|---|---|---|---|---|---|
| 1/8" - 27 NPSM | 10.287 | 0.405 | 9.246 | 27 | 0.941 |
| 1/4" - 18 NPSM | 13.716 | 0.540 | 12.217 | 18 | 1.411 |
| 3/8" - 18 NPSM | 17.145 | 0.675 | 15.545 | 18 | 1.411 |
| 1/2" - 14 NPSM | 21.336 | 0.840 | 19.279 | 14 | 1.814 |
| 3/4" - 14 NPSM | 26.670 | 1.050 | 24.638 | 14 | 1.814 |
| 1" - 11 1/2 NPSM | 33.401 | 1.315 | 30.759 | 11.5 | 2.209 |
| 1 1/4" - 11 1/2 NPSM | 42.164 | 1.660 | 39.497 | 11.5 | 2.209 |
| 1 1/2" - 11 1/2 NPSM | 48.260 | 1.900 | 45.568 | 11.5 | 2.209 |
| 2" - 11 1/2 NPSM | 60.325 | 2.375 | 57.607 | 11.5 | 2.209 |
| 2 1/2" - 8 NPSM | 73.025 | 2.875 | 69.266 | 8 | 3.175 |
| 3" - 8 NPSM | 88.900 | 3.500 | 85.166 | 8 | 3.175 |
| 3 1/2" - 8 NPSM | 101.600 | 4.000 | 97.739 | 8 | 3.175 |
| 4" - 8 NPSM | 114.300 | 4.500 | 110.388 | 8 | 3.175 |
| 5" - 8 NPSM | 141.300 | 5.563 | 137.363 | 8 | 3.175 |
| 6" - 8 NPSM | 168.275 | 6.625 | 164.186 | 8 | 3.175 |
Reference values only. Verify against the current edition of the governing standard before use in production drawings or manufacturing. Provided by Micro Components as a free engineering resource.