NPSC – Internal Straight Pipe Thread
NPSC is a lesser-known pipe thread standard series defined in ASTM B1.20. These Internal Straight (parallel) Pipe Threads are used to manufacture pressure-tight fittings when assembled with an NPT external taper thread. This series applies to internal threads only. (The external thread is the standard NPT thread).
NPSC, Internal Straight Pipe Thread Dimensions Chart
- Dimensions in Inches
- The dimensions are identical to the standard internal NPT profile except for the parameters that are listed in the below chart
| Thread | Pipe | Pipe OD | Pitch (TPI) | Minor Diameter (Min) | Pitch Diameter (Range) |
|---|---|---|---|---|---|
| 1/8-27 NPSC | 1/8 | 0.405 | 27 | 0.34 | 0.3701 - 0.3771 |
| 1/4-18 NPSC | 1/4 | 0.54 | 18 | 0.442 | 0.4864 - 0.4968 |
| 3/8-18 NPSC | 3/8 | 0.675 | 18 | 0.577 | 0.6218 - 0.6322 |
| 1/2-14 NPSC | 1/2 | 0.84 | 14 | 0.715 | 0.7717 - 0.7851 |
| 3/4-14 NPSC | 3/4 | 1.05 | 14 | 0.925 | 0.9822 - 0.9956 |
| 1-11.5 NPSC | 1 | 1.315 | 11.5 | 1.161 | 1.2305 - 1.2468 |
| 1 1/4-11.5 NPSC | 1 1/4 | 1.66 | 11.5 | 1.506 | 1.5752 - 1.5915 |
| 1 1/2-11.5 NPSC | 1 1/2 | 1.9 | 11.5 | 1.745 | 1.8142 - 1.8305 |
| 2-11.5 NPSC | 2 | 2.375 | 11.5 | 2.219 | 2.2881 - 2.3044 |
| 2 1/2-8 NPSC | 2 1/2 | 2.875 | 8 | 2.65 | 2.7504 - 2.7739 |
| 3-8 NPSC | 3 | 3.5 | 8 | 3.277 | 3.3768 - 3.4002 |
| 3 1/2-8 NPSC | 3 1/2 | 4 | 8 | 3.777 | 3.8771 - 3.9005 |
| 4-8 NPSC | 4 | 4.5 | 8 | 4.275 | 4.3754 - 4.3988 |
