3-1/2" NPT Thread Specifications
Complete dimensions for 3-1/2" NPT pipe thread. TPI: 8, Pitch: 0.125" (3.175 mm).
Thread Dimensions
| Designation | 3-1/2" NPT |
| Nominal Pipe Size | 3-1/2" |
| TPI | 8 |
| Pitch | 0.125" (3.175 mm) |
| Outside Diameter | 4" (101.6 mm) |
| Pitch Diameter | 3.9188" (99.54 mm) |
| Minor Diameter | 3.8466" (97.7 mm) |
| Taper Angle | 1.7899° (1:16 taper ratio) |
| Thread Depth | 0.0866" (2.2 mm) |
Tap Drill Size
Tap drill: 3.8466" (97.7 mm)
Common Applications
- Plumbing connections
- Gas piping
- Hydraulic fittings
- Pneumatic connections