Home Pipe Threads 12" NPT

12" NPT Thread Specifications

Complete dimensions for 12" NPT pipe thread. TPI: 8, Pitch: 0.125" (3.175 mm).

Thread Dimensions

Designation12" NPT
Nominal Pipe Size12"
TPI8
Pitch0.125" (3.175 mm)
Outside Diameter12.75" (323.85 mm)
Pitch Diameter12.6688" (321.79 mm)
Minor Diameter12.5966" (319.95 mm)
Taper Angle1.7899° (1:16 taper ratio)
Thread Depth0.0866" (2.2 mm)

Tap Drill Size

Tap drill: 12.5966" (319.95 mm)

Common Applications