4 NPT Thread Dimensions

Standard: ANSI B 1.20.1
Pitch of thread: 3.175
Thread Angle: 60°
Taper Angle: 1°47′
Nominal Pipe Size: 4″
Outside Dia(D): 114.3 mm
Pitch diameter at plane of hand-tight engagement (E): 111.433 mm
position of handtight engagement(L1):21.438mm/6.75Gg
usefull external thread(L2): 33.020mm
external thread with complete thread profile(L4): 26.670mm
Tapping Drill Size: 107.00 mm