
29. Basic profile of threads ■American Standard Taper Pipe Threads (NPT) Production data Truncation Unit : mm Threads Section fc=fr per inch Internal Thread Central axis External Thread line of thread ■Dryseal American Standard Taper Pipe Threads (NPTF) Truncation Unit : mm Threads Section fc fr per inch Internal Thread Central axis line of thread External Thread ■Metric Trapezoidal Screw Threads (Tr) ■29˚ Trapezoidal Screw Threads (TW) Internal Thread Internal Thread External Thread External Thread d2 or D2 d1 or D1 d2 or D2 d or D D1 d1 D d Information Technical Technical-93