29. Basic profile of threads Production data ■American Standard Taper Pipe Threads Truncation Unit : mm Threads Section fc=fr per inch Internal Thread Threads per inch Central axis External Thread line of thread ■Dryseal American Standard Taper Pipe Threads Truncation Unit : mm Threads Section fc fr per inch Internal Threads per inch Thread Central axis External Thread line of thread ■Metric Trapezoidal Screw Threads ■29˚ Trapezoidal Screw Threads Internal Thread Internal Thread External Thread External Thread d1 or D1 d2 or D2 d or D d1 D1 d2 or D2 d D Technical Information Threads per inch Technical-83 854