THREADING PIPE THREADS AND TOOL SELECTION ●Parallel Pipe Threads G(PF) Thread Type Number of threads Standard internal diameter G1/16 .258" 28 G1/8 .337" G1/4 .451" 19 G3/8 .589" G1/2 .734" G5/8 .811" 14 G3/4 .949" G7/8 1.098" G1 1.193" G1·1/8 11 1.376" G1·1/4 1.534" Note 1) Same as PF. ●Taper Pipe Threads R(PT), Rc(PS) G Thread Type Number of threads Standard internal diameter R1/16 .258" 28 R1/8 .337" R1/4 .451" 19 R3/8 .589" R1/2 14 .734" – – – R3/4 14 .949" – – – R1 11 1.193" – – – R1·1/4 11 1.534" Note 1) Same as Rc and PT. · The pitch is pre-determined for each nominal diameter. Note the minimum machining diameter especially when internal threading. G009