Threading Full profilePartial profileFull profilePartial profileFull profilePartial profilePartial profilePartial profilePartial profile Introduction  Tooling application table (External thread) Metric Unified Parallel pipe Whitworth Tapered pipe American nationaltapered pipe30˚ trapezoidal Thread types M UN, UNCUNF, UNEF G(PF) W R(PT)(BSPT) NPT Tr Internal Internal Internal Internal Internal Internal Internal 1˚47' 1˚47' 30˚ Thread shape 60˚ 60˚ 55˚ 55˚ 55˚ 60˚ TP TP TP TP TP TP TP External External External External External External External Pitch mm TPI TPI TPI TPI TPI mm Toolholder shape KTN (KTN-JCT) 0.5~5.0 24~8 19~11 16~11 28~11 18~11.5(0.5~3.0)(24~8)(19~11)(16~11)(28~11)(18~11.5)- 0.5~5.0 48~5 28~11 40~5 28~11(0.5~3.0)(48~8)(28~11)(40~8)(28~11)- 2.0~5.0(2.0~3.0) KTNS 0.5~3.0 24~8 19~11 16~11 28~11 18~11.5 - J 0.5~3.0 48~8 28~11 40~8 28~11 - 2.0~3.0 Sleeve holder S-KTN KTT 1.0~2.0 - - - - - - 0.5~3.5 56~8 28~11 24~7 28~11 - - KTTX 0.5~2.0 56~14 28~11 24~11 28~11 - - S-KTTX 0.5~2.0 56~14 28~11 24~11 28~11 - - KTKF KTKF(Goose-neck holder) 0.2~1.5 64~18 28~19 40~16 28~19 - - Pitch inside ( ) indicates KTN-JCT. J4