Thread Milling Tools BSP ( G ) B.S.84: 1956 INTERNAL / EXTERNAL ISO 228 - 1: 1994 BSP NUT R.O.137P 55 R.O.137P BBSSPP SCREW SCREW STRAIGHT FLUTES THREAD SIZE PITCH ORDERING L L1 D1 D2 NO. OF TPI CODE FLUTES 1 1/16"-1/8" 28 TMX06059L11 28BSP 57 11.3 6 5.9 3 2 1/4"-3/8" 19 TMX10099L16 19BSP 73 16.6 10 9.9 4 3 1/2"-7/8" 14 TMX12119L22 14BSP 83 22.7 12 11.9 4 4 1"-2" 11 TMX16159L32 11BSP 105 32.1 16 15.9 4 5 6 BSPT SCREW 7 8 9 BSPT ( Rc ) 10 INTERNAL / EXTERNAL 11 B1.2S.21: 1985 BSPT NUT R.O.137P 13 27.5 27.5 14 15 R.O.137P 1 47 BSPT SCREW 16 S1T7 RAIGHT FLUTES 18 THREAD SIZE PITCH ORDERING L L1 D1 D2 NO. OF TPI CODE FLUTES 19 210 1/16"-1/8" 28 TMX06059L11 28BSPT 57 11.3 6 5.9 3 221 1/4"-3/8" 19 TMX10099L16 19BSPT 73 16.6 10 9.9 4 232 1/2"-7/8" 14 TMX12119L22 14BSPT 83 22.7 12 11.9 4 4 1"-2" 11 TMX16159L32 11BSPT 105 32.1 16 15.9 4 6 26 7 90