Thread Milling Tools BSP ( G ) B.S.84: 1956 INTERNAL / EXTERNAL ISO 228 - 1: 1994 BSP NUT R.O.137P 55 R.O.137P BSP SCREW HELICAL FLUTES THREAD PITCH ORDERING L L1 D1 D2 NO. OF SIZE TPI CODE FLUTES 1 1/16" 28 TMG06059L11 28BSP 57 11.3 6 5.9 3 2 1/8" 28 TMG08079L14 28BSP 63 14.0 8 7.9 3 3 1/4"-3/8" 19 TMG10099L16 19BSP 73 16.6 10 9.9 4 4 1/2"-7/8" 14 TMG12119L22 14BSP 84 22.7 12 11.9 4 5 1"-2" 11 TMG16159L32 11BSP 105 32.1 16 15.9 4 6 1"-6" 11 TMG20199L40 11BSP 105 40.4 20 19.9 5 HELICAL FLUTES WITH COOLANT HOLE THREAD PITCH ORDERING L L1 D1 D2 NO. OF SIZE TPI CODE FLUTES 1 1/16" 28 TMGB06059L11 28BSP 57 11.3 6 5.9 3 2 1/8" 28 TMGB08079L14 28BSP 63 14.0 8 7.9 3 3 1/4"-3/8" 19 TMGB10099L16 19BSP 73 16.6 10 9.9 4 4 1/2"-7/8" 14 TMGB12119L22 14BSP 84 22.7 12 11.9 4 5 1"-2" 11 TMGB16159L32 11BSP 105 32.1 16 15.9 4 6 1"-6" 11 TMGB20199L40 11BSP 105 40.4 20 19.9 5 11