Thread Milling Tools UN INTERNAL ANSI B1.1 - 1982 UN NUT 1/4P 60 1/8P UN SCREW THREAD LENGTH – UP TO 3D D = NOMINAL THREAD SIZE THREAD SIZE PITCH ORDERING L L1 D1 D2 NO. OF TPI CODE FLUTES COARSE UNC FINE UNF 1 0-80 80 TMC03011L3 80UN 39 3.9 3 1.18 3 2 1-72 72 TMC03014L5 72UN 39 5.8 3 1.44 3 3 1-72 72 TMC06014L5 72UN 57 5.8 6 1.44 3 4 2-56 3-56 56 TMC03016L6 56UN 39 6.8 3 1.66 3 5 2-56 3-56 56 TMC06016L6 56UN 57 6.8 6 1.66 3 6 2-56 3-56 56 TMCL06016L6 56UN 100 6.8 6 1.66 3 7 4-40 40 TMC06021L8 40UN 57 8.1 6 2.12 3 8 4-40 40 TMCL06021L8 40UN 100 8.1 6 2.12 3 9 5-40 40 TMC06024L9 40UN 57 9.8 6 2.46 3 10 6-32 6-40 32 TMC06025L10 32UN 57 10.7 6 2.57 3 11 6-32 32 TMCL06025L10 32UN 100 10.7 6 2.57 3 12 8-32 32 TMC06032L12 32UN 57 12.7 6 3.22 3 13 10-32 32 TMC06037L15 32UN 57 15.5 6 3.70 3 14 10-32 32 TMCL06037L15 32UN 100 15.5 6 3.70 3 15 12-28 28 TMC06042L16 28UN 57 16.0 6 4.20 3 16 1/4"-28 28 TMC06052L19 28UN 57 19.3 6 5.20 3 17 1/4"-28 28 TMCL06052L19 28UN 100 19.3 6 5.20 3 18 5/16"-24 24 TMC08066L24 24UN 63 24.2 8 6.65 3 19 1/4"-20 7/16"-20 20 TMC06048L19 20UN 57 19.4 6 4.85 3 20 1/4"-20 7/16"-20 20 TMCL06048L19 20UN 100 19.4 6 4.85 3 21 5/16"-18 18 TMC06059L23 18UN 57 23.0 6 5.90 3 22 3/8"-16 16 TMC08069L28 16UN 63 28.5 8 6.90 3 17