Threading Technology – Clamping Technology 520

208 Roll Form Taps UNC UNF M MF G STI SELF-LOCK Tech. Info v c Product Finder 2.17 Recommended tap drill sizes for cold-forming internal threads UNC Unified coarse thread ASME B1.1 (Tol. 2B) Nominal Size D 1 (2B) Rec. tap drill size D P [T.P.I.] min. max. No. 1 64 0.0661 0.0681 0.0669 No. 2 56 0.0780 0.0799 0.0787 No. 3 48 0.0894 0.0917 0.0906 No. 4 40 0.1004 0.1016 0.1004 No. 5 40 0.1134 0.1154 0.1142 No. 6 32 0.1228 0.1252 0.1240 No. 8 32 0.1492 0.1508 0.1496 No. 10 24 0.1697 0.1724 0.1713 No. 12 24 0.1957 0.1980 0.1969 1 / 4 20 0.2252 0.2276 0.2264 5 / 16 18 0.2846 0.2890 0.2874 3 / 8 16 0.3437 0.3480 0.3465 7 / 16 14 0.4016 0.4051 0.4035 1 / 2 13 0.4610 0.4661 0.4646 9 / 16 12 0.5201 0.5252 0.5236 5 / 8 11 0.5787 0.5843 0.5827 3 / 4 10 0.6980 0.7043 0.7028 7 / 8 9 0.8169 0.8248 0.8228 1 8 0.9346 0.9429 0.9409 UNF Unified fine thread ASME B1.1 (Tol. 2B) Nominal Size D 1 (2B) Rec. tap drill size D P [T.P.I.] min. max. No. 0 80 0.0547 0.0563 0.0551 No. 1 72 0.0669 0.0681 0.0669 No. 2 64 0.0791 0.0807 0.0795 No. 3 56 0.0909 0.0925 0.0913 No. 4 48 0.1024 0.1043 0.1031 No. 5 44 0.1146 0.1161 0.1150 No. 6 40 0.1264 0.1280 0.1268 No. 8 36 0.1508 0.1528 0.1516 No. 10 32 0.1752 0.1764 0.1752 No. 12 28 0.1988 0.2020 0.2008 1 / 4 28 0.2331 0.2354 0.2343 5 / 16 24 0.2925 0.2949 0.2933 3 / 8 24 0.3551 0.3579 0.3563 7 / 16 20 0.4130 0.4169 0.4154 1 / 2 20 0.4756 0.4799 0.4783 9 / 16 18 0.5354 0.5390 0.5374 5 / 8 18 0.5980 0.6020 0.6004 3 / 4 16 0.7193 0.7244 0.7224 7 / 8 14 0.8398 0.8445 0.8425 1 12 0.9583 0.9646 0.9626 American Standard Threads 60° D D 1 P ISO Metric Threads 60° D D 1 P M ISO Metric coarse thread DIN 13 (Tol. 6H) Nominal Size D 1 (6H) Rec. tap drill size D P [mm] min. [mm] max. [mm] [mm] [inch] M 2 0.4 1.84 1.88 1.85 0.0728 M 2.5 0.45 2.32 2.36 2.33 0.0917 M 3 0.5 2.79 2.83 2.8 0.1102 M 3.5 0.6 3.24 3.28 3.25 0.1280 M 4 0.7 3.69 3.73 3.7 0.1457 M 4.5 0.75 4.16 4.23 4.2 0.1654 M 5 0.8 4.64 4.68 4.65 0.1831 M 6 1 5.55 5.63 5.6 0.2205 M 7 1 6.55 6.64 6.6 0.2598 M 8 1.25 7.41 7.49 7.45 0.2933 M 10 1.5 9.28 9.39 9.35 0.3681 M 12 1.75 11.16 11.29 11.25 0.4429 M 14 2 13.02 13.14 13.1 0.5157 M 16 2 15.02 15.14 15.1 0.5945 M 18 2.5 16.73 16.89 16.85 0.6634 M 20 2.5 18.73 18.9 18.85 0.7421 M 22 2.5 20.73 20.9 20.85 0.8209 M 24 3 22.47 22.65 22.6 0.8898 MF ISO Metric fine thread DIN 13 (Tol. 6H) Nominal Size D 1 (6H) Rec. tap drill size P D [mm] min. [mm] max. [mm] [mm] [inch] M 4 x 0.5 3.79 3.83 3.8 0.1496 M 5 x 0.5 4.79 4.83 4.8 0.1890 M 6 x 0.75 5.67 5.73 5.7 0.2244 M 8 x 0.75 7.67 7.74 7.7 0.3031 M 8 x 1 7.55 7.64 7.6 0.2992 M 10 x 1 9.55 9.64 9.6 0.3780 M 10 x 1.25 9.41 9.49 9.45 0.3720 M 12 x 1.5 11.29 11.39 11.35 0.4469 M 14 x 1.5 13.29 13.39 13.35 0.5256 M 16 x 1.5 15.29 15.39 15.35 0.6043 M 18 x 1.5 17.29 17.39 17.35 0.6831 M 20 x 1.5 19.29 19.40 19.35 0.7618 M 22 x 1.5 21.29 21.40 21.35 0.8406 M 24 x 1.5 23.30 23.40 23.35 0.9193 Tap drill sizes of Metric fine threads which are not listed can be found by considering the diameter difference. G Whitworth pipe thread DIN EN ISO 228 Nominal Size D 1 Rec. tap drill size D P [T.P.I.] min. [mm] max. [mm] [mm] [inch] G 1 / 16 28 7.25 7.29 7.25 0.2854 G 1 / 8 28 9.25 9.29 9.25 0.3642 G 1 / 4 19 12.48 12.59 12.55 0.4941 G 3 / 8 19 15.99 16.09 16.05 0.6319 G 1 / 2 14 20.02 20.15 20.1 0.7913 G 5 / 8 14 21.97 22.1 22.05 0.8681 G 3 / 4 14 25.5 25.65 25.6 1.0079 G 7 / 8 14 29.26 29.4 29.35 1.1555 G 1 11 32.05 32.21 32.15 1.2657 Straight Pipe Threads 55° D D 1 P