Threading Technology – Clamping Technology 520

154 Machine Taps UNC UNF UNEF UN-8 M MF NPSF Rp (BSPP) G NPT NPTF Rc (BSPT) STI SELF-LOCK Accessories NPSM/NPSC Tech. Info v c Product Finder 1.16 Recommended tap drill sizes for tapping internal threads M ISO Metric coarse thread DIN 13 and DIN ISO 965-1, ASME B1.13M Nominal Size Minor thread dia. of the internal thread (Tol. 6H) Rec. tap drill size D P [mm] D 1 min. [mm] D 1 max. [mm] [mm] [inch] M 2 0.4 1.567 1.679 1.6 0.0630 M 2.5 0.45 2.013 2.138 2.05 0.0807 M 3 0.5 2.459 2.599 2.5 0.0984 M 3.5 0.6 2.850 3.010 2.9 0.1142 M 4 0.7 3.242 3.422 3.3 0.1299 M 4.5 0.75 3.688 3.878 3.7 0.1457 M 5 0.8 4.134 4.334 4.2 0.1654 M 6 1 4.917 5.153 5 0.1969 M 7 1 5.917 6.153 6 0.2362 M 8 1.25 6.647 6.912 6.8 0.2677 M 9 1.25 7.647 7.912 7.8 0.3071 M 10 1.5 8.376 8.676 8.5 0.3346 M 11 1.5 9.376 9.676 9.5 0.3740 M 12 1.75 10.106 10.441 10.2 0.4016 M 14 2 11.835 12.210 12 0.4724 M 16 2 13.835 14.210 14 0.5512 M 18 2.5 15.294 15.744 15.5 0.6102 M 20 2.5 17.294 17.744 17.5 0.6890 M 22 2.5 19.294 19.744 19.5 0.7677 M 24 3 20.752 21.252 21 0.8268 M 27 3 23.752 24.252 24 0.9449 M 30 3.5 26.211 26.771 26.5 1.0433 M 33 3.5 29.211 29.771 29.5 1.1614 M 36 4 31.670 32.270 32 1.2598 M 39 4 34.670 35.270 35 1.3780 M 42 4.5 37.129 37.799 37.5 1.4764 M 45 4.5 40.129 40.799 40.5 1.5945 M 48 5 42.587 43.297 43 1.6929 M 52 5 46.587 47.297 47 1.8504 MF ISO Metric fine thread DIN 13 and DIN ISO 965-1, ASME B1.13M Nominal Size Minor thread dia. of the internal thread (Tol. 6H) Rec. tap drill size P D [mm] D 1 min. [mm] D 1 max. [mm] [mm] [inch] M 4 x 0.5 3.459 3.599 3.5 0.1378 M 5 x 0.5 4.459 4.599 4.5 0.1772 M 6 x 0.75 5.188 5.378 5.2 0.2047 M 8 x 0.75 7.188 7.378 7.2 0.2835 M 8 x 1 6.917 7.153 7 0.2756 M 10 x 1 8.917 9.153 9 0.3543 M 10 x 1.25 8.647 8.912 8.8 0.3465 M 12 x 1.5 10.376 10.676 10.5 0.4134 M 14 x 1.5 12.376 12.676 12.5 0.4921 M 16 x 1.5 14.376 14.676 14.5 0.5709 M 18 x 1.5 16.376 16.676 16.5 0.6496 M 20 x 1.5 18.376 18.676 18.5 0.7283 M 22 x 2 19.835 20.210 20 0.7874 M 24 x 2 21.835 22.210 22 0.8661 M 27 x 2 24.835 25.210 25 0.9843 M 30 x 2 27.835 28.210 28 1.1024 M 36 x 3 32.752 33.252 33 1.2992 M 42 x 3 38.752 39.252 39 1.5354 M 48 x 3 44.752 45.252 45 1.7717 M 52 x 4 47.670 48.270 48 1.8898 ISO Metric Threads 60° D D 1 P Tap drill sizes of Metric fine threads which are not listed can be found by considering the diameter difference.