ISO METRIC THREADS FINE TAPPING DRILL SIZES If you have been pointed directly to this page by a search engine, please also see:- http://homews.co.uk/page29.html and http://homews.co.uk/ SIZE OUT CORE PITCH TAP DEP DIA. DIA. DRILL TH mm mm mm mm % M2 x 0.25 2.0 1.69 0.25 1.85 49 M2 x 0.25 2.0 1.69 0.25 1.80 65 M2 x 0.25 2.0 1.69 0.25 1.75 82 M2.5x 0.35 2.5 2.07 0.35 2.25 58 M2.5x 0.35 2.5 2.07 0.35 2.20 70 M2.5x 0.35 2.5 2.07 0.35 2.15 82 M3 x 0.35 3.0 2.57 0.35 2.75 58 M3 x 0.35 3.0 2.57 0.35 2.70 70 M3 x 0.35 3.0 2.57 0.35 2.65 82 M4 x 0.50 4.0 3.39 0.50 3.65 57 M4 x 0.50 4.0 3.39 0.50 3.60 65 M4 x 0.50 4.0 3.39 0.50 3.55 73 M5 x 0.50 5.0 4.39 0.50 4.65 57 M5 x 0.50 5.0 4.39 0.50 4.60 65 M5 x 0.50 5.0 4.39 0.50 4.55 73 M6 x 0.75 6.0 5.08 0.75 5.50 54 M6 x 0.75 6.0 5.08 0.75 5.40 65 M6 x 0.75 6.0 5.08 0.75 5.30 76 M8 x 0.75 8.0 7.08 0.75 7.50 54 M8 x 0.75 8.0 7.08 0.75 7.40 65 M8 x 0.75 8.0 7.08 0.75 7.30 76 M8 x 1.00 8.0 6.77 1.00 7.30 57 M8 x 1.00 8.0 6.77 1.00 7.20 65 M8 x 1.00 8.0 6.77 1.00 7.10 73 M10 x 1.25 10.0 8.47 1.25 9.10 59 M10 x 1.25 10.0 8.47 1.25 9.00 65 M10 x 1.25 10.0 8.47 1.25 8.90 72 M12 x 1.00 12.0 10.77 1.00 11.30 57 M12 x 1.00 12.0 10.77 1.00 11.20 65 M12 x 1.00 12.0 10.77 1.00 11.10 73 M12 x 1.50 12.0 10.16 1.50 10.90 60 M12 x 1.50 12.0 10.16 1.50 10.80 65 M12 x 1.50 12.0 10.16 1.50 10.70 71 M16 x 1.00 16.0 14.77 1.00 15.30 57 M16 x 1.00 16.0 14.77 1.00 15.20 65 M16 x 1.00 16.0 14.77 1.00 15.10 73