挤压丝锥公制螺纹底孔直径一览表 螺纹公称尺寸 M× P M2× 0.4 M2.2× 0.45 M2.5× 0.45 M3× 0.5 M4× 0.7 M5× 0.8 M6× 1 M7× 1 M8× 1.25 M8× 1 M10× 1.5 M10× 1.25 M10× 1 推荐 钻头直径 D 1.83 2.00 2.30 2.78 3.68 4.63 5.53 6.53 7.39 7.53 9.24 9.39 9.53 最小直径 1.81 1.98 2.28 2.76 3.65 4.59 5.48 6.48 7.34 7.48 9.18 9.34 9.48 最大直径 1.85 2.03 2.33 2.81 3.70 4.66 5.57 6.57 7.41 7.57 9.28 9.41 9.57 螺纹公称尺寸 M× P M12× 1.75 M12× 1.5 M12× 1.25 M14× 2 M14× 1.5 M16× 2 M16× 1.5 M18× 2.5 M18× 1.5 M20× 2.5 M20× 1 推荐 钻头直径 D 11.12 11.24 11.39 13.00 13.27 15.00 15.27 16.73 17.28 18.73 19.28 最小直径 11.05 11.18 11.34 12.92 13.21 14.92 15.21 16.63 17.22 18.63 19.22 最大直径 11.15 11.28 11.41 13.04 13.30 15.04 15.30 16.78 17.31 18.78 19.31