1、公制螺纹钻底孔用钻头直径尺寸表 M1:粗扣螺距 0.250.75 细扣螺距 0.20.8M2:粗扣螺距 0.41.6 细扣螺距 0.251.8M3:粗扣螺距 0.52.5 细扣螺距 0.352.7M4:粗扣螺距 0.73.3 细扣螺距 0.53.5M5:粗扣螺距 0.84.2 细扣螺距 0.54.5M6:粗扣螺距 1.05.0 细扣螺距 0.755.2M8:粗扣螺距 1.256.7 细扣螺距 1.0 , 0.757,7.2M10:粗扣螺距 1.58.5 细扣螺距 1.25 , 1.0 , 0.758.7,9,9.2M12:粗扣螺距 1.7510.2 细扣螺距 1.5 , 1.25 , 1.01
2、0.5,10.7,11M14:粗扣螺距 2.011.9 细扣螺距 1.5 , 1.25 , 1.012.5,12.7,13M16:粗扣螺距 2.014 细扣螺距 1.5 , 1.014.5,15M18:粗扣螺距 2.515.4 细扣螺距 2.0 ,1.5 ,1.015.9,16.5,17M20:粗扣螺距 2.517.4 细扣螺距 2.0 , 1.5 , 1.017.9,18.5,19M22:粗扣螺距 2.519.5 细扣螺距 2.0 , 1.5 , 1.019.9,20.5,21M24:粗扣螺距 3.020.9 细扣螺距 2.0 , 1.5 , 1.021.9,22.5,23生产中钻螺纹底孔公
3、式：t1mm: Dz=d-tt1mm: Dz=d-(1.041.06)t式中 t 螺距（毫米）Dz 攻丝前钻头直径（毫米）d 螺纹公称直径（毫米）公制螺纹钻底孔用钻头直径尺寸表公称直径 d 螺距 t 钻头直径 公称直径 d 螺距 t 公称直径 d M1 粗 0.25 =0.75 M2 粗 0.4 =1.6 细 0.2 =0.8 细 0.25 =1.75 M3 粗 0.5 =2.5 M4 粗 0.7= 3.3 细 0.35 =2.65 细 0.5 =3.5 M5 粗 0.8 =4.2 M6 粗 1.0 =5.0细 0.5 =4.5 细 0.75 =5.2 M8 粗 1.25 =6.7 M10 粗
4、 1.5 =8.5 细 1.0 =7.0 细 1.25 =8.7 细 0.75 =7.2 细 1.0 =9.0 细 0.75 =9.2 M12 粗 1.75 =10.2 M14 粗 2.0 =11.9 细 1.5 =10.5 细 1.5 =12.5 细 1.25 =10.7 细 1.25 =12.7 细 1.0 =11.0 细 1.0 =13.0 M16 粗 2.0 =13.9 M18 粗 2.5 =15.4 细 1.5 =14.5 细 2.0 =15.9 细 1.0 =15.0 细 1.5 =16.5 细 1.0 =17.0 M20 粗 2.5 =17.4 M22 粗 2.5 =19.4 细
5、 2.0 =17.9 细 2.0 =19.9 细 1.5 =18.5 细 1.5 =20.5 细 1.0 =19.0 细 1.0 =21.0 M24 粗 3.0 =20.9 M27 粗 3.0 =23.9 细 2.0 =21.9 细 2.0 =24.9 细 1.5 =22.5 细 1.5 =25.5 细 1.0 =23.0 细 1.0 =26.0 M30 粗 3.5 =26.3 M33 粗 3.5 =29.3 细 3.0 =26.9 细 3.0 =29.9 细 2.0 =27.9 细 2.0 =30.9 细 1.5 =28.5 细 1.5 =31.5 细 1.0 =29.0 M36 粗 4.0
6、 =31.8 M39 粗 4.0 =34.8 细 3.0 =32.9 细 3.0 =35.9 细 2.0 =33.9 细 2.0 =36.9 细 1.5 =34.5 细 1.5 =37.5 M42 粗 4.5 =37.3 M45 粗 4.5 =40.3 细 4.0 =37.8 细 4.0 =40.8 细 3.0 =38.9 细 3.0 =41.9 细 2.0 =39.9 细 2.0 =42.9 细 1.5 =40.5 细 1.5 =43.5 M48 粗 5.0 =42.7 M52 粗 5.0 =46.7 细 4.0 =43.8 细 4.0 =47.8 细 3.0 =44.9 细 3.0 =48.9 细 2.0 =45.9 细 2.0 =49.9 细 1.5 =46.5 细 1.5 =50.5
