各种螺纹加工前的底孔尺寸.doc

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1、普通螺纹钻底孔的钻头尺寸表钻底孔钻头直径的计算公式:p<1时dT=d-pp>1时dT≈d-(1.04-1.08)p式中:p-螺距(mm)【说明】普通螺纹代号为“M”,牙型角a为60°,一般连接d-螺纹公称直径(mm)多用粗牙.细牙用于薄壁零件,细牙的自锁性能较好,dT-攻螺纹前钻头直径(mm)螺纹强度削弱少,但易滑扣.(mm)螺纹直径d螺距p螺纹内径推荐钻头直径dT螺纹直径d螺距p螺纹内径推荐钻头直径dTMaxMinMaxMinM2粗0.41.6771.5671.6M27粗324.13223.75223.9细0.25

2、1.8091.7291.75细225.13524.83524.9M3粗0.52.5992.4592.51.525.62625.37625.5细0.352.7212.6212.65126.11825.91826.0M4粗0.73.4223.2423.3M30粗3.526.63126.21126.3细0.53.5993.4593.5细326.926.8826.7M5粗0.84.3344.1344.2228.13527.83527.9细0.54.5994.4594.51.528.62628.37628.5M6粗15.118

3、4.9185.0129.11828.91829.0细0.755.3785.1185.2M33粗3.529.63129.21129.3M8粗1.256.8876.6476.7细231.13530.83530.9细17.1186.9187.01.531.62631.37631.80.757.3787.1187.2M36粗432.1531.6731.8M10粗1.58.6268.3768.5细333.13232.75232.9细1.258.8678.6478.7234.13533.83533.919.1188.9189.0

4、1.534.62634.37634.50.759.3789.1189.2M39粗435.1534.6734.8M12粗1.7510.38610.10610.2细336.13235.75235.9细1.510.62610.37610.5237.13536.83536.91.2510.86710.64710.71.537.62637.37637.5111.11810.91811.0M42粗4.537.67937.12937.3M16粗214.13513.83513.9细339.13238.75238.9细1.514.62

5、614.37614.5240.13539.83539.9115.11814.91815.01.540.62640.37640.5M20粗2.517.63417.29417.4M45粗4.540.67940.12940.3细218.13517.83517.9细342.13241.13241.91.518.62618.37618.5243.13542.83542.9119.11818.91819.01.543.62643.37643.5M24粗321.13220.75220.9M48粗543.11842.58842.7细

6、222.13521.83521.9细345.13244.75244.81.522.62622.37622.5246.13545.83545.9123.11822.91823.01.546.62646.37646.5英寸制螺纹钻底孔的钻头尺寸表钻底孔钻头直径的计算公式:螺纹公称直径铸铁与青铜钢与黄铜3/16”~5/8”dT=25(d-1/n)dT=25(d-1/n)+0.13/4”~11/2”dT=25(d-1/n)dT=25(d-1/n)+0.2注:dT-攻螺纹前钻头直径(mm)d-螺纹公称直径(寸)【说明】英寸制螺

7、纹牙型角a为55°n-每寸牙数公称直径d(寸)每寸牙数n钻头直径dT(mm)螺距P(mm)螺纹直径(mm)铸铁青铜钢黄铜大径dd中径d2小径d13/16243.73.71.0584.7624.0853.4081/4205.05.11.2706.3505.5374.7245/16186.46.51.4117.9387.0346.1313/8167.87.91.5889.5258.5097.4927/16149.19.31.81411.1129.9518.7891/21210.410.52.11712.70011.345

8、9.9895/81113.313.52.30915.87514.39712.9183/41016.316.42.54019.05017.42415.7987/8919.119.32.82222.22520.41818.6111821.922.03.17525.40023.36721.33411/8724.624.73.62928.57526.2