我们采用M值标准棒和带平测头的千分表测奇数槽丝锥中径,方法简便易行。现介绍如下。由螺丝中径计算公式可知: M=d_中+3d_0-0.866t (牙型角60°)式中,d_中——被测螺纹标称中径; d_0——三针直径; t——被测螺纹螺距。用本方法测量时,如测普通螺纹一样,测M值即可。以中心孔为加工基准制作M值标准棒,其直径可在立式光学计或万能测长仪上用4等 We use the standard M-value rod and flat probe with a flat dial measuring odd-numbered taps tap diameter, the method is simple and easy. Now introduced as follows. From the calculation formula of the screw diameter, we can see that: M = d_ in + 3d_0-0.866t (tooth angle 60 °) Where, d_ in the measured diameter of the nominal diameter; d_0-- three-pin diameter; t- - thread pitch to be measured. With this method of measurement, such as measuring the same thread, M value can be measured. To the center hole for the processing of standard M-value standard rod, the diameter of the vertical optical instrument or universal length measuring instrument with 4