在加工螺纹时,常用螺纹量规和三针测量,使螺纹中径达到要求。其中三针仅能测量外螺纹,螺纹量规不能知道实际的中径数值,还避免不了中径超差。我们知道,利用钢珠也能测量中径,但是钢珠圆滑易滚动,不便在操作时应用。我们经过多次改进,将钢珠焊在钢珠座上,钢珠座固定在千分尺测砧的定位套上。定位套的 Thread in the processing, the commonly used thread gauge and three-pin measurement, the thread diameter to meet the requirements. Three of them can only measure the external thread, thread gauge can not know the actual value of the median, but also can not avoid the diameter tolerance. We know that the use of steel balls can also measure the diameter, but the ball is easy to roll rolling, inconvenience in the operation of the application. After many improvements, we welded the ball to the pedestal and the ball pedestal was fixed on the positioning sleeve of the micrometer anvil. Positioning sleeve