用止端螺纹环规检验外螺纹零件,是控制普通螺纹中径下偏差的常用方法。但在特殊情况下,对已超差的螺纹,用不同的止规旋合,却又可能得出合格的结论。现就止规的b/2处于下限尺寸、而被检螺纹的实际牙型半角又过于偏小造成的问题做一简要讨论。 With end-thread ring gauge test of external thread parts, is to control the deviation of ordinary thread diameter under the common method. However, in exceptional circumstances, the already exceeded the thread, with different stop screwing, but may come to a qualified conclusion. Now on the rules of b / 2 in the lower limit size, and was seized thread actual teeth half-angle is too small to make the problem a brief discussion.