工厂使用的游标卡尺外测量爪多数带刀口。由于刀口的存在,在修理研磨外测量爪平面度和平行度时不易磨平,当两测量面闭合时在刀口处有间隙存在,有人为此把研磨器改小,研磨时只研磨宽面,其结果是宽面中间稍凹,宽面和刀口过渡部分稍高,两测量面闭合时只在过渡处接触,平面度和平行 Most of the vernier calipers used by the factory have a knife edge. Because of the existence of the knife edge, it is not easy to polish the flatness and the parallelism of the measuring claw when the grinding is repaired. When the two measuring surfaces are closed, there is a gap at the knife edge. Some people change the grinder to small, The result is a slightly concave in the middle of the wide face, the transition of the wide face and the knife edge is slightly high, and the two measuring faces are only in contact with each other when they are closed, and the flatness and the parallelness