修理后的游标卡尺常常发现这样的情况:游框基面与主尺基面平直度均好,零位也正确,但被检查的诸点都超差0.01～0.02mm。这时应检查一下零位附近主尺基面有无较严重的磨损。因为卡尺在使用过程中,在主尺的零位附近游框移动频繁,主尺这一部位的基面受磨损较其它部位的基面低(图1),在修理主 Repair vernier caliper often found such a situation: travel base surface and the main scale base surface flatness are good, zero is correct, but the checkpoints are beyond the tolerance of 0.01 ~ 0.02mm. At this time should check the main scale near the zero base for more serious wear and tear. Because calipers in the process of using the main scale in the vicinity of the zero travel around the box, the main surface of this part of the base of the other parts of the wear and tear of the lower surface (Figure 1)