The bolt trimming die manufacturer tells you that the hole measurement of metal stamping parts is the minimum value according to the measurement method of the pass and stop gauge, so you can generally record the minimum value when you use calipers to measure and record (excluding too small values, such as measurement errors caused by error), (does not rule out special circumstances) recording the maximum value and the average value has no practical significance, the bolt trimming die manufacturer tells you that the size difference in the measurement of the aperture in all directions should be recorded in the roundness of the shape and position tolerance. , not the aperture.

In addition, if it is surveying and mapping, and there is no size to refer to, you should determine it according to the cross-section, not just take the average value. For example, the minimum value you measure may be caused by the wear of the punch somewhere. At this time The bright band of the section is extremely small, so this minimum value is meaningless.
The bolt trimming die manufacturer tells you that generally speaking, the wear of the punch leads to the reduction of the punching hole (the special-shaped hole needs to be analyzed in detail), so the maximum value can be taken when surveying and mapping, and the quality of the section should not be forgotten. The bolt trimming die manufacturer tells you that because When the punch is manufactured, the basic size of the hole diameter + the maximum value within the allowable deviation is multiplied by 0.5~0.75 to leave the wear amount. After a period of use, the punching hole becomes smaller, but as long as the quality of the section is acceptable, then its value It is still within the tolerance range, and it is correct to take the maximum value at this time.