Stamping hole in accordance with the general check gauge measurement ways is little value, so you do with calipers measurement record general can record small value (
Rule out a small value, for example the error of the measurement error)
Do not rule out in special circumstances)
Record average value with big no practical significance, for measuring the size of the aperture in every direction difference, should be recorded into the form tolerance of roundness, rather than the aperture.
Can refer to the other if the surveying and mapping, and there is no size of the case, you should be subject to the section, not only take the average value, such as you measured values may be the result of the punch somewhere wear, cross section of light with minimal at this time, the minimum is no significance.
In general the punch wear is caused by punching smaller (
Special-shaped hole should be concrete analysis)
So at the time of surveying and mapping can take its maximum, cross section quality and don't forget, because made in punch time is a basic size of aperture + deviation within the allowed maximum value multiplied by zero.
5 to 0.
, 75, in order to leave wear after a period of time the use of punching smaller, but as long as the cross section quality will get by, so its value is still in the tolerance range, the large value is correct.