Metal stamping hole briefly stamping hole measurement according to the check gauge measuring ways take is minimum, so you do with calipers measurement record general can record the minimum (
Rule out a small value, for example the error of the measurement error)
Do not rule out in special circumstances)
Record the maximum and average 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.
The other if you are a surveying and mapping, and in the absence of any size can be reference, you should be subject to the section, not only take the average value, such as minimum values you measured may be the result of the punch somewhere wear, cross section of light with minimal at this time, so it is no meaning to the minimum.
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, then its value in the tolerance range, still take the maximum is correct at this time.
A: on the hardness of metal stamping parts of the lock