Why are the same M4×8countersunk head screw dimensions with different head sizes?

Mr. Li purchased M4*8 countersunk head screw dimensions from two different hardware stores before and after. But when he received the goods for measurement, the two countersunk screws were not the same size. Why is this?

When Mr. Li asked about the two customer service, the customer service told Mr. Li that their screws were produced according to the standard. Mr. Li feels that if they are produced according to the standard, the countersunk head screw dimensions will not be different. Who knows that the head of the countersunk screw bought is not the same size.

Later, Mr. Li knew that although the two screws were produced according to the standard, they did not meet the same standards. At that time, Mr. Li did not know much about the knowledge of screw fasteners, and did not ask the customers according to what standards. The countersunk head screw dimensions, one is produced according to the head 90 °, one is produced according to the size of 80 °.

For countersunk screws, the angle of the head is not the same, the same size of the screw, the head size is also different.

If you want to customized different countersunk head screw dimensions  please send an email: annie.li@szsst88.com