Custom carbon steel phillips drive black zinc plating shoulder screw

Industry knowledge：

How to inspect screws?

1. Screw inspection should start from the thread, screw head quality, size, hardness and torque.
2. Check the forming of the screw head, check the appearance of the formed screw and check whether there are burrs, and check the size and length of the formed screw to see whether these sizes meet the standard or the specific requirements of the customer
3. Check the thread to see if it is damaged, missing or damaged after collision during transportation