socket head cap screw dimensions – size requirements before and after plating

Whether it is before or after plating, we have to ensure that the size of the hexagonal cup head screw is in line with the customer’s requirements and allows the customer to complete the assembly. According to this need, what are the requirements for the socket head cap screw dimensions before and after plating?

Socket head cap screw dimensions requirements before plating:

Unless it is required to meet the functional requirements, the thread or other parts are clearly specified to allow the plating to be made thicker than the standard thread as much as possible. Otherwise, the dimensions before plating shall comply with the corresponding national standards or other applicable standards.

The thickness of the coating is suitable for ordinary threads according to GB/T 192, GB/T 9145 and GB/T 2516, and depends on the availability of the basic deviation, and also depends on the thread and the following tolerance band position: external thread: g, f ,e

These tolerance band positions are preferred for the plating layer.

Socket head cap screw dimensions requirements after plating:

After electroplating, the ordinary thread is in accordance with the provisions of GB/T 3934: the external thread is inspected separately by the general gauge with the tolerance zone position h or H.

The suitability of the recommended plating for common threads is limited by the basic deviation of the thread and the pitch and the position of the tolerance band. In the case of external threads, the coating should not exceed the zero line (basic size).

If you want to customized m4 x 30 socket cap head screw zinc plated, please send an email: annie.li@szsst88.com