Countersunk head self-tapping screw

The countersunk head self-tapping screw is a kind of screw, the head is flat head, and it can also be called flat head screw. It is used in electronic machinery, digital products, decoration, electrical equipment and other fields.

The countersunk head means that the screw head will not be higher than the fixed surface after the screw is tightened. Self-tapping means to open a small hole first and fix it with the screw directly without tapping.

Self-tapping screws are mostly used for the connection between thin metal plates (steel plates, saw boards, etc.). When connecting, first make a threaded bottom hole for the connected part, and then screw the self-tapping screw into the threaded bottom hole of the connected part. Due to the high hardness of the threaded surface of the self-tapping screw, the internal thread can be tapped in the threaded bottom hole of the connected part to form a connection.

Countersunk head self-tapping screws are generally made of carburized steel, and the surface hardness of the material after heat treatment is not less than 45HRC. Compared with the thread of ordinary screws, the thread pitch is larger and the minor diameter is slightly smaller at the same major diameter, which has been standardized.

Self-tapping screw materials can be divided into two types: carbon steel and stainless steel, among which carbon steel materials are usually 1022 medium carbon steel. Usually used in doors and windows, iron sheet. Its head is a bearing surface formed by the part of one end made into an enlarged shape. For thread forming and thread cutting self-tapping screws (self-tapping screws), countersunk head, round head, pan head, hexagonal head and hexagonal wire head are the most important. These five head types account for almost 90% of all self-tapping screws. , This should be considered first when using self-tapping screws (self-tapping screws).

Countersunk screws can usually be removed and retightened at will without loss of efficiency, provide greater strength than nails, and are reusable. On the product material used for the countersunk head screw, the head can sink completely, and the screw head will not act as a hindrance.