The head angle of the countersunk head screw is not a fixed value and needs to be distinguished according to the grade. 100° and 130° are often encountered in aerospace components, and 90°, 110° and 120° are commonly used. In the process of using countersunk screws, the angle of the countersunk head screw of the precision mechanical fastener needs to be judged according to the tensile strength that the fastener needs to bear.
The countersunk screws are mostly used in places where the surface of the parts cannot be raised after being installed. The parts to be fastened are thick and thin. The so-called thick, that is, the thickness of the parts to be fastened is larger than the head of the countersunk head screw. Thickness, after the screw is tightened, some of the screw threads do not enter the threaded hole. In this case, the countersunk screw can be tightened.
There is usually also a case where the thickness of the fastened part is less than the height of the head of the countersunk head screw, which is common in mechanical equipment in sheet metal parts, such as the hinge of the case and the connection of the door and the case; the sheet metal of the device The connection of the cover to the device, etc. Sometimes, although the screw is tightened, the sheet metal is jammed instead of being pressed. In this case, although the screw is felt to be tightened, the sheet metal member is not tightened. This is a very common situation. Therefore, the countersunk screws of different angles need to be matched with the corresponding angle of the screwdriver.