Generally, after the installation of countersunk self-tapping screws, the appearance of the parts is flat and there will be no bulge. Its tightly fixed parts are divided into thin and thick parts. Thickness refers to the relative ratio between the thickness of parts and the thickness of countersunk self-tapping screws. The former should be greater than the latter. When tightening, there will be some threads on the outside, but one thing to note is that the countersunk screws must be tightened.
Cross recessed round head self-tapping screw
In addition, the thickness of the part is less than the head thickness of the countersunk self-tapping screw, which is another case. In most mechanical equipment, there will be sheet metal parts, such as the connection between the equipment and the sheet metal cover, and the door connection between the boxes. Because the thickness of the fastening part is small, the screw through hole forms a conical hole. When tightening the countersunk self-tapping screw, the screw head does not press the sheet metal part, but the bottom of the screw and the top of the threaded hole squeeze each other to death. Because of this, sometimes we feel that the screws are particularly tight, but the sheet metal is not really tight.
External hexagon thread self-tapping screw
During the installation of countersunk head tapping screws, the reaming taper should be less than or equal to 90 degrees and not more than 90 degrees. If there are many holes made by countersunk screws on the parts, it is necessary to maintain the accuracy and avoid the deviation during processing to ensure the beauty after assembly. If there is a small error, it can be adjusted and slightly tightened. But the diameter of the screw should not exceed 8mm, which should be kept in mind. If the thickness of the countersunk self-tapping screw is greater than the thickness of the sheet metal, it is necessary to replace the smaller screw or enlarge the hole. In order to avoid loosening of parts, it is recommended not to expand the reaming diameter.
In short, be careful when installing countersunk head tapping screws. First, it can ensure the smooth installation, and second, it can make the installation effect ideal. The above is a summary of the use methods and precautions of countersunk head tapping screws. I believe that reading this article will help you.
Post time: Feb-03-2023