What is the reason why the countersunk head self-tapping screw is not tightened

Update:30-06-2021
Summary:

Everyone is not unfamiliar with self-tapping screws. Ha […]

Everyone is not unfamiliar with self-tapping screws. Have you ever experienced screw loosening when using stainless steel self-tapping screws? Next, the self-tapping screw manufacturer Hangzhou Lizhan Hardware Co., Ltd. will analyze several reasons for the self-tapping screws.

1. The thickness of the fastened component is greater than the thickness of the head of the countersunk head tapping screw, so that after the screw is screwed, some threads will not be screwed into the screw hole, and the screw does not fit well with the workpiece, so the screw will not be screwed. tight.

2. Contrary to the above situation, if the thickness of the fastened part is less than the thickness of the head of the countersunk head tapping screw, it will not work. solid. Because when the thickness of the component is small, the screw may form a conical shape after passing through. When the screw is tightened, it is not the head of the screw and the tapered surface that are pressed, but the bottom of the screw head and the top of the screw hole are pressed to Relatively fixed, in this case you will feel as if the screws are tightened, but in fact they are not.

3. The wrong angle of the countersunk hole on the workpiece will also cause the countersunk self-tapping screw to be unable to be tightened. The self-tapping screw we produce generally has a cone angle of 90 degrees, but the top angle of some drills is 120 degrees, so the After the screw is tightened, the conical head will not receive force, but the bottom of the screw head is under force, so it will not be able to be tightened.

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