The expansion screws we talk about basically refer to metal expansion screws by default. The expansion screws are mainly composed of a screw and an expansion tube, as shown in the figure below. One end of the screw is threaded, and the other end is tapered. When the nut is tightened, the screw moves outward, and the axial movement of the thread causes the cone part to move, thereby forming a large positive pressure on the outer circumferential surface of the expansion tube. In addition, the cone The angle is very small, so that friction and self-locking are formed between the wall, the expansion tube and the cone, thereby achieving a fixed effect. The main role of the spring washer here is to prevent the nut from loosening.

Physical picture of expansion screws

Installation process of expansion screws

Many friends need to use expansion screws when they want to hang items at home, but they are If you don’t know how to use or install expansion screws, the editor will briefly list the steps for you. You can refer to them for installation. There are illustrations after the text that users can view.

1. First, before installation, confirm the maximum force required by the screw, so as to select the expansion bolt of the corresponding specification. For example, an M6 screw normally installed in concrete will have its maximum static force. The force is about 120KG. Similarly, the maximum force of M8/M10/M12 is basically around 170KG/320KG/510KG.

2. After selecting the expansion bolts of the correct specifications, we need to insert the screws into the holes you have pre-drilled.

3. Next I will use the working principle I just mentioned. We need to lock the nut on the threaded end of the expansion screw. While locking, the taper will be pulled into the expansion tube. The expansion tube will be stretched and then simply fixed to the wall.

Illustration of the principle of expansion screws

After these few steps, the expansion screws can be installed successfully, but because the force is not very stable, it is not recommended that you install them during use. Dangerous items such as ceiling fans.

You don’t need to worry about the appearance or subsequent problems during use, because the expansion screws are exposed flat after use and can be removed at will