Screws are used everywhere in daily life. So what is a non-standard screw? Except for national regulations, bolts formulated in accordance with international technical requirements are standard screws. On the contrary, the adopted specifications are not within the national standard but are special sizes, which are generally used for applications with fewer parts. This type of screw is a non-standard screw.

Common non-standard screw types and usage occasions:

1. Embedded screws are mainly used for suspending and fixing air-conditioning pipes, water pipes, electric pipes, ceilings, etc.

2. Torsion type flat head non-standard screws can be used on cement concrete, brick walls and hollow bricks, etc., for fixing bathroom equipment.

3. Internally forced non-standard screws with internal teeth are used to fix marbles, water pipes, electric pipes, and angle irons.

4. Sleeve-type non-standard screws are mainly used for fixing soundproof walls and bathroom equipment.

5. Externally forced internal thread non-standard screws are mainly used for hanging and piping of water pipes, electric pipes, air conditioners, and fixing various angle irons and section steels.

6. Non-standard screws for torsion casing are used to fix lighting, light steel dragon skeleton, and sanitary equipment.

7. Hollow non-standard screws, suitable for fixing door frames, cabinet frames, bathroom accessories, and wall decorations.

Note: When using non-standard screws, you must use an impact drill (hammer) in the hole of the corresponding size on the fixed body, and then install the bolt and expansion tube into the hole, and tighten the nut to make the bolt, expansion tube, and installation parts integrated with the fixed body. After tightening, it will expand. The bolt tail has a large head. The bolt is covered with a round tube slightly larger than the bolt diameter. There are several openings in the tail part. When the bolt is tightened, the large head-tail is brought into the open tube. Make the pipe bigger to achieve the purpose of expansion, and then fix the bolt on the ground or wall to achieve the purpose of rooting.