It is a screw with a drill bit, which is constructed by a special electric tool. Drilling, tapping, fixing and locking can be completed at one time. Self-tapping screws are mainly used for the connection and fixing of some thinner plates, such as the connection of color steel plates and color steel plates, the connection of color steel plates and purlins, wall beams, etc. The penetration capacity generally does not exceed 6mm, and the maximum does not exceed 12mm. Self-tapping screws are often exposed outdoors, and they have strong corrosion resistance; their rubber sealing ring can ensure that the screw does not seep water and has good corrosion resistance.

　　 Self-tapping screws are usually described by three parameters: screw diameter series, number of threads per inch length and screw length. There are two types of screw diameter grades: 10 and 12. The corresponding screw diameters are 4.87mm and 5.43mm respectively; there are three levels of 14, 16, and 24 threads per inch. The more threads per inch, the more The stronger the drilling ability.

　　 generally refers to pointed, coarse-toothed, hard-textured wood screws, and also used for aluminum alloys and plastics. A special self-tapping screw used to thread metal holes is called a tap.

　　 Self-tapping screws have high hardness, wide thread spacing, deep threads, and non-smooth surface. Wood screws are the opposite. The other difference is more obvious. There is no thread in the back of wood screws. Wood screws are thin, blunt and soft. The thread of self-tapping screws is thick, sharp and hard.

One-die two-stroke heading machine|Two-die three-stroke cold heading machine|Screw machine