There are many types of screws, mainly mechanical screw, self-tapping screw and self-drilling screw.

Mechanical screw

Mechanical screws are mainly used in construction engineering, automotive, machinery, electronics, aerospace, etc. For normal use, it will be used with a nut or a hole with a pre-drilled internal tooth. Regardless of the head shape, the manufacture of mechanical teeth is the simplest. In the market, apart from the low-tolerance aerospace screws, the ultra-small precision screws for mobile phones (with the lowest tolerance), and the screws for medical (implantation), basically the same standard mechanical fasteners are produced.

Self-tapping screws

Self-tapping screws are mainly used in construction engineering, wood use, and decoration. Compared with the pre-drilled holes required for mechanical screws, self-tapping screws completely omit this step. Its convenience has always been the mainstream fastener in European and American construction projects.

Self-drilling screw

Self-drilling screws are mainly used in construction projects, roofs, tin houses, etc. Before the self-drilling screws are developed, most of the iron plates can be pre-drilled, and some 1mm thin plates can barely be inserted with self-tapping. The design of the self-drilling screws is mostly fine.