There are many types of screws. Different types are use […]
There are many types of screws. Different types are used in different fields according to actual conditions. Many people can't distinguish between self-tapping screws and self-cutting screws. The following is an analysis based on their shape, material and purpose.
1. The shapes of self-tapping screws and self-cutting screws are different:
Self-tapping screws generally refer to pointed, coarse-toothed, hard-textured wood screws, as well as aluminum alloy and plastic. The head shape of the self-cutting screw has round head, flat head, half countersunk head and countersunk head.
2.The materials of self-tapping screws and self-cutting screws are different:
Self-tapping screws are used for non-metal or softer metals. The drilled holes are holes that do not need to be tapped. The screws used are different from ordinary ones. The head is pointed and the pitch is relatively large. It is a bit like a chipless tap. It can be screwed in directly without tapping. This method is usually used for metals and plastics.
Self-cutting screw materials can be divided into two types: carbon steel and stainless steel. The carbon steel material is usually 1022 medium carbon steel. The material is generally carburized steel, and the surface hardness of the material after heat treatment is not less than 45HRC. Compared with the threads of ordinary screws, when the same major diameter is used, the pitch is larger and the minor diameter is slightly smaller, which has been standardized. Stainless steel self-cutting screws are usually used on doors, windows and iron sheets.
3.The purpose of self-tapping screws and self-cutting screws are different:
The self-tapping screw can be used on the material to be consolidated, relying on its own thread, to "tap-drill, squeeze, and press" the consolidated body to produce corresponding threads to make them closely match each other.
Self-tapping screw is also called self-tapping screw. The English name is Self-tapping Screw. It is a kind of threaded fastener that is self-tapping to match female threads in the pre-drilling of metal or non-metal materials. Self-tapping screws are mostly used for the connection between thin metal plates (steel plates, saw plates, etc.). When connecting, first make a threaded bottom hole for the connected piece, and then screw the self-tapping screw into the threaded bottom hole of the connected piece. Since the threaded surface of the self-tapping screw has high hardness (≥45HRC), the internal thread can be tapped in the threaded bottom hole of the connected part to form a connection.