Screws, self-tapping screws, what is the difference between the three wood screws?

1. Screws: It is also a type of fasteners composed of two parts, a head and a screw, which can be divided into three categories according to the purpose-machine screws, set screws and special purpose screws. The machine screw is mainly used for the fastening connection between a part with an internal threaded hole and a part with a through hole, without the need for a nut to fit (this type of connection is called a screw connection, which is also a detachable connection; It can be matched with a nut to fasten the connection between two parts with a through hole. The set screw is mainly used to fix the relative position between the two parts. The special purpose screw has a ring screw for hoisting parts.
2. Self-tapping screws: similar to machine screws, but the thread on the screw is a special self-tapping screw thread. It is used to fasten and connect two thin metal components into one piece. Small holes need to be made in the component in advance. Because this kind of screw has high hardness, it can be directly screwed into the hole of the component to make the component hole Corresponding internal threads are formed in the center. This type of connection is also a detachable connection.
3. Wood screws: also similar to machine screws, but the thread on the screw is a special wood screw thread, which can be directly screwed into the wooden component (or part) to use a metal (or non-metal) with a through hole The parts are firmly connected to a wooden component. This type of connection is also a detachable connection.