The concept and classification of hardware standard parts

Hardware standard parts are standard parts made of metal. I personally think the following points are for reference only:

1. Bolt: 　　

　　 A type of fastener consisting of two parts, a head and a screw (cylinder with external threads), which need to be matched with a nut to fasten and connect two parts with through holes. This type of connection is called bolt connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection.　　

2. Stud: 　　

　　 There is no head, only a type of fastener with external threads on both ends. When connecting, one end of it must be screwed into the part with internal threaded hole, the other end must pass through the part with through hole, and then the nut is screwed on, even if the two parts are tightly connected as a whole. This type of connection is called a stud connection, which is also a detachable connection. It is mainly used where one of the connected parts has a large thickness, requires a compact structure, or is not suitable for bolt connection due to frequent disassembly.　　

3. Screw: (Guide: Mold Management Skills) 　　

　　 is also a type of fasteners composed of two parts, a head and a screw, which can be divided into three categories according to their uses: machine screws, set screws and special purpose screws. Machine screws are mainly used for a tightening connection between a part with a 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 also be Cooperate with nut, used for fastening connection between two parts with through holes.) Set screw is mainly used to fix the relative position between two parts. Special purpose screws such as eyebolts are used for lifting parts.　　

4. Nut: 　　

　　 has an internal threaded hole, the shape is generally flat hexagonal cylinder, there are also flat square cylinder or flat cylinder, with bolts, studs or machine screws, used to fasten the connection of two parts. Become a whole.　　

5. Self-tapping screws: 　　

　　 is similar to machine screws, but the thread on the screw is a special thread for self-tapping screws. 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. Form the corresponding internal thread. This type of connection is also a detachable connection.　　

6. Wood screws: 　　

　　 is also similar to machine screws, but the thread on the screw is a special wood screw thread, which can be screwed directly into the wooden component (or part) to connect a metal (or non-metal) part with a through hole with A wooden component is firmly connected together. This connection is also a detachable connection.　　

7. Washer: 　　

　　 A type of fastener with an oblate ring shape. It is placed between the supporting surface of bolts, screws or nuts and the surface of the connected parts, which increases the contact surface area of u200bu200bthe connected parts, reduces the pressure per unit area and protects the surface of the connected parts from damage; another type of elastic washer, It can also play a role in preventing the nut from loosening.　　

8. Retaining ring: 　　

　　 is installed in the shaft groove or hole groove of the machine and equipment, and plays the role of preventing the parts on the shaft or hole from moving left and right.　　

9. Pin: 　　

　　 is mainly used for parts positioning, and some can also be used for connecting parts, fixing parts, transmitting power or locking other fasteners.　

10. Rivet: 　　

　　 A type of fastener composed of two parts, a head and a nail shaft, used to fasten and connect two parts (or components) with through holes to make them into a whole. This type of connection is called rivet connection, or riveting for short. It is connected with non-detachable. Because to separate the two parts connected together, the rivets on the parts must be broken.　　

11. Assembly and connection pair: 　　

　　Assembly refers to a type of fastener supplied in combination, such as a combination of machine screws (or bolts, self-supplied screws) and flat washers (or spring washers, lock washers); A type of fasteners supplied in combination of special bolts, nuts and washers, such as high-strength large hexagon head bolts for steel structures.　　

12. Welding nail: 　　

　　 A heterogeneous fastener consisting of a nail rod and a nail head (or no nail head), which is fixedly connected to a part (or component) by welding, so that it can be connected with other parts.

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