1. What are fasteners?
Fasteners are a general term for a type of mechanical parts used to fasten two or more parts (or components) into a whole. They are also called standard parts in the market.
2. It usually includes the following 12 types of parts:
Bolts, studs, screws, nuts, self-tapping screws, wood screws, washers, retaining rings, pins, rivets, assemblies and connecting pairs, and welding nails.
(1) Bolt: A type of fastener consisting of a head and a screw (a cylinder with external threads). It needs to be matched with a nut to fasten and connect two parts with through holes. This type of connection is called a bolt connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection.
As shown in the figure below:
(2) Stud: A type of fastener without a head, with only external threads on both ends. When connecting, one end of it must be screwed into the part with an internal threaded hole, and the other end must pass through the part with a through hole, and then the nut is screwed on, even if the two parts are fastened together as a whole. This type of connection is called a stud connection, which is also a detachable connection. It is mainly used in situations where one of the connected parts is thicker, requires a compact structure, or is frequently disassembled and bolt connection is not suitable.
As shown in the figure below:
(3) Screws: It is also a type of fastener consisting of a head and a screw. According to their use, they can be divided into three categories: steel structure screws, set screws and special purpose screws. Machine screws are mainly used for fastening a part with a set threaded hole to a part with a through hole, and do not require a nut (this type of connection is called a screw connection, which is also a detachable connection; it can also be used with a nut to fasten two parts with through holes.) Set screws are mainly used to fix the relative position between two parts. Special purpose screws, such as eye screws, are used for hoisting parts.
As shown below:
(4) Nut: with an internal thread hole, the shape is generally a flat hexagonal column, but also a flat square column or a flat cylindrical column. It is used with bolts, studs or steel structure screws to fasten two parts together to form a whole.
As shown below:
(5) Self-tapping screw: similar to a screw, but the thread on the screw is a special self-tapping screw thread. It is used to fasten two thin metal components together to form a whole. Small holes need to be made in advance on the components. Since this screw has a high hardness, it can be directly screwed into the hole of the component to form a corresponding internal thread in the component. This connection form is also a detachable connection.
As shown below:
(6) Wood screw: similar to a screw, but the thread on the screw is a special wood screw thread, which can be directly screwed into a wooden component (or part). It is used to fasten a metal (or non-metal) part with a through hole to a wooden component. This connection is also a detachable connection.
As shown in the figure below:
(7) Washer: A type of fastener in the shape of an oblate ring. Placed between the supporting surface of the bolt, screw or nut and the surface of the connected part, it increases the contact surface area of the connected parts, reduces the pressure per unit area and protects the surface of the connected parts from being damaged; another type of elastic washer can also prevent the nut from loosening.
As shown in the figure below:
(8) Retaining ring: It is installed in the shaft groove or hole groove of steel structures and equipment to prevent the parts on the shaft or hole from moving left and right.
As shown in the figure below:
(9) Pin: It is mainly used for positioning parts, and some can also be used to connect parts, fix parts, transmit power or lock other fasteners.
As shown in the figure below:
(10) Rivet: A type of fastener consisting of a head and a nail rod, used to fasten and connect two parts (or components) with through holes to make them a whole. This type of connection is called rivet connection, or riveting for short. It is a non-detachable connection. Because in order to separate the two connected parts, the rivets on the parts must be destroyed.
As shown below:
(11) Assemblies and joints: Assemblies refer to a type of fasteners supplied in combination, such as a machine screw (or bolt, self-supplied screw) and a flat washer (or spring washer, lock washer); joints refer to a type of fasteners supplied in combination with a special bolt, nut and washer, such as a high-strength large hexagonal bolt joint for steel structures.
As shown below:
(12) Welding nails: A heterogeneous fastener consisting of a bare rod and a nail head (or no nail head) is fixed and connected to a part (or component) by welding so that it can be connected to other parts.
As shown below:
