What are the common types of fasteners and their uses?

Common types of fasteners and their uses: Small parts with big implications

Fasteners, as "connectors" in the industrial field, play an indispensable role in many industries such as construction, machinery manufacturing, and the automotive industry with their rich variety and wide applicability. From basic connection and fixation to precise assembly under special working conditions, different types of fasteners meet diverse application needs with their unique structural design and performance characteristics. A deep understanding of these common types and their uses will help us better understand the functions and values of fasteners.

1. Bolts and nuts: widely used fastening combinations

Bolts and nuts are common types of fasteners. They are usually used together to fasten objects by screwing together. Bolts are composed of a head and a screw, while nuts have internal threads that match the external threads of the bolts. This fastening combination is widely used in building steel structures, mechanical equipment, automobile manufacturing and other fields.

In building steel structures, high-strength bolts are key components for connecting important components such as steel beams and steel columns. Taking large bridge construction as an example, high-strength bolts can provide strong preload, so that the steel structure components of the bridge are tightly connected and jointly bear the effects of vehicle loads and the natural environment. In mechanical equipment, ordinary bolt and nut combinations are used to connect various parts, such as the bed and base of machine tools, motors and transmission devices, etc., to ensure the relative position of various components of the equipment during operation. In automobile manufacturing, bolts and nuts are everywhere, from the precise assembly inside the engine to the connection of the body frame, they are inseparable from their tightening function.

2. Screws: Expert in direct penetration fastening

Screws look similar to bolts, but they are usually not used with nuts. Instead, they are screwed directly into holes with internal threads, or tapped directly into the material of the connected parts through their own threads. There are many types of screws, including self-tapping screws, wood screws, machine screws, etc., each with different uses.

Self-tapping screws are often used to connect thin metal plates, plastics and other materials. The thread is sharp and the pitch is large. There is no need to pre-tap during installation. It can directly tap into the material to form an internal thread to achieve fastening. It is widely used in the assembly of electronic product shells and the connection of furniture panels. Wood screws are specially designed for wood connection. Its head shape is diverse, including countersunk head, semicircular head, pan head, etc., which are suitable for different wood processing and decoration needs. They are often used in the production of wooden structures and wooden furniture. Machine screws are usually used to connect mechanical parts with high precision requirements. They need to be used in conjunction with holes with pre-processed internal threads. They are commonly used in the assembly of instruments and small mechanical equipment.

3. Rivets: a symbol of long-term fastening

Rivets are fasteners that connect riveted parts by self-deformation or interference fit. They are permanent connections. One end of the rivet has a head and the other end is a shank. When installing, the shank is inserted into the hole of the connected part, and then the other end of the shank is deformed by hammering, pressure, etc. to form a second head, thereby fastening the connected parts together.

In the aerospace field, rivets are important parts for connecting the aircraft skin and frame. Since aviation materials are mostly light alloys and have extremely high requirements for structural strength and sealing, rivets can ensure the connection strength while avoiding excessive damage to the materials, thereby ensuring the aerodynamic shape and structural integrity of the aircraft. In automobile manufacturing, rivets are also commonly used to connect body structures, especially some parts that have high strength requirements and need to withstand large loads, such as doors and frames. In addition, in some decorative projects, aesthetic rivets such as blind rivets are also used to connect metal sheets, glass and other materials, combining practicality and decorativeness.

4. Washers: An important supporting role in auxiliary fastening

Washers are usually used with bolts and screws. Although they seem inconspicuous, they play an important role in the tightening process. The main types of washers are flat washers and spring washers. The function of flat washers is to increase the contact area of the connected parts, reduce the damage to the surface of the connected parts caused by pressure, and prevent the nuts from loosening; spring washers generate axial tension through their own elastic deformation, increase the friction between the nut and the bolt, and play a role in preventing loosening.

In the installation of mechanical equipment, flat washers are often used to protect the surface of the equipment to prevent the bolt head from directly contacting the surface of the equipment and causing scratches or damage. In the connection of some equipment with large vibrations, such as engines and fans, spring washers are essential anti-loosening components that can effectively prevent nuts from loosening and falling off in a vibrating environment, ensuring the safe operation of the equipment.

5. Pin: a versatile tool for positioning and connection

Pins are mainly used for positioning, connecting or preventing loosening between parts. Common types include cylindrical pins, conical pins, cotter pins, etc. Cylindrical pins and conical pins are fixed in pin holes through interference fit or transition fit to play a positioning and connecting role. In mechanical processing, cylindrical pins are often used to position molds and fixtures to ensure the accurate relative position of each component; conical pins have good self-locking properties when subjected to lateral forces due to their taper characteristics, and are often used to connect parts that need to be disassembled frequently. Cotter pins are mainly used to prevent nuts from loosening. Inserting them into the hole at the end of the bolt and the groove of the nut, and then prying them open, can effectively prevent the nut from rotating. They are widely used in the assembly of agricultural machinery, bicycles and other equipment.

There are many common types of fasteners, each with its own unique structural characteristics and applicable scenarios. From basic connection and fixation to precise assembly under special working conditions, these seemingly tiny parts, with their own advantages, jointly build a stable and reliable connection system in the industrial field. With the continuous advancement of technology, more new fasteners will emerge in the future to provide stronger support for the development of various industries.