Classification Of Threaded Fasteners

Bolts: Consist of a head and a shank; they mate with nuts to fasten two parts that have through-holes. This method is known as a bolted connection and is a type of detachable connection.

Studs: Threaded at both ends with no head; one end screws into a part with a threaded hole, while the other passes through a part with a through-hole and is secured with a nut. This method is known as a stud connection-also a detachable connection-and is commonly used in compact assemblies or applications requiring frequent disassembly.

Screws: Categorized into machine screws, set screws, and special-purpose screws. Machine screws fasten a part with a threaded hole to a part with a through-hole; set screws fix the relative position of two parts; and special-purpose screws, such as eyebolts, are used for lifting components.

Nuts: Feature an internally threaded hole and mate with bolts, studs, or machine screws to fasten two parts together.

Washers: Flat, ring-shaped fasteners placed between a bolt, screw, or nut and the connected parts; they increase contact area, reduce pressure per unit area, and protect the surface of the connected parts from damage. Certain elastic washers also serve to prevent nuts from loosening.

Assemblies and fastener sets: An assembly refers to a type of fastener product where specific machine screws (or bolts/self-tapping screws) are supplied pre-combined with flat washers, spring washers, or locking washers. A fastener set refers to a combination of bolts, nuts, and washers specifically designed for a particular application-such as the high-strength, large-hex-head bolt assemblies used in steel structures.