Bolts, studs, and screws are all threaded fasteners, but they differ significantly in structure, usage, and application. The core differences are as follows:
1. Bolt
– Structural characteristics: The head is usually hexagonal or square, and the shank is smooth or partially threaded, requiring a nut for use.
– Connection method: Passes through a through hole in the connected parts and is tightened with a nut to form a detachable connection.
– Typical applications: Widely used in machinery, construction, bridges, and other applications requiring high-strength, detachable connections.
2. Stud
– Structural characteristics: Headless, with external threads at one or both ends, and a smooth shank in the middle; common types include double-ended studs (threaded at both ends) and welded studs.
– Connection method: One end is screwed into a threaded base hole, and the other end passes through the connected parts and is tightened with a nut.
– Typical applications: Suitable for applications where one of the connected parts is thick, frequent disassembly is required, or space is limited, such as engine blocks and pressure vessels.
3. Screws
– Structural characteristics: Various head types (e.g., flat head, Phillips head, countersunk head), shank is usually fully threaded, allowing it to be screwed into a threaded hole independently.
– Connection method: Screwed directly into the internal thread of the machine body, generally without a nut, and can also be used on wooden or plastic parts.
– Typical applications: Used for fastening, positioning, or adjustment, commonly found in electrical appliances, instruments, and lightweight structures.
– Classification examples:
– Machine screws (for metal threaded holes)
– Wood screws (for wood)
– Self-tapping screws (can tap their own threads)
– Set screws (used to fix the relative position of a shaft and hub).
