Common Screws for Office Chairs
Common screw types for office chairs include wood screws, self-tapping screws, machine screws (bolts), and some special-specification screws, with specific features and application scenarios as follows:
Wood screws are fasteners specifically designed for wooden materials. They have deep threads with larger spacing, which can effectively embed into wood fibers and enhance connection stability. The common diameter range is 3-6mm, and the length is between 20-50mm, suitable for solid wood chairs or plywood splicing scenarios. For example, wood screws are often used to fix the wooden connections between the chair seat and legs. Their self-tapping property can reduce the step of pre-drilling holes, but it is necessary to choose specifications that match the wood density to avoid wood cracking due to overly long screws.
Self-tapping screws have a built-in drill bit structure at the tail, allowing them to be screwed directly into the material without pre-drilling holes, significantly improving assembly efficiency. Their diameters are usually M4-M6, and the length range is 10-40mm, particularly suitable for plastic chairs or metal chairs that require quick assembly. For example, self-tapping screws are often used for the connection between the plastic chair back and the seat. Their pointed design can penetrate the plastic surface and form a firm thread; in metal frames, the hard alloy material of self-tapping screws can resist the reaction force of the metal, but the screwing depth needs to be controlled to prevent slippage.
Machine screws (bolts) need to be used in conjunction with nuts to achieve high-strength connections through double-end fixation. Common specifications are M5-M8, with lengths of 15-50mm and strength grades ranging from 4.8 to 8.8. They are suitable for metal chair frames or detachable structures. For example, 8.8-grade bolts are often used for the connection between the chair legs and the frame, as their high strength can withstand the weight of the human body and the stress generated by frequent movement; while 4.8-grade bolts are used for internal non-load-bearing structures, such as armrest fixation, balancing cost and strength requirements.
In addition, there are also special-specification screws among the hardware screws for office chairs, such as 12.9-grade black hexagon socket set screws M3, M4 concave-end set screws, M8*20 black zinc 8.8-grade anti-slip internal and external hexagon screws, M6M8 serrated flange bolts, etc. These screws are mostly used for precision adjustment or anti-loosening scenarios. For example, hexagon socket set screws are used for concealed fixation, the anti-slip design can prevent nut loosening, and serrated flange bolts enhance friction through surface texture, suitable for chair frame connections in vibration environments.
When choosing screws, it is necessary to comprehensively consider the material, load-bearing requirements, and assembly method to ensure the structural safety and service life of the office chair.
