Socket screws are industrial fasteners identified a hexagonal socket, designed for high-torque applications and use in limited-space areas where externally wrenched fasteners are impractical.
They are available in a variety of head styles and materials.
Head Types
Socket screws come in five head types, each suited for specific applications:
- Socket Cap Head Screws: These have a cylindrical head with a height equal to the shank diameter, offering the highest head strength and superior clamping force. They are the most popular socket screw type for general machine assembly.
- Socket Button Head Screws: Characterised by a rounded, low-profile dome head that provides a clean, aesthetic finish while preventing snagging. They are used for lighter fastening applications than cap head screws.
- Socket Countersunk Screws: These have a flat, tapered head designed to fit flush with or below the surface of a pre-drilled hole, ideal when a smooth surface finish is required.
- Socket setscrew: Also known as a grub screw, is a headless, fully-threaded fastener with an internal hexagonal drive designed to secure one component inside another or against a shaft without any protruding parts.
- Socket shoulder bolt: A precision-engineered fastener with an unthreaded, smooth, enlarged shank (the shoulder) and a threaded end, featuring an internal hexagonal drive. The unique design allows for movement or rotation of components around the unthreaded shoulder, making it suitable for applications that require a pivot point or accurate alignment.
Materials
- Carbon/Alloy Steel: Often used for high-tensile applications and available in grades like 8.8, 10.9, and 12.9 for high strength. They may have a black oxide or zinc-plated finish for corrosion resistance.
- Stainless Steel: The most popular choice for general use due to its corrosion resistance.
- A2 (304 grade): Suitable for interior and exterior use.
- A4 (316 marine grade): Offers superior corrosion resistance for harsh and marine environments.
