S-91253A337 5/16"-24 x 1 1/4" ASME B18.3 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 130,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure in critical assemblies.
• Precise Class 3A thread fit provides superior engagement and vibration resistance, minimizing loosening in dynamic applications.
• Black-oxide finish on alloy steel offers enhanced corrosion resistance and a durable, non-reflective surface suitable for industrial environments.
• Fully threaded design allows for maximum grip and adjustability along the entire length, simplifying installation in varied material thicknesses.
• 82° countersink angle and flat head profile enable a flush, secure fit that reduces protrusion and improves aerodynamic or aesthetic finishes.
• Hex drive (3/16") facilitates easy installation and removal with standard tools, speeding up assembly and maintenance processes.
• Compliance with ASME B18.3, ASTM F835, RoHS 3, and REACH ensures adherence to industry standards and environmental regulations, supporting global supply chain requirements.

Professional Applications & Engineering Value

This 5/16"-24 UNF flat head socket cap screw is engineered to address common industrial challenges such as vibration-induced loosening and corrosion in demanding environments. The black-oxide alloy steel construction, combined with a Rockwell C39 hardness, provides durability and resistance to wear, making it ideal for machinery, automotive, and aerospace applications where reliability is critical. The fine UNF thread and Class 3A fit ensure tight, secure fastening in precision assemblies, while the fully threaded design and 82° countersink allow for seamless integration into components requiring low-profile, high-strength connections. These features collectively enhance assembly efficiency, reduce maintenance needs, and support long-term operational integrity in industrial fastening systems.

Specification Summary & Compliance

This screw adheres to precise dimensional standards, including Class 3A thread fit for tight tolerances and UNF fine threading (5/16"-24) to ensure accurate engagement. It meets ASME B18.3 and ASTM F835 specifications for socket cap screws, guaranteeing consistent quality and performance. Additionally, the product is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for use in environmentally conscious and regulated industries.