S-91263A184 5/16"-18 x 4" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 130,000 PSI ensures reliable performance in demanding applications, reducing the risk of fastener failure.
• Superior corrosion resistance from zinc plating protects the alloy steel, extending service life in harsh industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies, minimizing loosening over time.
• Partially threaded design allows for effective clamping force on specific joint sections, enhancing structural integrity.
• 82° countersink angle and flat head enable a flush finish, improving safety and aesthetics in assembled products.
• Hex drive compatibility with a 3/16" drive size offers easy installation and high torque application, speeding up assembly processes.
• Compliance with major standards including ASME B18.3 and ASTM F835 ensures consistent quality and interoperability in professional settings.

Professional Applications & Engineering Value

This 5/16"-18 UNC flat head screw is engineered to address critical fastening challenges in industrial and construction sectors. Made from zinc-plated alloy steel, it combats corrosion and wear, making it ideal for outdoor machinery, automotive assemblies, and structural frameworks where exposure to elements is a concern. The coarse thread spacing and Class 3A thread fit provide excellent grip in softer materials or pre-tapped holes, reducing the likelihood of strip-out under high vibration. With a partially threaded shank, it concentrates clamping force precisely, preventing joint slippage in dynamic loads. These features, combined with a right-hand thread and standardized dimensions, ensure quick, reliable installations in high-stress environments, boosting productivity and reducing maintenance downtime.

Specification Summary & Compliance

This screw adheres to precise dimensional standards, including a Class 3A thread fit per UNC specifications, ensuring tight tolerances for secure fastening. It meets ASME B18.3 and ASTM F835 manufacturing guidelines, guaranteeing consistency and reliability. Additionally, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, confirming adherence to environmental and safety regulations for hazardous substances.