S-91257A126 5/16"-18 x 10" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 150,000 psi tensile strength for reliable performance in demanding applications
• Superior corrosion resistance through zinc yellow-chromate plating that protects against industrial environments
• Optimized thread engagement with UNC coarse spacing and Class 2A fit ensuring secure fastening and vibration resistance
• Enhanced durability from Rockwell C33 hardness providing excellent wear resistance and longevity
• Easy installation and removal with external hex drive design allowing for high torque application
• Precision engineering compliance meeting ASME B18.2.1 and SAE J429 specifications for quality assurance
• Versatile partial threading offering both threaded and unthreaded sections for specific clamping requirements

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, this Grade 8 hex head screw delivers exceptional performance where failure is not an option. The zinc yellow-chromate plating provides superior corrosion protection in harsh environments, while the UNC coarse thread spacing ensures rapid installation and reliable holding power in structural assemblies, machinery, and equipment. The partially threaded design allows for precise clamping force distribution, making it ideal for applications requiring both threaded engagement and smooth shank benefits. With 150,000 psi tensile strength and Rockwell C33 hardness, this fastener maintains integrity under extreme loads and vibration, reducing maintenance cycles and downtime in critical operations.

Specification Summary & Compliance

This 5/16"-18 UNC hex head screw features Class 2A thread fit for precise dimensional accuracy and proper assembly clearance. Manufactured to comply with ASME B18.2.1 and SAE J429 specifications, ensuring consistent quality and performance standards. The inch system measurement provides compatibility with North American industrial equipment and existing fastener inventories. The product meets industry standards for dimensional tolerances, mechanical properties, and material composition required for Grade 8 heavy-duty fasteners in critical applications.