S-91257A774 9/16"-12 x 4 1/2" 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 Grade 8 strength rating and 150,000 psi tensile strength for reliable performance in high-stress applications
• Superior corrosion protection through zinc yellow-chromate plating that extends service life in harsh industrial environments
• Optimized thread engagement with UNC coarse threading and Class 2A fit ensuring secure fastening and vibration resistance
• Enhanced installation efficiency featuring external hex drive and standard hex head for easy tool access and high torque application
• Precision manufacturing compliance meeting ASME B18.2.1 and SAE J429 standards for consistent quality and dimensional accuracy
• Material durability assurance with Rockwell C33 hardness providing excellent wear resistance and structural integrity
• Environmental regulation compliance meeting RoHS 3 and REACH standards for safe usage across global markets

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical performance in demanding industrial applications where failure is not an option. The zinc yellow-chromate plated steel construction provides exceptional corrosion resistance for outdoor equipment, machinery, and structural assemblies exposed to harsh environments. The 9/16"-12 UNC coarse thread configuration ensures rapid installation and superior holding power in both soft and hard materials, while the partial threading design allows for precise clamp load distribution. Engineered to withstand extreme vibration and dynamic loads, these heavy-duty hex screws are ideal for construction equipment, automotive frames, and industrial machinery where 150,000 psi tensile strength and Rockwell C33 hardness prevent stripping, shearing, and fatigue failure under continuous operation.

Specification Summary & Compliance

This 4 1/2" length hex head screw features precise Class 2A thread fit tolerances with 9/16"-12 UNC coarse threading and partial threading extending 1 3/8" minimum. Manufactured to ASME B18.2.1 and SAE J429 Grade 8 specifications, ensuring dimensional consistency and mechanical performance. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, guaranteeing safe usage across international markets while maintaining the highest quality standards for industrial fastener applications.