S-91257A824 5/8"-11 x 9" 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, ideal for high-stress industrial applications
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh environments
• Reliable thread engagement with UNC coarse threading and Class 2A fit, ensuring secure fastening and vibration resistance
• Optimized torque transmission through the external hex drive design, enabling efficient installation with standard tools
• Enhanced durability from Rockwell C33 hardness, maintaining structural integrity under repeated stress
• Versatile partial threading allowing for both clamping and alignment functions in complex assemblies
• Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for guaranteed performance

Professional Applications & Engineering Value

This Grade 8 hex head screw delivers critical engineering solutions for heavy-duty applications where failure is not an option. The 5/8"-11 UNC coarse threading with Class 2A fit provides superior resistance to vibration loosening in machinery, structural steel connections, and industrial equipment. The zinc yellow-chromate plating creates a protective barrier against corrosion in demanding environments including manufacturing facilities, outdoor structures, and automotive assemblies. With partial threading and substantial 9" length, this fastener offers precise clamping force distribution while accommodating thick materials and complex joint configurations. The combination of 150,000 psi tensile strength and Rockwell C33 hardness ensures reliable performance in critical load-bearing applications where safety and durability are paramount.

Specification Summary & Compliance

This hex head screw features precision 5/8"-11 UNC coarse threads with Class 2A thread fit for consistent engagement and reliable performance. Manufactured to exacting ASME B18.2.1 and SAE J429 Grade 8 specifications, ensuring dimensional accuracy and mechanical properties. The fastener is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, containing no restricted substances. With partial threading extending to a minimum of 1 3/4" and overall 9" length, this industrial-grade fastener meets the highest standards for quality and reliability in professional applications.