S-91257A884 3/4"-16 x 6 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 150,000 psi tensile strength for demanding industrial applications
• Superior corrosion resistance through zinc yellow-chromate plating, extending service life in harsh environments
• Precise thread engagement with Class 2A thread fit ensuring reliable fastening and vibration resistance
• Optimized torque transmission via external hex drive and 1 1/8" head width for secure installation
• Enhanced durability with Rockwell C33 hardness maintaining structural integrity under heavy loads
• Versatile partial threading allowing both clamping and alignment functions in structural assemblies
• Regulatory compliance assurance meeting ASME, SAE, RoHS 3, and REACH standards for global industrial use

Professional Applications & Engineering Value

This Grade 8 hex head screw delivers critical engineering solutions for heavy machinery, structural steel connections, and industrial equipment assemblies. The 3/4"-16 UNF fine thread configuration provides superior resistance to vibrational loosening while maintaining high clamping forces. The zinc yellow-chromate plating creates a protective barrier against corrosion in outdoor or chemically aggressive environments, significantly reducing maintenance frequency. With partial threading design, engineers can achieve optimal load distribution between threaded and unthreaded sections, preventing joint failure in dynamic loading conditions. These steel fasteners are engineered to withstand extreme mechanical stress while maintaining dimensional stability, making them ideal for construction, mining equipment, and heavy vehicle manufacturing where reliability is paramount.

Specification Summary & Compliance

Manufactured to ASME B18.2.1 and SAE J429 Grade 8 specifications with Class 2A thread fit tolerance for precision engagement. The 3/4"-16 UNF fine thread maintains consistent pitch accuracy across the 2" minimum threaded length. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations ensures global acceptability. The external hex drive with 1 1/8" head width and 1/2" head height provides standardized tool compatibility for industrial installation equipment.