S-91257A950 7/8"-14 x 8 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 and Grade 8 classification for reliable performance in high-stress applications
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh industrial environments
• Precise thread engagement with UNF fine threading and Class 2A fit ensuring secure fastening and vibration resistance
• Optimized mechanical properties featuring Rockwell C33 hardness for excellent wear resistance and durability
• Enhanced installation efficiency with external hex drive design allowing for high torque application and easy installation
• Versatile partial threading providing both threaded and unthreaded sections for specific clamping requirements
• Regulatory compliance assurance meeting ASME B18.2.1 standards and environmental regulations including RoHS 3 and REACH

Professional Applications & Engineering Value

This Grade 8 hex head screw delivers exceptional engineering value for heavy machinery, structural assemblies, and industrial equipment where high tensile strength and reliable fastening are critical. The 7/8"-14 UNF fine threading provides superior resistance to vibrational loosening while maintaining precise clamping force in demanding applications. The zinc yellow-chromate plating offers enhanced corrosion protection, making it ideal for outdoor equipment, construction machinery, and manufacturing environments exposed to moisture and chemicals. The partially threaded design allows for optimal load distribution, preventing thread damage during installation while providing maximum grip length. Engineered to withstand extreme conditions, this heavy-duty fastener ensures long-term reliability in critical joints and structural connections.

Specification Summary & Compliance

This 8 1/2" length hex head screw features precise Class 2A thread fit with 7/8"-14 UNF fine threading and 2 1/4" minimum thread length. Manufactured to ASME B18.2.1 specifications where applicable per SAE J429 standards. The fastener is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting current environmental regulations for industrial components. The Grade 8 classification ensures consistent mechanical properties including 150,000 psi tensile strength and Rockwell C33 hardness for reliable performance in critical applications.