S-91251A399 1 1/8"-7 x 6 1/2" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Black-oxide coating on alloy steel provides enhanced corrosion resistance and a durable, non-reflective finish suitable for harsh environments.
• Coarse UNRC thread design offers faster installation and superior resistance to vibration loosening in industrial settings.
• 7/8" hex drive socket head allows for high-torque tightening with standard tools, ensuring secure assembly and easy maintenance.
• Partially threaded shank provides precise clamping force control, ideal for applications requiring accurate load distribution.
• Rockwell C37 hardness rating delivers excellent wear resistance and long-term durability under repetitive mechanical stress.
• Compliance with ASTM A574 guarantees consistent quality and dimensional accuracy for engineering-critical fastening solutions.

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these socket head cap screws combine black-oxide alloy steel construction with coarse UNRC threads to address common engineering challenges. The 1 1/8"-7 thread configuration ensures rapid installation in heavy machinery, automotive assemblies, and structural frameworks where vibration resistance is critical. The partially threaded design allows precise engagement in tapped holes while maintaining maximum tensile strength across the 6 1/2" length. This makes them ideal for high-load connections in manufacturing equipment, construction projects, and aerospace components where reliability and corrosion resistance are paramount. The 7/8" hex drive accommodates standard industrial tools for efficient maintenance and disassembly cycles.

Specification Summary & Compliance

This socket head cap screw features Class 2A thread fit for consistent assembly tolerance and UNRC coarse thread standard with 1 1/8"-7 threading. Manufacturing complies with ASTM A574 specifications for high-strength alloy steel fasteners. The product is fully RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, meeting international environmental and safety standards for industrial use.