S-91251A021 1 1/4"-7 x 7" 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.
• Durable black-oxide coating on alloy steel provides enhanced corrosion resistance, extending service life in demanding industrial environments.
• Coarse UNRC thread design allows for faster installation and better performance in materials prone to stripping or where vibration is a concern.
• 7/8" hex drive with standard socket head offers secure tool engagement and high torque capability, minimizing cam-out and improving assembly efficiency.
• Class 2A thread fit ensures consistent, reliable engagement with standard nuts and tapped holes, facilitating smooth assembly processes.
• Partially threaded shank provides unthreaded grip length for precise clamping in structural and machinery applications.
• Compliance with ASTM A574, RoHS 3, and REACH guarantees material quality and environmental safety, meeting global industrial and regulatory standards.

Professional Applications & Engineering Value

Engineered for heavy-duty industrial use, these socket head cap screws deliver superior clamping force and fatigue resistance in critical assemblies. The black-oxide alloy steel construction, combined with a Rockwell C37 hardness, withstands high dynamic loads and harsh conditions, making them ideal for machinery, construction equipment, and automotive systems. The coarse UNRC thread and 7/8" hex drive enable quick, secure fastening even in applications subject to vibration, reducing maintenance needs and downtime. These partially threaded fasteners provide precise load distribution, preventing joint loosening and enhancing the longevity of assembled components in demanding engineering environments.

Specification Summary & Compliance

This socket head cap screw features a 1 1/4"-7 coarse thread with Class 2A thread fit per UNRC standards, ensuring dimensional accuracy and compatibility. It meets ASTM A574 specifications for high-strength alloy steel fasteners and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for global industrial use without hazardous substances.