S-91251A390 1 1/8"-7 x 4 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 industrial applications, reducing the risk of fastener failure.
• Corrosion-resistant black-oxide finish on alloy steel enhances durability and provides protection in demanding environments, extending service life.
• Precise Class 2A thread fit with coarse 1 1/8"-7 UNRC threading allows for easier assembly and secure fastening, minimizing cross-threading issues.
• Partially threaded design offers optimal grip and clamping force where needed, improving joint stability in machinery and structural assemblies.
• High hardness rating (Rockwell C37) maintains thread integrity and resistance to wear, ensuring long-term reliability under repetitive loads.
• 7/8" hex drive socket head enables high-torque installation with standard tools, facilitating efficient maintenance and reducing assembly time.
• Compliance with ASTM A574, RoHS 3, and REACH guarantees material quality and environmental safety, meeting global regulatory standards for industrial use.

Professional Applications & Engineering Value

Engineered for heavy-duty applications, this black-oxide alloy steel socket head cap screw addresses critical challenges in industrial settings, such as vibration resistance and corrosion prevention. The coarse UNRC thread and Class 2A fit ensure quick, secure fastening in equipment like machinery frames, automotive assemblies, and construction projects, where high tensile strength (170,000 psi) and Rockwell C37 hardness combat fatigue and deformation. Its partially threaded configuration provides focused clamping force, reducing stress concentration and enhancing joint integrity. Ideal for industrial fasteners requiring reliable performance, this screw's compliance with ASTM A574 and environmental standards supports sustainable, long-lasting engineering solutions.

Specification Summary & Compliance

This socket head cap screw features a 1 1/8"-7 coarse UNRC thread with Class 2A tolerance for precise fit, a 4 1/2" length, and a 7/8" hex drive. Manufactured to ASTM A574 specifications, it ensures consistent quality and performance. The product is fully RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, adhering to environmental and safety regulations for industrial use.