S-91251A163 1 1/8"-7 x 3" 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.
• Superior corrosion resistance from the black-oxide finish extends service life in demanding industrial environments.
• High hardness rating (Rockwell C37) provides excellent wear resistance, maintaining thread integrity over repeated use.
• Precision Class 2A thread fit with coarse UNRC threads enables quick assembly and secure fastening in various materials.
• Full threading along the 3" length offers maximum adjustability and holding power across the entire fastener.
• Heavy-duty 7/8" hex drive allows for high torque application with standard tools, preventing stripping and ensuring tight installations.
• Compliance with ASTM A574 guarantees consistent quality and mechanical properties for engineering-critical applications.

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these black-oxide alloy steel socket head cap screws deliver exceptional performance where reliability is non-negotiable. The combination of 170,000 psi tensile strength and Rockwell C37 hardness makes them ideal for high-vibration environments, machinery assembly, and structural frameworks requiring permanent, vibration-resistant fastening. The coarse UNRC threads with Class 2A fit provide superior engagement in both metals and composites, while the black-oxide surface treatment significantly enhances corrosion resistance without compromising dimensional accuracy. These fully threaded cap screws with 7/8" hex drive are specifically designed to withstand extreme mechanical stresses in manufacturing, automotive, and construction sectors where fastener failure is not an option.

Specification Summary & Compliance

These socket head cap screws feature 1 1/8"-7 UNRC coarse threads with Class 2A tolerance for precise fitment, 3" fully threaded length, and are manufactured to ASTM A574 specifications for consistent mechanical properties. The fasteners are RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, meeting international environmental and safety standards for industrial use.