S-91251A331 1"-14 x 8" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure.
• Precise Class 3A thread fit provides superior engagement and vibration resistance in critical assemblies, minimizing loosening over time.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance, extending service life in demanding industrial environments.
• Fine UNRF thread profile allows for smoother adjustments and better load distribution compared to coarse threads.
• Partially threaded design combines a secure grip in the threaded section with unthreaded shank strength, ideal for clamping applications.
• 3/4" hex drive socket enables high-torque installation with standard tools, speeding up assembly without stripping the drive.
• Compliance with ASTM A574, RoHS 3, and REACH ensures material consistency and environmental safety for global supply chains.

Professional Applications & Engineering Value

This Black-Oxide Alloy Steel Socket Head Cap Screw is engineered to address common industrial challenges such as vibration-induced loosening and corrosion in heavy machinery. The 1"-14 UNRF fine thread and Class 3A fit deliver tight tolerances that prevent backlash in precision equipment, while the partially threaded rod type optimizes clamping force in structural joints. With a Rockwell C37 hardness and 170,000 psi tensile strength, it withstands dynamic loads in automotive, aerospace, and manufacturing assemblies. The black-oxide surface treatment resists rust without adding significant thickness, maintaining dimensional accuracy in confined spaces. Ideal for high-strength fastening applications, this screw ensures long-term reliability where failure is not an option.

Specification Summary & Compliance

This socket head cap screw features a 1"-14 UNRF fine thread with Class 3A thread fit for high precision, a minimum thread length of 2 1/2", and an overall length of 8". It is manufactured in accordance with ASTM A574 specifications, ensuring consistent quality and performance. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting environmentally responsible sourcing and usage in industrial markets.