S-91251A171 5-40 x 3/16" 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 in demanding applications.
• Superior corrosion resistance from the black-oxide finish on alloy steel extends service life and maintains integrity in harsh industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies, minimizing loosening and improving operational safety.
• Hex socket drive design with a 3/32" drive size allows for easy installation in confined spaces using standard tools, enhancing assembly efficiency.
• Coarse UNRC right-hand threads enable quick engagement and disassembly, saving time in maintenance and repair operations.
• Full threading along the 3/16" length offers uniform load distribution and flexibility in adjustment, accommodating various material thicknesses.
• Compliance with ASTM A574, RoHS 3, and REACH ensures adherence to industry standards and environmental regulations, supporting sustainable and safe usage.

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 machinery and equipment. The high tensile strength and Rockwell C37 hardness provide durability for heavy-duty applications, including automotive assemblies, aerospace components, and precision manufacturing tools. Its 5-40 UNC coarse threads and Class 3A fit ensure reliable fastening in dynamic environments, while the hex drive design simplifies installation in tight spaces. By combining robust material properties with standardized dimensions, this fastener enhances structural integrity and reduces maintenance downtime, making it ideal for industrial screws in critical engineering projects.

Specification Summary & Compliance

This product features precise dimensions, including a 3/16" length, 5-40 UNRC coarse threads with a Class 3A fit for accurate thread engagement. 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, ensuring environmental safety and regulatory adherence in industrial use.