S-91251A170 5-40 x 1/8" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength (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.
• Precise Class 3A thread fit provides secure, vibration-resistant connections for critical assemblies.
• High hardness (Rockwell C37) offers excellent wear resistance and durability under repeated use.
• Compact 1/8" length and 3/32" hex drive allow for easy installation in confined spaces with standard tools.
• Fully threaded coarse UNC design ensures rapid installation and strong holding power in various materials.
• Compliance with ASTM A574, RoHS 3, and REACH guarantees material quality and environmental safety for global supply chains.

Professional Applications & Engineering Value

These black-oxide alloy steel socket head cap screws are engineered to address common industrial challenges such as vibration loosening, corrosion, and space constraints. The UNC coarse thread and Class 3A fit provide superior grip and alignment in metals and plastics, minimizing assembly errors. The socket head design with a 3/32" hex drive allows for high-torque installation in tight areas, making them ideal for machinery, automotive, and electronics applications. Their high tensile strength and corrosion-resistant coating ensure long-term reliability in harsh conditions, reducing maintenance costs and downtime.

Specification Summary & Compliance

This screw features a 5-40 UNC thread with Class 3A fit and coarse spacing, ensuring precise dimensional accuracy. It is manufactured to ASTM A574 specifications for consistent quality and performance. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, meeting international environmental and safety standards for industrial use.