S-90128A107 4-40 x 5/16" 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 zinc plating protects against rust and environmental degradation, extending service life in harsh industrial settings.
• Precise Class 3A thread fit guarantees tight tolerances and secure fastening, minimizing backlash and improving assembly accuracy.
• High hardness rating (Rockwell C37) provides excellent wear resistance, maintaining thread integrity through repeated installations and removals.
• Fully threaded design allows for consistent clamping force along the entire length, enhancing joint stability in various material thicknesses.
• Coarse UNC threads enable quicker installation and better performance in materials prone to stripping or where vibration is a concern.
• Hex socket drive offers high torque transmission and reduced risk of cam-out, ensuring efficient installation with standard tools.

Professional Applications & Engineering Value

These 4-40 UNC thread socket head cap screws are engineered from zinc-plated alloy steel to address critical industrial challenges like vibration loosening and corrosion. The coarse thread spacing and Class 3A fit provide superior grip in soft materials and high-vibration environments, such as machinery, automotive assemblies, and electronic enclosures. The fully threaded rod type ensures uniform stress distribution, preventing joint failure in dynamic loads. With a hex drive style and standardized socket head profile, they facilitate quick, secure installations in confined spaces, reducing assembly time and maintenance costs while meeting rigorous performance standards.

Specification Summary & Compliance

This fastener features a 4-40 UNC thread with Class 3A fit for precise dimensional accuracy, ensuring compatibility with standard nuts and tapped holes. It complies with ASTM A574 manufacturing specifications for consistency and reliability. Additionally, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, adhering to environmental and safety regulations for global industrial use.