S-90128A102 4-40 x 1/8" 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.
• Corrosion-resistant zinc-plated alloy steel provides enhanced durability and longevity, even in harsh industrial environments.
• Precision Class 3A thread fit offers superior engagement and vibration resistance, minimizing loosening in dynamic assemblies.
• Standard hex drive (3/32") allows for easy installation with common tools, speeding up assembly and maintenance processes.
• Fully threaded right-hand UNC coarse design ensures quick installation and strong holding power across the entire length.
• High Rockwell C37 hardness maintains thread integrity and resists wear, extending the screw's service life.
• Compliance with ASTM A574, RoHS 3, and REACH guarantees material quality and environmental safety for global supply chain requirements.

Professional Applications & Engineering Value

This 4-40 UNC Socket Head Cap Screw is engineered to address critical challenges in precision machinery, automotive, and aerospace assemblies where space constraints and high loads are common. The zinc-plated alloy steel construction combats corrosion, while the Class 3A thread fit and coarse thread spacing provide secure fastening that resists vibration-induced loosening. Its compact 1/8" length and standard socket head profile enable access in tight spaces, making it ideal for mounting components in electronic enclosures or mechanical linkages. By integrating high tensile strength with consistent dimensional accuracy, this fastener reduces assembly time and maintenance needs, delivering long-term reliability in demanding industrial fasteners applications.

Specification Summary & Compliance

This socket head cap screw features a 4-40 UNC thread with Class 3A fit for precise tolerance, ensuring optimal thread engagement. Dimensions include a thread diameter of 0.112", head diameter of 0.183", and length of 1/8", with a right-hand, fully threaded rod type. It meets ASTM A574 specifications for high-strength alloy steel fasteners and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, affirming its suitability for restricted substance-controlled environments.