S-90289A103 4-40 x 1/8" ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Enhanced corrosion resistance with black-oxide coating, extending service life in demanding industrial environments
• Superior thread engagement with Class 3A fit for precise, vibration-resistant assemblies in critical applications
• High-strength performance from Rockwell C45 hardened alloy steel, ensuring reliable holding power under heavy loads
• Secure anti-rotation locking through serrations that bite into mating surfaces, preventing unintended loosening
• Optimized torque transmission via 0.050" hex drive design, enabling efficient installation in confined spaces
• Concentrated contact pressure from cup tip design, providing deeper penetration for permanent component positioning
• Industry-standard compatibility with UNC coarse threads, ensuring broad interchangeability across equipment and machinery

Professional Applications & Engineering Value

This 4-40 UNC set screw delivers exceptional engineering value for precision assemblies requiring permanent component fixation. The black-oxide alloy steel construction provides superior corrosion protection while maintaining Rockwell C45 hardness for maximum strength in high-stress applications. The combination of hex drive and headless design enables installation in confined spaces where conventional fasteners cannot operate. Serrations create positive mechanical locking against rotational forces, while the cup tip concentrates pressure for secure shaft-hub connections. Ideal for precision machinery, automotive components, and industrial equipment where vibration resistance and permanent positioning are critical.

Specification Summary & Compliance

Manufactured to ASME B18.3 specifications with Class 3A thread fit for precision tolerance. Features 4-40 UNC coarse threads with right-hand direction and 1/8" length. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global markets.