S-90289A112 4-40 x 1/2" ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Exceptional holding power with Class 3A thread fit for precise, secure fastening in demanding applications.
• Superior corrosion resistance provided by the black-oxide finish on alloy steel, extending service life in harsh environments.
• High-strength durability with a Rockwell C45 hardness rating, resisting wear and deformation under load.
• Secure, non-slip installation enabled by the hex drive and serrations, preventing loosening from vibrations.
• Reliable positioning and clamping due to the cup tip design, ensuring components stay firmly in place.
• Broad industrial compatibility with UNC coarse threads and right-hand direction, fitting standard 4-40 components.
• Streamlined, space-saving design as a headless set screw, ideal for confined assemblies.

Professional Applications & Engineering Value

This 4-40 UNC set screw is engineered to solve critical challenges in precision assemblies, such as shaft collars, gears, and pulleys, where vibration resistance and positional stability are paramount. The black-oxide alloy steel construction offers excellent protection against rust and wear, while the Rockwell C45 hardness ensures the screw maintains its integrity under repetitive stress. Its hex drive and serrations provide a firm grip during installation, reducing the risk of tool slippage and ensuring consistent torque application. The cup tip concentrates force for a secure hold, making it a reliable choice for machinery, automotive, and electronics industries requiring high-performance fastening solutions.

Specification Summary & Compliance

This set screw adheres to ASME B18.3 specifications, ensuring dimensional accuracy and reliability. It features a Class 3A thread fit for tight tolerances and a coarse UNC thread with a 4-40 size and right-hand direction. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) standards guarantees environmental safety and regulatory acceptance in industrial markets.