S-90289A539 1/4"-20 x 5/8" ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Superior holding power with Class 3A thread fit ensuring precise, vibration-resistant connections in demanding applications.
• Enhanced corrosion resistance from the black-oxide finish on alloy steel, prolonging service life in harsh industrial environments.
• High-strength durability with Rockwell C45 hardness, providing reliable performance under heavy loads and repeated use.
• Secure locking capability through serrations that bite into mating surfaces, preventing loosening from dynamic stresses.
• Easy installation and removal with the 1/8" hex drive, allowing efficient assembly in confined spaces without head interference.
• Optimized force distribution from the cup tip design, minimizing surface damage while maintaining firm clamping pressure.
• Broad compatibility with UNC coarse threads and right-hand direction, suitable for standard industrial components and machinery.

Professional Applications & Engineering Value

This 1/4"-20 UNC set screw is engineered to address critical challenges in industrial assemblies, such as shaft-hub connections and precision alignment systems. The black-oxide alloy steel construction offers excellent wear and corrosion resistance, reducing maintenance needs in environments exposed to moisture or chemicals. With a Class 3A thread fit and coarse UNC thread type, it ensures quick installation and reliable grip in materials where fine threads might strip. The combination of serrations for locking and a cup tip provides superior anti-vibration performance, preventing unintended disassembly in high-stress applications like motor mounts or gear assemblies. This headless set screw with hex drive is ideal for compact designs, offering engineers a dependable solution for maximizing equipment uptime and safety.

Specification Summary & Compliance

This set screw adheres to ASME B18.3 specifications, ensuring dimensional accuracy and performance reliability. The thread fit is Class 3A with UNC coarse threads, providing tight tolerances for secure fastening. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing environmental safety and material sustainability. Manufactured from alloy steel with a black-oxide surface treatment, it meets industrial standards for durability and corrosion resistance in various applications.