S-90778A103 4-40 x 1/8" ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with 316 Stainless Steel construction, ideal for harsh environments and extended service life
• Superior thread engagement and holding power ensured by the precise Class 3A thread fit for reliable, vibration-resistant assemblies
• High-strength performance with a Rockwell B80 hardness rating, providing excellent durability and resistance to wear
• Secure and flush installation thanks to the headless and cone point (118° angle) design, preventing component protrusion and slippage
• Efficient installation and removal enabled by the 0.050" hex drive, allowing for high torque application with standard tools
• Wide compatibility with the 4-40 UNC coarse thread, making it suitable for common industrial components and fastening needs
• Regulatory compliance and safety meeting ASME B18.3 specifications, RoHS 3, and REACH standards for environmentally conscious manufacturing

Professional Applications & Engineering Value

This 4-40 UNC set screw is engineered to address critical challenges in precision assemblies where space is limited and corrosion is a concern. The headless design and cone point tip (118° angle) allow for flush mounting and secure positioning of components on shafts, collars, and gears, minimizing the risk of loosening under vibration. Manufactured from 316 Stainless Steel, it offers superior resistance to chemicals, moisture, and extreme temperatures, making it ideal for marine, chemical processing, and outdoor equipment. The Class 3A thread fit and coarse thread spacing ensure quick assembly and reliable torque transmission, reducing installation time while enhancing the longevity of the joint in high-stress industrial applications.

Specification Summary & Compliance

This set screw adheres to ASME B18.3 standards, with a Class 3A thread fit for precise dimensional accuracy and optimal performance. It features a 4-40 UNC coarse thread, right-hand direction, and a 0.050" hex drive for compatibility with standard tools. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it meets environmental and safety requirements for industrial use.