S-92991A103 4-40 x 1/8" ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance from brass construction, ideal for harsh environments and reducing maintenance costs
• Exceptional thread engagement with Class 3A fit for secure, vibration-resistant fastening in precision assemblies
• Optimized torque transmission via 0.050" hex drive, preventing tool slippage and ensuring consistent installation
• Secure component positioning with cup tip design, minimizing surface damage and providing reliable holding power
• Enhanced durability with Rockwell B55 hardness, maintaining thread integrity under repeated use
• Broad compatibility with 4-40 UNC coarse threads, simplifying sourcing and replacements in industrial systems
• Regulatory peace of mind through compliance with ASME B18.3, RoHS 3, and REACH standards

Professional Applications & Engineering Value

This 4-40 UNC brass set screw delivers critical performance in precision mechanical systems where corrosion resistance and reliable clamping force are paramount. The headless design with hex drive allows flush mounting in confined spaces, while the Class 3A thread fit ensures minimal backlash in assemblies subject to vibration. Engineers specify this component for electrical connectors, instrumentation, and precision machinery where the brass material prevents galvanic corrosion when mating with dissimilar metals. The cup tip concentrates clamping force without damaging shaft surfaces, making it ideal for securing gears, pulleys, and collars in demanding industrial environments.

Specification Summary & Compliance

Manufactured to ASME B18.3 specifications with 4-40 UNC coarse threads and Class 3A thread fit for precision tolerance. Complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Features 1/8" length, 0.050" hex drive, and Rockwell B55 hardness for consistent mechanical performance.