S-90328A101 4-40 Locknuts

Key Features & Benefits at a Glance

• Superior vibration resistance through integrated external-tooth lock washer that maintains secure fastening in high-motion environments
• Enhanced corrosion protection with black zinc-plated steel construction for extended service life in industrial conditions
• Reliable thread engagement with Class 2B thread fit ensuring consistent performance and easy assembly
• Optimized for coarse threading applications using 4-40 UNC right-hand threads for robust connections in machinery and equipment
• Industry-standard compatibility with 1/4" hex profile and external hex drive for seamless integration with standard tools
• Environmental compliance assurance meeting both REACH and RoHS 3 standards for safe usage in regulated industries
• Dual-material performance combining steel lock washer with zinc-plated steel nut for maximum locking security

Professional Applications & Engineering Value

This 4-40 UNC locknut with integrated external-tooth lock washer addresses critical vibration-induced loosening challenges in industrial machinery, automotive assemblies, and electrical enclosures. The black zinc-plated steel construction provides essential corrosion resistance while maintaining the structural integrity required for heavy-duty applications. The coarse UNC threading ensures rapid installation and reliable performance in high-vibration environments where fine threads might fail. Engineers specify this solution for permanent fastening applications requiring Class 2B thread fit precision, particularly in assembly lines where consistent torque values and vibration resistance are paramount. The external hex drive design accommodates standard wrenching tools, streamlining maintenance procedures while the locking mechanism prevents rotational slippage under dynamic loads.

Specification Summary & Compliance

This heavy-duty locknut features precise Class 2B thread fit with 4-40 UNC coarse threads and right-hand direction. Manufacturing specifications include 1/4" width across flats and 1/8" height profile with integrated steel external-tooth lock washer (0.281" OD). The assembly is fully compliant with REACH (EC 1907/2006) regulations and RoHS 3 (2015/863/EU) directives, ensuring environmental safety standards are met for industrial distribution and usage. The component maintains dimensional accuracy per inch measurement system requirements for reliable interchangeability in mechanical systems.