S-99291A690 7/16"-20 Locknuts

Key Features & Benefits at a Glance

• Superior vibration resistance through top-lock distorted thread design that maintains secure fastening under dynamic loads
• Enhanced corrosion protection with zinc-flake coating that provides superior defense against harsh industrial environments
• Reliable performance in high-stress applications backed by ASTM Grade C certification for consistent mechanical properties
• Precise thread engagement with Class 2B fit ensuring smooth assembly and optimal clamping force distribution
• Industry-standard compatibility with 7/16"-20 UNF fine threads for seamless integration into existing systems
• Easy installation and removal using standard wrench tools thanks to the external hex drive design
• Environmental compliance assurance meeting both REACH and RoHS 3 standards for responsible manufacturing

Professional Applications & Engineering Value

This zinc-flake-coated steel locknut delivers exceptional engineering value in applications where vibration-induced loosening poses significant reliability concerns. The distorted thread technology creates consistent interference along the mating threads, providing permanent locking action without requiring additional locking elements. The UNF fine thread configuration offers superior load distribution compared to coarse threads, making it ideal for precision equipment, automotive assemblies, and heavy machinery where fine adjustment and vibration resistance are critical. The external hex drive ensures compatibility with standard industrial tools while the robust ASTM Grade C material maintains structural integrity under repeated stress cycles. This combination addresses the fundamental challenge of maintaining joint integrity in dynamic environments while providing long-term corrosion resistance through its advanced coating system.

Specification Summary & Compliance

This locknut features precise Class 2B thread fit per UNF standards with 7/16"-20 fine thread specification. Manufacturing complies with ASTM Grade C requirements for mechanical properties and dimensional accuracy. The product meets REACH (EC 1907/2006) compliance for substance restrictions and RoHS 3 (2015/863/EU) directives for hazardous materials limitation. Physical dimensions include 11/16" width across flats and 3/8" height, providing optimal strength-to-size ratio for space-constrained applications while maintaining full distorted thread locking functionality at the top engagement area.