S-99291A590 1/2"-13 Locknuts

Key Features & Benefits at a Glance

• Superior vibration resistance through distorted top-lock threads that maintain clamp force in high-shock environments
• Enhanced corrosion protection with zinc-flake coating that provides superior defense against rust and chemical exposure
• Reliable performance under heavy loads thanks to ASTM Grade C strength classification and steel construction
• Precise thread engagement with Class 2B thread fit ensuring consistent installation and removal cycles
• Industry-standard compatibility with UNC coarse 1/2"-13 threads for broad application across industrial equipment
• Secure environmental compliance meeting both REACH and RoHS 3 standards for workplace and environmental safety
• Easy installation and removal with standard external hex drive compatible with common wrenching tools

Professional Applications & Engineering Value

This zinc-flake-coated steel locknut addresses critical vibration-induced loosening in industrial machinery, construction equipment, and transportation systems. The distorted top-lock thread design creates continuous interference that resists rotational forces from impact loads and machinery vibration, eliminating the need for secondary locking devices. The UNC coarse thread profile ensures rapid assembly in field maintenance situations while maintaining Class 2B thread fit precision. The zinc-flake coating system provides exceptional corrosion resistance exceeding standard zinc plating, making it ideal for outdoor applications and harsh chemical environments. Engineered to ASTM Grade C specifications, this external hex locknut delivers consistent clamping force in heavy-duty bolted connections where vibration resistance and long-term reliability are paramount.

Specification Summary & Compliance

This 1/2"-13 UNC locknut features Class 2B thread fit tolerances per ASME B1.1 standards with coarse thread spacing for industrial applications. Manufacturing complies with ASTM Grade C mechanical properties and dimensional requirements. The product is fully compliant with REACH (EC 1907/2006) regulations (current as of 06/10/2022, 224 SVHC) and RoHS 3 (2015/863/EU) environmental directives. Physical dimensions include 3/4" width across flats and 7/16" height with right-hand thread direction and external hex drive configuration.