S-99291A260 1/2"-20 Locknuts

Key Features & Benefits at a Glance

• Superior vibration resistance through top lock distorted thread design, preventing loosening under dynamic loads
• Enhanced corrosion protection with zinc yellow-chromate plating for extended service life in harsh environments
• High-strength performance meeting ASTM Grade C requirements for demanding industrial applications
• Precise thread engagement with Class 2B fit ensuring reliable fastening and consistent torque values
• Easy installation and removal using standard wrenches thanks to external hex drive design
• Fine thread spacing (UNF 1/2"-20) providing better adjustment and load distribution
• Dimensional stability with standardized 3/4" width and 7/16" height for consistent performance

Professional Applications & Engineering Value

This 1/2"-20 UNF locknut with top lock distorted thread technology addresses critical vibration-induced loosening challenges in heavy machinery and automotive systems. The zinc yellow-chromate-plated steel construction provides dual protection against corrosion and wear, while the ASTM Grade C certification ensures reliable performance under high-stress conditions. The distorted thread locking mechanism creates permanent friction that maintains clamp force without requiring additional locking elements, making it ideal for industrial equipment, construction machinery, and transportation applications where safety and reliability are paramount. The fine thread configuration offers superior resistance to vibrational loosening compared to coarse threads, while the external hex drive facilitates quick installation in confined spaces.

Specification Summary & Compliance

This heavy-duty locknut features UNF 1/2"-20 fine threads with Class 2B thread fit for precision engagement, manufactured to ASTM Grade C strength requirements. The product complies with RoHS and REACH environmental standards and follows ASME/ANSI specifications for dimensional accuracy. The top lock distorted thread design provides permanent locking capability without compromising reusability, while the zinc yellow-chromate plating meets industry standards for corrosion protection in demanding applications.