S-99291A220 1/4"-28 Locknuts

Key Features & Benefits at a Glance

• Superior vibration resistance with top lock distorted thread design that maintains secure fastening under dynamic loads
• Enhanced corrosion protection through zinc yellow-chromate plating that extends service life in harsh environments
• Reliable performance certification meeting ASTM Grade C standards for consistent quality and strength
• Precise thread engagement with Class 2B fine UNF threads ensuring accurate fit and reduced loosening risk
• Easy installation and removal using standard external hex drive compatible with common tools
• Optimized dimensional stability with 7/16" width and 7/32" height providing consistent performance across applications
• Right-hand thread direction for standard assembly procedures and compatibility with existing systems

Professional Applications & Engineering Value

This 1/4"-28 UNF lock nut with distorted thread technology addresses critical vibration-induced loosening challenges in industrial equipment, automotive assemblies, and machinery. The zinc yellow-chromate plated steel construction provides dual-layer protection against corrosion while maintaining the structural integrity required for ASTM Grade C performance standards. The top lock distorted thread design creates consistent interference that resists rotational forces without compromising the Class 2B fine thread precision, making it ideal for applications where thermal cycling and mechanical stress would compromise standard fasteners. The external hex drive profile ensures straightforward installation with common tools, reducing assembly time while delivering reliable vibration-resistant performance in demanding environments.

Specification Summary & Compliance

This locknut features 1/4"-28 UNF fine threads with Class 2B tolerance for precise fit, manufactured in compliance with ASTM Grade C standards. The distorted thread top lock design follows industry locking mechanisms, while the zinc yellow-chromate plating provides corrosion resistance meeting common industrial requirements. Dimensions include 7/16" width across flats and 7/32" height with right-hand thread direction for standard applications.