S-90675A030 5/16"-18 Locknuts

Key Features & Benefits at a Glance

• Superior vibration resistance through integrated external-tooth lock washer that bites into mating surfaces to prevent rotation
• Enhanced corrosion protection with zinc-plated steel construction for extended service life in harsh environments
• Reliable anti-loosening performance maintains consistent clamping force under dynamic loads and vibration
• Quick installation with standard 1/2" hex profile compatible with common wrench tools
• Precision thread engagement with Class 2B UNC coarse threads ensuring smooth assembly and secure fit
• Optimized load distribution from the 0.578" OD lock washer that spreads pressure across wider surface area
• Right-hand threading compatibility with standard industrial equipment and existing fastener systems

Professional Applications & Engineering Value

This heavy-duty 5/16"-18 UNC locknut addresses critical vibration-induced loosening challenges in industrial applications. The zinc-plated steel construction provides essential corrosion resistance for machinery exposed to moisture or chemical environments, while the integrated external-tooth lock washer creates permanent mechanical locking action that outperforms friction-based solutions. The Class 2B coarse threads enable rapid installation in high-volume assembly operations without compromising connection integrity. Engineered for demanding environments including automotive assemblies, construction equipment, agricultural machinery, and industrial manufacturing systems, this vibration-resistant fastener maintains joint integrity where constant motion and dynamic loads would cause conventional nuts to fail.

Specification Summary & Compliance

This locknut features 5/16"-18 UNC coarse threads with Class 2B thread fit per ASME B1.1 standards, ensuring proper clearance and engagement with mating components. The external hex drive measures 1/2" across flats with a total height of 21/64". The integrated external-tooth lock washer has an outer diameter of 0.578" and is manufactured from steel with zinc-plated finish for corrosion protection. Manufactured in compliance with industrial fastener specifications and suitable for applications requiring reliable vibration resistance.