S-91853A545 5/8"-18 Locknuts

Key Features & Benefits at a Glance

• Superior vibration resistance through cotter pin locking mechanism that prevents loosening in high-stress applications
• Excellent corrosion resistance from 18-8 stainless steel construction, ideal for harsh industrial environments
• Precise thread engagement with Class 2B thread fit ensuring reliable, consistent fastening performance
• Easy installation and removal with standard external hex drive compatible with common wrench tools
• Enhanced safety and reliability with castle design accommodating 5/32" cotter pins for positive mechanical locking
• Regulatory compliance assurance meeting both RoHS 3 and REACH standards for environmental and safety requirements
• Optimized slot dimensions with 0.21" minimum depth and 0.18" width for secure cotter pin retention

Professional Applications & Engineering Value

This 5/8"-18 UNF stainless steel castle locknut delivers exceptional performance in demanding mechanical systems where vibration-induced loosening poses significant risks. The 18-8 stainless steel material provides outstanding corrosion resistance, making it ideal for outdoor equipment, marine applications, and industrial machinery exposed to moisture and chemicals. The UNF fine thread configuration offers superior load distribution compared to coarse threads, while the cotter pin locking mechanism creates a positive mechanical lock that eliminates the need for constant retightening in high-vibration environments such as automotive suspensions, agricultural equipment, and rotating machinery. The external hex drive ensures compatibility with standard tools, streamlining maintenance procedures while maintaining secure fastening integrity.

Specification Summary & Compliance

This castle locknut features 5/8"-18 UNF fine threads with Class 2B thread fit for precise engagement, measuring 15/16" across flats and 23/32" in height. The nut accommodates 5/32" cotter pins with minimum slot dimensions of 0.21" depth and 0.18" width. Manufactured to industry standards, this fastener is fully RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, meeting current environmental and substance restriction requirements for industrial applications.