S-99851A106 3/8"-24 MS21046C6, NASM21046 Locknuts

Key Features & Benefits at a Glance

• Superior vibration resistance through flex-top locking design that maintains secure fastening in high-vibration environments
• Enhanced corrosion protection with silver-plated 18-8 stainless steel construction for extended service life in harsh conditions
• Precise thread engagement with Class 3B UNF fine threads ensuring tight, reliable connections in critical applications
• Industry-standard compatibility meeting MS21046C6 and NASM21046 specifications for guaranteed performance and interchangeability
• Easy installation and removal with standard external hex drive design for efficient maintenance and assembly operations
• Environmental compliance assurance with RoHS 3 and REACH compliance for safe use across regulated industries
• Optimal strength-to-weight ratio from 18-8 stainless steel material providing durable performance without excessive weight

Professional Applications & Engineering Value

This 3/8"-24 UNF flex-top locknut delivers exceptional engineering value in demanding industrial applications where vibration resistance is critical. The silver-plated 18-8 stainless steel construction provides superior corrosion resistance while maintaining the material's inherent strength, making it ideal for aerospace, automotive, and heavy machinery applications. The flex-top locking mechanism creates consistent friction against mating threads, preventing loosening under extreme vibration conditions without damaging threads. The Class 3B thread fit ensures precise engagement with mating components, reducing the risk of cross-threading and providing reliable, repeatable fastening performance. These MS21046C6 compliant locknuts are engineered to maintain clamping force in high-stress environments, offering maintenance-free operation and reducing downtime in critical systems.

Specification Summary & Compliance

This precision locknut features 3/8"-24 UNF fine threads with Class 3B thread fit for superior engagement and meets MS21046C6 and NASM21046 manufacturing specifications. The external hex drive design provides standard 9/16" width across flats with 25/64" height profile. The product is fully RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant (including 224 SVHC substances as of 06/10/2022), ensuring environmental responsibility and regulatory adherence for global industrial applications.