S-98438A215 0.129" ID x 0.285" OD ASME B18.21.1 External-Tooth Lock Washers

Key Features & Benefits at a Glance

• Superior vibration resistance through external teeth design that bites into mating surfaces, preventing fastener loosening under dynamic loads
• Exceptional corrosion resistance with 400 Series Stainless Steel construction, ideal for harsh industrial environments
• Optimized dimensional precision with 0.129" ID and 0.285" OD ensuring perfect fit for No. 5 screws in inch system applications
• Enhanced mechanical strength from Rockwell C34 hardness rating, providing reliable performance under high stress conditions
• Industry-standard compliance with ASME B18.21.1 specifications, guaranteeing consistent quality and interchangeability
• Environmental responsibility through RoHS 3 and REACH compliance, meeting global regulatory requirements
• Reduced maintenance requirements with durable construction that maintains locking performance through multiple installation cycles

Professional Applications & Engineering Value

These external tooth lock washers deliver critical vibration-resistant fastening solutions across demanding industrial sectors. The 400 Series Stainless Steel composition provides excellent corrosion resistance for applications in chemical processing, marine environments, and outdoor equipment where moisture exposure is common. The precisely engineered external teeth configuration creates multiple biting points that dig into both the fastener head and mounting surface, effectively resisting rotational forces that cause conventional fasteners to loosen. This design proves particularly valuable in heavy machinery, automotive assemblies, and electrical enclosures where vibration-induced failures can lead to costly downtime. The combination of Rockwell C34 hardness and controlled thickness (0.014-0.020") ensures these washers maintain their spring tension and locking capability without deforming under load, providing reliable performance in critical joint applications where safety and reliability are paramount.

Specification Summary & Compliance

This No. 5 external tooth lock washer features precise dimensional specifications including 0.129" internal diameter, 0.285" outer diameter, and thickness ranging from 0.014" to 0.020". Manufactured to ASME B18.21.1 standards for mechanical fasteners, these washers ensure proper fit and function within inch system applications. The product maintains full compliance with RoHS 3 (2015/863/EU) regulations and REACH (EC 1907/2006) requirements, including the latest SVHC updates as of June 14, 2023. The 400 Series Stainless Steel construction combined with Rockwell C34 hardness provides the necessary mechanical properties for reliable performance in industrial locking applications.