S-90900A007 0.14" ID x 0.289" OD ASME B18.21.1 Countersunk External-Tooth Lock Washers

Key Features & Benefits at a Glance

• Superior vibration resistance with external teeth that bite into mating surfaces, preventing loosening in high-stress applications
• Excellent corrosion resistance provided by 400 Series Stainless Steel, ensuring long-term reliability in harsh industrial environments
• Precise flush mounting with an 82° countersink angle that matches standard screw heads for smooth, secure installations
• Enhanced durability from Rockwell C34 hardness, maintaining structural integrity under repeated loading and vibration
• Reliable performance for No. 6 screws with 0.14" ID, ensuring perfect fit and optimal locking force in demanding assemblies
• Full regulatory compliance with RoHS 3 and REACH standards, making them suitable for global industrial and commercial applications
• Industry-standard quality meeting ASME B18.21.1 specifications for consistent dimensional accuracy and mechanical performance

Professional Applications & Engineering Value

This Countersunk External Tooth Lock Washer delivers critical vibration-resistant performance in demanding industrial applications where secure fastening is non-negotiable. Manufactured from 400 Series Stainless Steel, it provides exceptional corrosion resistance for machinery operating in humid, chemical, or outdoor environments. The precisely engineered 82° countersink angle ensures flush mounting with standard fastener heads, eliminating protrusions in precision assemblies while the external tooth configuration creates maximum bite force against mating surfaces. These washers are particularly valuable in automotive, aerospace, and heavy equipment applications where No. 6 screw assemblies require reliable locking under constant vibration and thermal cycling, preventing costly downtime from fastener failure.

Specification Summary & Compliance

This washer features precise dimensional specifications including 0.14" ID, 0.289" OD, and thickness ranging 0.017-0.021" for consistent performance with No. 6 screw applications. Manufactured to ASME B18.21.1 standards, it ensures proper tooth configuration, material properties, and dimensional tolerances. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, containing no restricted substances and meeting current SVHC requirements as of June 2023. With Rockwell C34 hardness and 400 Series Stainless Steel construction, it delivers reliable mechanical performance across industrial applications.