S-90069A120 0.22" ID x 0.421" 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 to prevent loosening under dynamic loads
• Enhanced corrosion protection through zinc-plated steel construction for extended service life in industrial environments
• Precision flush mounting with 82° countersink angle ensuring seamless integration with countersunk fastener heads
• Exceptional durability backed by Rockwell C44 hardness rating for reliable performance in high-stress applications
• Guaranteed dimensional accuracy with 0.22" ID and 0.421" OD specifications ensuring perfect fit for No. 12 screws
• Industry-standard compliance meeting ASME B18.21.1 specifications for quality assurance and interchangeability
• Environmental responsibility with RoHS 3 and REACH compliance for safe use across regulated industries

Professional Applications & Engineering Value

These countersunk external tooth lock washers deliver critical vibration-resistant performance in demanding industrial applications. The zinc-plated steel construction provides essential corrosion protection while maintaining the Rockwell C44 hardness necessary for high-load scenarios. The precisely engineered 82° countersink angle ensures flush mounting with fastener heads, eliminating protrusions in machinery and equipment. The external tooth configuration creates positive locking action by embedding into both the fastener and workpiece, effectively preventing rotational loosening caused by vibration or thermal cycling. These ASME B18.21.1 compliant washers are particularly valuable in automotive assembly, heavy machinery, electrical enclosures, and structural applications where vibration resistance and reliable fastening are paramount.

Specification Summary & Compliance

Manufactured to ASME B18.21.1 standards with precise dimensional specifications: 0.22" internal diameter, 0.421" outer diameter, and 0.020-0.025" thickness range. The external tooth lock washer features an 82° countersink angle and is designed specifically for No. 12 screw applications. Material certification includes zinc-plated steel with Rockwell C44 hardness verification. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations ensures environmental responsibility and workplace safety.