S-90069A103 0.113" ID x 0.213" OD ASME B18.21.1 Countersunk External-Tooth Lock Washers

Key Features & Benefits at a Glance

• Superior vibration resistance through external tooth design that bites into mating surfaces, preventing loosening under dynamic loads
• Enhanced corrosion protection with zinc-plated steel construction for extended service life in industrial environments
• Precise countersunk seating with 82° angle for flush mounting and optimal load distribution in countersunk applications
• Exceptional hardness rating of Rockwell C44 ensures maintained tooth integrity and locking performance under high stress
• Reliable dimensional accuracy with 0.213" OD and 0.113" ID for perfect fit with No. 4 screws
• Industry-standard compliance with ASME B18.21.1 specifications for guaranteed performance and interchangeability
• Environmental responsibility through RoHS 3 and REACH compliance, meeting strict international regulatory standards

Professional Applications & Engineering Value

This external tooth lock washer delivers critical vibration-resistant performance in demanding industrial applications where fastener security is paramount. The zinc-plated steel construction provides essential corrosion resistance for machinery, automotive assemblies, and electrical enclosures exposed to harsh environments. The 82° countersink angle ensures perfect flush mounting in countersunk applications, eliminating protrusions while maintaining uniform pressure distribution. With external tooth location, the washer creates maximum biting action against both the fastener and seating surface, effectively preventing rotational loosening caused by vibration, thermal cycling, or dynamic loading. This engineering solution is particularly valuable in assembly lines, heavy equipment, and precision instruments where maintenance downtime must be minimized.

Specification Summary & Compliance

This No. 4 external tooth lock washer features precise dimensional specifications including 0.213" OD, 0.113" ID, and thickness range of 0.015-0.019". Manufactured to ASME B18.21.1 standards for dimensional accuracy and performance reliability. The washer is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and regulatory acceptance for global industrial applications. The Rockwell C44 hardness rating guarantees consistent locking performance throughout the product's service life.