S-90069A215 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 black oxide steel construction for extended service life in demanding environments
• Optimal countersunk seating with 82° angle design ensuring flush installation in countersunk screw applications
• Consistent performance maintained through Rockwell C40 hardness for reliable spring tension and tooth engagement
• Precision dimensional control with 0.22" ID and 0.421" OD ensuring perfect fit for No. 12 screw applications
• Industry-standard compliance with ASME B18.21.1 specifications guaranteeing interchangeability and quality assurance
• Environmental responsibility through RoHS 3 and REACH compliance for safe use across global markets

Professional Applications & Engineering Value

These countersunk external tooth lock washers deliver critical vibration resistance in high-stress assembly applications where traditional flat washers fail. The black oxide steel construction provides essential corrosion resistance while maintaining the Rockwell C40 hardness necessary for sustained spring action. The precisely engineered 82° countersink angle ensures perfect alignment and flush mounting in countersunk fastener systems, eliminating protrusion issues in precision machinery. The external tooth configuration creates maximum biting action into both the bolt head and workpiece surface, making these lock washers ideal for automotive, heavy equipment, and industrial machinery applications where vibration-induced loosening compromises safety and performance. The combination of material strength and geometric precision addresses the fundamental challenge of maintaining clamp load in dynamic operating conditions.

Specification Summary & Compliance

Manufactured to exact ASME B18.21.1 standards with dimensional specifications including 0.22" inner diameter, 0.421" outer diameter, and 0.020-0.025" thickness range. The countersunk tooth lock washers feature standardized 82° countersink angle and are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Designed specifically for No. 12 screw applications with external tooth location for maximum locking effectiveness.