S-97775A520 0.168" ID x 0.381" OD ASME B18.21.1; MS35335-31 Mil. Spec. 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
• Enhanced durability from Rockwell C40 hardness, maintaining structural integrity under repeated load cycles
• Reliable corrosion protection through zinc plating, extending service life in industrial environments
• Precision dimensional fit with 0.168" ID and 0.381" OD, ensuring proper alignment with No. 8 screws
• Industry-standard compliance meeting ASME B18.21.1 and MS35335-31 specifications for guaranteed performance
• Consistent thickness control (0.018-0.023") for uniform clamping force distribution
• Optimized for inch-system applications in North American industrial equipment and machinery

Professional Applications & Engineering Value

This zinc-plated steel tooth lock washer delivers critical anti-vibration performance in demanding industrial settings where mechanical fasteners face constant dynamic loads. The external tooth configuration creates multiple biting points that dig into both the fastener head and base material, effectively resisting rotational loosening caused by machinery vibration, thermal cycling, and impact forces. Engineered to Rockwell C40 hardness, these No. 8 washers maintain their spring tension and tooth sharpness through countless compression cycles, making them ideal for assembly lines, heavy equipment, automotive systems, and electrical enclosures where fastener security is non-negotiable. The zinc plating provides essential corrosion resistance while the precise dimensional control ensures consistent performance across production runs.

Specification Summary & Compliance

Manufactured to exacting inch system dimensions with 0.168" internal diameter, 0.381" outer diameter, and controlled thickness between 0.018-0.023". This external tooth lock washer complies with ASME B18.21.1 mechanical standards and military specification MS35335-31, ensuring dimensional accuracy and mechanical properties meet industrial requirements. The product conforms to RoHS and REACH environmental directives while the zinc-plated steel construction provides reliable performance in various operating conditions.