S-90900A112 0.318" ID x 0.599" OD ASME B18.21.1 Countersunk External-Tooth Lock Washers

Key Features & Benefits at a Glance

• Superior vibration resistance with external tooth lock design that bites into mating surfaces to prevent loosening under dynamic loads
• Exceptional corrosion resistance provided by 400 Series Stainless Steel construction for long-term reliability in harsh environments
• Optimized countersunk seating with 82° angle for flush mounting and even load distribution in countersunk applications
• Enhanced durability with Rockwell C34 hardness rating that maintains tooth integrity and locking performance through repeated use
• Precision dimensional control ensuring perfect fit for 5/16" fasteners with consistent ID, OD, and thickness specifications
• Industry-standard compliance meeting ASME B18.21.1 specifications for reliable performance in demanding applications
• Environmental responsibility with RoHS 3 and REACH compliance for safe use across regulated industries

Professional Applications & Engineering Value

This 5/16" external tooth lock washer delivers critical vibration resistance in demanding industrial applications where fastener security is paramount. Engineered from 400 Series Stainless Steel, the washer provides excellent corrosion resistance while the external tooth configuration creates positive locking action that prevents rotational loosening in machinery, automotive assemblies, and structural frameworks. The 82° countersink angle ensures proper seating in countersunk applications, distributing clamp load evenly while maintaining surface integrity. With Rockwell C34 hardness, these washers maintain their locking teeth through repeated assembly cycles, making them ideal for maintenance-intensive equipment and heavy-duty applications where reliability cannot be compromised.

Specification Summary & Compliance

This precision external tooth lock washer features dimensional specifications of 0.318" ID, 0.599" OD, and 0.023-0.028" thickness, specifically designed for 5/16" screw size applications. Manufactured in compliance with ASME B18.21.1 standards for tooth lock washers, the product ensures consistent performance and interchangeability. The washer meets RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) regulations regarding substance restrictions, making it suitable for use across various regulated industries and international markets.