Black Washers - 3/8 ID x 5/8 OD Chamfer (10)

ARP Black Washers 3/8 ID x 5/8 OD Chamfer (10-pack) are precision-engineered flat washers designed for high-performance fastening applications where load distribution and surface protection are critical. These special-purpose washers feature a chamfered edge design that accommodates bolt head geometry while maintaining secure clamping force across a wide bearing surface. The 3/8-inch inner diameter and 5/8-inch outer diameter specification positions these washers for use in medium-duty mechanical assemblies where standard flat washers would prove inadequate.

Manufactured from chromoly steel with black oxide coating, each washer provides corrosion resistance and durability in both indoor and harsh outdoor environments. The 0.062-inch thickness delivers rigidity without excess weight, ensuring proper load distribution during tightening sequences. The chamfered design reduces stress concentration at washer edges and promotes consistent bolt preload by conforming to standard bolt head angles. Black oxide finish resists oxidation while maintaining a low-profile aesthetic suitable for firearm component assembly, engine work, and industrial fastening applications.

This 10-piece set serves firearms builders, mechanical engineers, and maintenance professionals who require specification-matched fastening components. The combination of chromoly material and black oxide finish makes these washers ideal for AR-platform builds, precision rifle assembly, and restoration work where corrosion mitigation and consistent surface finish are essential. ARP's reputation for precision manufacturing ensures dimensional accuracy and material consistency across the entire set, delivering reliable performance in critical fastening applications where washer quality directly impacts final assembly integrity.