Lock Washers 5/16 25pk

The ALLSTAR PERFORMANCE Lock Washers 5/16 25-pack (ALL16121-25) delivers dependable fastener security for automotive, mechanical, and assembly applications where vibration resistance is critical. These split-style lock washers prevent bolt and screw loosening in high-vibration environments, making them essential hardware for engine work, suspension assembly, frame repairs, and industrial machinery maintenance.

Each washer features a 0.313-inch inside diameter (ID) with a 0.583-inch outer diameter (OD) and 0.082-inch thickness, sized specifically for 5/16-inch fasteners. Manufactured from zinc oxide-coated steel, these washers provide corrosion resistance while maintaining the spring tension that locks fasteners in place. The split design creates radial pressure as the bolt is tightened, gripping the fastener head and preventing rotation caused by thermal cycling, road vibration, or mechanical shock. The 25-piece quantity supplies a full range for multiple projects or inventory replacement.

Technicians and builders depend on lock washers for any assembly where fastener failure creates risk or downtime. Engine rebuilds, suspension work, transmission assembly, and frame-mounted component installation all benefit from the anti-vibration protection these washers provide. The zinc oxide coating resists rust and oxidation in both dry and moderately corrosive environments, extending fastener service life and maintaining security throughout the product lifecycle.

Split lock washers remain the industry standard for applications where bolt preload must be maintained under vibration. Unlike smooth washers, the split design generates continuous outward pressure that compensates for micro-movements and fastener relaxation, ensuring connections stay tight through service intervals. Stock this 25-pack for routine maintenance, system rebuilds, or assembly shops requiring consistent fastener security.