Lock washers are designed to reduce the loosening of bolts and screws from their mating assembly. Lock washers come in a variety of types, the most common being the split and toothed washer. The spring tension of these washers prevents loosening by creating pressure against a fastener’s threads and its mating part. Split lock washers are a helically split ring whose open ends dig into its partnering fastener and join material to reduce counter clockwise rotation. Toothed washer varieties are available with either internal or external teeth, also called tangs. When a screw or bolt is tightened down onto these washers, the tangs “bite” into the fastened material with moderate spring resistance against the fastener reducing the likelihood of loosening caused by vibrations. • Offered in alloy, carbon, and stainless steel • Available in plain, zinc clear, and zinc yellow finishes • External toothed washers are commonly used with bearing locknuts