ARP 10mm ID Insert Washer, Stainless Steel, each

Brand: Automotive Racing Products (ARP)

These hardened, parallel-ground stainless steel washers have a special "insert" design that fits into an oversized hole to help support and protect the material around the hole. This protection is especially critical in applications such as aluminum cylinder heads, where torquing the head bolts could force the aluminum to collapse into the hole. Holes which see radial forces (such as motor mount plates) will also benefit from these hardened inserts.

This metric size fits 10mm bolts and has an oversized 20mm OD. The hole must be bored to 12.7mm ID (1/2") to accommodate the insert. Polished, corrosion-resistant stainless steel. Sold individually.