Eye nuts differ in terms of material and finish. Metallic eye nuts can be made of:
aluminum
brass
bronze
steel
hardened steel
stainless steel
titanium
proprietary alloys
Aluminum is lighter than steel, but not as strong. Brass and silicon bronze are common copper-base alloys. Many different grades of carbon steel and alloy steel are used as fastener materials. Stainless steel may not require anti-corrosion coatings, but cannot be hardened to the same degree as carbon steels. Titanium, a metal that is used widely in the aerospace industry, is suitable for specialized applications. In terms of finish, eye nuts are often anodized, galvanized, or plated with gold, silver, tin, or zinc. Black oxide is an eye nut coating that causes virtually no dimensional change. Phosphate coatings provide corrosion resistance and a better surface for the adhesion of primers and paints. Eye nuts with zinc chromate finishes are also available.
