Forgefix flat washer heavy duty zp forgefix 100hdwash6 these forgefix heavy duty form a flat washers are thicker than the more popular form b type washers they are bright zinc plated for increased corrosion resistance and conform to din125 standards washers provide a smooth surface for the nut or bolt to bear on making it less likely to loosen as a result of an uneven fastening surface the main purpose of a washer is to distribute the load under a bolt head or the nut face on all manner