This standard specifies four types of spring-action washers: a) Steel, stainless steel, and phosphor bronze spring washers used for general purpose bolts, machine screws, nuts, etc.; b) For general purpose bolts, machine screws, nuts, hexagon socket head bolts, etc. Steel countersunk washers used: c) Steel and phosphor blue steel toothed halves used for general purpose bolts, machine screws, nuts (), etc.: d) General purpose bolts, machine screws, nuts () ), etc. Made of steel, stainless steel, and phosphor bronze wave spring washers