Abstract: A method for electrostatically applying a thermoplastic resin coating on a threaded portion of a fastener to provide a self locking element thereon. A plurality of fasteners are moved by a spaced pair of endless belts passed a spray station where a stream of powdered resin is directed toward the threaded ends of the fasteners. The fasteners and resin are polarized to opposite polarities at the spray station whereby the powdered resin is attracted to and clings to the threaded ends of the fastener and extends completely about the circumference of said ends. Air jet nozzles located downstream of the spray station may direct streams of compressed air against certain portions of the powdered resin to remove the resin therefrom to provide uncoated lead threads and to regulate the distance that the resin extends circumferentially about the threaded ends to provide a coating extending between 180 degrees and 360 degrees about the threaded ends.