The self-locking process consists of a nylon patch permanently sprayed onto the threads of a fastener (upper left) or embedded into the threads as a pellet or strip (upper right). When threads mate, the nylon compresses and then tries to regain its original shape, creating a strong counterforce and metal-to-metal contact that sets up a positive resistance to vibration. Locking properties are retained at temperatures to 250°. The fasteners are unaffected by gasoline, alcohol, caustic soda, jet fuels, hydraulic fluids, and most commercial solvents