Abstract: A bolt, lock washer and nut combination which will not loosen under vibration. The bolt includes a pair of longitudinally extending slots which slidably receive inwardly projecting lugs of the lock washer. A plurality of leaf springs integrally mounted to the lock washer project into recesses formed in the adjacent surface of the nut threaded onto the bolt. The leaf springs are sized relative to said main body to be completely contained within said main body without projecting therefrom when fully depressed. In one embodiment, the lock washer is provided with a weather sealing washer mounted thereon which is positioned on the side adjacent the bolt head. Indicating means are provided on the lock washer and nut for indicating when the leaf springs are positioned within the recesses formed on the nut.