Abstract: A jam nut apparatus for fastening to a threaded end of a bolt to secure the bolt where the threaded end has first handed threads includes a locking nut having an internal nut passageway with nut internal threads, the nut passageway having a first passageway end with an inwardly extending locking flange, a bolt end cap having a tubular cap side wall, the cap side wall having an open end with a locking edge and an inner surface with first handed internal threads, for engagingly receiving the threaded end of the bolt, the cap also having an outer surface with second handed external threads opposite to the first handed thread direction, external threads onto which the locking nut threads engagingly fasten, where the locking nut threads are oriented in the second handed direction.