Abstract: A self-aligning arbor nut system is disclosed. The self-aligning arbor nut system, according to the present invention, includes a body formed with a duct substantially coincident with the longitudinal axis of the body. A substantially circular ring known as a swivel also is provided. The ring is engageable with either end of the duct. An o-ring is included. The o-ring is engageable with a groove in the wall of the ring, and with a slot formed on the inner surface of the duct at both ends of the duct to reverse engagement of the nut with an arbor. The swivel is engageable with at least one end of the body, and in fact is engageable with both ends of the body. When mounted on an arbor, the swivel aligns and helps prevent a bent or distorted arbor. A circumferential depression may be formed around the outside surface of the body. One or more bores is formed in the circumferential depression for manipulation with a key.