A self-centering shaft adapter may include a first jaw, a second jaw, and an actuation mechanism, wherein the first jaw and the second jaw define an opening for receiving a shaft therein. The actuation mechanism may be able to exert a force upon the first jaw and the second jaw creating a movement in the first jaw and the second jaw in opposite directions. The movement of the first jaw and the second jaw may increase or decrease the size of the opening. In some cases, the opening may maintain a relatively constant center regardless of the size of the opening. In some cases, the actuation mechanism may be a wedge. In other cases, the actuation mechanism may be a double-threaded screw.