An optical disk recorder, or other apparatus, use a rotary actuator for supporting a work tool, such as an objective lens which is pivotable or rotatable about a pivot pin. Rotation causing or tracking coils on the rotary actuator are disposed adjacent to permanent magnets to selectively effect rotation of the rotary actuator about the pivot pin. A bias electrical current is supplied to these coils to generate magnetic fields which are in opposite rotational senses; such fields force the rotary actuator against the pin in such a manner that the point of contact between the rotary actuator and the pin follows the rotation of the actuator about the pin.