Abstract: A self-contained knob contains a bushing which fits on a control shaft of a control element and extends axially through each of an annular disk and a pedestal. The annular disk slidingly rests upon the pedestal. The disk and pedestal contain between them a pair of concentric, radially separated tracks of spring loaded balls and cavities. The balls momentarily engage the cavities in arc movement as the knob is turned. The pedestal receives at the bottom and is prevented from rotating by a fastener of the control element.