Abstract: A base is arranged to be secured to the support frame of a planer and supports a slide for movement toward and away from the planar knife head. The slide supports a grinding stone, and a lever connected between the base and the slide is arranged to move the slide and the stone toward and away from the knife head. The guard for the knife head on the planer has an opening through which the present jointing apparatus works. An adjustable stop is provided between the jointer base and the slide to provide precision operation of the slide and the stone in jointing operations.