Sherline 7603 Sherline 1/4"-3/8" 2-position Rocker Tool Post Now Sherline offers an optional 2-positon tool post that will hold both 1/4" and 3/8" square shank tools and also has the rocker feature on each side to allow for adjustment of the tool tip height. Body Dimensions (H x W X D) 1.5″ x 1.25″ x 1.25″