Abstract: A milling cutter having an annular body with a plurality of seating slots formed in the outer peripheral surface extending generally longitudinally of the body and circumferentially spaced thereabout. An indexable insert cutter member is positioned in each slot and retained therein by a wedge member. An axial backing plate member is positioned and secured behind each cutter member in the slots. The bottom edge of the backing member is configured so as to permit the backing member to rock against the bottom surface of the slot to insure accurate line contact between the front edge of the backer plate and the rear edge of the insert cutter member.