Abstract: An open ended mold for a continuous metal casting machine is disclosed having a pair of sidewalls and a pair of end walls narrower than the sidewalls, which define an open ended mold cavity. The end walls each define a convex surface with a crest extending between the open ends of the mold, for casting therein a continuous strand having at least a shell of solidified metal and with the oppositely facing end surfaces each defining a continuous concave arch. The convex end walls of the mold are movable toward and away from each other between the sidewalls for casting such strands of different widths.