The invention is directed to a method for adapting injection molding machines utilizing horizontally opening and closing molds and their opening and closing mechanisms to vertically opening and closing molds and their opening and closing mechanisms and vice versa. An injection molding machine might, for example, be utilized to inject hot synthetic resin substantially horizontally into a cavity between horizontally opening and closing molds associated with horizontally opening and closing mechanisms. This horizontal mold and its opening and closing mechanism is removed relative to the injection molding machine and substituted therefor is a vertically opening and closing mold and its associated vertically opening and closing mechanisms. The hot plastic material from the horizontal injection molding machine is initially constrained in movement horizontally but subsequently vertically into the cavity of the vertically opening mold. This allows molds to be utilized with presses which might otherwise heretofore been structurally and functionally incompatible.