Abstract: A method and a device for cutting out pieces of material webs, the cutting taking place between a spherical surface and a sharp edge. The spherical surface consists of a freely movable, non-driven ball. The ball can be made of hard material such as steel and the cutting edge of softer material, or vice versa. The device consists of a roller over which the web is led and a member acting against it. The roller has a groove corresponding to the desired contours of the formed piece. A ball, guided by the groove made in the roller, presses against the edge of the groove for cutting through the web.