Abstract: A rotary cutting die which is mountable on a metal cylinder. The rotary cutting die includes a rotary die plate having a concave, inner surface which is magnetically attractable and magnetically mountable on a metal cylinder. A cutting blade is mounted on a concave, outer surface of the die plate. Connectors may be engaged with the cutting blade and the die plate. A plurality of magnetic elements, such as neodymium magnets, are in the rotary die plate. The magnetic elements make the inner surface of they die plate magnetically attractable to the metal cylinder, thereby providing that the rotary cutting die is mountable on the metal cylinder without having to use screws, clamps or other mechanical holding devices. To prevent creep of the cutting die during operation, a magnetic member, such as a rubber magnet, may be magnetically mounted on the die cylinder, against the die plate.