Abstract: A quick change cassette hole punch unit for punching business forms allows the punch cylinder to be changed in a simple and effective manner. The cassette includes a frame having side members and a top member, and an anvil cylinder mounted on an anvil shaft for rotation about an axis stationary with respect to the frame, and a drive gear also mounted on the anvil shaft. A punch cylinder shaft is mounted on bearing assemblies for reciprocal movement with respect to the frame side members upon rotation of a screw shaft associated with each bearing assembly. The punch cylinder shaft can be disconnected from one of the bearing assemblies, slit with respect to the bearing assemblies to expose a free end, and the punch cylinder mounted on the punch cylinder shaft moved off the free end and replaced. All associated drive gear for the punch cylinder shaft is also replaced at the same time.