This invention concerns a device used to set up work rollers in the work roller head of the deep rolling tool of a deep rolling unit designed to deep-roll grooves or radii that limit the journals of crankshafts in the axial direction. The prism pattern has a plurality of parallel prisms on a light-exiting surface. The jaws open and close for insertion of the flexible tube either under manual or pneumatic force. The contraceptive device is then expanded and released from the delivery system by actuating a second actuator.