A slitting machine includes a pair of parallel arbors structured to support a plurality of cutting knives. The arbors are mounted to a head stock and tail stock on the slitting machine. The head stock and tail stock each rotatably support eccentrics which support the end portions of the arbors. Angular contact bearings, such as tapered roller bearings or ball bearings with inclined races, are positioned between the head stock and tail stock and the respective eccentrics and also within the eccentrics between the arbors and the eccentrics. Mechanisms are provided for providing an axial load across all of these bearings to eliminate play and so to accurately position the arbors so that cutting accuracy can be maintained. One such mechanism is a collet/piston supporting the operator's end of the arbors. The collet piston is received in a cylinder to which hydraulic pressure can be applied through a rotary coupling. When pressurized, the collet piston is forced onto a tapered end of the arbor, accurately positioning the arbor. At the same time, because the cylinder is mounted to the inclined bearings within the eccentric, the reaction force is transmitted through the angular contact bearings to the machine frame, precisely locating the arbors centrally of the bearings in which they are mounted. The collet piston may be made double acting so that it can assist in removing the arbor from the collet/piston. This permits self locking tapers to be used.