Abstract: A cartridge is configured for slitting a mill roll in a slitting machine. The cartridge includes a first shaft mounted in bearings in a pair of endplates, with one end of the shaft having a driven yoke for rotation thereof. The first shaft includes a row of first circular blades spaced longitudinally by corresponding first spacers. A second shaft is pivotally mounted in the endplates, and is spaced parallel with the first shaft. A dovetail bar is fixedly joined to the second shaft parallel therewith. And, a row of blade holders are mounted along the dovetail bar, with each holder including a second circular blade aligned with a corresponding one of the first blades for cutting in shear a web unwound from the mill roll. The cartridge may be quickly replaced in the slitting machine for each production run thereof for alignment with cores on a corresponding arbor.