The harvester (1) has a drum (3) equipped with multiple knives (4). A device (8) controls rotational speed (n) of the drum. The drum is set into rotation opposite to a stationary shear bar (5) to comminute crop (7) fed in a region of a cutting gap that is formed by knives and the shear bar during harvesting operation. The device controls the rotational speed of the drum during a maintenance procedure of a comminution assembly (2) depending on a property of the drum. A tool is designed as a sharpening device for the knives of the drum.
