Abstract: A knife holder unit combined with a rotary knife pair includes a frame composed of an upper frame part and a lower frame part; and an upper and a lower knife holder assembly supported in the upper and the lower frame part, respectively. Each knife holder assembly includes a bearing shaft composed of a first bearing shaft part having a longitudinal axis and an adjoining second bearing shaft part. The first bearing shaft part is received in a recess of a respective frame part for turning motions therein about the longitudinal axis. A first securing arrangement immobilizes the first bearing shaft part relative to the respective frame part. A rotary bearing surrounds the second bearing shaft part and has a rotary axis which is offset relative to the longitudinal axis to define an eccentricity therewith. A rotary knife is mounted on the rotary bearing.