A granulating device for plastic strings passing through a perforated plate (1) comprises a cutter head (3) mounted on an axially split shaft. One shaft section (5) carries the cutter head and the other section (6) is a hollow-bored drive shaft. The shaft sections are connected by flexible bellows (7) for torque transmission, the bellows being expandable for axial displacement of the cutter head. Preferred Features: A pump may supply a hydraulic fluid through the hollow-bored section to expand the bellows. Alternatively, a gas (air) may be used. A further alternative is the use of a spring (especially a coiled spring) disposed between the shaft sections. The first shaft section (5) may be mounted on a stub shaft which is integrally connected to the perforated plate (1). The bellows may be of elastomer or metal.
