Abstract: A tool system includes a machine-proximal shank configured to be introduced into a driven tool receptacle and containing a device for transferring a rotating movement to be picked up from the driven tool receptacle. A tool-proximal shank is configured as a tool holder or to have a tool holder releasably connected thereto. A gear mechanism disposed between the machine-proximal shank and the tool-proximal shank is configured to transfer a rotating movement transmitted by the device in a reduced manner to the tool-proximal shank. At least one insert seat configured on the tool holder for receiving an interchangeable cutting insert is provided on an end face of the tool holder extending transversely to a longitudinal axis of the tool holder. A method for machining a workpiece is also provided.