A tool positioning device for use in combination with a machine for working paperboard blanks conveyed in a horizontal direction through the machine. The machine includes pairs of parallel rotary shafts wherein each pair of shafts includes upper and lower shafts and carry a plurality of tool heads. The positioning device includes a plurality of coupling members actuated in a vertical direction by actuators wherein the coupling members are moved downwardly into engagement with the tool heads. The coupling members are supported on an actuator support which is mounted to a transfer structure wherein the transfer structure moves the actuator support in axial movement to thereby slide the tool heads along their respective shafts to preselected positions along the shafts.