A method of working paperboard blanks is disclosed. The method includes providing first and second pairs of parallel rotary shafts supporting first and second pairs of tool heads respectively. The first pair of tool heads is moved to a predetermined longitudinal position along the first pair of shafts to define a first line of working. Likewise, the second pair of tool heads is moved to a predetermined longitudinal position along the second pair of shafts to define a second line of working wherein a center of the first line of working is displaced relative to a center of the second line of working. The paperboard blank is conveyed between the first and second pairs of tool heads to form a panel line on the paperboard blank. The tool heads may be automatically positioned along their respective shafts by coupling members which move linearly parallel to the shafts.
