A folding-carton gluing machine comprising a machine frame, an inserter, conveying means for the flat carton blanks, a crossbeam on the frame, carton working tools slidably mounted on the crossbeam, means for adjusting the position of the tools relative to a blank, the tools being movable from a working position which they are to occupy in the machine into a position in which they are spaced from the working position, and a sliding table for a flat carton blank adapted to be moved under the tools when the latter are spaced from their working position.