Abstract: A drive shaft of the gumming and folding section of an envelope machine rotates at a preselected speed and is drivingly connected through meshing gears to the input shaft of a variable speed drive mechanism. The input shaft is connected to an output shaft through a differential transmission so that the output shaft is driven at a preselected ratio relative to the speed of the input shaft. The output shaft is drivingly connected to a web feeding apparatus that conveys a continuous web of material from a supply roll at a preselected speed. Thus, the web feeding apparatus is driven at a predetermined ratio relative to the speed of the drive shaft. A web cutting apparatus is drivingly connected to the input shaft so that a cut off knife is rotated at a fixed speed relative to the drive shaft to cut the continuous web at preselected intervals to form envelope blanks having a bottom flap connected to a closure flap.