Abstract: A machine for cutting or perforating webs of materials comprises a frame, a splined first shaft carrying a plurality of angularly spaced first tools and rotatable in the frame, a second shaft rotatable in the frame and parallel to the first shaft, supporting plates carried by the second shaft, a third shaft parallel to the first and second shafts and carrying a plurality of angularly spaced second tools for co-operating with the first tools, the third shaft being rotatable in the supporting plates eccentrically to the second shaft, a spur gear fixed to the third shaft, an intermediate gear in mesh with the spur gear loosely rotatable on one of the supporting plates, a central gear in mesh with the intermediate gear and mounted on the second shaft for rotation relatively to the supporting plates, a lever fixed to the central gear, an entrainment bolt on the lever selectively insertable in one of a plurality of holes which are provided in a swing arm at the same angular spacing as the first tools, the swing arm