drum the movement of the modules toward or away from definition of a cylindrical working surface of the drum is a function of the existing operational means employed by the existing drum such as the existing operational means employed in the drum disclosed in the u201c 016 38 patent u201d such operational means provides for radial movement of the segments of the main deck with such movement of the segments of the main deck being substantially followed by the segments of the secondary deck it will be recognized that the present invention positions the secondary deck radially further away from the central axis of the drum than the positions of the main deck so that minimum and maximum obtainable diameters employing the secondary deck is substantially enhanced over the minimum and maximum obtainable diameters of the preexisting drum and its main deck referring to fig2 3 4 and 5 a 10 mounting of each of the modules on the drum is accomplished by means of manually operable locking latches in the depicted embodiment of the present invention there is provided on each of the opposite ends 44 46 of the central segment 34 a quick release latch 64 for releasably securing each of the multiple modules in operable relationship to the existing drum in short the present invention provides for the u201c addition u201d of a secondary deck outer or inner circumferential working surface onto an existing main drum without altering the functionality of the drum so that later on the modules of the secondary deck may be removed and the drum can return to use of its main deck after the present modules have been.