loading and unloading the battery cans will be well understood by those skilled in the automation art they preferably include magnetic holders for transferring the battery cans such details not being material to the present invention the timing diagram for the circular path traversed by the work pieces is divided into circular segments 50 that show the relative time allocated to each of the operations of the surface treatment units two such segments or units of time 52 are required to load the work piece onto the work piece holder five time units 54 are required to move the work piece holder from a loading position to a processing position and to enclose a work piece within a surface processing enclosure the battery cans are then processed during a time of seventy eight time units 55 five time units 56 are required to open the surface processing enclosure and move the work piece holder from a processing position to a loading position and two time units 58 are required to strip the part from the work piece holder to a pocket corresponding to segment 30 a on the unloading dial 30 the actual times for accomplishing these operations depend upon the rotational speed of the work rice carrier the relative time for each operation are merely exemplary however in order to provide a universal cleaning and plating system at minimum cost all four units and their timing diagrams are designed to be identical in the present case referring now to fig3 and 4 of the drawing the apparatus is illustrated in its preferred form as comprising a stationary base 60 which in its preferred form is circular fig3 shows the outside edge of the stationary base 60 at a.