may be noted that it is also possible to provide only one counter pressure roller but that a revolver or other roller changer should then be provided on the carriage 13 in order to place the respectively compatible pressing roller opposite the one counter pressure roller yet other pairs of rollers can also be provided in order to complete the beading in smaller angular increments the actuating apparatus 17 between the carriage 13 and the bearer 12 comprises a pneumatic cylinder which with can be charged with a high pressure such that the carriage 13 is ultimately arrested on the bearer 12 this setting is selected if the pairs of rollers a and b are active when finally closing the hem using the pair of rollers c a predefined pressure is exerted on the pneumatic cylinder such that a particular actuating force or closing force is exerted when closing the hem the successive hemming steps are shown in fig3 a 3 b and 3 c before roll hemming the body part 20 already exhibits a pre formed hemming edge on the one side of the hemming edge the body part 20 forms a viewed area 21 and on the other side a rim strip 22 which is already beaded by.