a hemming apparatus is provided for use with a robot in performing a hemming operation . the hemming apparatus comprises a support housing which mounts to a machine and has a pressurizable interior chamber having forward and rearward portions . a slide member includes a piston which is disposed in the chamber , and a plunger extends outwardly from the piston . means are provided for attaching the housing to a nose having a central passageway . a bearing shaft is disposed within the central passageway , and means are provided for connecting the bearing shaft to the plunger . a hem roller is attached at the end of the bearing shaft . the rearward and forward portions of the chamber are connectible to a source of fluid pressure such that adjusting the chamber pressures moves the piston , thereby causing the bearing shaft to drive the hem roller into engagement with a work piece .