1. An apparatus for trimming a contoured non-round workpiece comprising: flame treatment means for trimming the workpiece by impinging a flame on the workpiece; holding means for supporting the workpiece, the holding means being rotatably mounted relative to the flame treatment means; control means for cooperating the holding means with the flame treatment means so that the flame treatment means follows the contour of the workpiece when the holding means is rotated relative to the flame treatment means; wherein the control means further includes means for linearly positioning the flame treatment means relative to the holding means based upon the contour of the workpiece in rotation; and wherein the control means comprises means for generating an electronic image having a contour following the contour of the workpiece, and means for guiding the flame treatment means according to the contour of the electronic image.