in an electrochemical machining system a continuous web metal is moved through a working region around a conductive roller in electrical contact therewith . part - cylindrical cathodes are disposed coaxially with the roller a slight distance radially therefrom to define a working gap between the cathodes and the web . the positive and negative terminals of a dc source are respectively connected to the roller and the cathodes and an electrolyte fluid is injected under pressure through bores in the cathodes into the working gap and removed therefrom through other bores in the cathodes or establish a current flow between the web and the cathode for removing material from the former . retainers confine the electrolyte emitting laterally from the working gap , and electrolyte falling vertically therefrom is collected in a basin . the speed of movement of the web around the roller may be varied as a function of the thickness of the machined web . longitudinal grooves may be utilized on the cathodes to provide a longitudinal ribbed configuration in the machined web .