tools and a workpiece situated therebetween and the thickness of the workpiece application_number US 81887401 A description referring to the drawings wherein identical reference numerals denote the same elements throughout the various views fig1 and 2 show an electrochemical machining ecm tool assembly 10 used for machining a workpiece 12 as shown in the figures the workpiece 12 is a rotor blade of the type used in a gas turbine engine such as a compressor blade or a turbine blade the rotor blade 12 includes a shank portion 14 for mounting the blade to a rotor disk and an airfoil 16 that either adds work in the case of a compressor blade to or extracts work in the case of a turbine blade from the gas flow within the gas turbine engine the airfoil 16 has a concave pressure side 18 and a convex suction side 20 joined together at a leading edge 22 and a trailing edge 24 the airfoil 16 extends chordwise from the leading edge 22 to the trailing edge 24 and spanwise from the shank portion 12 to its outer tip it should be noted that a rotor blade workpiece is used here only as one example to facilitate description of the present invention the present invention is also applicable to other types of workpieces the ecm tool assembly 10 includes first and second tools 26 and 28 arranged on opposite sides of the workpiece 12 each tool 26 28 has a suitable configuration.