An apparatus, method and means is provided for electrochemical machining of hydrodynamic bearing assemblies in spindle motors. In an aspect, a cartridge is provided that receives and accurately positions an electrode in three dimensions in a near frictionless manner. The electrode reaches and maintains an equilibrium position in response to a first and second predetermined force, the equilibrium position being a predetermined three dimensional orientation relative to the work piece and defining a critical orifice with the work piece. In an aspect, a hydrostatic bearing is employed within the electrode for radially adjusting the electrode.