Abstract: A vectoring and orbiting control unit for electrical discharge machines (EDM). The unit is an adjunct to conventional EDM machines having a microprocessor-controlled electrical power supply/control unit that includes a gap detector/processor, position detector, and z-axis translator. The vectoring and orbiting control unit controls the electrode movement in the x-y, or polar, coordinate plane directly, and provides z-axis command data to the system controller of the power supply/control unit, the latter capable of moving the electrode along a z-axis. The vectoring and orbiting control unit displays a menu of various canned vectoring and orbiting modes available, permits the operator to select a desired mode, and enables the operator to input, in a verifiable, user-friendly manner, various machining values consistent with the mode selected by the operator.