Abstract: An electrical resistance welding apparatus for spot welding workpieces together is comprised of a mounting on which two anvil blocks are supported for displacement relative to one another in order to engage and clamp a workpiece to the mounting in preparation for welding. At least one of the blocks which engages a workpiece is also electrically conductive to serve as one welding electrode in the spot welding process. A secondary electrode positioned in the vicinity of the electrically conductive anvil block clamps a second workpiece against the first on the mounting for spot welding. The mounting is electrically conductive and is electrically connected with the conductive anvil block for transmitting welding current from an electrical power source.