Provided is a tip dresser blade blank comprising a casting of M-2 steel hardened to a Rockwell C hardness in the range of 63 to 66, inclusive, by double tempering. The casting may be ground to provide a specific first geometry or a specific second geometry.

A rotary cutter includes a pair of recessed receivers which receive the respective tip ends of a pair of electrode tips, and a through portion which runs through in a rotation axis direction and provides an opening that communicates with each of the recessed receivers. A cover case covers the lower recessed receiver of the rotary cutter and has a notch which is associated with the lower recessed receiver. Over the upper recessed receiver of the rotary cutter, a cover plate is fixed to cover the upper recessed receiver. An electrode tip insertion hole is cut through a center portion of the cover plate.

A welding electrode for resistance spot welding includes a weld face comprising rings of ridges that project outwardly from a base surface of the weld face. The rings of ridges are positioned on the weld face to contact and impress into a sheet metal workpiece surface during resistance spot welding. If the welding electrode is used during resistance spot welding of light metal alloy workpieces, such as those of aluminum alloy or magnesium alloy, the rings of ridges on the weld face can contribute to improved welding performance.

The air blow nozzle includes a nozzle body configured to be connected to an air compressor one end thereof and includes an air discharge portion another end thereof, the air discharge portion is capable of discharging compressed air supplied from the air compressor. The air discharge portion is configured to be movable to a position that does not correspond to an upper communication hole as the nozzle body is slid to one side. The nozzle body includes a nut configured to position the air discharge portion in a predetermined position near a rotary holder as the nozzle body is slid to another side.

A tip dressing system includes a tip dressing machine having a gear unit. A holder is installed in the gear unit, and a cutter is installed on the holder. The holder may include mechanical structure corresponding to the gear unit that prevents the holder from being installed incorrectly and further prevents a holder that does not match the machine from being installed in the gear unit. The cutter may include mechanical structure corresponding to the holder to prevents the cutter from being installed incorrectly and further prevents a cutter that does not match the holder from being attached to the holder. The machine, holder, and cutter may include indicators configured for being scanned by a scanning device, and a controller may determine whether the scanned components match.