In the process of jointing, it is the same as many different requirement of the client such as: Slope in front of jointing, welding line, surface after jointing, machining surface of the metal into the tole, cutting of small profiled bar and so on. If replacing with the steel wire wheel or affixing different sand paper polishing rag in the millstone, it can be used for cleaning of rust or polishing with the surface of metal, rubdown the low layer of the paint, rubdown and polishing with the surface(surface of nonmetal such as timber.