The nut is a part which is used for fastening the bolt or screw. The nut is a part which is closely connected with the mechanical equipment. Its variety, common with national standard, British standard, American Standard, Japanese standard nut, according to different materials for carbon steel, high strength, stainless steel, plastic and other several types, according to the threaded fittings product attributes corresponding to the countries of different standards, for ordinary, non - standard, (old) GB, the new national standard, American, British, German standard.
