Nut is a fastener which tighten up bolts or screw screwed together . All part of the manufacturing machinery must use this wide range of original. Nut, we are so common gb, British standard, American standard, day mark nut. Nut according to the material of different, divided into carbon steel, high strength, stainless steel, plastic and so on several big type. According to the product attributes corresponding countries of different standards, divided into ordinary, non-standard, (old) gb, new gb, asme, imperial, Germany standard. In different sizes and threads differ divided into different specifications. General gb, din BiaoYong maroleng says (such as M8, M16), asme, imperial USES scores or # said specifications (such as 8 #, 10 #, 1/4, 3/8) fasteners

2, the nut is closely connected to mechanical equipment parts, through the inside of the thread, coequal norms nut and screw, can connect together, for example the M4-0.7 nut only with M4-0.7 screw to match (in nut, inner diameter approximately M4 refers to the nut 4mm, 0.7 refers to the distance between the two threaded tooth is 0.7 mm), The us-made products also, such as 1/4-20 of nut and only 1/4-20 of screw to match (1/4 refers to approximately 1/4 inch in diameter nuts, 20 refers to every inch, there are 20 teeth).