Nuts and bolts consist a major link in the family of industrial fasteners and are used by every industry. Bolt is a piece of metal rod, whose one end is upsettled and other end is threaded. Nut is the item which rolls on these threads. Nut and bolts are available in various shapes, designs and sizes. Bolts are for the assembly of two unthreaded components, with the aid of a nut. Screws in contrast are used in components which contain their own thread, and the screw may even cut its own internal thread into them.