Washers are flat sheet metal componentsusually in a round shaped profile with a center hole punched through, to accommodate the bolt through the nut or suitable threaded part. Washers are either used to distribute the load off the bolting or reduce the vibrations of the bolted joint. High quality bolted joint requires hardened steel washers to prevent the loss of pre-load due to the brinelling after the torque is applied.
Most of these fastening washers are a product of sheet metal moulding, punching in cold forming or hot formed condition. However due to unavailability of required sheet metal stock, washers can be machined from suitable bar stock.