Descriptions A standard flat round washer with a hole that is normally in the centre. Used for two main reasons: To minimise scouring or scratch damage to mating material as a result of nut rotation To increase the effective bearing surface of the bolt or nut. That is, to distribute the load of a threaded fastener over a larger area and prevent deformation of the bearing surfaces. Made of mild steel Available in Hot-Dip Galvanised, Yellow Zinc, Zinc and Plain finish.