A Nut is a type of hardware fastener with a threaded hole. Nuts are almost used opposite a mating bolt to fasten a stack of parts together. The two partners are kept together by a combination of their threads’ friction, a slight stretch of the bolt, and compression of the parts. The most common shape is hexagonal.

These are available in all types and metal finishing. The other main types are Square, Cap (Acron), Flange, Locknuts, Split, Weld etc.

A Bolt/ Screw is a type of fastener characterized by a helical ridge, known as an external thread or just thread, wrapped around a cylinder. The most common uses of screws are to hold objects together and to position objects and this used in all industrial and consumer applications. Often screws have a head, which is a specially formed section on one end of the screw that allows it to be turned, or driven.

The Bolt and Screw are used synonymously with each other. It is difficult to identify the difference but in sluggish terms it is said that Bolt is driven through torque by pressing or hammering and screw is normally driven screwdrivers and wrenches. So, the caps of both are identified differently as per their driving force.

These are available in various types and metal finishing. There are numerous shapes of the caps available like the Round, Pan, Oval, Flange, Countersunk etc that can be driven as in Slot, Plus, Hex, Poly, Star, Tri-wing etc ways.

A Washer is a thin plate (mainly disk-shaped) with a hole (typically in the middle) normally used to distribute the load of a threaded fastener, such as a screw or nut. Other uses are as a spacer, spring, wear pad, locking device, and to reduce vibration (rubber washer). Washers usually have an outer diameter about twice the length of their inner diameter.

These are available in various types and metal finishing. There are numerous shapes of the washers available like the Plain, Split, Belleville or Conical, Wave, Spherical, Torque washers etc.