Plain Washers

Form A washers, plain washers, and spring washers are all types of mechanical fasteners used in various assembly and construction applications to distribute load, provide spacing, or offer a locking mechanism. Form A washers are a specific category of plain washers according to British standards, characterised by their larger outer diameter in comparison to other types of plain washers. This larger size allows for a better distribution of force over a wider area, making them suitable for use in applications where the load is significant or where the material under the washer is soft and could be damaged or deformed. Plain washers, in general, serve to distribute the load of a threaded fastener like a bolt or screw, preventing damage to the surface being fastened and reducing the chance of the fastener loosening due to vibration.

Spring washers, on the other hand, are designed to provide a spring force between the head of the fastener and the base of the application, creating friction and resistance to rotational movement. This makes them particularly useful in preventing bolts and screws from loosening under vibration or thermal expansion and contraction. Unlike Form A or plain washers, which primarily distribute load, spring washers act as locking devices. Each type of washer serves a distinct purpose in assembly and maintenance tasks: Form A and plain washers for load distribution and surface protection, and spring washers for preventing fastener loosening. The choice between these washers depends on the specific requirements of the application, including the need for load distribution, the material of the components being fastened, and the operational environment, which may involve vibrations or temperature variations.