Fender washers are flat washers with a much larger outside diameter than other types of standard washers. They have an oversized design to help distribute forces applied during tightening and provide extra bearing surface.
These washers are used in automotive, sheet metal and plumbing applications. They also help prevent corrosion between a mechanical part and a screw or bolt. They’re available in zinc-plated and stainless steel finishes.
Corrosion Resistance
The corrosion resistance of fender washers is determined by several factors. The chemical composition of the material and its environment, as well as protective coatings are all important.
Steel containing more than 12% chromium, known as stainless steels, are especially resistant to rusting in the presence of moisture. The chromium reacts with oxygen to form a very thin, chemically stable and passive oxide film on the steel’s surface.
This oxide film keeps oxygen from contacting the underlying metal, preventing corrosion. Moreover, the steel contains nickel and molybdenum that strengthen the passive film and enhance corrosion resistance.
However, pitting corrosion occurs in saline and chloride environments, particularly when dissolved oxygen is mixed with chlorine ions. For this reason, some stainless steels are designed with a low chromium content, such as type 18-8 stainless.
Durability
Fender washers are designed to distribute the load of a fastener across a large surface area. This helps prevent damage from occurring during tightening.
The large outer diameter of a fender washer also helps spread the force that is applied during tightening. They are commonly used for sheet metal applications, as well as plumbing and electrical work.
In addition, fender washers are durable and suitable for use in corrosive environments. They can be plated in a variety of materials, including zinc and stainless steel.
Fender washers are available in both standard and extra thick versions, which provide more surface area for the load they distribute. They are also offered in a variety of colors and sizes.
Size
Fender washers differ from standard flat washers in that they have a much larger outside diameter in proportion to their center hole. This design allows them to be placed under the head of a bolt or nut, helping distribute forces that are applied when tightening the fastener.
The oversized outside diameter also helps to provide more bearing surface for the load of the fastener. This is particularly useful for fastening to soft or thin materials, and can help reduce point-load stresses.
Generally used for automotive, sheet metal, plumbing and electrical projects, fender washers are available in zinc-coated or stainless steel options. The zinc-coated option is typically used in less demanding applications, while the stainless steel version provides more corrosion resistance.
Material
Fender washers, or penny washers, are flat, thin-gauge metal washers with a proportionally larger outer diameter than the inner hole. They distribute load force on sheet metal and are commonly used for auto-body restoration, sheet metal, plumbing and electrical work.
They are available in a variety of material options including low-carbon steel, various spring steels and stainless steel. Stainless steel fender washers are the preferred choice for applications that require optimal corrosion resistance, strength and durability.
In addition, fender washers are ideal for sealing leaks in electrical and plumbing applications. They also reduce abrasion and noise and provide insulation in hydraulic projects. They are available in many sizes and finish options including zinc plated or without a finish.