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What Is the Purpose of a Washer?

Within the realm of fastener assemblies, washers are a common component that is very useful for facilitating a load. Typically coming in the form of a thin, disk-shaped plate with a hole, washers may be paired with a threaded fastener such as a bolt or nut in an assembly in order to better distribute its load. While mainly serving to assist with loads, washers may also serve other applications such as preventing galvanic corrosion or acting as a spacer, wear pad, locking device, vibration reducer, and more. As there are many types of washers that one may use when creating an assembly, it is crucial to have a general understanding of the more common variations and their capabilities.

Plain washers are the most common type of washer available, typically serving to distribute the load of a fastener over an area. As such, they are useful for when assembled surfaces require protection from damage. Flat washers are a subtype of plain washer, coming in the recognizable form of a circular, flat metal sheet that accommodates a matching bolt. As a general use item, one should ensure that the washer hole is not too big or small for the bolt it will be paired with. Torque washers are another subtype of plain washer, typically implemented in assemblies in order to prevent a bolt from rotating while a nut is secured. These types are often paired with carriage bolts and are found within woodworking applications.

When one wishes to secure an assembly with the means of preventing rotating or friction loss, the lock washer type is a great choice. Split lock washers, or helical washers, are those that are non-continuous with ends bent outwards in opposite directions. External tooth lock washers have external teeth on their outer diameter, digging into surfaces for securing wide-headed fasteners. As a final common type, the internal tooth lock washer is similar to external tooth types, albeit having its teeth set protruding inwards from the inner diameter. Generally, these types are useful for locking shallow-headed fasteners that may be affected by shock or vibrations.

Thrust washer or bearing washer types are a special form of flat washer, specifically intended for use with bearings. Providing a smooth surface to the assembly, rolling elements can ride across the washer to reduce fatigue and wear. Additionally, the thrust or bearing washer may also mitigate movement along the axis of shafts that are bearing an axial load. For their application, such washers may be combined with a needle roller or cage assembly and will serve as a fatigue liner or soft housing.

When an assembly and its components need protection from vibration or shock, the spring washer type is another common variation set that may be very beneficial. The conical spring washer is one that is useful for maintaining tension while expansion and contraction occurs, and such components are well capable of managing a high load with little deflection. To determine the load-deflection capabilities, the washer may be adjusted for its height and thickness ratio. The curved spring washer is another common type that supports smaller loads, though is capable of a wider deflection range. Generally, such types are reserved for flexible and load-cycling products. Alongside such examples, other common spring washers include dome spring washers, finger spring washers, and wave spring washers.

Beyond determining the specific type of washer that one may need for their assembly, the material of the component is also a crucial factor that can make the difference between a perfect fit and one that will cause issues later down the line. While countless materials may be used for creating washers, the most common ones include stainless steel and steel alloys, copper, phosphor bronze, aluminum, titanium, fiber, mica, rubber, nylon, polyester, PTFE, and phenolic. To find which is most suitable for a given application, one should consider environmental conditions, stresses, other present materials, and more.

Whether you find yourself in need of a lock washer, bearing washer, washer concave component, shoe washer, or other various types, look no further than NSN Gamut. NSN Gamut is a leading distributor of all types of aviation tools that are required for aircraft maintenance, and we are unmatched in our offerings and pricing. As you explore our expansive part catalogs, we invite you to fill out and submit an RFQ form through our website for the items that you are interested in in order to receive a quote for your comparisons. At NSN Gamut, we are your strategic partner for all your operational needs. Contact us today and see what we can do for you!


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