Washers distribute loads when coupled with threaded fasteners, such as bolts and screws. Washers are also used as spacers or wear pads, or installed to reduce levels of vibration. Different types of washers play different roles in a joint, based on the material, design and size.
Plain Washers
Flat washers are most often made from metal and used primarily to distribute load and create a more dependable joint. Used in conjunction with metal nuts, plain or flat washers can also be used to cover any gaps created by a small fixing nut.
A fender washer is a special type of plain washer designed with an O.D. (or outer diameter) that is proportionately larger than the central washer hole. Used in automobile applications, fender washers are also used on sheet metal applications.
Other commonly used plain washers include spherical washers and torque washers. Some flat washer styles may be used for spacers.
Spring Washers
The most common type of spring washer in use today is called the Belleville washer. This conical-shaped washer is used with bolts and creates flexibility in the joint, as well as applying pre-load. Multiple Belleville washers can be used in one joint, creating a stiffer application (washers stacked together or in the same direction) or higher levels of spring (washers stacked in alternating or opposite direction).
Curved disk washers look similar to Belleville washers and perform a similar function, although the singular curved shape provides four contact points and exerts a lighter amount of pressure. Wave washers are similar to both, although their shape and design do not allow for as much force as the Belleville style.
Locking Washers
It's difficult to find a truly locking washer; most applications rely on a locking nut to provide this assurance and extra level of protection.
Split washers are not universally recommended. Often called spring lock washers, these fasteners are split at a single point in the ring and shaped into a helical form.
A toothed lock washer is often used in wooden applications. This washer has serrations or teeth formed into the washer that bite into the joint material when tightened. This forms a fairly solid bond within the joint, although vibration, shrinkage and other conditions can loosen those teeth and cause the joint to fail.
Rubber Washers
Used mainly to absorb vibration in certain applications, rubber washers can also be used for maintenance, as a temporary measure. This material provides excellent wear in automotive, aerospace and heavy equipment applications, although it may breakdown when exposed to certain chemicals.
Rubber washers can also be used as a seal in the medical and food industries. Always be sure that the rubber used to manufacture your washer is graded for use in your application.
How to Choose the Right Fastener For Your Application
Consider what you need from your fastener in terms of performance. Are you simply looking to redistribute load with the least amount of cost? Install a flat washer. If you're looking for something to reduce vibrations and create a more comfortable, durable joint, a rubber washer may be just the thing. Need corrosion resistance, spring and a spacer? A stainless steel Belleville washer provides flexibility and space in your joint.
Various types of washers are used with different fasteners to achieve a certain result. Whether you opt for a flat washer, Belleville washer or toothed lock washer, buy from a reputable fastener distributor to ensure the leading products at reasonable prices.
Mike Moore is published on more than 300 websites. He writes about industrial fasteners and building, commercial building, and home building projects . He is published on various website including http://www.melfast.com