Types of washers and their uses
Common Types of Washers
Washers are typically used to help distribute the shock load of threaded fasteners. This prevents them from becoming damaged or unscrewed during normal operations. Washers are thin, usually disk-shaped plates with holes in the middle for workers to install fasteners through. They’re generally made of metal or plastic materials. In this blog post, we’ll take a look at three of the most common types of washers and some examples of each.
Plain Washers
Plain washers are the most common, used to spread loads, prevent surface damage, as well as provide insulation against electric currents. In general, they’re used in applications where the hole is larger than the nut. There are many different subcategories of plain washers, two of which you can see below.
Examples of Plain Washers:
Fender washers: round washers that provide a greater load-bearing surface under the fastener that prevents pullthrough.
Flat washers: round, thin plates with center holes used to distribute the loads of threaded fasteners.
Spring Washers
Spring washers are axially flexible and prevent loosening of product components when they vibrate. Vibrating motors use spring washers to mitigate wear and tear. Spring washers are also used on aircraft carriers, where they’re commonly found in actuators for flight controls and landing gear.
Examples of Spring Washers:
Finger Spring Washers: Used to counteract noise, excess wear and tear, vibrations. They’re also used to reduce kidding wear on rotating elements.
Wave Washers: Provide greater load-bearing capability due to their three-point contact and sharper curves. Typically used in thrust-loading applications for small deflections.
Locking Washers
Locking washers are a subtype of spring washers. They prevent nuts, bolts, screws and other fasteners from unscrewing during machine operation. While there are many different variations of locking washers, they all have the same basic function: holding the nut and bolt in place.
Examples of Locking Washers:
External Tooth Lock Washers: Prevents a nut or bolt head from loosening with its teeth strut action. This fastener is preferred when the greatest loosening resistance is required.
Helical Washers: Acts like a spring under compression to provide additional holding force. Helical washers also decrease frictional resistance during the assembly process.
A relevant point worth mentioning
What is the difference between a spring washer and a plain washer?
Plain washers are flat, whereas spring washers are curved. For most applications, plain washers are typically used. For machines and objects that vibrate, spring washers are recommended. Spring washers are unique because they provide an axial load that counters vibrations and, thus, prevents fasteners from loosening.