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Different Types of Lock Washers

On average, the typical large airliner has nearly one million fasteners, yet there is little discussion around the integral role they play in aircraft production. While fasteners are used in other sectors, the aviation industry takes advantage of them in a multitude of ways. For this reason, there are numerous types of fasteners to suit a myriad of aerospace applications.

Aircraft in particular, require the use of special fasteners. As airplanes produce excessive or prolonged vibration during flight, the fasteners used for them must have anti-vibration characteristics. Fortunately, lock washers are widely available on the market, those of which are usually used in conjunction with a bolt for added security.

Unlike conventional washers, lock washers are specifically designed to resist vibration. More than that, they prevent bolts from loosening when exposed to vibration as well. Similar to other fasteners, lock washers are made in several subtypes, some of which we will cover in the next section.

  1. Split

Split lock washers are distinguished by their split design, and they consist of a ring-shaped piece of metal with a small groove. In addition, they are not completely flat. Instead, they are slightly bent to achieve a helical shape. The major benefit of these lock washers is they can resist great vibrations while ensuring that bolts stay in place.

  1. Internal Tooth

Internal tooth lock washers feature teeth that point inward, allowing them to dig into surfaces. Additionally, like other washers, they can be placed around a bolt. The teeth are capable of absorbing shock and vibration with ease.

  1. External Tooth

External tooth lock washers, on the other hand, feature outward-pointing teeth. They are similar to internal tooth lock washers but with reversed teeth. To install them, you must place them underneath a nut or the head of a screw or bolt. In applications that have both a nut and a bolt, the external tooth lock washer should be placed in between them.

  1. Wave

As their name suggests, wave washers feature a unique wave design, and they are not completely circular or flat. Moreover, the axial wave construction acts as a compression spring. Wave lock washers compress the head of a bolt and the adjacent surface by pushing against them. This compressive force protects the bolts from loosening when placed under vibration.

  1. Belleville

Belleville washers have been around for over 100 years, making them one of the oldest types of lock washers on the market today. Also called disc spring washers, Belleville washers are a common type of lock washer that is characterized by a cupped design. They have a conical shape that has a higher inner hole and a lower outer perimeter.


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November 18, 2022
August 1, 2022


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