How Lock Nuts Work?

Fasteners are components that are crucial to aircraft construction, allowing for parts to be affixed in non-permanent and permanent fashions. When a threaded fastener such as a bolt is used for creating assemblies, a nut is always paired with the bolt in order to ensure that the connected objects are secure. As aircraft are often subject to high amounts of vibration during flight, nuts may loosen over time and lose their integrity. As such, special components known as lock nuts are often implemented in order to protect assemblies from loosening under vibration.

Also referred to as stiff nuts, lock nut components are specifically designed to withstand the forces of vibration and remain securely in place. Before such aircraft parts were available, many manufacturers would simply use two nuts for each threaded fastener when there was a concern over vibration. While this method of securing fasteners was quite efficient in practice, it created a cost problem as two nuts would be required for every assembly which doubled manufacturing costs. As a rapid response to such issues, lock fastener components began to enter the market.

In the 1930s, the lock nut was introduced as a more cost effective method of securing threaded fastener components. Instead of using multiple nuts, the lock or stiff nut would be capable of securing the assembly by itself. As lock nuts require more than simply applying torque for tightening and loosening, they are not free spinning and thus can withstand the typical forces that they are subjected to during fligh.

Generally speaking, more conventional nut fasteners will feature a basic inner thread for attachment to another component. With such a design, vibrations can cause the nut to slowly loosen over time until the assembly fails. With lock nuts, however, various methods may be used to secure the component to the assembly, and different types may be procured to accommodate varying applications. Across all the lock nuts available on the market, some common types include metal lock nuts, nylon lock nuts, and distorted thread lock nuts.

With the metal lock nut, a crowned top is used to secure the nut in place through crimping. As crimping requires the deformation of metal surfaces, the components can be attached securely and may withstand the various forces of flight. As compared to the metal lock nut, nylon types utilize a nylon material to cover the interior threading of the component. As the component is tightened to a threaded fastener, the nylon fibers will expand to fill the gap and create a strong grip.

Distorted lock nuts are somewhat comparable to metal lock nuts, both utilizing deformation to secure an assembly. As such nuts are often constructed from solid metals, they can typically be used in applications featuring extremely hot temperatures reaching upwards of 1,400 degrees Fahrenheit. Due to their high strength, such nuts are also not recommended for pairing with low strength fasteners as they may damage threading. Depending on the need of the assembly, distorted lock nuts come in the form of elliptical offset nuts, centerlock nuts, toplock nuts, and partially depitched nuts.

With the pairing of threaded fasteners and lock nuts, aviation parts can be assembled securely and may withstand the forces of vibration without loosening. At Veritable Aerospace, we serve as a premier purchasing platform for a diverse set of aircraft components that have been sourced from leading global manufacturers. With our market expertise and purchasing power, we leverage competitive pricing and rapid lead-times on all of our offered items for your time and cost savings. Get started on the purchasing process today and experience why customers choose Veritable Aerospace for their operational needs.