Lock Nuts vs Hex Nuts – What’s the Difference

Lock Nuts vs Hex Nuts

If you have ever worked with nuts and bolts, you have probably encountered two types of nuts – hex and lock nuts. While both types of nuts are used extensively in various applications, they have distinct differences that make them useful for specific purposes. This blog will explore the differences between lock and hex nuts and help you determine which is better suited for your project.

What is Lock Nuts?

Lock nuts are a type of nut that use friction to provide extra resistance against loosening due to vibration, shock, or torque. The most common types of lock nuts utilize nylon inserts, metal locking devices such as serrated flanges and Belleville washers, or chemical adhesives. Unlike regular hexagonal nuts, lock nuts offer superior vibration resistance and can be used during extreme conditions for the utmost security.

What is Hex Nuts?

Hex Nuts are a type of hardware fastener consisting of a hexagonal-shaped nut. They have internal threads, often used with bolts and other threaded rods to secure two or more materials. The six flat sides of the nut provide a good grip when tightened, making them ideal for many applications requiring strength and reliability.

Difference Between Lock Nuts and Hex Nuts

Lock nuts and hex nuts are threaded fasteners, but lock nuts have a locking feature to help ensure the nut does not become loose. Lock nuts have added locking features such as nylon inserts or wire sticking out from under the head of the nut, which secures it against loosening due to vibration or tampering. On the other hand, hex nuts do not have any additional locks, so they can loosen over time with vibration and should be checked regularly for security.

Design and Construction

Hex nuts have six sides and a flat top and bottom surface. They are designed to be tightened with a wrench or pliers and provide a secure holding force to the bolt. On the other hand, lock nuts have an added feature to prevent the nut from coming loose. They have a nylon insert, which acts as a locking mechanism that grips the threads on the bolt and provides resistance against vibration, shock, and other forces that can cause the nut to loosen.


Installing hex nuts is relatively easy as they require a wrench or similar tool to tighten them securely to the bolt. On the other hand, lock nuts can be a bit more challenging to install as they require an additional step of screwing the nut down with fingers to a specific torque value to ensure the nylon insert is engaged and provides the necessary resistance against vibration.


Hex nuts are typically used in applications with little to no movement, such as machinery and equipment with stationary components. However, lock nuts are ideal for applications that may experience vibration or other forces that can cause the nut to come loose, such as automotive components, machine tools, and heavy equipment.


Both hex nuts and lock nuts are made from various materials, such as steel, stainless steel, brass, and titanium, to name a few. However, when selecting a nut material, it is important to consider the application, environment, and corrosion resistance.


Hex nuts tend to be less expensive than lock nuts, as the added feature of the nylon insert in lock nuts increases production costs. However, the added security and peace of mind of using a lock nut in applications subject to vibration or other forces can be well worth the added cost.


In conclusion, hex and lock nuts have distinct differences that make them useful for specific applications. Hex nuts are ideal for stationary machinery and equipment. In contrast, lock nuts are better suited for applications that may experience vibration or other forces that can cause the nut to come loose. When selecting a nut, consider the environment, application, and material requirements to ensure you have the right type for your project.



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