Locknut

Locknut

A locknut is a type of nut that is used to prevent loosening or backing off of the nut from the bolt or screw it is fastened to. Locknuts are commonly used in various mechanical and structural applications to ensure that the fastener remains secure under vibration or dynamic loads.

A nylon locknut, also known as a nyloc nut.

Types of Locknuts

There are several types of locknuts, each designed for specific applications and environments. Some of the most common types include:

Nylon Insert Locknut

The nylon insert locknut, also known as a nyloc nut, features a nylon collar insert that grips the threads of the bolt when tightened. This type of locknut is effective in preventing loosening due to vibration. The nylon insert provides a friction fit that resists loosening without damaging the threads of the bolt.

Jam Nut

A jam nut is a thin nut that is tightened against a standard nut to lock it in place. The jam nut is typically used in pairs with another nut, and the two nuts are tightened against each other to create a locking effect.

All-Metal Locknut

All-metal locknuts do not use a nylon insert but instead rely on the deformation of the metal to create a locking action. These locknuts are suitable for high-temperature applications where nylon inserts would not be effective.

Serrated Flange Locknut

A serrated flange locknut has a built-in washer with serrations that grip the surface of the material being fastened. The serrations prevent the nut from loosening by increasing the friction between the nut and the surface.

Applications

Locknuts are used in a wide range of applications, including:

• Automotive
• Aerospace
• Construction
• Machinery

They are essential in any application where vibration or dynamic forces could cause a standard nut to loosen over time.

Advantages

Locknuts offer several advantages, such as:

• Increased safety and reliability in assemblies
• Prevention of equipment failure due to loosening
• Reusability in some designs, such as all-metal locknuts

Disadvantages

Some potential disadvantages of locknuts include:

• Increased cost compared to standard nuts
• Potential for galling or thread damage in some designs
• Limited reusability in nylon insert locknuts

Related Pages

• Nut (hardware)
• Bolt (fastener)
• Threaded fastener
• Vibration