ThePipingMart Blog Fasteners What is Hex Lock Nut? Dimensions, Properties and Uses

What is Hex Lock Nut? Dimensions, Properties and Uses

Hex lock nuts are important fasteners that come in handy for several applications. They are specifically designed to provide better security to threaded fasteners and protect against loosening. Whether you are an industrial manufacturer, a maintenance engineer, or a DIY enthusiast, understanding hex lock nuts is essential for successful installation and optimal equipment performance. In this blog post, we will take you through hex lock nuts’ dimensions, properties, and uses.

What is Hex Lock Nut?

A hex lock nut, also known as a hexagon thin or jam nut, is a type of fastener used in industrial and automotive applications. It features six sides for increased surface area contact, which locks parts with greater torque than regular nuts. It is often used when required for vibration isolation or tampering and loosening prevention. These nuts come in several sizes and material grades to suit individual needs.

Hex Lock Nut Dimensions

Diameter Pitch Depth of Nut Across Flats
M2 0.4mm 1.2mm 4.0mm
M2.5 0.45mm 1.6mm 5.0mm
M3 0.5mm 1.8mm 5.5mm
M4 0.7mm 2.2mm 7mm
M5 0.8mm 2.7mm 8mm
M6 1.0mm 3.2mm 10mm
M8 1.25mm 4.0mm 13mm
M10 1.5mm 5mm 17mm
M12 1.75mm 6mm 19mm
M14 2mm 7mm 22mm
M16 2mm 8mm 24mm
M18 2.5mm 9mm 27mm
M20 2.5mm 10mm 30mm
M22 2.5mm 11mm 32mm
M24 3.0mm 12mm 36mm
M27 3.0mm 13.5mm 41mm
M30 3.5mm 15mm 46mm
M33 3.5mm 16.5mm 50mm
M36 4mm 18mm 55mm
M39 4mm 19.5mm 60mm
M42 4.5mm 21mm 65mm
M45 4.5mm 22.5mm 70mm
M48 5mm 24mm 75mm
M52 5mm 26mm 80mm
M56 5.5mm 28mm 85mm
M60 5.5mm 30mm 90mm

Hex Lock Nut Properties

Hex lock nuts come with various properties, making them the perfect choice for various applications. These include their ability to resist vibrations, high torque, and loosening. Hex lock nuts feature a tapered design that creates tension between the nut and bolt to prevent unwanted movement. Additionally, they are typically coated with various materials to protect against corrosion and damage from harsh environmental conditions.

Hex Lock Nut Uses

Hex lock nuts are used in various applications, from automotive to aerospace to electrical and plumbing installations. They are commonly used in machinery and equipment with high vibration levels, such as generators, engines, and heavy-duty construction equipment. Additionally, they are used in applications where safety is paramount, such as aeroplane engines, bridges, and towers.

Hex Lock Nut Installation

Installing hex lock nuts is a simple process that requires a few basic tools. Ensure that the threaded bolt or screw is the right size and shape for the nut. Once you have the right nut, screw it in place and tighten it using a wrench or pliers. Apply moderate force to secure the nut, but avoid overtightening as this might damage the threads and weaken the joint.

Hex Lock Nut Maintenance

Hex lock nuts require minimal maintenance to ensure their optimal performance. Regular inspection is necessary, especially if the equipment is used in harsh environmental conditions. Check for any signs of corrosion, damage, or loosening. If you notice any issues, immediately replace the nut to prevent further damage.


In conclusion, hex lock nuts are essential fasteners in various applications to provide secure and reliable joints. They come in various sizes, dimensions, and properties, making them suitable for different applications. Installing a hex lock nut is straightforward, and it requires minimal maintenance. If you plan to use hex lock nuts for your equipment or machinery, choose the right size and material for optimal performance.

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