The Ultimate Fastener Nut Handbook: Types, Uses, and Selection Tips

A fastener nut is a fundamental component in various assemblies, providing secure and reliable connections. So, this is a guide to fastening nuts, offering insights into different types and their applications and tips for selecting the right according to your needs.

The Ultimate Fastener Nut Handbook: Types, Uses, and Selection Tips

Common Types

Hex Nuts: These are the most common ones, characterized by their hexagonal shape and internal threads. They offer simplicity and efficiency in many applications.

Square Nuts: Similar to hex nuts but with a square shape, providing a larger surface area in contact with the part being fastened. They offer better resistance to loosening and are less likely to strip over time.

Cap (Acorn) Nuts: Known for their domed end, they enclose the external thread of a bolt. They protect the bolt and any objects that might contact its sharp end, also adding a finished aesthetic​​.

Locknuts and Their Specialties

Locknuts are designed to prevent loosening under vibration. Popular types include:

Keps Nut (K-nut, Washer, or Keps-K Locknut): Features a free-spinning external star-type lock washer, making assembly convenient.

Stover® Locknuts: One-piece hex nuts that withstand severe vibration and shock loads. They are reusable and heat resistant up to 450°F.

Nylon Insert Hex Locknuts: Incorporates a nylon insert for added security against loosening from vibration​​.

Selecting the Right Ones for Your Application

When choosing nut fasteners, consider the following factors:

Material and Environment: Select a material compatible with the environment, such as stainless steel, for corrosion resistance.

Size and Thread Match: Ensure its size and thread match the bolt or screw being used.

Load Requirements: Consider the load it will need to bear. Heavier loads may require stronger ones.

Vibration and Movement: In environments with vibration, locknuts are ideal.

Grades and Standards

Grades indicate their strength and are essential in choosing the right nuts fasteners. Common standards include SAE (Society of Automotive Engineers) and ASTM (American Society for Testing and Materials). Higher grade numbers usually mean better strength, making them suitable for higher-stress applications.

For Unique Applications

In addition to standard ones, there are specialized types designed for specific needs:

Wing Nuts: Ideal for applications requiring frequent manual adjustments. Their wing-like projections allow for easy hand tightening and loosening.

Flange Nuts: Come with a wide flange acting as an integrated washer, distributing the pressure over a larger area. They are excellent for uneven surfaces.

T-Nuts: Designed to be hammered into wooden, plastic, or composite materials, providing a strong and stable hold.

Tips for Installation and Maintenance

Proper Torquing: Use a torque wrench to ensure they are tightened to the correct specifications.

Regular Inspections: Periodically check them for signs of wear, corrosion, or loosening.

Use with Compatible Materials: Avoid galvanic corrosion by using fastener nuts and bolts of compatible materials.

Lubrication: Apply appropriate lubricants to prevent seizing and galling, especially in high-load or high-temperature applications.

Safety Considerations

Safety is paramount in any application involving fasteners. Always adhere to manufacturer guidelines and industry standards to ensure the fasteners are used as intended. It’s critical to use the correct tools for installation to prevent accidental injuries and ensure a secure fit. Ensure the use of appropriate personal protective equipment, like gloves and safety glasses, to protect against potential hazards during installation. Regularly check the condition of tools and equipment to maintain safety standards and prevent malfunction.


Choosing the right fastening nuts is crucial for the integrity and longevity of any assembly. Understanding the different types, their applications, and how to select and maintain them is key to ensuring successful and safe outcomes in your projects. Whether it’s t for a household fix or a specialized locknut for industrial machinery, the right one can make all the difference.

Author: David Beckham

I am a content creator and entrepreneur. I am a university graduate with a business degree, and I started writing content for students first and later for working professionals. Now we are adding a lot more content for businesses. We provide free content for our visitors, and your support is a smile for us.

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