A Comprehensive Guide to the Different Types of Nuts and Bolts

When it comes to fastening, choosing the types of bolts and nuts can make all the difference in the strength, durability, and reliability of your project. Depending on several factors, you need to apply the right fasteners to always get the best results. Some may be suitable for certain materials and environments, while others may have totally different properties.

To maximize the effectiveness of your work and the durability and security of your projects, memorize the names of the types of nuts and bolts, along with their properties and recommended uses!

Types of Bolts

Bolts are a type of fastener used to join two or more pieces of material together.

They come in a wide variety of shapes and sizes, each designed for a specific purpose. Here are some of the most common types of bolts:

Hex Bolts

Hex bolts (also called hex cap screws, tap bolts, hex cap bolts, or hex head screws) are the most common type of bolts that can be easily recognized by their hexagonal heads. 

Thanks to this shape, you can easily use them with a wrench or other common tools. Hex bolts are often used in construction, machinery, furniture assembly, or electrical and plumbing systems.

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Lag Bolts

Lag bolts (lag screws) are heavy-duty screws used for woodworking where significant holding power is essential. Thanks to their outstanding strength and durability, they can provide stability even in high-stress applications. 

Interestingly, lag bolts don't require nuts because they’re threaded directly into the material. They’re commonly used for securing heavy wooden elements, building decks and fences, attaching wood to metal or concrete, and more.

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Carriage Bolts

Carriage bolts (sometimes incorrectly called carriage screws) have a smooth, large-diameter head that resists pull-through in softer materials and have a square neck to prevent turning when tightening the nut. 

As a result, they work great with wood and other soft materials. Carriage bolts are frequently used for fences, decks, gates, furniture assembly, boat building and other purposes requiring connecting wood to wood or wood to metal.

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Machine Screws

Machine screws can be classified as both bolts and screws. They come either coarse-threaded or fine-threaded and are typically a bit smaller in length than other fasteners. 

They are perfect for projects involving securing heavy loads, so they are commonly applied in such industries as automotive, manufacturing, electronics, HVAC and plumbing, or furniture assembly.

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Socket Cap Screws

Socket cap screws are versatile fasteners with a low-profile head design that can be used in space-constrained places. Their installation is really easy, thanks to their precision-machined hex socket—you can simply use a hex Allen key or a socket wrench. 

You can often encounter socket cap screws in such industries as automotive and transportation, machine assembly and manufacturing, construction and infrastructure, or electronics and appliances.

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Types of Nuts

Nuts are typically used together with bolts or threaded rods to fasten two elements. Even though they’re small in size, they can carry amazingly heavy loads and resist tough conditions. However, it’s crucial to choose the right type of nut to achieve the best results in your project. Here are some of the most popular nuts:

Hex Nuts

Hex nuts are probably the most commonly used hex nuts in the world. Thanks to their hexagonal shape, installation and removal can be done conveniently and quickly with standard wrenches and other tools. 

As they are available in various sizes, they can be used to accommodate many different projects. Some of their most popular applications are joining steel beams in buildings and bridges, securing engine components, fastening electronic elements to printed circuit boards, assembling furniture, etc.

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Jam Nuts

Jam nuts are hexagonal low-profile fasteners, usually half the height of standard nuts. They're vibration-resistant and often used to lock another nut in place by being tightened against it, thus preventing the main nut from coming loose. 

Moreover, they are also applied when a component is required to move freely on the bolt of a stud. You can use jam nuts to secure bolts in machinery, secure pipes and fittings, protect suspension components and steering linkages in vehicles, and more.

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Cap Nuts

Cap nuts (sometimes also called acorn nuts) are easily recognized by their domed head, which covers exposed threads, adding more protection and improving their visual appearance. 

They’re available in multiple sizes to match with various bolts. Cap nuts are frequently used in applications where aesthetics matter, for example, in furniture assembly, light fixtures, or outdoor constructions like handrails.

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Flange Nuts

Flange nuts have a built-in washer-like flange that distributes pressure more evenly over the surface and protects the fastened components. This eliminates the need to use separate washers, making the installation process easier and faster. 

They usually have much coarser threading than other nuts, so you can fasten them more securely even if you can’t achieve a perfect fit. Moreover, flange nuts are vibration-resistant, so they can be used in automotive, machinery, and aerospace applications. Furthermore, they are often found in furniture, outdoor furniture, medical devices, and more.

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Coupling Nuts

Coupling nuts, also known as extension nuts, are fasteners used to join two male threaded components, most commonly threaded rods. They essentially function as connectors, allowing you to extend the length of a threaded rod or connect two separate rods together.

As they’re typically hexagonal on the outside, you can easily tighten or loose them with a wrench or spanner. As coupling nuts are very strong and reliable, they can be used for such demanding assemblies as airframe structures. Apart from that, they are common in many structural, machinery, or industrial applications.

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Wing Nuts

Wing nuts (thumb nuts, butterfly nuts) can be easily distinguished by their two wing-like projections that allow for easy tightening or loosening by hand without the need for any tools. 

This speeds up the assembly processes and reduces labor time. Wing nuts are suitable for a wide range of applications, including bicycles, musical instruments, electronics, laboratory equipment, and furniture.

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Lock Nuts

Lock nuts are secure fasteners designed to resist loosening under vibration, shock, or dynamic loads. Unlike standard nuts that rely solely on friction between the threads and the bearing surface to stay tight, lock nuts incorporate various mechanisms to enhance their resistance to loosening.

They are manufactured with precision thread to provide a snug fit and reliable connection. Lock nuts are frequently used in vehicles, aircraft and spacecraft, industrial machinery, agricultural equipment, buildings, bridges, electronic devices and appliances, and more.

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Different Types of Nuts and Bolts - Comparison Table

Common Bolt Materials

Choosing the best material for your fasteners is crucial, as it significantly affects their strength, durability, and resistance to environmental factors like corrosion and temperature changes.

Here are some of the most common materials used to produce different types of bolts:

Steel

• Carbon Steel: It offers a balance of strength, affordability, and versatility. Grades 2, 5, and 8 are the most frequently used in construction, automotive, and industrial applications.
• Alloy Steel: It combines steel with other substances like chromium, nickel, or molybdenum to enhance strength, hardness, and corrosion resistance. Alloy steel bolts are often used in high-stress applications, including machinery and aerospace.
• Stainless Steel: Stainless steel bolts contain chromium, which provides excellent corrosion resistance. As a result, they’re often used in marine, outdoor, and food-grade applications. Common grades include 304 (general-purpose) and 316 (superior corrosion resistance, ideal for saltwater exposure).

Brass

Brass bolts are non-magnetic and highly resistant to corrosion, making them a great choice for electrical, plumbing, and decorative applications. However, as they are softer than steel, brass bolts should not be used in high-load applications. 

Some of the most common applications of brass bolts are:

• Pipe fittings, valves, faucets, and other plumbing fixtures.
• Components of boats, ships, and maritime equipment.
• Securing wires, connectors, and components in electrical panels.
• Protecting industrial machinery parts, fastening conveyor systems, and maintaining factory equipment.

Bronze

Bronze bolts are stronger and more durable than brass ones. They’re mainly made from copper combined with silicon and small amounts of other metals like manganese. This composition enhances their mechanical properties and makes them resistant to corrosion, saltwater, and various chemicals.

What’s more, bronze bolts are non-magnetic, so they can be used in environments where magnetic interference is a concern, such as electrical assemblies.

On top of that, they can develop a beautiful natural patina which makes them perfect for decorative applications.

A few examples of their frequent uses are:

• Boat building, ship maintenance, and dock construction.
• Securing outdoor fixtures and sculptures in architectural designs.
• Chemical plants and oil refineries.
• Electrical power distribution systems.

Aluminum

Aluminum alloy bolts are lightweight and resistant to corrosion, making them suitable for applications where weight reduction is critical. 

However, they are not as strong as steel or titanium bolts, so they are best suited for low-stress applications.

Aluminum bolts are popular for:

• Aircraft and aerospace applications, where reducing weight is crucial to improve fuel efficiency and performance.
• Body panels, engine components, and interior fixtures in the automotive industry, helping to reduce overall vehicle weight and improve fuel economy.
• Boat building, dock construction, and various marine equipment applications, as they’re resistant to saltwater.
• Sporting goods and recreational equipment, such as bicycles, camping gear, and outdoor furniture.
• Construction and building applications, particularly in facades, roofing, and structural components

Titanium 

Titanium bolts offer a high strength-to-weight ratio, excellent corrosion resistance, and biocompatibility. They’re also non-magnetic and resistant to high temperatures, which makes them suitable for a wide range of challenging applications.

Some of them are as follows:

• Critical components such as airframes, landing gear, and engine parts in aircraft and spacecraft
• Securing suspension systems, wheels, and engines in race cars, motorcycles, and other racing vehicles
• Orthopedic implants, such as joint replacements and bone fixation devices, as well as dental implants and surgical instruments, due to their biocompatibility
• Shipbuilding, marine hardware, and various marine equipment
• Medical devices like MRI machines, due to their non-magnetic properties

Plastic 

Typically made from nylon or other polymers, plastic bolts are resistant to chemicals and non-conductive. They’re significantly lighter than metal bolts, which can be advantageous in applications where weight reduction is important,

Furthermore, they’re frequently used for purposes where metal corrosion is a concern.

However, compared to metal bolts, plastic bolts generally have lower tensile strength and load-bearing capacity, and they’re less resistant to high temperatures and UV radiation.

Here are some of their popular applications:

• Circuit boards, electrical enclosures, and various electronic devices to secure components and prevent electrical hazards.
• Protecting interior panels, seats, and door trims in vehicles.
• Cable clamps and terminals in electronic devices, due to their high electrical insulation.
• Boat building, dock construction, outdoor furniture, and other outdoor equipment where exposure to moisture and harsh weather conditions is a concern.
• Securing lightweight building panels and partitions, particularly in humid environments where corrosion resistance is crucial.

Types of Nut and Bolt Finish Options

Selecting the right finish for bolts and nuts is important for ensuring their performance, durability, and aesthetic appeal. Namely, various finishes provide different levels of corrosion resistance, strength, and appearance. 

Here’s an overview of common finish options for different types of bolts and nuts:

1. Plain (Uncoated) Finish

• What it is: Unfinished steel without any additional coating.
• Best for: Indoor applications where corrosion is not a concern.
• Pros: Cost-effective and sufficient for low-risk environments.
• Cons: Prone to rust and oxidation in humid or outdoor conditions.

2. Zinc Plating

• What it is: A thin zinc coating applied to steel bolts to improve their corrosion resistance.
• Best for: General-purpose use in dry environments or mild outdoor exposure.
• Pros: Affordable, readily available, and provides basic rust protection.
• Cons: Not suitable for harsh weather, marine environments, or high-moisture conditions.

3. Hot-Dip Galvanized (HDG)

• What it is: A thick zinc coating applied through a hot-dipping process, offering superior corrosion resistance.
• Best for: Outdoor structures, bridges, fences, and marine applications.
• Pros: Highly durable and resistant to rain, snow, and saltwater.
• Cons: Thicker coating can cause fitment issues if not matched with hot-dip galvanized nuts.

4. Black Oxide

• What it is: A chemically-applied finish that enhances corrosion resistance and reduces glare.
• Best for: Automotive, firearms, and industrial applications where appearance matters.
• Pros: Provides a sleek, black finish and mild corrosion protection when combined with oil.
• Cons: Not as corrosion-resistant as galvanized or stainless steel coating for nuts and bolts.

5. Nickel Plating

• What it is: A shiny, silver finish that provides moderate corrosion resistance and a visually appealing look.
• Best for: Decorative types of bolts and nuts, electrical components, and light-duty applications.
• Pros: Smooth, attractive appearance with improved wear resistance.
• Cons: Less durable than hot-dip galvanizing or stainless steel in tough environments.

6. Chrome Plating

• What it is: A polished, shiny finish applied over a layer of nickel.
• Best for: Motorcycles, classic cars, furniture, and decorative hardware.
• Pros: Rust-resistant, highly reflective, and provides a luxurious look.
• Cons: Can chip or peel over time if exposed to rough handling or outdoor elements.

7. Stainless Steel (Natural Finish)

• What it is: Stainless steel nuts and bolts naturally resist rust without the need for extra coatings.
• Best for: Marine environments, food processing, medical applications, and outdoor projects.
• Pros: Long-lasting, corrosion-resistant, and requires minimal maintenance.
• Cons: More expensive than standard steel fasteners.

8. Phosphate Coating

• What it is: A chemical treatment that gives a matte gray or black finish while increasing resistance to wear and corrosion.
• Best for: Military, automotive, and industrial applications.
• Pros: Provides good lubrication when used with oil, reducing friction and wear.
• Cons: Offers only moderate corrosion resistance compared to zinc plating or stainless steel.

9. Cadmium Plating (Less Common Today)

• What it is: A finish that was once popular for its excellent corrosion resistance, especially in aircraft and military applications.
• Best for: Used in aerospace and vintage machinery, but less common due to environmental restrictions.
• Pros: Highly resistant to corrosion and extreme conditions.
• Cons: Toxicity concerns have led to its decline in many industries.

Choosing the Right Types of Bolts and Nuts for Your Project

To choose the right nuts and bolts for your project, you need to consider more than just picking the right size—take into account such factors like material, strength, corrosion resistance, and intended use. 

If you use the wrong fasteners, your project may be weak, deteriorate quickly, or even fail under stress, which can be highly dangerous. For this reason, always make sure to use the proper types of nuts and bolts to ensure safety and efficiency.

Some of the most important factors you should take into consideration include:

Load Requirements

Think how much weight or force the fasteners will need to withstand. If the load in your project will be high (like in the construction or automotive industry), pick high-strength types of bolts and nuts. 

On the other hand, for light-duty applications (like furniture or household projects), you can go for less sturdy fasteners that are likely to be cheaper while still sufficient for your needs.

Bolt Type

Choosing one of the aforementioned different types of bolts can make or break your project. If you’re planning to make something from wood, carriage or lag bolts should provide a strong grip. 

For metal-to-metal applications, hex bolts, machine bolts, or flange bolts are good choices. When it comes to a decorative finish, cap nuts are the best choice.

Nut Type

Apart from the types of bolts, you also need to pick the right nuts. For applications susceptible to vibrations (like in vehicles or machinery), you can certainly use lock nuts. 

When you need built-in load distribution without a washer, choose flange nuts. If you know you will have to make frequent adjustments, select wing nuts that allow tool-free tightening and loosening.

Material and Environment Matching

Always remember to match the material with the environment correctly for the best results. If your project requires outdoor and water exposure, use stainless steel or hot-dip galvanized bolts and nuts to prevent rust.

For high-temperature applications, titanium fasteners will be an excellent choice as they’re lightweight and heat-resistant. 

In the case of corrosive environments (involving chemicals or saltwater), opt for silicon bronze or brass nuts and bolts.

Thread Type

Fine threads are more difficult to install and remove, but they provide more strength. If you’re working with soft materials like wood, choose coarse threads which are easier to work with. 

Also, keep in mind that threaded bolts provide maximum grip, while partially threaded bolts allow for stronger shear resistance.

Right Finish

Another significant factor is selecting the right finish from the ones mentioned before. If only mild corrosion resistance is required, you can go for zinc-plated nuts and bolts. For indoor uses where aesthetics and mild protection matter, black oxide finishes can be a good choice. 

However, if your project involves extreme outdoor exposure, hot-dip galvanized fasteners are the most recommended.

Sizing and Compatibility

Make sure that the length bolt is appropriate, as if it’s too short, it won’t secure the joining properly, and if it’s too long, it may interfere with other components. Apart from that, you need to match bolt diameter and thread pitch with the correct nut size. 

On top of that, if you’re using washers, choose the right size to distribute load effectively.

The Final Note

Being able to name types of nuts and bolts along with their properties and recommended uses will help you make more informed decisions and pick the right fasteners for your work. 

At Fastenere, we provide a wide selection of high-quality nuts, bolts, and other fastening products to meet your specific needs. No matter the application—whether it's construction, automotive, electronics, or DIY projects—we have the right solutions to help you get the job done right.

Now that you understand the different types of nuts and bolts, you're ready to make the best choice for your next project. Browse our collection today and find the perfect fasteners to ensure strength, stability, and long-term performance!

FAQ

What are bolts and nuts?

Nuts and bolts are fasteners used to securely join two or more objects together. A bolt typically features an external thread and is paired with a nut, which has an internal thread that screws onto the bolt, creating tension and holding the components in place.

How do I determine torque requirements for my fasteners?

Torque requirements vary based on factors such as material, size, and application. It's best to consult manufacturer specifications or guidelines provided by industry standards for accurate torque settings.

How should I store nuts and bolts?

Store nuts and bolts in a cool, dry place to prevent rust or corrosion. Use labeled containers or bins to keep different sizes organized and easily accessible.

What are the different types of bolt heads?

Many head types exist, including hex, square, socket (Allen), Phillips, slotted, button, pan, flat, and carriage.  The head type is chosen based on the application and the tools available.