What is a nut? What is a nut?
Nuts are fastening elements that are typically used to provide a firm hold for screws, bolts or threaded rods. They work by screwing onto the external thread of a bolt, securely connecting two or more parts. Manufactured from a variety of materials such as steel, stainless steel, brass, aluminum or plastic, nuts are selected according to the required strength, corrosion resistance and other environmental factors.
There are various shapes and sizes of nuts, including hex nuts, wing nuts and lock nuts, which are used in various industrial, trade and everyday applications. Particularly in safety-critical areas such as the automotive industry or aviation, nuts have special properties that prevent loosening due to vibrations or dynamic loads. They are therefore indispensable components in fastening technology and ensure reliability and safety in mechanical production and assembly.
What types of nuts are there?
- Hexagon nut: The most common type of nut, suitable for a wide range of applications and easy to tighten with wrenches.
- Square nut: A square-shaped nut that is usually used in T-slots of machine tools or in channel beams.
- Octagonal nutThe octagonal nut, also known as an octagon nut, is a special type of nut with eight sides. Compared to the conventional hexagon nut, it offers a larger surface area and more contact surfaces for tools. This can be particularly useful in hard-to-reach areas where full access to the tool is difficult. Octagonal nuts are often used in heavy machinery and applications that require a high tightening torque.
- Flanged nutA nut with a wide flange at one end that acts as an integral washer. This helps to distribute the load and reduce the pressure on the fastening material, which is particularly useful with soft materials.
- Welding nut: A nut that is specially designed for welding to a workpiece. It usually has a flange with studs to facilitate the welding process.
- Lock nut: A nut used together with a cotter pin or locking pin to prevent it from coming loose.
- Parallelogram nut: This special type of nut has an internal thread in the shape of a parallelogram. This design allows an even load distribution on the thread and is used especially in precision machines that have high accuracy requirements.
- Combination nut: This nut combines two or more functions or shapes, such as a locknut with an integrated washer. They are often used where installation space is limited and several functions need to be combined in a single component.
- Cone nut: Cone nuts have a conical shape that allows them to be fitted into a corresponding conical opening. They are often used in connections where centering assembly is necessary, such as in wheel hubs or in high-precision devices.
- Twelve-sided nut (double hexagon nut): This type of nut has twelve sides and offers more contact surfaces for tools compared to a standard hex nut. This means that it is easier to grip, especially in tight spaces where it may be difficult to get a complete grip with a wrench. Twelve-square nuts distribute the load in a similar way to hex nuts, but offer greater flexibility during assembly and disassembly. They are commonly used in the automotive industry and other mechanical applications where space is limited or frequent adjustment is required.
Rectangular nut: Rectangular nuts are specialized nuts with a rectangular or sometimes square outer profile. They are often used in T-slots as found in machine tools or heavy industrial equipment. The flat sides fit exactly into the T-slots, which prevents the nut from rotating within the slot. This enables a stable and secure fastening. Rectangular nuts are ideal for applications where there is a high load and the nut needs to be held in position without rotating.
- Wing nutThis nut has two large "wings" on the sides so that it can be easily tightened or loosened by hand. It is ideal for applications where frequent manual adjustments are required.
- Lock nut (lock nut): Locknuts have a special design that prevents them from loosening on their own. They are available in various versions, including with a nylon insert or as an all-metal version.
- Cap nut: This nut has a closed top that covers the thread ends and thus offers protection. It is often used for aesthetic reasons or to protect against injury.
- Slotted nut: This nut is tightened with a screwdriver and is practical when access with a wrench is difficult.
- Knurled nut: Knurled nuts have a ribbed surface that makes them easy to turn with your fingers. They are often used in electronic devices.
- High-strength nut: These nuts are designed for applications that require high strength. They are used in conjunction with high-strength bolts in critical, load-intensive applications.
- Cage nut (rack nut): A special nut used in racks for electronic equipment that is inserted into a special hole to keep it in place.
- Self-locking nut (stop nut): This nut uses a mechanism, usually a nylon insert, which exerts friction on the thread and prevents self-loosening.
- Coupling nut: A long nut used to connect two pieces of threaded rod or bolts together.
- T-slot nut: Developed for use in T-slot rails, which are often found on machine tools and assembly systems. They slide into the T-slot rail and are used to fasten workpieces or machine parts.
- Press-in nut: These nuts are inserted into a pre-punched hole and then fastened by deforming the material around the hole. They are useful in applications where screws cannot be inserted from the back.
- Spacer nut (distance nut): These nuts have a longer body shape and are used to create gaps between two parts or to keep components at a distance.
- Dome nut: A variation of the cap nut in which the dome is higher and usually not completely round in order to provide even better protection for the thread.
- Wing clamping nut: A variation of the wing nut that has been specially developed to clamp materials quickly without the use of tools.
- Sheet metal nut: Designed for use with sheet metal, these nuts grip into the material and provide a stable fastening that is secured against pulling out.
- Torque nut: These nuts are designed to prevent further tightening when a certain torque is reached, which is important for precise applications where over-tightening could cause damage.
- Joint nut: Special nut with a joint mechanism that can be mounted at angles, ideal for uneven surfaces or fastenings at different angles.
- Knurled screw with nut head: A screw with a knurled nut head for easy manual adjustment, often found in camera or photographic equipment.
- Thread-rolling nut: These nuts cut their own thread into the material as they are screwed in, reducing the need for pre-drilling or tapping.
Which nut fits which screw?
To find the ideal nut for a particular bolt, you should pay attention to some important factors to ensure that the connection is secure and effective. First of all, it is crucial that the thread size and type of the nut exactly match those of the bolt. The materials of the bolt and nut should also be compatible to prevent corrosion and ensure the required strength.
The strength class of the nut must also be at least the same as that of the screw. In environments that are exposed to special conditions, such as extreme humidity or chemicals, the material of the nut should be correspondingly resistant.
For applications where vibration is a factor, self-locking nuts or those with locking elements are recommended to prevent loosening. Finally, assembly requirements should also be considered; depending on accessibility and tool availability, a special nut such as a wing nut may be most suitable.
What threads are there for the different nut types?
The types of threads used on different types of nuts vary depending on the specific application and compatibility requirements with screws or bolts. Here are some commonly used thread types:
Metric thread (M): This is the most commonly used thread system for nuts and bolts worldwide. Metric threads are identified by the letter "M" followed by a numerical value that indicates the nominal diameter in millimeters (e.g. M8, M16).
Unified National Coarse (UNC) and Unified National Fine (UNF): These thread types are common in North America and identify screws and nuts in inch sizes. UNC is a coarse thread, while UNF is a fine thread. They are often used in the automotive and aviation industries.
British Standard Whitworth (BSW) and British Standard Fine (BSF): These threads are common in Great Britain and are similar to UNC and UNF, but with different thread pitches and profiles.
ISO thread: ISO threads are part of an international standard that is very closely linked to the metric system. They offer high accuracy and are frequently used in technical and industrial applications worldwide.
Trapezoidal thread: This thread form is mainly used for spindles, such as in vices or linear drives. The trapezoidal thread enables a high load capacity and is robust against wear.
Saw thread: Saw threads offer high axial load-bearing properties and are often used in heavy-duty applications such as press spindles.
Round thread: Round threads are particularly smooth and are used in areas where easy disassembly is required, such as bottle caps or pipe connections.
ACME thread: Another type of trapezoidal thread, mainly used in the USA. ACME threads offer a good combination of strength and ease of manufacture.
For each type of nut, the thread must match that of the screw or bolt to ensure an effective and secure connection. This includes not only the type of thread, but also other specifications such as diameter and pitch.
Customized nuts from Schuhl & Co.
Schuhl & Co. is an experienced manufacturer of nuts. In particular, we produce customized nuts, special nuts and cold extruded parts with dimensional accuracy and to the highest quality for customers from a wide range of industries. Please contact us with a non-binding enquiry for your individual nut
Conclusion on the different types of nuts
Choosing the right nut for a specific bolt is crucial for the safety and functionality of any fastening application. A correctly selected nut not only ensures a reliable connection, but also protects the components and increases the service life of the entire structure. It is therefore of utmost importance to consider the thread size, material, strength class and environmental factors when making a selection. In addition, it is helpful to consider the specific application and assembly requirements in order to select the most suitable nut that is both practical and efficient.
Overall, a thorough understanding of the different types of nuts and their respective properties helps to make optimal decisions in fastening technology. Whether in industrial applications, trade or everyday use, being able to choose the correct nut means maximizing the performance and safety of structures. Take advantage of our expertise to use the most suitable fasteners for every installation or repair.
