An Introduction to Fasteners – Types of Bolts and Nuts


If you have ever experienced visiting a hardware store, you might have observed a great variety of fasteners there. You can find their applications everywhere around you. Whether you’re working on a DIY or automotive project in an industry, you’ll need fasteners to hold your objects in place. You might not know about every type of fastener in a hardware tool kit, but some familiar ones are nuts and bolts.

In this article, we’ll let you know about various types of fasteners along with a detailed description of nuts and bolts. So, let’s start with a brief introduction to fasteners.


What are Fasteners?

Fasteners are hardware tools specified for holding materials together mechanically. Typically, this single word covers a broad range of tools, including bolts, nuts, screws, washers, rivets, and so on. Usually, fasteners are responsible for making non-permanent joints so that you can separate the two connected parts whenever needed. However, the rivet is a permanent fastener that offers an eternal attachment.


What are the Different Types of Fasteners?

The fasteners are divided into many divisions according to their shapes and functions. Here is a whole picture of various types and subtypes of fasteners.




Bolts The fasteners with external threads that can hold two unthreaded components together are called bolts. ●      Hex bolts

●      Lag bolts

●      Double end bolts

●      Shoulder bolts

●      Elevator bolts

●      Hanger bolts

●      Eye bolts

●      Socket head bolts

●      Carriage bolts

●      U-bolts

Nuts These are the fasteners with internal threads that work with the bolts. ●      Cap nuts

●      Castle nuts

●      Coupling nuts

●      Weld nuts

●      Hex nuts

●      Wing nuts

●      Tri-groove nuts

●      Shear nuts

●      Square nuts

●      Flange serrated nuts

Screws Unlike bolts, screws are versatile fasteners that don’t use other fasteners to keep them in place. ●      Sheet metal screws

●      Machine screws

●      Wood screws

●      Self-driving screws

●      Deck screws

●      Set screws

●      Hex lag screws

●      Head screws

Nails Nails are without threading and offer high shear strength. ●      Common nails

●      Box nails

●      Finishing nails

●      Flooring nails

●      Roofing nails

●      Framing nails

Washers These are flat disc-shaped fasteners that work by distributing the load of the fastener. ●      Flat washers

●      Spring washers

●      Lock washers

Rivets A rivet consists of a head and an unthreaded tail that helps in creating a permanent joint between two parts. ●      Pop rivets

●      Multi-grip rivets

●      Tri-fold rivets

●      Large flange rivets

Anchors These fasteners embed themselves deep into the material to hold the object in place. ●      Mechanical expansion anchors

●      Clamping anchors

●      Concrete wedge articles

●      Anchor rods

●      Sleeve anchors


Types of Bolts and Nuts

Bolts and nuts hold an important position among all types of fasteners. They come in different shapes and designs. In order to develop a better understanding of bolts and nuts, other types are explained below. Let’s have a detailed account!

Bolt Definition

A bolt is a non-tapered fastener that can’t work without the assistance of a nut or washer. The nuts or washers help the bolts hold the parts together. As the bolts contain threads, their types typically differ in thread specifications, head shape, and length. Here are some significant types of bolts.

1. Hex Bolts

Hex bolts or hexagon head bolts can be found in various sizes and threading varieties. These bolts possess hexagonal heads and threaded shafts, usually made from steel. Installers can tighten hex bolts with wrenches or sockets. Moreover, you can grab them from different angles due to their shape while installing them.

2. Lag Bolts

Lag bolts are counted among the sturdiest fasteners. Due to their toughness, people use them to connect heavy materials that bear intense loads. As compared to other bolts, lag bolts are larger in size (one inch longer) and thickness ( ¼ inch thick). However, in order to install a lag bolt, you first need to drill a pilot hole with a relatively smaller diameter and then insert the lag bolt through the area. Primarily, lag bolts are available in different materials such as zinc, stainless steel, and steel/hot dip galvanized.

3. Carriage Bolts

A carriage bolt features a round or dome head, a flat tip, and a partially threaded shaft. Plus, a square section is below the head to keep the bolt safe when tightening. Most commonly, carriage bolts are used to fasten the wood to metal parts or two different metal components.

4. Double End Bolts

As the name suggests, double-ended bolts contain a threaded portion at both bolt ends without any head. Both ends are designed to perform different functions. One is to be threaded into the hole of the part, usually tapped with a mated thread, whereas the other end is threaded to hold the nut. Double-end bolts are also known as studs. You can use these bolts to aim high-strength bolting.

5. Eye Bolts

The head of the eye bolt is ring-shaped or looped, while the shaft is threaded. Generally, eye bolts are attached to the structures in order to tie the ropes, cables, or shackles to them for security purposes. They are fully threaded bolts that may have shoulders, making them ideal to be used with angular loads up to 45°. You shouldn’t use the eye bolts without a collar or shoulder for angular loads. Eye bolts are suitable for masonry applications.

6. Shoulder Bolts

Shoulder or stripper bolts consist of three parts: the head, shoulder, and threads. Some portion of the shaft is threaded while the other larger portion, known as the shoulder, is unthreaded. They are perfect to use with ball bearings and other precision parts due to their tight tolerances.

7. Hanger Bolts

The Hanger bolt is deprived of the head on the upper end. Yet, both ends are threaded. You may use hanger bolts for wood and metal bolting purposes.

8. Elevator Bolts

Elevator bolts mainly consist of a thin, rounded head and a partially threaded shank. They are specifically used in elevator systems due to their thin heads, as they don’t interrupt the operations of elevators and allow them to move up and down freely.

9. U-bolts

As the name implies, u-bolts are the fasteners having the shape of the letter U. Both ends of the bolts are threaded. Some of these bolts also feature rubber coating. You can find the applications of U-bolts in various areas, from supporting pipes to automotive applications.

10. Socket Head Bolts

Socket head bolts feature a variety of head shapes, including cylindrical, domed buttons, and flat countersunk. You may select the one according to the demands of your project. Furthermore, these bolts are tightened by Allen wrenches or hex socket tools.


Types of Nuts

Manufacturing companies use different nuts to make the bolting process easier. Some types of nuts are explained below:

1. Cap Nuts

To protect bolt threads, cap nuts are widely used. They not only improve the safety of the material but also give it a smooth look. Whenever an object needs a delicate finishing touch, a cap nut does the job and increases the aesthetic appearance of the material.

These nuts are available in a variety of ranges. Two of the common styles of cap nuts are:

  • Low crown nuts
  • Acorn nuts

2. Castle Nuts

Unlike traditional nuts, Castle nuts help in providing a tighter lock to the object. You can trust them to secure your wheel on the axle or give a more protective look to the material. Being manufactured with stainless steel, castle nuts provide a rounded modification to the object.

3. Coupling Nuts

Extension nuts or coupling nuts have the primary purpose of connecting two threads or hanger bolts. Hence, you can use these nuts for various applications, including the attachment of threaded rods or hanger bolts.

4. Flange Serrated Nuts

One of the common types of hex nuts is flange serrated nuts. On the lower side, they contain serrations that help in the tightening process. CNC machining industries use such nuts to prevent loosening in irregularly or randomly shaped holes.

5. Weld Nuts

For spot welding purposes, weld nuts are critical in the manufacturing industry. They are specially designed for industrial products due to their compelling nature in connecting a metal workpiece. These nuts are available in multiple styles and variable sizes in the market.

6. Hex Nuts

One of the most commonly used nuts in the CNC industry today is Hex nuts. Due to a strong combination of bolts, screws, and other components, these nuts are perfect to use for metal and woodwork. These are hexagonal-shaped and open-end wrenches used for their opening and closing.

7. Wing Nuts

Compared to all other nuts, wing nuts are popularly used for boats and bicycles. They can easily hold two or more objects and can even twist them for better conjunction. Above all, these nuts require lower force and hence lower torque for tightening the object.

8. Tri-groove Nuts

If you need a secure assembly and disassembly of material, then Tri-groove nuts are the perfect option. They are used in a variety of applications, including carriage bolts, and have a tapered diameter. Unlike other nuts, you can remove them easily with the help of a socket driver.

9. Shear Nuts

There are some materials and metal objects that need permanent fastening at once. Shear nuts are the ones that help in providing permanent installments to the workpiece. They are readily available in the market and perfect for indoor and outdoor applications.

10. Square Nuts

Square nuts are the ideal nuts you can use as a foundation in your furniture and rail channels. These four-sided nuts contain a square bolt and a strong washer so that the material can get an excellent tightening in blind locations.



The combination of bolts and nuts offers a strong and sturdy attachment for holding the parts together. This is because the nut provides the axial clamping force to the bolt, preventing axial movement. Yet, you may also use other types of fasteners in your different projects according to the requirements.

Extensive Industry Knowledge
Related Blogs

Precision is key in advanced manufacturing. Honing is an intricate machining process that has
Read more

Case hardening, an essential metallurgical process, transforms metal components and their functionality across industries
Read more

Screen printing stands out for its wide-ranging application across industries - fashion and advertising.
Read more

Request A Quote

Do you need our services? Contact us now by phone, email or through our contact form.

Sign Up For Our Newsletters

You cannot copy content of this page