From holding together the biggest skyscrapers to the tiniest electronics, these humble fasteners play an instrumental role in so many applications. But despite being everywhere, it can be hard to tell the difference between the types of nuts, bolts, and screws and pick the right one for the job.
In this comprehensive guide, we’ll dive into the fascinating world of fasteners, uncovering their differences and discovering their critical functions. So, you’ll be well-equipped to tackle any project that comes your way.
What are nuts, bolts, and screws?
The names of nuts, bolts, and screws are often used interchangeably, so it can get quite confusing. They’re all versatile fasteners that securely join objects together, but these are their distinct differences.
Nuts are typically hexagonal, though they come in other shapes as well. They have an internal thread that screws onto a bolt to create tension and hold pieces together.
Bolts, on the other hand, have an external thread. It’s usually secured with a nut on the end or driven into a tapped hole. They’re designed to endure significant tension and shear forces, making them ideal for heavy-duty applications.
Screws, similar to bolts, are also threaded rods. The key difference is that screws are typically driven into an untapped hole. They create their own threads as they’re driven into materials like wood or plastic.
Types of nuts and their uses
Nuts come in an array of options that match up with different kinds of bolts, each designed for a specific purpose or application.
As the most commonly used nut, hex nuts are found in many applications, particularly construction and machinery. They have six sides and are typically tightened using a wrench or socket when paired with a hex bolt.
These nuts are designed to stay in place even in the face of vibration or other forces that could loosen them. They have a nylon insert that deforms to grip the threads of the bolt, preventing the nut from coming loose. This makes them ideal for machinery and automotive applications.
Shaped like a pair of wings, these nuts are designed to be tightened and loosened by hand. This makes them a good choice for situations where assembly and disassembly need to be quick and tool-free, such as furniture or machinery that require regular adjustment.
Sheet metal nuts
Also known as speed nuts, they are so called because of the speed at which they can be installed and removed compared to traditional nuts. They don’t require any special tools for installation. You can simply push them onto a bolt or screw. This means they’re suited for applications where it could be challenging to access the fastener with a tool.
Different bolts and their applications
Bolts come in lots of sizes and designs, but the main difference is the head. Here’s how each type of bolt will suit certain projects.
These popular bolts are commonly used with washers and nuts for stability. They’re ideal for fastening timber or metal, providing a long-lasting and secure solution. Hex bolts are available in stainless steel and other non-corrosive metals. They feature a hexagonal head for easy installation and offer a robust grip when coupled with a wrench.
Recognisable for their smooth, rounded heads, these bolts are great for wood applications and for offering enhanced security. Their round shape makes them challenging to grip or wrench. So they’re ideal for securing valuable items and deterring theft or vandalism.
Flat head bolts
Known for their space-saving design, flat head bolts sit flush with the surface when installed. Perfect for doors, door frames, woodworking, and joinery projects, they provide a secure fastening.
Common uses for screws
Screws might appear simple, but their versatility is unmatched. Like bolts, they vary in size and design, so it’s important to choose the right screw for your project.
Round-head screws are commonly used in general-purpose applications. They are suitable for fastening materials where aesthetics and visibility are not a concern but structural stability is of the utmost importance.
With their cone-shaped head, countersunk screws are hidden within the surface when installed. They create a neat and professional finish. This makes them ideal for applications where appearance matters.
Grub screws, also known as set screws, lack a traditional head and are fully threaded. You can use them to secure one object within another, such as attaching handles to shafts or securing components in place.
Socket head cap screws
These screws have a cylindrical head with an internal hex socket. This allows for easy installation with an Allen wrench. Socket head cap screws offer high tensile strength. And they are commonly used in machinery and mechanical applications.
Materials and finishes
Nuts, bolts, and screws come in various materials and finishes, fitting for any environment and suited to any style. From the strength of stainless steel to the weather resistance of yellow zinc, each material has unique properties of durability, functionality, and corrosion resistance. The finishes range from plain to galvanised or coated for added protection.