Angle grinders are handy tools that can do a variety of tasks, from cutting metal and concrete to grinding and polishing. However, with the wide range of angle grinder sizes available in the UK, it can be difficult to know which size is right for your needs.

In this guide, I will explain the different sizes of angle grinders that are sold in the United Kingdom (UK) and that will help you choose the right size depending on the tasks you are planning to do.

They are measured by the diameter of the disc or wheel that they use. It's really important to verify the compatibility of the grinder with specific disc sizes as per the manufacturer's recommendations before use.

Choosing the Right Angle Grinder Size for Your Needs

Picking the right angle grinder size is really important so as you can get the right performance and safety from the tool. Each size offers distinct capabilities and caters to specific applications. Let's look a little closer at what that means in practise.

Angle grinders come in various sizes for three main reasons:

1. They can do different jobs and tasks
2. They can be used on different materials
3. Different people prefer various options

115mm Angle Grinders: Precision and Perfect for Light-Duty Tasks

115mm (4 ½") angle grinders are the smallest and lightest option. They are often called mini angle grinders. Their compact size and maneuverability make them the perfect choice for light-duty tasks and precision cutting in tight spaces. People who buy these use them for:

• Grinding metal, removing rust, and smoothing out welded joints
• They use them to cut thin materials like sheet metal, pipes, and conduit
• They use them to perform delicate work on intricate surfaces
• Also used when working in confined areas where larger grinders are impractical to use.

Despite their smaller size, 115mm angle grinders still pack a powerful punch. They typically operate at higher RPMs, resulting in faster cutting speeds. However, their smaller disc size limits their cutting depth to around 30mm.(1.18")

125mm Angle Grinders: Versatility and Power for General-Purpose Tasks

125mm (5") angle grinders are very popular in the UK. As you would imagine, they are slightly larger and heavier than the smaller 115mm grinders. The key difference is that the cutting depth improves to around 38mm. (1.5") This makes them more suitable for a wider range of tasks, including:

• Cutting thicker materials like metal bars, pipes, and concrete slabs
• Grinding larger surfaces and removing more material faster and easier
• Really good for general purpose construction and renovation work
• Handling tasks that require a combination of cutting and grinding

125mm angle grinders are a popular choice for DIY enthusiasts, tradespeople, and professional contractors due to their versatility and ease of use.

230mm Angle Grinders: Heavy-Duty Power for Deep Cutting and Demolition

230mm (9") angle grinders are the largest and most powerful option. They are designed for the big heavy duty applications such as deep cuts and and demolition work. Their larger disc size give you cutting depths of up to 70mm (2.75"), making them ideal for:

• Cutting thick metal plates, beams, and concrete slabs
• Performing demolition work and removing concrete or masonry
• Handling large-scale construction and industrial projects

230mm angle grinders are typically the choice of professional contractors and specialized applications due to their power and cutting capacity. However, their larger size and higher weight require more control and may be less suitable for smaller projects or confined spaces.

In summary:

• For light-duty tasks and precision cutting, 115mm angle grinders are the perfect choice
• For general-purpose work and thicker materials, 125mm angle grinders are your best choice
• For any heavy duty applications and/or deep cutting, 230mm angle grinders offer unmatched power.

Other Considerations

There are a few other considerations worth thinking about.

Surface Area Coverage

Larger discs can cover a greater surface area, allowing for more efficient work on larger projects. This is advantageous when working on extensive surfaces like floors or walls. The larger grinders also get the job done much faster.

Power and Torque

The larger grinders have more powerful motors and that means they are capable of handling tougher materials and providing higher torque, making them suitable for any heavy-duty applications.

Safety Considerations

Smaller angle grinders are often preferred for their maneuverability and ease of control, particularly by those less experienced with power tools. Larger grinders might require more expertise and control due to their power and potential kickback. For that reason I would recommend looking for for angle grinders with safety features like:

• Safety guards: These Work like a barrier and  protect your hands and face from flying debris or accidental contact with the spinning disc.
• Dust guards: These are useful attachments that help reduce any dust inhalation, which can be harmful to your lungs.

RPM (Rotations per Minute)

RPM stands for revolutions per minute and refers to the speed at which the angle grinder's disc rotates. A higher RPM generally translates to faster cutting speeds, which can be beneficial for certain tasks. That said, it's important to note that excessive RPM can also generate more heat, increasing the risk of disc breakage or material damage. Some of the better angle grinders have variable speed, and I would always recommend that type.

Arbor Size

The arbor is a shaft on the grinder that connects the motor to the disc. Almost every angle grinder has a standard arbor size of 22.23mm (7/8") diameter. There is the very odd exception to this. It is always worthwhile checking that the arbor size of your angle grinder matches the arbor hole of the discs you intend to use. I have shown a typical disc below, and as you can see the hole in the centre of the disc is standard at 22.2mm, and will fit over the arbor perfectly.

Soft-start mechanisms

An angle grinder with a soft start mechanism gives you a lot more control. This feature gradually increases the disc speed, and prevents any sudden jolts. That greatly reduces the risk of losing control of the tool. Having used grinders without this and then with it, the difference is huge and just makes your life a great deal simpler and safer.

My Final Thoughts

The choice of angle grinder size that you want to buy primarily depends on the specific task at hand, the material being worked on, the frequency of use, and your individual preferences. By carefully considering the information above you will be able to select the right tool for the job. You may also find it helpful to read our article on the various types of angle grinders, or our full angle grinder buying guide.

Further Reading

You may also find it helpful to read our article on the various types of angle grinders, or our full angle grinder buying guide.