How to cut Concrete with an Angle Grinder: Cutting Concrete with an Angle Grinder

You’ll find that dealing with concrete is a labor-intensive task that’s very common in most construction projects.

Luckily, if you have an angle grinder lying around, you can easily use it to cut through this tough material. Granted, this isn’t the only tool to tackle concrete, but it’s the most practical, beginner-friendly, and cost-effective option for DIYers. For heavy-duty concrete cutting, however, you’ll need a concrete saw.

Even though there aren’t many steps to cutting concrete with an angle grinder, there are several aspects to take into account for a safe and efficient operation

In this guide, you’ll find everything you need to know about the angle grinder and how to use it to cut concrete!

Can an angle grinder cut concrete?

How to cut metal with an angle grinder

An angle grinder can indeed be used to cut concrete, among many other things, but only if it’s equipped with the right attachment. Grinding concrete with an angle grinder is another popular use for this tool!

Let’s start with the basics for those who are new to this piece of equipment. Angle grinders have round attachments called discs (or wheels, when they’re thicker than ½ inch) that are mounted on a geared head driven by the motor.

There are certain types of discs that are specifically designed to cut concrete, and as the motor makes them spin at very high speeds (usually between 8000 and 11000 RPM), they’re worn away until they become small and need to be replaced.

Thanks to the speed of the grinder and the strength of the disc, you can easily make sharp-edged cuts in a concrete block and even smooth out concrete surfaces.

Read on to learn how to choose the right angle grinder disc to cut concrete.

What attachment do I need to cut concrete with an angle grinder?

It’s important to take the time to understand the advantages (and the disadvantages!) of the different styles and bonds of angle grinder attachments for two reasons. The first is to avoid damaging your workpiece, and the second, to work efficiently.

The specific concrete-cutting attachments are called diamond grit blades, and they have a steel core with a sharp edge made of synthetic diamonds.

When it comes to disc materials, they’re your best and only option. Metal cutoff discs, for example, won’t be as effective because they’ll cut slower through such a dense material as concrete, so they’re better for grinding and cutting metals.

Make sure to get a diamond disc that can be used for both wet and dry cutting of concrete. While you can use a dry-cutting blade with or without water, a wet blade must be used with water

When it comes to the shape of the blade’s edge, you do have a couple of options:

Segmented rim diamond blades: They have a segmented rim with ventilation gullets (the space between the segments). These separations help to extract cutting dust and debris and cool the blade. They also add a small degree of flexibility to the blade, so it can be used for demanding tasks without cracking.

Segmented rim blades are used both for dry and wet cutting, but bear in mind they’ll give a rough cut.

Something to consider when buying a segmented rim blade is the abrasiveness of the material you’re cutting. The more abrasive the material is, the wider the gullets should be.

Turbo rim diamond blades: They have cooling holes in their metal body, close to the center. These small segments are designed to draw out heat, dust, and debris while the blade is spinning.

Turbo rim blades are used for both dry and wet cutting, and since they’re in constant contact with the material, they offer a cleaner and smoother cut.

You might come across continuous rim blades as well, but you should stay away from them as they don’t have gullets or holes. They can only be used for wet cutting because it’s the water that cools down the blade and washes away the dust buildup. They’re used for cutting fragile materials that are prone to chipping such as marble, granite, porcelain tile, and ceramic tile.

Diamond blades are usually expensive, but their versatility makes them a good investment. An angle grinder equipped with one of these blades can slice everything from stone to granite, cast iron, and brickwork.

In simple words, to cut concrete with an angle grinder you’re going to need a diamond grit blade that either has a segmented rim for making rough cuts, or a turbo rim for cleaner cuts.

How to use an angle grinder to cut concrete?

Angle Grinder

Now that you know how to equip your angle grinder to cut concrete, you can learn the proper procedure and techniques to operate this tool, starting with the safety measures you should take.

Getting ready

All power tools can be dangerous if not handled properly, and angle grinders are no exception. Different grinder models might have different features that require specific safety precautions, so be sure to read the manufacturer’s instructions.

To avoid any accidents and the consequent injuries, you should always wear your personal protective equipment (PPE). A complete gear for cutting  concrete includes the following items:

●     Safety goggles – to protect your eyes from sparks and debris produced by cutting.

●     Earmuffs – to protect your ears from the loud noise produced by the grinder.

●     A dust mask or face shield – to avoid inhaling any silica or concrete dust produced while cutting.

●     Gloves – for a better grip and to prevent accidental cuts on your hands.

●     Safety boots – to protect your feet from any concrete debris that might fly down.

●     Tightly fitting clothing – to avoid fabric getting caught by the disc.

Preparing your workspace, grinder, and concrete piece

Safety measures don’t only include your person, but also your workspace. Declutter the area, paying special attention to the floor, to prevent any accidents and avoid tripping and falling.

As regards preparing your angle grinder, you should always set the disc before you plug the tool into the power source. It’s quite easy to do, just open the spindle, insert the diamond disc of your choice, and then fasten the spindle nut in place.

Remember to make sure that both the grinder and the disc are in good condition before using them. Turn on the tool and run it for about 30 seconds to check that everything is secured and works as it should.

Finally, you need to prepare the concrete piece you’ll be working on. Mark the place where you want to make the cut using a piece of chalk and trying to keep the edges as straight as possible.

If you want to cut small pieces of concrete, blocks, or slabs, they should be clamped down firmly to your workstation to prevent dangerous slips.

Cutting the concrete piece

Once you have everything ready, it’s time to begin the concrete cutting process. This is what you should you:

  1. If you have a corded angle grinder, plug it into the power source. Otherwise, skip to the following step.
  2. Adjust the blade guard so that it’s positioned between your body and the tool.
  3. Turn the angle grinder on and allow the disc to reach full speed before setting it down on the concrete surface to achieve smoother and better results.
  4. Holding the tool firmly with both of your hands, set down the disc lightly on the layout you’ve marked at a 90° angle.
  5. Score the concrete piece by making an initial divot of about half of your desired depth, then work the grinder horizontally across the length of your outline.
  6. Start moving the grinder back and forth along the divot. You might need to apply some pressure, but start lightly and carefully. Don’t force the tool into the concrete, and let it do the job for you instead to avoid kickback.

And that’s it, you’ve successfully cut your concrete piece!

FAQ

Angle grinder sanding metal pipe

Can any angle grinder be used to cut concrete?

The short answer is no. Since concrete is a very dense material, it’s crucial that your angle grinder has the right size and enough power to handle the job.

You’ll need a grinder that’s between 4-inches and 7-inches and that has a motor of 5-9 amps. Angle grinders can reach up to 15 amps, and for this task, the more power yours has, the better.

Remember that heavy-duty concrete cutting requires a concrete saw. If you try to use your angle grinder for this, there are a few things that can happen.

The most obvious one is that you risk having an accident. Secondly, you’ll wear out your diamond discs faster, and you’ll have to replace them numerous times. This will make the whole process less efficient and more expensive. You might also overload the motor and kill it.

Are there any disadvantages of using an angle grinder to cut concrete?

Yes, using an angle grinder to cut concrete has a few disadvantages, but they’re mainly related to leveling and grinding a concrete floor.

Grinders usually use discs that are between 5-inches and 7-inches, so working on a large concrete surface can take a lot of time. What’s more, working on a floor with an angle grinder requires that you be on your hands and knees, which can be really uncomfortable to do for long periods.

How deep can an angle grinder cut?

When working on concrete, a 4-inch angle grinder can approximately go 1 to 1 ½-inches deep, whereas a 9-inch angle grinder can go about 3 to 3 ½-inches deep. You can use a 4-inch grinder for concrete that’s thicker than 1 ½ inches, but you’ll have to turn the piece over to work on the other side as well and complete the cut. If you want to complete the job faster, you might want to consider using a bigger grinder.

Conclusion

Thank you for reading our post on how to cut concrete with an angle grinder! Angle grinders are extremely versatile tools, and even though they weren’t primarily designed with concrete in mind, they can become a great ally for the handyman who needs to do occasional and small concrete cutting work.

You just have to equip your grinder with a diamond blade, put on your safety gear and follow the instructions we’ve provided!

Liam Weissman

Hello and welcome to PowerToolGenius! My name is Liam and for the last 9 years, I have worked extensively with various power tools and accessories. I have tested hundreds of different brands and models and understand the industry extensively and have been working with tools my entire life!

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