One of the most popular power tools found in any hardware store, the angle grinder can be used for a wide variety of purposes. From grinding, cutting, and polishing all kinds of materials to sharpening blades and dull edges, this tool is definitely a favorite among woodworkers, metalworkers, and DIYers alike.
There are many projects that can be tackled with this piece of equipment, but this time we’re going to focus on how you can use an angle grinder to cut metal and everything else you need to know to do it.
How does an angle grinder work?
Before we start, it might be useful to understand how an angle grinder works first.
This tool can be powered by an electric motor or compressed air, and either be corded or cordless. The grinding and cutting are carried out by a disc or wheel that spins at a high speed, usually between 8000 and 11000 RPM.
Mounted on a geared head driven by the motor, a disc is a thin, round attachment that wears away as it’s used until it becomes small and needs to be replaced. When a disc is thicker than ½ inch, it’s called a wheel, which is generally used for stripping old paint, removing rust, and polishing.
There are many styles of discs and wheels available to suit all kinds of tasks, making the angle grinder a very versatile piece of equipment worthy of being part of your arsenal.
As regards features, most grinders nowadays come with an adjustable guard and side handle to allow a safe two-handed operation.
What types of metal cuts can I do with an angle grinder?
Equipped with an angle grinder, you can make rough cuts on small and medium gauge metal stock such as sheet metal, aluminum, rebar, and other mild types of steel. Cutting through dense materials like angle iron and cast iron, and hard items like rods, bolts and metal piping can also be done by attaching the right disc or wheel.
What attachment do I need to cut metal with an angle grinder?
As we’ve mentioned before, discs come in different grains, thicknesses, and sizes. To cut through most types of metal, you’re going to need a metal cutting disc, also known as an abrasive cutoff disc. This type of disc has an edge made of aluminum oxide, a softer bond that results in fast and smooth cuts.
For projects that involve thin metal, you should choose a 1.0 mm or 0.8 mm cutoff disc to make a quick job of cutting your piece, leaving a cleaner finish, and minimizing discoloration.
There are other types of discs, such as the iron-free stainless steel cutting discs, which, as the name suggests, are used to cut through steel and stainless steel. For this task, you should go for a 1 mm or 1.6 mm disc.
For heavier steel and harder metals, such as cast iron, you will need a diamond disc that’s between 1.6 mm and 2.5 mm thick. Bear in mind that thicker wheels cut slower and generate more friction, inevitably leading to discoloration and requiring extra smoothing and polishing steps.
Before buying a new disc or wheel, you should make sure that it’s the correct size to fit your angle grinder, and that the maximum RPM of the disc or wheel is higher than that of the tool to prevent damaging either of them and injuring yourself.
How to use an angle grinder to cut metal?
The hacksaw is usually the go-to tool for cutting metal, since that’s what it was originally designed for, after all. However, if you want to make a quick job of it with minimal effort on your part, then using an angle grinder is the way to go.
So, let’s go step by step and see what you need to do to cut metal with an angle grinder.
1. Getting ready
As with any other power tool, grinders can be dangerous if not used properly. Be sure to read the manufacturer’s instructions, as different angle grinder models might require specific safety precautions.
As a rule of thumb, you should always wear your personal protection gear to avoid any accidents and consequent injuries. This is what you’re going to need for cutting metal:
- 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 fumes or dust produced while cutting.
- Gloves – to prevent accidental cuts on your hands.
- Safety boots – to protect your feet from any pieces of metal that might fly down.
- Tightly fitting clothing – to avoid fabric getting caught by the disc.
2. Preparing your workspace, workpiece, and grinder
Declutter your workspace and secure the floor to prevent any accidents and avoid tripping and falling.
Next, you should mark the place where you want to make the cut. You can use a scratch awl or a permanent marker to outline the design. Once that’s done, you have to hold your workpiece firmly in a bench vise or clamp it down to your workstation to prevent dangerous slips.
Finally, before you plug the tool into the power source, you need to set the disc. To do this, you just have to open the spindle and insert the correct metal disc (we’re going to discuss this in detail later on). Then, you should fasten the spindle nut in place.
Remember to always check that both the tool and the disc are in good conditions before using them.
3. Cutting the metal piece
Now we can start with the fun part, learning the proper technique for cutting metal with an angle grinder:
- If your grinder is corded, plug it into the power source.
- Adjust the guard so that it’s positioned between your body and the tool.
- Once you turn the angle grinder on, allow the disc to reach full speed to achieve smoother and better results.
- Holding the tool firmly with both of your hands, set down the disc lightly on one of the lines you’ve previously marked at a 90° angle.
- Start cutting by moving the grinder back and forth along each set line. Don’t apply too much pressure and let the tool do the job for you to avoid kickback.
Depending on the thickness of the metal, you might need to apply some pressure, but make sure you do it slowly and carefully.
And that’s it, simply continue the process until you reach the other end of your outline and the piece is cut.
If you need to change directions while cutting, avoid doing it suddenly to ensure that the cut remains precise, and you don’t lose control of the tool.
4. Finishing the cut
In most cases, cutting metal with an angle grinder will lead to sharp edges that can make your workpiece dangerous to handle. Luckily, you can use the same tool to smooth them and deburr your workpiece.
This step is optional, and whether you carry it out depends entirely on the type of finish your project requires. However, we highly recommend that you do it as it won’t take long and might prevent accidents.
Simply remove the current disc and insert a flapper wheel instead. Position the tool at a 10°-15° angle over the sharp edge and gently run it along the surface, applying even pressure.
Now you’ve learned another of the many uses of an angle grinder!
When you get down to it, cutting metal with an angle grinder is not really a difficult task. As long as you follow the safety procedures and equip your angle grinder with the right disc or wheel, you can slice most metals with ease.
However, you might need some practice before you can achieve clean and efficient cuts. You might want to consider trying out your tool on a piece of scrap metal before getting to work on your piece.
Thanks for reading our guide on how to use an angle grinder to cut metal! You now know the basics of how an angle grinder works and how to operate it. All that’s left is for you to perfect your technique!