Techniques For Using Angle Grinder To Cut Steel Beams

Steel beams are an essential building material in construction and engineering projects. They are commonly used to provide support and stability for structures and bridges, and are also utilized in the creation of machinery and equipment. While steel beams are incredibly strong and durable, they may need to be cut to fit a particular project or to accommodate certain specifications. Cutting a steel beam can be challenging, but with the right tools and techniques, it can be done safely and effectively.

One tool that is commonly used to cut steel beams is an angle grinder. An angle grinder is a handheld power tool that uses a rotating abrasive disc to cut, grind, and polish various materials, including metal. In this article, we’ll provide you with a step-by-step guide on how to cut a steel beam with an angle grinder, as well as tips on how to stay safe while doing so.

Steps for Cutting Steel Beams with an Angle Grinder

Step 1: Choose the Right Angle Grinder

Before you begin, it’s essential to choose the right angle grinder for the job. Angle grinders come in various sizes, from small hand-held units to larger bench-mounted models. For cutting steel beams, you’ll need a larger angle grinder with a cut off wheel that’s at least 4-1/2 inches in diameter. Make sure to choose a high-quality angle grinder that’s powerful enough to handle the job and has a good grip to prevent slippage.

Step 2: Choose the Correct cut off wheel

Choosing the correct cut off wheel size is essential to the success of the cutting process. The cut off wheel should be appropriate for the thickness of the steel beam and the size of the angle grinder. Using the wrong size cut off wheel can be dangerous and can damage the angle grinder.

To determine the correct size cut off wheel, you should consult the manufacturer’s instructions for both the angle grinder and the cut off wheel. The cut off wheel size is typically expressed in inches and is based on its diameter. For example, a 4.5-inch cut off wheel is suitable for an angle grinder with a 4.5-inch diameter.

Step 3: Prepare the Steel Beam

Before cutting the steel beam, you’ll need to prepare it. First, remove any debris or dirt from the surface of the beam using a wire brush. Then, use a measuring tape to mark the cut line on the beam. Make sure to use a straight edge to create a clean and accurate cut line.

Step 4: Put on Safety Gear

It’s essential to wear the right safety gear when cutting steel beams with an angle grinder. This includes safety glasses, a face shield, gloves, and a dust mask. The dust mask will protect your lungs from inhaling any metal particles that may be released during the cutting process.

Step 5: Attach the cut off wheel to the Angle Grinder

To attach the cut off wheel to the angle grinder, first, make sure the grinder is unplugged. Then, remove the existing disc by holding the locking button on the side of the grinder and turning the disc counterclockwise. Once the disc is removed, replace it with the cut off wheel by aligning the holes in the wheel with the flange on the grinder. Then, tighten the flange nut securely with a wrench.

Step 6: Make the Cut

To make the cut, hold the angle grinder firmly with both hands and slowly lower the cut off wheel onto the steel beam. Apply light pressure and move the grinder back and forth along the cut line. Be patient and don’t try to force the cut. Let the cut off wheel do the work, and keep your hands steady to ensure a straight cut.

Step 7: Finish the Cut

Once you’ve made the cut, turn off the angle grinder and let the cut off wheel come to a complete stop before setting it down. Use a metal file or a 60 grit sandpaper to smooth out any rough edges or burrs left by the cut off wheel.

Tips for Cutting Steel Beams with an Angle Grinder

Here are some additional tips to help you achieve a clean and safe cut when cutting steel beams with an angle grinder:

  • Use a new cut off wheel:Always use a new cut off wheel when cutting steel beams. Old or worn cut off wheels can be dangerous and are more likely to break or shatter.
  • Keep the grinder stable:When cutting, make sure to keep the angle grinder stable and firmly in place. This will help prevent the grinder from slipping and causing an accident.
  • Don’t rush the cut:Cutting steel beams takes time and patience. Don’t rush the cut, and let the cut off wheel do the work. Applying too much pressure or moving too quickly can cause the cut off wheel to break or shatter.
  • Use the right speed:Different cut off wheels require different speeds. Make sure to check the manufacturer’s instructions for the cut off wheel you’re using and adjust the speed of the angle grinder accordingly.

  • Stay clear of sparks and debris: Cutting steelbeams with an angle grinder produces sparks and debris that can be dangerous. Make sure to keep other people and flammable materials away from the work area.
  • Check the cut line frequently:As you’re cutting, check the cut line frequently to ensure that you’re staying on track. This will help you avoid any mistakes that could compromise the structural integrity of the beam.
  • Use clamps:If possible, use clamps to secure the steel beam to a work surface. This will help prevent the beam from moving during the cutting process and will make the cut more precise.
  • Use a guide:If you’re having trouble staying on track with the cut, consider using a guide. You can make a simple guide by clamping a straight edge to the beam along the cut line.


Cutting steel beams with an angle grinder can be a challenging task, but with the right equipment and technique on how to cut steel beams with an angle grinder, it can be done safely and efficiently. Remember to choose the right angle grinder, prepare the steel beam, wear the right safety gear, and take your time to achieve a clean and accurate cut. By following these tips, you’ll be able to cut steel beams with confidence and precision, making your construction or DIY projects a success.

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