How to Use an Angle Grinder For Metal Cutting

An angle grinder is the most powerful and versatile tool for your workshop. While it's used for sanding, polishing, and grinding, it excels at cutting tough materials like tile, concrete, and—most commonly—metal. When a hacksaw or other hand tools just won't cut it, an angle grinder paired with the right disc makes quick work of metal stock.

Here is a step-by-step guide on how to safely and effectively cut metal using an angle grinder.

Step 1. Preparation: Gather Your Tools and Safety Gear

Safety is essential when using an angle grinder, as it generates high speeds and sparks. Make sure you have all the safety gear you'll need on hand before you start cutting.

Step 2. Set Up the Angle Grinder

Attaching the correct accessory is critical.

1. Mount the Disc: Make sure the battery is removed or the angle grinder is not turned on. Place the thin metal cut-off wheel onto the spindle, making sure the label faces the grinder.
2. Secure the Disc: Hand-tighten the spindle nut (flange nut) onto the spindle. Then, use the spanner wrench (usually included with the grinder) to firmly tighten the nut. It must be secure, but avoid overtightening.
3. Adjust the Guard: Position the grinder guard so that it protects your body from the spark stream and debris. Never operate the grinder without the guard.

Step 3. Secure the Metal and Mark Your Cut

The metal you are cutting must be completely stationary and stable.

1. Mark the Line: Draw a clear, accurate line where you need to cut using a color marker and a ruler.
2. Clamp Securely: Use a vise or heavy-duty C-clamps to lock the metal piece onto a workbench or solid surface. Ensure the section you are cutting off hangs slightly over the edge so the disc can pass through completely without hitting the workbench.

Step 4. Execute the Cut

With the setup complete, it's time to cut.

1. Grip the Grinder: Hold the angle grinder firmly with both hands—one hand on the body or rear handle, and the other on the side handle for stability and control.
2. Start the Cut: Before touching the metal, turn on the grinder and let it run at maximum speed.
3. Use Light Pressure: Slowly and gently bring the spinning cut-off disc into contact with your marked line. Do not force the tool. The weight of the grinder and the speed of the disc should do the work. Excessive pressure causes overheating, premature disc wear, and can increase the risk of kickback.
4. Maintain Consistency: Keep the disc moving steadily along the marked line. It's best to start any cut completely over. Stopping halfway and attempting to restart on the same kerf can lead to a sloppy cut and increase the risk of binding.
5. Finish the Edge: After cutting the piece, before putting the grinder down, make sure the disc stops spinning and turn it off. Check the cut edge for any sharp edges or roughness. If necessary, you can use a grinding wheel or flap disc to smooth these out.

Safety Note: If the grinder kicks back (jumps suddenly), immediately release the trigger and maintain a firm grip. Kickback usually happens when the disc binds or twists in the cut. Always cut slowly and keep the disc perpendicular to the metal.

Read More: Types of Grinding Wheels