How to sharpen lawn mower blades with grinder? (Step-By-Step Guide)

Sharpening mower blades is a great way to keep your lawnmower working at its best. By sharpening the blades, you’re ensuring a better cut and a longer-lasting edge. To properly sharpen your mower blades, you’ll need an angle grinder. But how to sharpen lawn mower blades with grinder ?

Sharpening your mower blades with an angle grinder is a fast and easy way to maintain them optimally. Here is a step-by-step guide to help you do the job safely and effectively. We also include safety tips to help you stay safe using your angle grinder.

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How To Sharpen Mower Blades With An Angle Grinder?

Let’s get started with the steps needed to sharpen mower blades with grinder.

What you’ll need before beginning:

  • Angle grinder
  • The correct grinding wheel for the job
  • Appropriate protective gear
  • Work gloves
  • Safety goggles or face shield

Step 1: Removing the blades from the mower

Now that we have all the necessary items let’s begin by removing the blades from the mower.

Preparing your workspace 

Before beginning, you’ll need to ensure your workspace is clear and safe. Move any flammable objects away from the area. You should also ensure the area is well-ventilated and free of dust or debris. This will help ensure a safe and successful sharpening process.

sharpen lawn mower blades with grinder

Detaching the blades from the mower 

Once the workspace is prepared, you can begin by detaching the blades from the mower. Depending on your model of the lawnmower, this process can be a little different. But generally, you’ll need to remove the bolts or screws that secure the blades to the deck of your mower. Make sure you have a container ready to store these screws as you go and use gloves when handling them.

sharpen lawn mower blades with grinder

Removing any debris or dirt buildup on blades and mower 

Once you’ve removed the blades from the mower, clean them carefully. Use a brush or cloth and soapy water to remove dirt or debris buildup. Be sure also to clean the mower deck where the blades were attached. This will help ensure that your sharpening process is safe and effective. You may need to use a wire brush for any more stubborn buildup.

sharpen lawn mower blades with grinder

Inspecting the blades for any damages 

Once the blades are cleaned, inspect them carefully for any signs of damage. Look for dents, scratches, or cracks in the blades that could be a sign of wear and tear. If you find any damages, replacing the blades rather than sharpening them may be best.

sharpen lawn mower blades with grinder

Step 2: Setting up the angle grinder

Now that the blades are removed, you can set up your angle grinder for use.

Preparing the grinder 

Gather all necessary items, such as the grinding wheel, work gloves, and safety goggles or face shields. Ensure the grinder is securely fastened into a bench vice so it won’t move while in use. You may also want to attach the guard of the angle grinder to ensure your safety while sharpening. This will help to minimize any potential risks.

Determining the correct grinding wheel 

The grinding wheel for the job will depend on what metal the blades are made of. Most mower blades are made of either carbon steel or high-speed steel. Make sure you choose the correct grinding wheel for your type of blade to ensure the best results. 

For instance, carbon steel blades should be sharpened with an aluminum oxide grinding wheel. At the same time, high-speed steel blades should be sharpened with a silicon carbide wheel.

Installing the grinding wheel on the angle grinder 

Once you’ve determined the correct wheel for your mower blades, it’s time to install it onto the angle grinder. Ensure the wheel is correctly aligned before you switch on and use the machine. Be sure to follow all safety instructions that come with your angle grinder. This will help ensure that you stay safe while using the machine.

Step 3: Grinding the blades

Let’s now move on to grinding the blades of your mower.

Adjusting the grinder to the correct speed 

To begin, you’ll need to adjust the grinder for sharpening lawn mower blades. Most grinders have adjustable speeds, so you can ensure the blades are sharpened at the right speed. You don’t want to go too fast, as this could cause your blades to become damaged or warped. This can compromise the sharpness of the blade.

Applying the grinder to the edges of each blade 

Now you’re ready to begin grinding your mower blades. Start by positioning the blade so that the angle grinder can contact it. Move the grinder slowly and steadily along the edges of the mower blades. Keep your gloves on and follow all safety instructions while doing this.

Achieving the desired angle and sharpness on each blade 

Once you’re done grinding, test the blade and ensure it is at the desired sharpness. You can do this by running your finger along the edge of the blade. If it isn’t as sharp or angled as you would like, repeat the process until you achieve the desired results.

Checking for consistency across all blades 

After each blade is sharpened, check for consistency across all the blades. Make sure that each blade has the same angle and sharpness as the others. You can use a ruler or measuring tape to help you do this quickly and accurately. This will ensure that your mower runs smoothly and efficiently when it’s time to use it again.

Step 4: Reinstalling the blades

Now that all your blades are sharpened, it’s time to reattach them to the mower.

Ensuring all blades are facing the same direction 

Before you begin, take a moment to inspect your blades and make sure they are all facing in the same direction. This is important as it will help ensure that your mower blades run correctly when you’re finished. Pay special attention to the direction of the cutting edge, as this should be uniform across all the blades.

Reattaching the blades to the mower 

Now that all the blades are facing in the same direction, you can start to reattach them to the mower. Securely fix the blades back onto the mower in their original positions using your screwdriver or wrench. Again, be sure to use gloves and safely store any screws or bolts while doing this.

Testing the mower to make sure it works correctly 

Finally, it’s time to test your mower and make sure that it works correctly. Start by turning on the mower and ensuring all blades are spinning as they should be. Make sure that there is an even balance across all the blades, as this will help ensure that the mower runs smoothly.

Cleaning up your workspace 

Now you’re done sharpening your mower blades! But before you call it a day, clean up your workspace. This includes properly disposing of any metal filings and storing the angle grinder in an appropriate spot. You should also take the time to check all the tools you used and properly clean them.

You’ll have no problem sharpening your mower blades like a pro by following these steps.

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6 Safety Tips for Sharpening Mower Blades with an Angle Grinder

Sharpening mower blades can be a dangerous process if done incorrectly. To help ensure that you stay safe, here are 6 safety tips to follow when using an angle grinder:

Precautions to take when using an angle grinder

Here are some precautions to take when using an angle grinder:

  • Keep children and pets away from your workspace
  • Hold the angle grinder firmly in both hands when in use
  • Move the grinder slowly and steadily around each blade.
  • Check that the guard is securely attached to the grinder before you start.
  • Disconnect the power cord after each use.

The protective gear necessary for the job

You should always wear the appropriate protective gear when sharpening blades with an angle grinder. This includes goggles, gloves, and a face shield to protect your eyes from flying debris. Make sure to put these on before you begin working, as this will help minimize potential risks.

Handling and disposing of metal filings correctly

Once you’re done sharpening your mower blades, you must dispose of any metal filings correctly. This includes disposing of them in the appropriate waste container and cleaning up any leftover filings from your workspace.

Proper disposal and storage of the grinder after use

After each use, make sure that you unplug the angle grinder and store it in a safe place. Make sure that you don’t leave it out in the open, as this can be dangerous. This is especially important if you have children or pets in your home.

Testing the mower blades one last time for safety’s sake

Before you put away your tools and call it a day, make sure that you give the mower blades one last test. This will help ensure that everything is running as it should be so that when you use the mower again, it runs smoothly and efficiently.

Regular maintenance to ensure a long lifespan of mower blades

Finally, make sure that you regularly maintain your mower blades. This includes sharpening them every few months and removing debris or dirt buildup from the blades. Regular maintenance will help keep your blades in top condition and ensure a long lifespan.

Frequently Asked Questions

Can I use an angle grinder to sharpen mower blades?

Yes, you can sharpen lawn mower blade with angle grinder. You’ll need the proper disc for your angle grinder, such as a diamond disc, to do the job correctly. You should always wear eye protection when sharpening blades with an angle grinder for safety.

What angle grinder disc to sharpen mower blades?

The best disc to mower blade sharpen is a diamond disc, which will provide the most precise results. If you’re using an angle grinder, be sure to choose a disc designed for this purpose that fits your machine’s requirements.

What is the best angle to sharpen a lawn mower blade?

To get the best results when sharpening your mower blades, most experts recommend using an angle of 30 degrees. This will ensure optimal sharpness and a clean, even cut.

How do I know if my lawn mower blade is dull?

If your mower blade is dull, you will notice that the grass takes longer to cut and may not be as cleanly cut. You may also notice that the blade leaves visible trails or marks in the grass after it’s been mowed.

Should mower blades be knife sharp?

No, your mower blade should not be as sharp as a knife. While an extremely sharp angle will give you a clean cut, it will also put more stress on the blade and may cause it to wear out faster. The best way to ensure that your blade is sharp enough is to use an angle of 30 degrees when sharpening.


Sharpening a lawn mower blade with an angle grinder is a great way to keep them in peak condition. This guide on how to sharpen lawn mower blades with grinder  has provided the techniques needed to do so safely. 

Always wear safety equipment when using the angle grinder, and follow all the steps precisely. Once you have finished sharpening your mower blades, don’t forget to lubricate them. With a little care and maintenance, your mower blades can remain sharp and effective for years to come.

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