Sharpen Blade with Angle Grinder

Did you know that you can actually sharpen your blade with an angle grinder? Yes, it’s not just for cutting and grinding metals, tiles, and stone! You can use it for sharpening a wide range of blades like shovels, knives, and lawn mower blades.


In the following sections, we will discuss sharpening a lawn mower blade. You want it to be as sharp as possible for effective and efficient lawn maintenance. Your safety is also at stake here since a dull lawn mower blade is also a hazard.

Sharpening the Blade Starts with Safety

Keep in mind that you’re dealing with two power tools, both of which have extra-sharp edges. The angle grinder’s disc and lawnmower’s blade can cut through skin, muscles and bones. You want to avoid direct contact with these power tools while in full operation.

These safety precautions must be adopted before putting the spinning disc on the blade.

  • Wear the right personal protective equipment (PPE). You should put on your safety goggles, ear muffs, and gloves. Your clothes should fit comfortably while allowing for free movement. Your shoes should be sturdy, too, preferably steel-toed boots.
  • Clear the work area of solid and liquid safety hazards. Sharpen the blade in an outdoor setting, if possible, for better movement.
  • Gather the necessary things for the job within easy reach.

These safety precautions must be adopted before putting the spinning disc on the blade:

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    Plastic wrap
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    Penetrating lubricant
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    Socket wrench
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    Angle grinder with the right disc
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    Scrap wood
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    Table vise
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    Wire brush
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You should also remember the safety measures and steps in the blade sharpening process. You cannot be complacent in the face of such sharp instruments.

Sharpening Step-by-step Guide

When you have everything ready for the job, your next steps are as follows:


Remove the blade. While designs among lawnmowers vary, the following steps apply to most of them.

  • Pull the spark plug wire to prevent accidental starting of the lawnmower.
  • Remove the gas cap. Place a piece of plastic over the gas opening. Return the gas cap. This setup will prevent gas leaks when the lawnmower’s placed on its side.
  • Flip the lawnmower on its side. The carburetor should be facing up for fast and easy access to the spinning blade.

If you have a riding lawnmower, you can ride it up a set of ramps. Once it’s up, you can get the blades before chocking the rear wheels and setting the brake.


  • Spray the area with a good dose of penetrating lubricant. Wait for a few minutes to let it seep through the nut.
  • Remove the nut using a socket wrench.
  • Slide off the blade from its frame.

The blade may spin while the nut’s being removed. You can use C-clamps to clamp a piece of wood underneath the lawnmower. This should stop the blade from spinning.


Hold the blade in place. You can place it on a table vise for this purpose. The more secure the blade is in its position, the safer and faster you can work.

You can only sharpen one end of the blade at a time. This is because the blade has two cutting edges on its opposite sides. You shouldn’t overreach with an angle grinder in your hands, thus, the one-at-a-time approach.


Clean the blade of its build-up of dirt, debris and grass. You can use a stiff wire brush or coarse sandpaper. You must wear gloves to reduce the risks of injuries.


Be sure to conduct a thorough visual inspection of the angle grinder before using it. When you’re satisfied with its good condition, you can fit the grinding stone disk.

  • Hold the disc perpendicular to the blade’s thin edge.
  • Run the disc in a side-to-side motion along the edge to smoothen the nicks. Check on a regular basis for more nicks.
  • Line up the disc and blade at an angle, usually 5 to 10 degrees from the horizontal. This will prevent the excess removal of metal.
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    Run the disc in a side-to-side motion along the blade’s beveled edge. Keep the disc moving constantly for even sharpening across all sides. Keep filing the edge until the edge is as sharp as can be.


Remove the blade from its secure holding place. Flip it over and secure it again. Repeat the above mentioned steps on the other side.


Remove the blade from the table vise. Hang it on a nail tacked on the wall; use the hole for the nut. Balance it on the nail to determine a thicker end. You can file the thicker end to reduce the weight and get a balanced blade.

You may continue these steps until the blade has a fairly balanced appearance on the nail. You should check the blade’s balance for safety and efficacy. An unbalanced blade will cut in uneven strokes and shake when in use.


The finishing steps are:

  • Spray or rub penetrating lubricating on the sharpened edges.
  • Reinstall the blade and replace the nut.
  • Remove the wood and clamp. Spin the blade to check its proper condition.
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    Remove the plastic from the gas cap and replace the latter.
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    Reattach the spark plug wire.
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    Return the lawnmower to its upright position.

Of course, you can test the lawnmower on your lawn as soon as the parts are in!

Final Words

Sharpening a lawnmower blade with an angle grinder is a rewarding task. You will not only know a few things about angle grinders but your lawnmower’s blade is sharper, too.

Your lawn will look better for it, as well. Just be sure to adopt the right safety measures and sharpening techniques. The spinning disc and lawnmower blade aren’t toys to play with.

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