Your grass will look tidier and stay healthier after mowing by making sure the business end of your machine has a sharp edge. Follow this easy guide to get the job done.
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When your lawn mower isn't making the cut anymore, usually it's because the blade has lost its sharp edge from use. It can seem a little intimidating to remove the blade and sharpen it yourself if you've never done it before. But it's actually a simple process, and you'll only need two tools to do it. Once you know how to sharpen a lawn mower blade, it'll take you a fraction of the time it takes to actually mow your lawn. To give your grass a crisp, clean cut again, just follow this step-by-step guide. Or if you don't want to worry about sharpening the blade, you can just remove it and bring it to a lawn mower repair service near you to take care of it.

Test Garden Tip: When grass blades have torn, ragged ends that turn brown after a mowing, chances are it's time to give the blade some attention. Most experts recommend sharpening power mower blades once or twice a season, depending on how often you use it.

What You Need

  • Wrench
  • Medium file
removing mower blade
Credit: Peter Krumhardt

Step 1: Remove Blade from Mower

Disconnect the spark plug on a gas mower or unplug an electric mower (to ensure the machine won't accidentally start while you're working on it). Gently lay the mower on its side and use a wrench to remove the nut that attaches the blade to the motor. Then, remove the blade from the mower. To make sure you replace it the right way in the machine, mark the bottom of the blade with spray paint so you know that should face the ground when you're done.

sharpening lawnmower blade
Credit: Chip Nadeau

Step 2: File Blade

Clean any dirt or grass clippings off the blade with a dry cloth. Stabilize the blade in a vise and use a medium file to smooth out imperfections along the blade edge (at the ends of mulching blades). Follow the existing angle of the blade, holding your file or sharpening tool at about a 45 degree angle. Move teh file in one direction, gliding out toward the edge, much like you would sharpen a kitchen knife. However, you're aiming to make the edge about as sharp as a butter knife, rather than your favorite chef knife.

clamp holding mower blade

Step 3: Check for Balance

After you hone the cutting edge on both halves of the blade, check to see if the blade is balanced. And easy way to do this is to pound a long nail into a wall in your garage and rest the center of the blade on the nail. If the blade isn't balanced, file a little more metal from the heavier side until the blade does balance.

attaching mower blade

Step 4: Reassemble Mower

When the blade is correctly balanced, put the mower blade back onto the machine using a wrench. Be sure to tighten the nut securely back into place. And don't forget to reattach the spark plugs.


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