How to Sharpen Lawn Mower Blades

Man removing lawn mower blade

Maintaining sharp lawn mower blades is a key part of keeping your lawn healthy. Dull lawn mower blades can tear at grass, leaving it ragged and vulnerable to disease and other harmful elements. A sharp blade will make a nice, straight cut through your grass and keep it looking great. We’ll show you how to sharpen your lawn mower blades to get the best cut possible. 

Skill Level: Beginner
Time:
  1. Step 1 Know How Often You Should Sharpen your Lawn Mower Blades

    hghgh

    Generally, you should sharpen your lawn mower blades before your first cut of the year, and once more throughout the growing season to keep them performing at their peak. If you hit a rock or some other hard surface while mowing, you’ll need to sharpen your blade immediately to remove any burrs or dents in the blade, which can cause inconsistent cutting and harm your lawn.    

  2. Step 2 Remove the Spark Plug and Power Source

    Person removing spark plug

    To avoid any harm while removing your blade, first, remove the spark plug and any other power source connected to the mower. This ensures that no power is getting to the machine and allows you to disassemble the blade from the machine safely.    

  3. Step 3 Remove the Lawn Mower Blade

    Man removing lawn mower blade

    Using a socket wrench, make sure you have the exact sized bit and remove the bolts from the blade face. Now you should be able to remove the blade. Having the right size bit is crucial because, with the amount of force you’re putting on the bolt to unscrew it, you can easily strip them if you’re not careful.    

  4. Step 4 Clean the Lawn Mower Blade

    Man cleaning blade of lawn mower

    Clean off all old grass and debris from the blade before sharpening. Steel wool works great here.

  5. Step 5 Sharpen the Lawn Mower Blade

    hghgh

    You can use multiple tools as a lawn mower blade sharpener. A file can be used with downward strokes to get a nice, sharp edge. There are attachments for your drill or rotary tool that can be used as well. A bench or angle grinder can also make short work of the sharpening process. When finished, you should have two sharp edges ready for mowing.

  6. Step 6 Check the Balance of the Blade

    Man making sure blade is balanced

    After you’ve sharpened your blade, be sure to check that it is balanced on both sides. Remember, when you’re sharpening, you’re removing metal from the blade and it can put the balance of the blade out of whack. Put a nail in a wall and hang the blade horizontally. If the blade rotates one way, take some extra metal off that side. When the blade sits parallel to the floor, it’s perfectly balanced and ready to be put back on the mower.    

  7. Step 7 Reinstall the Lawn Mower Blade

    Man reinstalling blade onto lawn mower

    Attach the blade back on the mower and tighten the bolts you previously removed. Once the blade is secure, you’re good to reattach the spark plug and any other power sources and start mowing.

  8. Step 8 Maintaining your Lawn Mower Blade

    Person wiping lawn mower with a cloth

    Be sure to sharpen your blade once or twice throughout the growing season. This is especially true if you hit a rock or hard surface, after which you’ll want to sharpen your blade immediately to remove burrs and dents from the blade that can rip or tear your grass.    

What You Need for This Project

Related Resources