How to Sharpen a Lawnmower Blade

1-2 hours

Keep your lawn looking flawless with a sharp lawn mower blade

Lawnmower Blade

A sharp mower blade is critical to a good-looking lawn. Mowing with a dull blade can create a ragged cut that quickly turns brown. Clean cuts with a sharp mower will promote good lawn health by preventing disease from getting a foothold in a sloppy, uneven cut. This guide will teach you how to sharpen your mower blade, a simple task that should be done every 1-2 months.


Remove the spark plug wire
Remove the spark plug wire - Sharpen Lawnmower Blade

This must be done to ensure that the mower does not accidentally start while you’re working on it.

Remove the blade
Remove the blade - Sharpen Lawnmower Blade

Using a wrench, remove the screw that secures the blade to the mower deck. You may want to wedge a piece of lumber between the blade and the deck to keep the blade from turning.

Sharpen the blade
Sharpen the blade - Sharpen Lawnmower Blade

Sharpen the edge of the blade using a file or grindstone, keeping the blade at roughly a 45-degree angle. Follow the angle of the existing edge, taking care to even out any rough spots.

Check the balance
Check the balance - Sharpen Lawnmower Blade

Mowers run smoother when the blade is balanced. Check the balance by supporting the blade under its center with a rod or other narrow horizontal support and then spin it to check its balance.

Reinstall the blade
Reinstall the blade - Sharpen Lawnmower Blade

Lastly, replace the blade, taking care to knock out any chunks of mud or grass that may have accumulated under the mower.