The logo for

One of the biggest challenges in maintaining a pristine lawn is mowing it.

The warmer months mean it’s time to get each blade sharp and ready to shear those grass blades down.

Detaching your lawn mower blade will depend on your model (push mower or ride-on), but the methods for sharpening are similar. You can either clamp the blade in a vise, then file using a mill file, or work using a drill with a sharpening stone attached.

Ready for mowing season? Here’s how to sharpen lawn mower blades – after all, if you invest in a great lawn mower, you’re going to want to take care of it!


Why Sharpen Lawn Mower Blades?

You need to sharpen your mower blades to ensure a clean job when you cut grass.

Dull blades will snag on the grass and rip it out, damaging your lawn. This will also put your lawn at risk of diseases like fungal infestation.

For the cleanest, most efficient cut while mowing, you’ll need to make sure your blades are sharp.

And while you can always have the blades professionally sharpened, you can do a DIY job if you’re up to it!

This is especially true if you use your mower as often as say, a professional lawn mowing service would.


Does Your Lawn Mower Blade Need Sharpening or Changing?

green lawn mower in the summer sun

Here’s a tricky question – do you just need to sharpen, or should you change your lawn mower blade entirely?

To answer that, check your blade at the start of mowing season. If the edge is simply dull and flat, then you only need to sharpen it. It’s the same if you notice uneven patches or tears in the grass.

On the other hand, if there are nicks or cracks in the blade, then you can’t simply sharpen it to fix it. This is the same case if there are bends or warping.

In this situation, you’re better off changing the blade out to a new one.


How Often to Sharpen Mower Blades

Ideally, you should sharpen lawn mower blades once every other month.

But always check the blade to see if it needs sharpening. If you mow very often, it may need filing more frequently.


Things To Know Before You Sharpen Your Lawn Mower Blade

Worker sharpening his blade lawn mower.

Do not aim for the sharpest blade possible – that’ll wear your blade too thin, causing it to perform inefficiently.

You’ll also need to sharpen it more frequently to retain that razor-sharp edge.

Instead, aim for “butter knife sharp” so that your blade holds up longer.

Also, check what tool you’ll use to sharpen the lawnmower blades. There are two main tools you can use:


Which you use depends on your budget and what’s available to you.

Lastly, it’s not possible to sharpen a mower blade without removing it. Not only will you do an inefficient job, you might also hurt yourself in the process.


Sharpening Lawn Mower Blades

Always start by unplugging the spark plug and removing the spark plug wire. This means your mower won’t accidentally turn on and injure you while you’re working.

You should also use appropriate protective equipment, such as goggles and gloves.


Removing the mower blade

lawnmower in backyard grass

For a push mower, you’ll need to tip the mower onto its back or side. This will expose the underside of the mower, allowing you to access the retaining bolt securing the blade to the deck.

For a ride-on mower, lower the mower deck to its lowest setting so you can access the blade.

Use spray paint or a marker to note the correct orientation when reinserting the blade. The last thing you want is to install the blade upside-down – that’ll cause your mower to cut incorrectly.


How to sharpen lawn mower blades using a file

For those who don’t mow as often, or are trying to save money, the simplest tool you can use to get a sharp blade is a file.

1. Clamp the blade and check the angle

Insert the blade into a vise and clamp it to hold it in place. Check for the proper filing angle and move in one direction only, pushing across the top side of the cutting edge.

2. Start filing

Take a 25cm (10in) mill bastard file and start running it along the sharp edge of the blade. Move in one direction and ensure you’re feeling the “cutting” action. Otherwise, your blade might be dull.

3. Test the balance

Use a balancer to check if the blade is properly balanced. An improperly balanced blade will cause damage to your mower in the long run.

4. Reinstall the blade

Reinsert the blade and tighten the main bolt. Ensure there’s no wobbling or looseness before reusing the mower.


How to sharpen lawn mower blades using a drill sharpener

lawn mower blade sharpening

There’s a heightened risk when using a drill sharpener due to the higher heat and speed involved.

However, it’ll get the job done faster with less effort.

1. Clamp the blade and prep the drill

Again, secure the blade with a vise to prevent it from moving.

Attach the sharpening stone attachment to your drill.

2. Insert the cutting edge

Insert the cutting edge between the plastic guide and the stone.

The guide should rest against the rear of the cutting edge.

3. Sharpen the blade

Activate the drill and run the sharpening attachment along the correct side of the blade.

Work until it’s sharpened. Then move to the other side.

It’s essential that you sharpen the same amount on each side so that the blade is balanced.

4. Test the balance

Use a blade balancer or a nail to test the balance of the blade. If one side lifts, file a bit more off the other side to even it out.

5. Reinstall the blade

Reinsert the blade into the deck and tighten the bolt.


Why Check a Mower Blade’s Balance?

Simple – an unbalanced blade will result in a poor cut.

It’ll cause excessive vibrations and wobbling while mowing, which can damage the motor by causing undue stress. You could also cause damage to the mower deck.


Maintain Your Lawn with Sharp Lawn Mower Blades

Nobody wants a patchy lawn with ripped-up grass, so ensure you know how to sharpen lawn mower blades so they’re ready to slice through grass cleanly.

This way, you can maintain a pristine lawn that you’re proud to show off to neighbours, visitors, and even yourself – no reason you can’t pat yourself on the back for your hard work!

About Author

Jamie Donovan

Jamie is an Australian horticulturalist and landscape designer. He enjoys writing about landscape architecture, garden design and lifestyle topics.


About Author

Jamie Donovan

Jamie is an Australian horticulturalist and landscape designer. He enjoys writing about landscape architecture, garden design and lifestyle topics.