Sumo Gardener

How to Sharpen Lawn Mower Blades

Are you wondering on how to sharpen lawn mower blades?

Did you know that a well-sharpened blade is necessary for you to be able to take care of your mowing needs?

Get to know how to sharpen lawn mower blades by reading the information below.


How to Sharpen Lawn Mower Blades?

Continuous usage of your lawn mower without taking care of the blade can make your lawn mower’s blade dull.

This can cause problems, including grass tearing instead of cutting the grass smoothly. Your lawn will also look ragged and make them susceptible to certain diseases. 

If you are one of the many who is unsure how to sharpen the blades, then you’re in luck because the tips below will help you how to sharpen lawn mower blades safely and quickly.

Tips on How to Sharpen Lawn Mower Blades

Preparing the Lawn Mower Blades

Tips on How to Sharpen Lawn Mower Blades

The first thing that you need to do is to disconnect the plug and as well as the power source of your lawn mower as this can cause problems while you are working on it.

You can easily disconnect the plug by removing the wire that is prominent on the front or side of the engine’s lawn mower.

Even after you have disconnected everything, you still need to wear eye protection and gloves to stay protected.

Accessing the Blade of Your Lawn Mower

How to access blade of your lawn mower?

For you to be able to access the blade, turning the lawn mower to its side is ideal. Avoid haphazardly turning the mower as the oil of the engine can spill to the air filter and carburetor.

The air filter and the carburetor by most of the mowers today are located in a boxy case that is made out of plastic and is on the side. You can check the manual if you are unsure about its location.

You may also opt to pour the mower's oil in a separate container to ensure that there will be no spillage no matter how you turn it.

Marking the Blade's Side that is Facing Downward

You need to mark the blade’s side that is facing downward for you to know how to reinstall it after sharpening the blade.

You can use a spray paint or a pen to mark the blade. You may also use some tape if you don’t want any stains in your blade.

Blocking and Loosening the Bolt

Now once you see the blade, you need to loosen the bolt that secures the blade. For you to easily do this, you can block the blade using wood for it to avoid moving.

In this way, you can easily remove the blade using a ratchet or a wrench. There are lawn mowers that have a threaded nut that is reverse which will help in holding the blade to the spindle.

Once you have to remove the bolt, you need to remember all the orientation and placement of the plates and washers that will come with the blade.

Cleaning the Blade of Your Lawn Mower

How to Clean the Blade of Your Lawn Mower?


Now that you have removed the blade take some time to clean it. You need to remove grime, grass clippings, rust or anything that is making the blade look dirty.

You can use a glove for your hands and a dry clean rag. But if you haven’t cleaned the blade for quite a long time, then it would be best to use soapy water and sponge to help remove any grime and materials that have accumulated.

Once done, make sure to wipe dry your blade.

Sharpening with the Use of a Bench Grinder

You can start sharpening the blade on the grinder by moving it back and forth. You need to carefully maintain the blade’s angle while you are sharpening it.

You may also opt to use a hand grinder that is equipped with a metal wheel to sharpen the blade.

Sharpening with the Use of a Belt Sander

You can also sharpen the blade of your lawn mower by using a belt sander. Start rubbing the blade at the right angle against a sandpaper that is abrasive as this will sharpen the blade gradually.

Once done, you can start inverting the blade of that the belt sander is facing up, while the lock’s switch will be turned on.

Sharpening with the Use of a File

Using a metal file, start running it along the blade’s cutting edge. You need to start stroking for the blade’s inside edge to the outside until it is shiny and clean.

Once done, you can flip the mower’s blade over and do the process again.

Sharpening with the Use of a File


When using a file, it would be best to use a face mask since there will always be dust that will be produced.

The mask will help protect your lungs against metal particles and airborne dust.

These are the tips on how you can sharpen your lawn mower’s blade. But it would be best to know some advice on how you can maintain it long term

Below are some long time maintenance tips that will help your lawn mower to work properly.

Maintenance Tips For Your Lawn Mower

Re-sharpening Twice Per Mowing Season

Every mowing season, it would be best to re-sharpen your blade twice since this is the time where you are frequently using it.

After mowing, always check the grass since it will help you know if your blade needs some sharpening. If your grass has smooth and clean edges, then this means that your blade is sharp.

Now if the grass is torn or frayed, then this is a sign that you need to sharpen the blade since it has already become dull.

Regularly Balancing the Blade

Regularly Balancing the Blade

You also need to ensure that your blade is well balanced because if not, it will only make the mower vibrate, which will then damage the mower’s internal parts.

To do this, you can use a balancer, which you can purchase at hardware stores or gardening centers.

For people who don’t have a balancer or ones who does not want to purchase, then using a wooden dowel will do.

If you notice that the blade is tilting high, you can start filing the opposite side. You can continue filing it until the mower’s blade has already lie flat.

Replacing Blades with Cracks or Deep Dents

If you notice some cracks or deep dents on the blade of your mower, it would be best to replace it before using the mower again.

These kinds of problems won’t be fixed by sharpening them.

There are blades available in hardware stores and replacing them immediately would be best. In this way, you can continue working on your lawn with ease.

Hiring a Professional Mechanic 

lawn mower blade sharpener

Now, if you are having problems with sharpening or having difficulties with the process of balancing the blade, then seeing a mechanic will do.

This will ensure that you won’t commit any mistakes that will put your safety at risk and won’t damage your blade.

Of course, there will always be a price to be for this, but it is more expensive to purchase a new lawn mower if you get your lawn mower damaged.

Wrapping Up How to Sharpen Lawn Mower Blades

Now that you know how to how to sharpen lawn mower blades, all you need to do now is to execute it and to follow the tips above to ensure that you are doing the right thing.

About the Author Ann Katelyn

I'm Ann Katelyn, Creator and Chief Author of Sumo Gardener. Since I was a child I've always been fascinated with plants and gardens, and as an adult this has developed into my most loved hobby. I have dedicated most of my life to gardening and started Sumo Gardener as a way to express my knowledge about gardening with the hope of helping other people's gardens thrive.

follow me on:

Leave a Comment:

1 comment
Charles Chapman says November 30, 2020

As the job will require the mower to be turned over to remove the blade, for safety reasons it would be worthwhile to drain the gas depending on the model. It is possible to tilt some models without leakage, although others can’t. In any case, at least remove the spark plug for the duration of the task. This is predominantly necessary for those models that have an auto-starter attached.

Add Your Reply