How to Sharpen Lawn Mower Blades

Ready to learn how to sharpen your lawn mower blades? Read on below to find out!

Why do we sharpen lawnmower blades?

Most of us notice the need to sharpen blades when we mow our lawn and our machine starts giving an uneven cut, but you may be interested to know there are other important reasons to keep those blades nice and sharp. Keeping your blades sharp helps to keep your grass healthy, reduces wear on your mower, and ensures an even cut at higher speeds. We’ll explore these reasons below, then explain how to sharpen your blades to get the most out of your mower and keep your grass lush and green!

Grass Health

Mowing the lawn puts the grass under stress. There are no two ways about it. However, there are things we can do to reduce the stress on our turf. Besides following the 1/3 rule for mowing, Maintaining sharp blades is our top priority. When blades are dull they tear the grass instead of making a clean cut. When the grass is torn, it puts far more stress on the grass and you’ll notice white tips where you mowed the next day. These white tips are a good indicator that it’s time to sharpen your blades.

Mower Engine Health

It may not seem like it makes much of a difference but keeping your blades sharp at all times can add hundreds of hours to the life of your engine. Making over 3000 revolutions per minute, all of those tiny cuts add up! Not to mention, you can cut the lawn a lot faster with sharp blades! The balance of your blades can greatly affect wear and tear as well. If you hit debris with your blades or sharpen them improperly, one side of your blade can become heavier than the other. This results in a wobbling effect that can lead to a poor cut and increased stress on the motor. Sharpening gives us a chance to reset the balance of our blades, and ensure they’re sharp enough to cut through grass like hot butter!

Proper Cut

This is what most people notice when it’s time to sharpen their mower blades. Staying on top of those blades gives you an even cut with no stragglers left sticking up. This isn’t the only thing on your machine that determines cut quality but it is one of the biggest factors.

When do I sharpen lawn mower blades?

As a general rule, you want to sharpen after every 8 hours of cutting. For homeowners, this would be about once a month and commercial companies, like Midwest Tur Pros, should sharpen their blades every day. Of course, if you hit rocks, wood, or other debris you should sharpen immediately afterward. If you buy new blades, then go ahead and sharpen them. Despite what anyone may tell you, they do not come sharp from the manufacturer.

How to Sharpen Lawn Mower Blades

Step 1: Raise the mower’s deck. Use the lever or handle on your mower to raise the deck so that the blades are exposed.

Step 2: Secure the mower: Use a floor jack to raise it to a workable position. Make sure to set jack stands under the mower before doing any work underneath the mower. These will help to keep the deck from moving while you work on it. You don’t want to get pinned under a mower.

Step 3: Remove the blades: Use the wrench to remove the bolts that hold the blades in place. Be careful, as the blades can be sharp and heavy.

Step 4: Sharpen the blades: After you’ve removed your blades from the mower, you can use an angle grinder or bench grinder to file them down. If using an angle grinder, you’ll want to secure the blade to a bench vice while you sharpen it. 60-80 grit flap disks work great on an angle grinder for sharpening.

Step 5: Balance the blades: Check the balance of the blades by holding them on a nail or other point. If a blade is not balanced, file or grind the heavy side until it is balanced. Most mower shops sell balancing cones that make this easier.

Step 6: Reinstall the blades: Reinstall the blades and tighten the bolts.

Step 7: Lower the deck: Lower the deck back to its original position.

When sharpening you can follow the factory grade as rule of thumb. However, if you really want to dial in your blade, use a protractor to check that your blade is at a 25 – 30 degree angle. This is the industry standard for a good balance between durability and cutting edge. These small yellow protractors (pictured below) work great for this. You can order one at this link

Protractor to check angle when sharpening lawn mower blades


Sharpening the blades of your lawn mower is an important task that should be done regularly to ensure that your lawn is well-maintained and your mower is running efficiently. A dull mower blade can cause damage to your lawn and make your mower work harder than it needs to, which can lead to costly repairs or even a shortened lifespan for your mower. By following the simple steps outlined in this blog post, you can easily sharpen your lawn mower blades and keep your lawn.

Looking for a lawn care company that sharpens their blades daily? Click here to get a free estimate. Midwest Turf Pros is quality, especially behind the scenes.

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Midwest has been caring for our lawn for the past year, and we couldn’t be happier. When we first called them, our lawn was suffering from patches of dead grass, and weeds galore. Now it is lush, green, and weed free. Highly recommended. Thanks guys!


Karen Singer