Knowledge Base

How to Sharpen Lawn Mower Blades

By December 21, 2016 No Comments

Have you ever needed or wanted to sharpen your lawn mower blades? This is something more than a few homeowners have wondered. You’ll be happy to know sharpening lawn mower blades is something just about anyone can accomplish. Even if it’s something you’ve never done before, and no expensive or fancy tools are required.

Why is blade sharpening needed?

Cutting your lawn with dull mower blades can have an adverse effect on the health and look of your lawn. This is because dull blades don’t cut the grass they chop it, which leaves a rough edge cut instead of the conventional smoothly cut blades of grass. This type of cut is one that leaves a lawn vulnerable to disease.

How often should blades be sharpened?

The answer depends on how much usage your mower gets, but the generally accepted practice is to sharpen the blades up to three times per cutting season. At the very least you should sharpen your blades before the first cut of the spring, and if you run you lawn mower over a large rock.

How to Remove the Blades from a Push Mower

When you remove lawn mower blades keep in mind at all times that safety is the single most important thing.

Before you do anything, you must be certain there is no way for the mower to be started accidentally while you’re in the middle of removing the blades. The best way to ensure it can’t start is to disconnect the spark plug wire.

Since you’ll have to turn the mower on its side to get to the blade, you need to either use all the gas in the tank or drain it. The easiest way to expose the mower blade is to tilt it front to back, so the underneath is exposed. This method also aids in avoiding fluid leaks.

You’ll want to restrain the blade, so it doesn’t move as you’re removing it. This can be accomplished by using a wooden 2” x 4” block. Once you secured the blade, you’ll be able to use a socket wrench to remove the nuts that secure the blades to the lawn mower. To avoid stripping the nuts be sure to select the correct socket wrench size.

How to Remove the Blades from a Riding Mower

If it’s at all possible for you to do, the best way to access the blades on a riding mower for removal is to raise it off the ground. Ideally, you want to raise it high enough from the ground to reach its underneath to safely remove the blades. Of course, you want to make sure the mower is off before attempting the blade removal.

To raise the mower up off the ground you can either use a lift or a few blocks of wood. For the sake of safety don’t forget to block the wheels so they unable to move out of position while you’re working on it.

Blade Sharpening

After the blades have been removed from you lawn mower it’s time to use your tools to sharpen the blade. Before you start sharpening, protect your eyes from the flying specks of metal by wearing glasses or safety goggles.

To secure the blade, you can use a pair of vice grip pliers. Then while doing so run your metal file over it in short forward motions at an angle. Repeat this for both edges.

If you have access to a drill that has a sharpening stone, this would be ideal to use for sharpening your blade. Alternatively, you could also use a bench or hand-held grinder if you have either of these tools available.

Checking the Blade for Balance

Part of what happens when you sharpen blades is you are removing some of the metal from it. As this is the case, it’s important that the blades are sharpened equally, so they remain balanced. Unbalanced blades can do severe damage to your lawn mower.

In order to check whether or not your blades are in proper balance, you can purchase a tool called a balance. You use the balance by placing the center of the mower blade over the balance and watch to see if either of the blades edges drops down. If one side or the other does drop down, the side that does should be sharpened more.

Another simple but effective way to balance the blade if you don’t have access to a balancing tool is to center the blade on a nail in the wall. Just like before if one side or the other shows that it’s heavier than the other by dropping that side and should be sharpened more until it’s balanced.

After the blades have been sharpened and balanced, they’re then ready to be reinstalled, and you’re ready for the upcoming cutting season.

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