For clean cuts, your lawnmower should have sharp blades. If the blade has minimal wear and tear, you can sharpen it. But when the blade is too rough or damaged, sharpening isn't enough. You need to replace it.
What confuses many lawn owners is when and how often to change lawn mower blades. And this is what we will be answering in this article.
We will explain the signs you need to consider and how to know the right time for replacement so that your lawn does not suffer. It will help you replace the blade before it's too late.
Signs to Look for to Change Your Lawn Mower Blades
Here are some signs that indicate your lawn mower might need a blade replacement.
Uneven Grass Cuts
When your lawnmower blade isn't sharp enough, you witness uneven grass cuts. Instead of cutting, the blade tears the grass tips, which exposes it to diseases and makes your lawn look horrible.
But uneven cuts do not always mean blade replacement. You can even solve the issue by sharpening the blade. Learn how to sharpen lawn mower blades.
But if the blade is in a very bad shape, it is better to replace it instead of sharpening. And if you have already sharpened it multiple times, think about replacement.
Severe Damage
If you see severe damage on the blades, it means you need to replace the blades. Sharpening can only work if there are minor nicks on the blade. An angle grinder can make the edge sharp and smooth.
But if there are deep and large gouges, you cannot get rid of them through sharpening. Even if you do, these gouges will still be there.
It's better not to waste time if there is severe damage. Replace the mower blade and get your lawn in shape.
Bent Blade
A lawnmower blade could bend due to hitting a hard object like a stone or tree root. It could bend from any side. If that's the case, the mower won't be able to cut properly.
You can try to straighten the bent blade, but it's better to buy a new one. It will last longer and work better.
Thinning of the Blade
When you sharpen the blades again and again, the metal starts to become thinner every time. Thus, after several sharpening attempts, the blade becomes too thin to perform like the original one. It loses its weight, which is necessary for clean cuts. You will not get the same performance as before.
If the blade has become thin, you should replace it. But if you have no idea whether the blade is thin or not, keep an eye on the mower's performance. If it's not offering clean and quick cuts even after sharpening, it means the blade is too thin.
Mower Vibration
If you feel any unusual vibration while mowing your lawn, it could be because of an unbalanced blade. This unbalancing could be due to bending of the blade, unbalancing, or any other issue.
If there is any issue with the blade, it means it's time to replace it. Often, lawnmower blades lose their shape and balance over time. Blade replacement is the best option.
How Often to Change Blades in Gas/Electric Mowers?
Gas/Electric mowers have reusable blades. You can sharpen them and reuse them as long as they are not severely damaged.
Typically, you need to sharpen the blade every 20-25 hours of use. Check the mower blade and see if it can be sharpened. If you see any bending or large/deep gouges, it means it's better to replace it.
Moreover, if the mower blade is very rusty, it will be a bit difficult to grind and sharpen it to bring it back to its original condition. Thus, in this case, you must get a new mower blade.
Generally, you need to replace your mower blade every 100-200 hours. For residential use, it could be more than a year or two. But if you use the mower commercially, you might need to replace the blade 2-4 times per year.
Check the blade every 20 hours of use. Other than that, you can examine if you accidentally hit a hard item, at the start of the season, and before winterizing your lawnmower.
How Often to Change Blades in Robotic Mowers?
Robotic lawn mowers use disposable blades. You cannot sharpen them as they are too thin. Every time you see a drop in performance, you can easily replace it.
Typically, you need to replace the blades 2-3 times every cutting season. They need replacement after 100-150 hours of use, depending on quality. Thus, you don't need to worry about sharpening every now and then.
Usually, manufacturers recommend a specific time after which you should replace the blades.
Check after the recommended time. If there is any drop in the cutting performance and it has hit something hard, examine the blade. If you see any visible damage on the blade, it means you must replace it.
How to Change Lawnmower Blades?
We have discussed when and how to change lawn mower blades. Now, let's see how to replace it on your own.
Gas/Electric Mowers
For removing the blade and safety, you need a socket wrench, heavy-duty gloves, and safety goggles.
Step 1: Disconnect the spark plug in Gas lawnmowers. Remove the connector to avoid any accidental start. Moreover, empty the fuel tank. In electric/battery-powered mowers, disconnect the plug or remove the battery.
Step 2: Tilt the mower to access the blade. While tilting, make sure the carburetor and air filter side is facing upwards.
Step 3: The lawnmower blade is secured using a nut, which is usually at the center of the blade. Carefully, hold the blade with one hand. Use a socket wrench and rotate anti-clockwise to loosen the nut. If you can't hold the mower blade with your hand, block it with a piece of wood.
Step 4: Take out the nut. Now, you can pull the lawnmower blade. Clean the deck before replacement. Now, place the new blade in its location and tighten the nut.
Robotic Lawn Mowers
Replacing blades in robotic lawn mowers is much easier.
Step 1: Turn off the mower and place it upside down on a clean surface.
Step 2: You will see multiple blades. Each blade is secured with a screw. Use a screwdriver to loosen the screw and take out the blade.
Step 3: Place the new blade in the same location and insert the screw. Tighten it using a screwdriver.
Final Words
You don't need to replace lawn mower blades every now and then. If you have a gas/electric mower, examine the blade every 20 hours of use. If it can't be sharpened, replace it. In robotic mowers, you need to replace the blade every 100-150 hours or according to the manufacturer's guidelines. Also, keep an eye on the signs to know when it's time to replace the mower blades.
FAQs
How do I know if my lawn mower needs new blades?
If your lawnmower is offering uneven cuts and the blade has deep gouges or bends, you should replace it. Examine the blade after 20 hours of use, and decide whether you should sharpen or replace it, depending on the condition. In robotic mowers, replace the blade when you use torn grass tips or according to the manufacturer.
How do I know if my lawn mower blade is dull?
If the mower is offering clean cuts and tearing the grass blades, it means the blade is dull. Instead of clean cutting, it damages grass tips, and you see uneven cuts.
Is it better to sharpen a lawn mower blade or replace it?
In gas/electric lawn mowers, you can sharpen the blade until you see deep gouges, cracks, bends, and severe conditions. When the blade is in very bad condition, you should replace it instead of sharpening it.
Is it worth replacing a lawn mower blade?
Yes, it's worth replacing a lawn mower blade. It is necessary if you want clean cuts in your lawn and want your mower to work well. It suffers from wear and tear over time, so it's better to replace it when it can't be sharpened.
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