how often should lawn mower blades be replaced

How Often Should Lawn Mower Blades Be Replaced?

Your lawn mower is a robust tool that’s designed for heavy duty, outdoor work. However, the parts aren’t going to last forever and there will come a point that they need replacing. Your lawn mower blades are no exception to this but many homeowners wonder how often you should change your lawn mower blade.

As a rule of thumb, you should be replacing lawn mower blades for every 200 hours of use. However, this will only be the case if you take good care of the blades and aim to sharpen them around every 25 hours of use.

There are factors that can affect how soon you will need to replace a lawn mower blade. For example, if the mower collides with a solid object and the blade becomes damaged. In this guide, we will tell you how to spot the signs that your lawn mower blade needs replacing.

How often to replace mower blades will depend on several factors such as how often you use the mower and the conditions it is working in. While it’s generally good practice to replace the lawn mower blade for every 200 hours of use, there are some signs that you can look out for that signal the time has come.

When Sharpening Isn’t Enough

When your lawn mower blade becomes dull, one of the first things that you’ll think to do is to sharpen it. Of course, this is a very wise idea but sometimes you will find that the blade just cannot undergo any more sharpening sessions.

When this happens, it’s time to think about buying a replacement blade. You see, when you sharpen the blade, you are removing material to create a new cutting edge. Over time, the blade will wear and sharpening is no longer enough.

If you have noticed that this is the case or that the condition of the blade is not what it used to be then the following signs can tell you everything you need to know.

Chips or Dents In The Blade

chips or dents blades

All lawn mower blades are going to have small dents, scratches or chips from the first use as they’re exposed to a lot while they are working. These tiny imperfections don’t usually cause an issue and can be overlooked.

However, when you start to notice big dents or chips then this is a pretty good indicator that the blades are no longer in a suitable condition for cutting. This normally occurs if you run over a hard object while mowing. This could be a rock, a metal pipe, concrete or anything else that might get in the way of your mower’s path.

When the blade sustains this type of damage, you can sharpen it all you like but it isn’t going to solve the problem. Even if the cutting edge remains quite sharp, you’re not going to get the results you want as it will end up cutting very unevenly. When this happens, it can cause damage to the grass so you will be left with no other choice but to replace the blade.

The Blade Is Bent

Chips and dents are just one kind of damage that can affect the performance of your lawn mower blade. Sometimes, you may find that the blade becomes bent and this is often the case after it has collided with a solid object such as those we talked about above. But just like a dent or a chip, a bend or warp in the blade will mean that you need to install a replacement.

You might think that a small, seemingly insignificant bend wouldn’t make too much of a difference to how the blade works but you would be wrong. Just a very small bend in the blade can have a huge impact on how uniformly it cuts. Plus, it’ll put more pressure on other parts due to things like vibrations so you’ll need to get it changed as soon as possible.

It’s usually pretty obvious when you have a bent blade as not only will the mower vibrate but it’ll also make sounds that it didn’t make before. It is potentially possible to straighten the blade but the chances of success are low so replacing it is normally the best option.

Uneven Grass Cut

uneven grass cut

When you mow your lawn, you want things to look neat, even, and tidy. But when you have a blunt lawn mower blade, this is nigh on impossible. After cutting, you might notice that the cut is not even or that the grass appears to be patchy. You’ll probably find that you have to make several passes over the same bit of lawn before you get anything that resembles an even cut.

This is almost always because the blade is dull. Even worse, you’ll find you need to exert much more effort to cut the grass so the job is instantly more tiring. Compare this to cutting with a freshly sharpened blade and you’ll easily see the difference.

If you have found that cutting the grass has suddenly become much more of a chore then this is probably telling you that the lawn mower blade needs to be replaced, or at the very least, sharpened.

The Blade Is Still Dull After Sharpening

It is important to stay on top of sharpening your lawn mower blade. In most cases, doing this once or twice each mowing season will be enough. Keep on top of this by paying attention to how the blade performs and when you notice that it isn’t cutting as well, or is tearing at the grass as opposed to cutting it, you should stop and sharpen the blade.

But, after several sharpening sessions, you may find that no matter how well you sharpen the blade, you still end up with the same problems. This is because lawn mower blades are not designed to be sharpened over and over again. There comes a point that sharpening is no longer effective and there is nothing else you can do but replace the blade.

When it comes to sharpening the blade, make sure that you assess how well it performs after you’re done. If the mower is still not cutting in a way that you expect then this is a good sign that the time has come to replace it.

How To Replace Lawn Mower Blades

Replacing lawn mower blades doesn’t need to be a difficult task. However, if you are at all unsure about what you’re doing, it’ll be safer for you and your lawn mower if you take it to a repair shop.

To do this at home, you will need to first make sure that the mower is disconnected from power. For gas mowers, this means removing the spark plug whereas electric or cordless mowers can simply be unplugged or have the battery taken out.

Next, you will need to tilt the mower onto its side. Note that if you are using a gas lawn mower, you must make sure to tip it so that the carb is facing up. If you don’t, then this can result in oil leaking and getting into parts of the engine where it’s not meant to be.

Before you remove the blade, be sure to note which way it is fitted on as you’ll need to install the new one in the same way. When you’re ready, remove the old blade and install the new one making sure to replace and tighten all washers and nuts.

Final Thoughts

Lawn mower blades can be resharpened several times. However, this isn’t something you will be able to keep doing as there will come a point that the blade wears and needs to be replaced.

Generally speaking, you should replace a lawn mower blade around every 200 hours of operation. But it’s important to keep in mind that they will only last this long if they are well taken care of so good blade maintenance is essential.

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Andrew Fisher

Andrew Fisher

Andrew is a dedicated father of three who really takes pride in his lawn and garden. You'll find Andrew behind the scenes of almost everything Edge Your Lawn produces. When he's not helping readers find all the information they need, he's in his backyard working on his lawn and garden landscaping. This year he hopes to build an outdoor deck and sort out his veg patches.

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