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How To Know When Lawn Mower Blades Need Replacing? Find Out Here!

Written by William
Last Updated on January 24, 2023

How To Know When Lawn Mower Blades Need Replacing?

The blades of your mower are without a doubt, the most important part of your machine, it is vital they are kept sharp and in good condition, otherwise, you risk ripping your grass rather than cutting it.

It can be difficult to know when your blades need replacing however, normally, a sharpening can make your blades seem brand new again.

Sharpening a blade that needs to be replaced can make it brittle, and depending on the quality of your blade and what you use it for, you may need to replace it every season.

So to figure out when the right time is to replace your mowers blade, we have listed out some signs you can be looking for which will let you know when your mowers blade has reached its end of life.

Let's get into it!

Different Types Of Mower Blades

Before we get into the signs of when your lawnmower's blades need to be replaced, it's a good idea to get to know the different types of blades out there for your machine.

This way you can ensure you are using the correct blade for what you are doing.

We have listed out the three most common types of mower blades below and what you can use them for.

  • Mulching blade - Mulching blades have curved edges and allow you to cut grass very finely in a 'mulch' style. This blade is very common and can be used on a variety of different lawnmowers to cut grass.
  • High-lift blades - These blades are perfect for that precise and professional cut and can go up in measurements to 20 inches. They also give airflow to push clippings in the discharge chute of your machine.
  • Gator blade - Gator blades tend to have serrated edges and have three in one options such as; high lift, medium and low for different cutting heights on your lawn.

When Do I Replace My Mowers Blades?

On average, a mower should be replaced every 200 hours or at the start of every season each year. This could be more often if you mow a lawn with lots of stick and stones as this can cause more wear on your blade.

Always sharpen your blade a couple of times before replacing it so as you can get the most use out of it possible, and if the blade becomes completely damaged before the end of the season you must replace it straight away.

Using a damaged blade is dangerous and may damage your mower/grass even more.

Common Signs It's Time To Replace Your Mower's Blades

From an uneven cut on your lawn to torn grass and chipped blades, there are a few sure signs you can be looking out for which should indicate to you when its time to get new blades for your lawnmower.

We have listed the most common signs below to help you out.

Your Blades Are Old

One of the easiest indications that it's time to replace your mowers blades is if they are old. After a few years of mowing with your blades, it's a good idea to replace them according to what your manufacturer recommends, even if you reckon they are in good condition.

Around two years or more is a good time to get a new set of blades for your mower.

It Cuts Grass Uneven

Dull blades will leave an uneven cut on your grass after mowing, if your blades are in good condition, all the grass should be cut to the same height and you should not need to go over the same area twice.

The Blade Is Dull After Sharpening

Using a mower that has old and dull blades will tear your grass and leave that horrible yellow look on your lawn after mowing.

If you sharpen your blade twice and your lawn is still getting similar results after cutting, then it's time to replace your blades.

Trying to sharpen a blade too many times at the end of its life will cause it to become brittle and become a safety hazard, so you should always replace it straight away when you notice it has become dull and can't be sharpened anymore.

Blades Are Damaged

If your blades have accumulated rust or they are bent/damaged then you should change them as soon as possible. Damaged blades can often happen if you have mowed over something hard like sticks or stones.

You can easily figure out if your blades are causing issues by; listening to see if your mower is vibrating, checking if your mower keeps stopping or a strange noise coming from the engine.

As soon as you figure out your mowers blades are damaged then get a new set and avoid turning on your machine till they arrive.

The Grass Is Torn

One of the last signs that you need to replace your mowers blades is by looking at the grass that has been mowed.

If the tips of your grass look torn rather than smoothly cut with a sharp blade then you need to get a replacement. This is important as it can affect the health of your lawn.

How To Replace Your Lawnmowers Blades?

Now we have figured out how to determine when your mowers blades need replacing, you might be wondering how to change them yourself at home.

We have listed out some simple steps for you to follow so you can replace the blades of your lawnmower with the correct tools and safety precautions.

Tools Needed

  • New blade of the correct size and type.
  • A putty knife.
  • A wrench.
  • Safety gloves.

Steps For Changing Your Blade

  • Step one - Remove the spark plug from your mower and tilt it on its side at a 45-degree angle with the carburettor facing up to prevent fuel/oil from leaking out of the machine.
  • Step two - Take off the nut that is securing your mowers blade with your wrench.
  • Step three - De-attach your old blade from your mower and put it away somewhere safe, use your knife to take out any old debris that was stuck around your old blade.
  • Step four - Attach your new blade to your mower and make sure it is in the correct cutting position (with the cutting edge pointing to the wheels of the mower).
  • Step five - Retighten the nut very securely till you can't turn it anymore, put the mower back on its feet and reattach the spark plug to the machine.

Frequently Asked Questions About When To Replace Blades On a Lawnmower

When should I sharpen my mowers blades?

This depends on how much your mower is in use, but they should be sharpened on average at least 1-2 times per season.

How can I tell if my blades just need sharpening rather than replacing?

Several factors can determine whether you should replace or just sharpen your blades. For example, if your blades are old, in constant use and they have obvious signs of wear and tear such as rust or dents then you should replace the blade.

However, if your blades are fairly new and you don't use them too much then they probably just need sharpening if you notice you are having more of a hard time cutting grass.

Is it easy to notice when my blades are damaged?

Yes, as soon as your blades are damaged you will notice a downgrade in the performance of your mower and how smoothly it cuts grass, some mowers may even start vibrating or making unusual noises.

Final Words

To round up our article, you should always replace your blade when its; old, damaged, tearing grass, cutting unevenly or still dull even after sharpening.

Always make sure you wear protective gloves when handling the blade of your mower for replacement and make sure the spark plug is removed from the mower before doing any kind of repair or maintenance.

About the author
Written by William
I have always had a passion for gardening and that with a background in selling lawn mowers for the past 10 years, I have become very knowledgeable in all types of gardening tools. The site was created as a hub where I can review and write about all of the tips around gardening.
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