sharpen lawn mower blade without removing

How To Sharpen Lawn Mower Blades Without Removing Them

Removing your lawn mower blades can be time consuming and there’s a risk that you might on put them back correctly which will affect their performance. But a lot of the time, you need to remove the mower blades in order to sharpen them but can you sharpen a lawn mower blade without removing it?

It is possible to sharpen a lawn mower blade without removing it and it’s really important to learn how. Dull blades can affect the health of your grass and won’t cut as neatly, leaving your lawn looking less than attractive.

Knowing how to sharpen lawn mower blades without removing them is an important skill for any homeowner. The advice below shows you how to do this quickly and efficiently. You will need to gather some tools together to do this so make sure you are able to get your hands on the following:

  • Eye protection
  • Gloves
  • A couple of pieces of scrap wood
  • Wire wool
  • Drill, angle grinder or steel file

Step 1 - Preparation

Before you get into the nitty gritty of sharpening lawn mower blades, you will need to make sure that everything is prepared. This isn’t a job that you’ll want to stop halfway through so getting everything ready beforehand will prevent you having to do this.

Firstly, you’ll want to gather the tools we discussed above. If you do not have wire wool, you can use something like a putty knife instead, although wire wool is the best option.

Also make sure that you have all of the relevant safety equipment. Protecting your eyes is imperative as small bits of debris could fly up and hit them. Moreover, it’s important to wear a high quality pair of work gloves that will resist being cut by the blades.

Now that you’ve got everything together, the final preparation is to do with your lawn mower. You’ll need to find a flat surface on which to work on it and, if you’re using a gas lawn mower, remove the spark plug. Ensure that the brake is applied as the last thing you want is for the mower to start moving around when you’re trying to perform this type of maintenance.

sharpen the blades of lawn mower - preparation

Step 2 - Disconnect The Power Supply

It is essential that, before working on your mower blades, there is no chance of the machine accidentally turning on. If it does, you risk a serious injury so it’s important to take a few moments to ensure that the power is disconnected.

With a gas mower, you will have already removed the spark plugs which takes away any chance of an accidental start up. If you are working with an electric lawn mower, ensure that the plug is not connected to a power outlet. For battery powered lawn mowers, take the batteries out entirely. Simply turning the safety key to the off position isn’t enough. If the batteries are removed, no power will get through.

Step 3 - Tilt The Mower On Its Side

Now that you have your lawn mower prepared and ready to work on, you will need to tilt it over to its side. This gives you easy access to the mower deck where the blade is located. However, what a lot of people aren’t aware of is that it is possible to tilt your mower the wrong way.

When you tip your lawn mower onto its side, you will need to make sure that the carburetor and air filter are both facing up. The reason for this is that, turning it the other way comes with a risk of leaking fuel. If this gets into places it shouldn’t, it can damage your lawn mower.

Step 4 - Restrain Blade Movement

Once the mower is on its side, you’re going to need to make sure it is secure. That’s where your wooden blocks come in. Rest these diagonally against the mower blade to keep it in place. For the most part, a tipped over lawn mower won’t go anywhere but it’s better to be safe than sorry.

Step 5 - Clean The Blade

Now this is a great opportunity to clean your mower blade. You don’t want to sharpen it while it’s dirty and anyway, it’s good practice to keep it clean and well maintained.

You’ll need to get all of the debris off the underside of the lawn mower and all around the deck. You can use your wire wool here or a wire brush but it’s also possible to use any number of blunt items that can scrape grass, dirt and other debris away.

You might also notice that there are areas of gunky mess and to get rid of these, some plain water should be the trick. It’s generally better to clean the mower deck before moving on to clean the blade. Note that it will be slightly more difficult to get rid of all the debris when the blade remains attached but it is possible to do a pretty decent job.

clean the balde of lawn mower

Step 6 - Sharpen The Lawn Mower Blade

Now for the main event; sharpening the lawn mower blade. There are a number of tools you can use to do this but generally speaking, a grinder or metal file will work best. It’s all down to what you have available and your personal preference.
Take your tool and put it over the cutting edge of the blade. Make sure that you maintain a consistent angle (we’ll talk more about this later on) and sharpen the blade on both sides equally. This can be difficult which is why it’s really important to take your time when doing this job.

Grind At 45 Degree Angle

It is recommended to sharpen your lawn mower blade to a 45 degree angle. This doesn’t need to be exactly spot on, you can use this figure as a ballpark but the key is to remain consistent. Taking your time will ensure that you can stay in line with the existing angle on the blade and retain the best cutting performance.

Make Sure It’s An Even Cut

When you don’t take the blade out of the mower to sharpen it, it can be more difficult to make sure it is balanced. For this reason, you’ll need to make sure that you sharpen both sides of the blade equally.

There really isn’t a surefire way to measure how much metal you’re taking off so you’ll need to use your best guess. Again, taking your time and monitoring the number of passes you make will help with this.

Go In One Direction

When you’re sharpening your mower blades, make sure that you always file in one direction. It’s best to begin at the back part of the blade and move out towards the end. There’s no huge amount of skill in this and you might compare it to a sawing motion. In any case, taking your time is the most important factor once again.

Things To Look Out For

While you might have wondered how to sharpen lawn mower blades without removing them, you also need to think about a few related things. For example, does the blade really need sharpening or should you replace it?

Should The Blades Be Sharpened Or Replaced?

Lawn mower blades are not designed to last forever which is why, from time to time, you’ll have to replace it. There’s no exact timeframe on when it’s best to replace a mower blade, this is all down to how often you use the mower, whether the blade has sustained damage and how many times it has already been sharpened.

Normally, you would expect to have to change the blade around every two to three mowing seasons. But it is important to regularly check it to make sure you don’t need to do it any sooner. If you notice any rust patches or other visible damage then the blade doesn’t need sharpening, you just need to get a new one.

Sharpen Blades When The Gas Tank Is Empty

We would highly recommend only sharpening your lawn mower blades when the gas tank is empty. This is because you will have to tip the mower onto its side which could mean that gas could leak into other parts of the mower.

This isn’t a huge risk but it is possible so emptying your fuel tank before you start this job is a wise idea.

Watch Out For Excess Vibration

After you have finished sharpening your blade you will need to pay close attention to how the lawn mower performs. You might notice that it is vibrating a little more than normal and this could be a sign that the blade is off balance.

It’s important to address this as running your mower with the blade off kilter means that it won’t perform as well and the cut won’t be as good. Moreover, not dealing with an off balance blade could result in damage to your mower which may be expensive and difficult to repair.

Important Tips

As well as considering the above advice, we would also urge you to read through the following important tips to make sure that sharpening your lawn mower blades goes as smoothly as possible.

  • Take the time to inspect your blades regularly. Check for damage to the blades but also look at your lawn. If there are any split tips or rough areas on the grass, this could be because of a dull blade.
  • Know when to replace the blades. Once they become beyond repair, sharpening will do nothing for them so it’s best to admit defeat and buy a new blade.
  • You may notice that your blades are notched. This does not mean that you have to replace them. In fact, in a lot of cases, a good sharpening will resolve the issue.
  • Strange noises coming from the mower when it is running could be another sign of unbalanced blades. Take them off to check them before continuing to use the lawn mower.

Summary

A lot of homeowners don’t have the time or the knowledge to take their lawn mower blades out when it’s time to sharpen them. So, if you’ve been wondering whether you can sharpen a lawn mower blade without removing it, you’re in luck because you can.

Make sure that you gather the right tools and disconnect the lawn mower from power. You’ll then need to tilt it on its side so you can access the blade and give everything a clean. Once you’ve done this, you can use a metal file or a grinder to sharpen the blades and have your mower cutting like new once again.

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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.