Hover mower blade sharpening. How to Sharpen Lawn Mower Blades Without Removing (Easiest Way)

How to Sharpen Your Lawn Mower Blade for a Cleaner Cut

Follow this easy guide to sharpening the business end of your mower and your grass will look tidier and stay healthier all season long.

Viveka Neveln is the Garden Editor at BHG and a degreed horticulturist with broad gardening expertise earned over 3 decades of practice and study. She has more than 20 years of experience writing and editing for both print and digital media.

When your lawn mower isn’t making the cut anymore, usually it’s because the blade has lost its sharp edge from use. Removing the blade and sharpening it yourself can seem intimidating if you’ve never done it before. But it’s actually a simple process, and you’ll only need two tools to do it.

Once you know how to sharpen your lawn mower blade, it’ll take you a fraction of the time it takes to mow your lawn. So, just follow this step-by-step guide to give your grass a crisp, clean cut again. Or, if you don’t want to worry about sharpening the blade, you can just remove it and bring it to a lawn mower repair service near you to take care of it.

Test Garden Tip: When grass blades have torn, ragged ends that turn brown after a mowing, chances are it’s time to give the blade some attention. Most experts recommend sharpening power mower blades once or twice a season, depending on how often you use your mower.

Step 1: Remove Blade from Mower

Disconnect the spark plug on a gas mower or unplug an electric mower (to ensure the machine won’t accidentally start while you’re working on it). Next, gently lay the mower on its side and use a wrench (27, The Home Depot) to remove the nut that attaches the blade to the motor. Then, remove the blade from the mower. To make sure you replace it the right way in the machine, mark the bottom of the blade with spray paint so you know that it should face the ground when you’re done.

Step 2: File Blade

Clean any dirt or grass clippings off the blade with a dry cloth. Stabilize the blade in a vise and use a medium file (10, The Home Depot) to smooth out imperfections along the blade edge (at the ends of mulching blades). Follow the existing angle of the blade, holding your file or sharpening tool at about a 45-degree angle. Move the file in one direction, gliding out toward the edge, much like you would sharpen a kitchen knife. However, your goal is to make the edge about as sharp as a butter knife rather than your favorite chef knife.

Step 3: Check for Balance

After you hone the cutting edge on both halves of the blade, check to see if the blade is balanced. An easy way to do this is to pound a long nail into a wall in your garage and rest the blade’s center on the nail. If the blade isn’t balanced, file a little more metal from the heavier side until it balances.

Step 4: Reassemble Mower

When the blade is correctly balanced, put the mower blade back onto the machine using a wrench. Be sure to tighten the nut securely back into place. And don’t forget to reattach the spark plugs.

How to Sharpen Lawn Mower Blades Without Removing (Easiest Way)

Maintaining a sharp blade on your lawn mower is extremely important for keeping your grass in the best condition it can be. Dull blades struggle to slice through grass and tear it instead. This results in yellowing, disease, pests, and an all-around unhealthy lawn.

The best way to sharpen lawn mower blades is to first remove them from the mower and take care of the sharpening and balancing at the same time. However, some property owners aren’t able to get their blades off. This could be due to missing tools, excess rust, or maybe just a lack of time. Whatever the reason might be, it begs the question of how to sharpen lawn mower blades without removing them. Let’s take a look at if this is possible, and if so, how exactly to go about doing it.

Can a Lawn Mower Blade Really Be Sharpened Without Removing It?

Yes, you can sharpen a lawn mower blade without removing it. I usually take my blade off to sharpen it, but if you want to hone yours while it’s attached to the mower you certainly can. Since sharpening your lawn mower’s blade while it’s bolted on requires a bit of a different approach to normal blade sharpening, I’ve listed the steps you should follow below.

Sharpening Lawn Mower Blades Without Removing Them (Step By Step)

Now that I’ve outlined the process, I want to dig into the details of how to sharpen push lawn mower blades without removing them. While this may seem like a complicated process, it’s actually pretty simple. Anybody can sharpen their own lawn mower blade with the right equipment, so follow along and let’s get it done.

Gather Equipment

Before we get into how to sharpen lawn mower blades without removing them, let’s talk about what you’ll need to get the job done. Luckily this project only requires a few things:

• Cut-resistant gloves.
• Eye protection.
• Wire brush, putty knife, prybar, or other scraper to clean off the mower’s deck and blade.
• One or two pieces of scrap wood/something to brace the mower.
• Steel file, angle grinder, or drill (with a grinding attachment).

Once you have your supplies together, set your mower up on your workbench or somewhere flat where you can kneel down and work on it.

Disconnect Power Supply

Now, before you go any further, make sure that you’ve disconnected the source of power to your lawn mower. On electric mowers, this means either removing the battery or making sure that the cord is unplugged. If you’ve got a gas mower, all you will need to do is remove the spark plug hood from the spark plug. Doing this ensures that your mower won’t start unexpectedly.

Tip Lawn Mower Over

Once you’ve got your mower where you want it, you’ll have to tip it onto its side so that you can access the blade. This step is actually very important. A lot of people don’t realize that there is a right and wrong way to tilt your mower.

The correct way to tip your mower over is to do so with the air filter and carburetor facing up. This makes sure that gas and oil won’t leak out of their reservoirs and into places they shouldn’t be.

Brace/Support Mower

With your mower flipped onto its side, you’re going to want to make sure that it doesn’t accidentally fall down. I like grabbing scrap 2×4 pieces of wood I have laying around and placing them diagonally against the mower, but anything goes as long as it can adequately support the machine. Lawn mowers usually won’t go anywhere once they’re on their side, but it’s always a good idea to set up a little extra support.

Clean Mower Deck and Blade

Use this opportunity to scrape off every bit of debris on the underside of your mower that you can. It’s best practice to regularly clean your mower’s deck and blade, but like flossing teeth, let’s be honest and acknowledge that a lot of us don’t do it enough.

You can use a wire brush or whatever blunt object you have on hand to scrape all of the dried dirt and grass off the deck and blade. For stubborn patches of gunk, using a little bit of water can help a lot. I usually tackle the deck first and then move on to cleaning the blade. This can be tricky with the blade fastened in place, but do the best you can to get it clean.

Block/Secure Blade

Once you’ve finished cleaning the blade, it’s a good idea to secure it in place so that it won’t move while you’re trying to put a new edge on it. If you have a specialized blade lock tool, great, but I think that the easiest way to go about securing your blade is with a set of locking pliers or a block of wood. You’ll either have to lock the pliers onto one edge of the mower deck to stop the blade from turning, or find a piece of scrap wood that is the right length and can be wedged between the blade and one side of the mower deck.

Some people just hold the blade with one hand while they sharpen it with the other, but this can be dangerous, especially if you’re using a drill or angle grinder. Also, it is a lot more difficult to hone your blade at the correct angle if you’re trying to do it with one hand.

Grind Blade

After doing all of the necessary prep, it’s time to actually hone your blade. There are a handful of options when it comes to what to use to sharpen your lawn mower’s blade, but I recommend using what you’re most comfortable with and have easy access to. Whatever tool you’re using, to sharpen your blade there are three big things you need to do:

Grind only the “top” side of the blade at a 45-degree angle.

Here, the top side of the blade refers to the side that faces the engine of the mower, not the ground. When grinding, you don’t need to be at exactly 45 degrees. You should be able to follow the existing angle on the blade so eyeball what seems about right and go slow and steady.

Go in one direction: from the center out to the end of the blade.

It’s really important that you file or grind smoothly in one direction. Start at the back of the blade (near the center where it’s mounted) and gently hone the edge as you push out towards the end. You don’t have to be an artist, but avoid any kind of sawing or back-and-forth motion.

Try to remove the same amount of material on both sides of the blade.

Since you won’t be removing the blade to check its balance, try to sharpen both sides of the blade evenly. While there’s no way of knowing exactly how much material you’re removing from each side of the blade, you will need to make a rough estimation. Just keep track of how many passes you do with your file or grinder and try to replicate it.

A Few Things to Be Aware Of

Now that you’ve got the main idea of how to sharpen lawn mower blades without removing them, I should mention a couple of things to be aware of. Though it’s a straightforward project, there are some things you should look out for before you get started, while working, and after you’ve finished.

Should the Blade be Sharpened or Replaced?

Sometimes there’s no need to sharpen your lawn mower’s blade because you’re actually due for a replacement. Lawn mower blades don’t have a specific lifespan, but generally, they should be swapped out every 2 or 3 seasons. The best way to tell if this is the case for you is to take a look at your blade. If the blade is bent, has large nicks/dents, or is suffering some serious rust damage, you should probably buy a new one. Knowing when to replace lawn mower blades can save you a ton of time.

Sharpen Blades When the Gas Tank is Empty

Maybe you don’t have much of a choice, but if you can, it’s best to do this project when you’re out of gas. Since your mower will be tilted on its side for quite a while, it helps to do this after you’ve run the gas out of your mower. This will prevent gas from leaking anywhere it shouldn’t be. Chances of leaks are slim, but try and prevent them if possible.

Watch for Excess Vibration

Once you’ve got your blade sharpened, and you’re out cutting grass again, be aware of how your mower is running. If there is more vibration to the mower than you remember, you might have shaved your blade a bit out of balance.

When you run your mower with an unbalanced blade, you could end up with poor cut quality and even cause structural damage to the mower. If you suspect your blade is out of balance, you may want to take it off the mower and check. Balancing lawn mower blades is a pretty easy process and could save you some trouble in the long run.

About Tom Greene

I’ve always had a keen interest in lawn care as long as I can remember. Friends used to call me the lawn mower guru (hence the site name), but I’m anything but. I just enjoy cutting my lawn and spending time outdoors. I also love the well-deserved doughnuts and coffee afterward!

Комментарии и мнения владельцев

Bad idea sharpening on mower. Anytime blades are sharpened they need to be balanced. Sharpening with a file is preferred because of heat buildup on the fine edge of the blade which removes the temper of the blade.

Hi Charles, I agree that sharpening a blade on a lawn mower isn’t the best idea, but if you can’t get it off, I wouldn’t recommend trashing the mower and buying a new one. I believe sharpening the blade still attached to the mower is a good alternative to replacing the mower. You’re certainly correct to say that a blade needs to be balanced, but I wouldn’t want to tell someone to trash a mower because they couldn’t balance the blade. When it comes to tempering, I’m definitely not an expert. I’m not sure I’d be concerned with a mower blade since it’s sharpened like a knife, and I’m not sure sharpening will heat the blade sufficiently enough to affect the actual heat-strengthening process. But I’m not an expert. Many Thanks, Tom.

Guru, your articles are great, and a real big help! Most.people want a quick easy fix. You gave those pointers. I followed to a T and my mower works great. Thanks!

How much torque should I expect to need to remove a tight blade bolt on a riding mower? The blade bolts on my Kubota have 30 mm heads. I am unable to remove them by hand using a breaker bar even. Were I to purchase a impact wrench, what torque level would you expect to be needed? Thanks.

How To Sharpen Lawn Mower Blades Without Removing Them Guide

Wondering how to sharpen lawn mower blades without removing them from the machine? Sometimes one doesn’t have the time or the energy to remove and then attach those blades back.

That is why we bring you our tried-and-tested step-by-step guide on how to get sharp mower blades without taking them off. Read ahead to learn not only this but other useful tips from lawn experts as well.

• How To Properly Sharpen Lawn Mower Blades Without Removing Them?

• 1. Gather the Right Tools and Keep Them at Hand
• 2. Use Protective Equipment To Stay Safe
• 3. Seal the Gas Tank
• 4. Remove Batteries
• 5. Tilt the Mower on Its Side
• 6. Restrain the Movement of the Blade
• 7. Clean the Blades
• 8. Sharpen the Lawn Mower Blades
• 9. Don’t Forget To Unseal the Fuel Tank
• 10. Test Your Lawnmower Blades
• 11. Resharpen the Blades After 20 Hours

• – Why Shouldn’t You Sharpen Both Sides of a Mower Blade?
• – How Sharp Should Ride-on Mower Blades Be?

How To Properly Sharpen Lawn Mower Blades Without Removing Them?

To properly sharpen lawn mower blades without removing them, you should tilt the mower on its sides, ensure all fuel has been removed, and if the lawn mower is electric, remove the batteries. Use a sharpening tool of your choice to sharpen each blade at an angle of 45 degrees.

Gather the Right Tools and Keep Them at Hand

Before you get down to the actual work, you need to make sure you have the right equipment. Trust us, organizing your tools beforehand will save you a lot of trouble later.

You will need a wood block to support the mower, an angle grinder with a metal blade for sharpening the mower blades, and a steel file. You will also need a flat tire, a putty knife, and a wire brush to scrub clean blades.

Lastly, a bucket of water and good-quality soap is also essential. Don’t worry if you don’t own one or more items on this list. They are easily available online or in your local hardware store at quite reasonable prices.

Use Protective Equipment To Stay Safe

To ensure you don’t end up harming yourself, you must take care of yourself. Invest in a pair of premium-quality cut-resistant gloves to wear while you sharpen your lawnmower blades.

You will also need protective eye goggles made of thick and resilient material. Safety glasses will prevent things from getting in your eyes accidentally and causing problems.

In addition, it would be best if you could wear full-sleeved shirts. but it’s really up to you. Wear your most comfortable clothes and choose a day when the weather is nice to carry this out.

Seal the Gas Tank

Take your mower to a flat surface and turn off its spark plug. This will prevent it from starting up accidentally while you are working. Apply parking brakes next, so it doesn’t start rolling away when you tip it later.

Unscrew the lid covering the gas tank. Seal the opening with a plastic sheet or plastic bag as tightly as possible. Put the lid back on and tighten it. This step is important and will prevent fuel leakage from the tank once the mower is tilted.

Remove Batteries

If your mower is of the electric type, then there is no fuel tank to seal in this case. Still, you must ensure that its cord is unplugged from the power supply.

Since you will be washing the blades, removing the batteries from the mower is necessary. Please remove the battery by disconnecting wires from both of its terminals.

Then remove any bar or strap thing holding the battery in its position. Carefully store the battery in a safe place until you put it back later on.

Tilt the Mower on Its Side

Tilting the mower on its side will enable you to gain access to its blades. Make sure it is placed on a flat, stable surface and will not fall back.

You can tell that your mower is tilted the right way when its fuel tank, air filter, and carburetor are facing upward. This is not only the best position to get access to the blades but will also make sure that no fuel leakage occurs from the gas tank.

Next, you need something to support the tilted mower with. The best option is to use a wooden block and place it diagonally on the opposite side of the mower.

Don’t worry if you can’t seem to find a block of wood big enough to support the mower. You can use anything similar as long as it provides the right support to the mower.

Restrain the Movement of the Blade

Restrain the lawn mower blade, so it doesn’t move around while you clean and sharpen it. This will make your task ten times easier. It is also a kind of safety measure so that you don’t end up accidentally hurting yourself while working on the edges.

A blade-locking tool will come in handy here. It will tightly secure the blade for as long as you want. Don’t sweat it if you don’t have a locking tool at home. Lawn mower blades can just as easily be locked using a block of wood or a pair of pliers.

When using a block of wood, choose one long enough to be stuck between the blade on one end and the mower deck on the other. Similarly, the pliers need also be locked between the blade and the deck to lock it effectively.

Clean the Blades

Before sharpening lawn mower blades, they must be clean. Fill the bucket with soap and water for this task. First, however, you will need some blunt object to properly scrape off the dried dirt and grass stuck to the blade and the deck.

We use a wire brush as this is a tool that removes all stuck debris within minutes. It is best to clean the deck first and then move on to the blade. If you find it difficult to clean the blade because it has been stuck, you can wash it first and then secure it afterward.

After removing the grass, wash off any remaining dirt or debris using the putty knife and a sponge. Use clean water at the end to ensure everything is spick and span.

Sharpen the Lawn Mower Blades

Now you are finally ready for the most important step of all. First, you need to decide what mower blade sharpening tool you will use. This mostly depends on op availability as well as what you are comfortable with. Your best options are using a metal file, a bench grinder, or an electric grinder.

Place the tool on the blade’s cutting edge at an angle of 45 degrees. Don’t worry about the exact measurement of the angle. Just follow the slant already present on the cutting edge and use your eyeball to make sure you sharpen it along it. For clarification, the cutting edge of the blade is one that faces the engine and not one that faces the grass.

While sharpening, move the tool in one direction, avoiding any back-and-forth motion. Secondly, don’t try to rush it by increasing your speed. Just go as steady as you can and utilize the entire length of the grinder in each stroke.

Go slowly from the center of the blade toward the edge. While at it, be careful of your hand, and don’t lose FOCUS for even one second. How much to sharpen each blade depends on you. It is okay to stop when you feel the mower blade has been sharpened enough.

Don’t Forget To Unseal the Fuel Tank

After its blades have been sharpened, tip the lawn mower back to its original position. The first thing you need to do is open the fuel tank cap and remove the plastic you had placed over it to seal it.

In the case of an electric lawn mower, put its batteries back. Make sure to attach each wire to the right terminal of the battery.

Unlock the mower blade by whichever mechanism you had locked it in earlier. Put the gas fuel back in the mower, attach it to the power plug, and start it back up.

Test Your Lawnmower Blades

Put your lawn mower to work and test how well those blades have been sharpened. If it seems to be running and working as it was before then, this means your operation was successful. It’s time to give yourself a congratulatory pat on the back for a well-done job.

If weird vibratory noises seem to be coming from the mower while you cut grass during lawn care, you might have shaved one of the blades more than the rest. This naturally puts your mower out of balance and affects its performance.

Another major sign of unbalanced blades is the grass cut poorly and unevenly. You cannot keep working with the mower in such a condition. It would be best to sharpen the blades again so they are balanced. You can have an expert do it for you this time if you don’t feel confident you have the required skills.

Resharpen the Blades After 20 Hours

It takes approximately 20 hours for lawn mower blades to become dull enough to need to be sharpened again. So if your lawn takes an hour to mow, then after 20 lawn mowings, you will need to repeat the whole procedure.

How often this happens depends on how much you mow your lawn as well as the condition in which it is kept. If you have planted a fast-growing grass type, you will need to mow more for efficient lawn care. This will get the blades dull much faster.

Similarly, if your lawn contains rocks and other hard debris, moving over these will dull the blades faster. Consequently, you will have to sharpen them more often.

Frequently Asked Questions

– Why Shouldn’t You Sharpen Both Sides of a Mower Blade?

You shouldn’t sharpen both sides of a mower blade to prevent affecting performance ! Sharpening both sides equally will dull both sides much more frequently than otherwise. The grass-cutting efficiency is hugely impacted as well. Sharpening both sides of the blades might seem tempting, though, but you should avoid it.

It would be best if you did not sharpen both sides of the mower blades. Ideally, one side of the blades should be razor sharp while the other side needs to be dull, just like the blades of scissors.

– How Sharp Should Ride-on Mower Blades Be?

Ride-on lawn mower blades should be as sharp as a butter knife but not as sharp as a razor. As a general rule of thumb, you must be able to run your finger across the cutting edge without getting cut.

For the technical ones among you, the cutting edge needs to be at an approximate angle of 45 degrees.

Conclusion

So, is sharpening the blades of a lawn mower without removing them the easiest thing ever, or what? Here’s the summary of our guide:

• Ensure you have everything ready and in order, before you begin, and don’t forget to don gloves and goggles for your protection.
• Remove the fuel and batteries from the mower before tilting it to the side and jamming its blades.
• Sharpen only one mower side using the tool of your choice at an angle of 45 degrees.

We understand why you don’t want to go through the hassle of removing and reattaching the blades of a mower every time to sharpen it. With the help of the information you digest from this guide, you will be able to sharpen the blades effectively and save yourself plenty of time.

How to sharpen your lawn mower blade

There is also an easy to follow YouTube video on my channel to support this article.

The tools I use

All of the tools above can be found in our Amazon affiliate shop.

Safety first

If your lawn mower is electric. Make sure it is unplugged from the power supply. If it is Battery operated remove the battery. And if it is a petrol mower then remove the spark plug cap before doing any maintenance on your machine.

Gloves may be necessary when handling the blade and eye protection is advisable when sharpening the blade. If you use an angle grinder then eye protection is a must and ear protection is advisable.

Getting the blade off

The first job is to get the blade off the lawn mower. I still have the spanner that came with my lawn mower but if you have lost yours I recommend buying the correct replacement. If you use a different type of spanner you run the risk of damaging the head of the retaining bolt.

An electric lawn mower and a battery powered mower are fine to turn on to their sides to gain access to the blade. However if you have a petrol mower it is best to tip it backwards so that the fuel and oil don’t leak out.

Now with access to the blade I can unscrew the retaining bolt. I do this by gripping the blade on the non sharpened side and turn the bolt anti clockwise. Once it is loosened I am able to unscrew it the rest of the way by hand.

As long as it’s not rusted on, the blade should be easy to get off. If it is difficult to remove, spray the bolt with some WD-40 or something similar. Leave it to soak in for 10-15 minutes and this should help you to unscrew it.

When I have removed the blade, I always put the bolt back into the lawn mower. Just screwed in loosely so that it doesn’t go missing.

Whilst the blade is off

Whilst I have the blade off, I take the opportunity to scrape around inside the lawn mower. Grass and mud accumulate over time and with the blade removed it is easy to scrape all of this away.

Holding the blade

Whichever way you choose to sharpen your blade it is important to hold it down securely when doing so. If the blade is not clamped down securely then you run the risk of it slipping or falling, possibly causing injury to yourself or damage to the blade.

I like to use a quick grip clamp, but a g-clamp would do just as well. In the video I clamp the blade to a garden bench which is ideal because it is flat. I sometimes use the workbench in my workshop.

Clamp the blade securely to a flat, stable surface. And make sure the edge to be sharpened is slightly overhanging. So when you are sharpening the blade you don’t damage the bench.

Method #1

With the blade firmly clamped down I use a metal file. I keep the file at the angle that the blade is ground to and make multiple passes keeping even pressure with each stroke. I do this until the blade comes to a sharp point and most of the chips in the blade have disappeared.

This method is great if the blade is still in good condition from the last sharpening. Or it just needs a little touch up. However if the blade has been neglected for a while. And it is very blunt and has many chips. Sharpening this way will take a long time.

Method #2

This method is a whole lot quicker. I own an angle grinder and I use it for numerous tasks around the workshop and on my home renovation jobs. With a metal grinding disc in the grinder it sharpens blades really quickly.

The theory is the same as it was for method #1. Keep the grinder at the angle that the blade was already ground to. And make multiple passes until the blade comes to a point and most of the chips have gone. Take your time though because an angle grinder will take too much off if you’re not careful.

But remember the grinder is noisy and throws out sparks. So eye protection and ear protection are a must.

Balancing the blade

A lawn mower blade spins at a very high speed. If the blade isn’t balanced then it will cause a lot of vibration. This is not good for your machine. So a simple job is to check if the blade is balanced. I do this by hammering a panel pin partially into a vertical surface. In the video I use the kids wooden climbing frame. But you could use a gate or a tree etc.

Put the blade onto the panel pin through it’s centre hole. If the blade is even both sides and levels out it is fine. If it is lower on one side then more metal needs to be ground off of the lower side.

Putting the blade back on

It may sound silly but be sure to put the blade back on to your lawn mower the correct way. Many blades have written on them ‘This side to grass.’ Make sure the retaining bolt is tight but do not over tighten it.

Enjoy cutting your lawn

So that’s how you sharpen your Lawn mower blade. Now that you have a sharp blade you should enjoy cutting the grass more. A sharp blade in a good, well cared for lawn mower will give great results and make for a healthier lawn.