Do You Need To Sharpen New Mower Blades (Beginners Guide To Blades). Honda mower blades sharpening
Do You Need To Sharpen New Mower Blades (Beginners Guide To Blades)
In this post, we’ll answer beginner questions about lawnmower blades. And also what you must not do when changing your lawnmower blade.
In the future, if you need video help on inspecting, removing, sharpening, balancing, refitting, and torquing your mower blade, check out “Mower blade sharpening video”.
Do I need to sharpen lawn mower blades?
Lawnmower blades need to be sharpened regularly. A dull blade will pull and tear on your grass blades causing jagged tips. The dull blade stresses the grass and the damaged grass tips turn yellow. A sharp blade will cut cleanly which is healthier for the lawn, easier on you and your mower engine.
How often should mower blades be sharpened?
At the very least your mower blade needs to be sharpened at the start of every new season, and more often if your yard is stony or large. Setting your mower cutting deck to the lowest level will cause the blade to impact objects more often and will obviously need more regular sharpening.
Sharpen once per season, at least.
When should I replace my mower blade?
A mower blade should be replaced about every third to the fourth season. But it really does depend on its condition, a mower blade that cuts a small mature yard will last longer. New yards usually have rocks, stones, and debris that impacts the blade causing it to become dull and wear out quickly.
Blade wear – Check out the wear on this blade, this mower was having all kinds of cutting and bagging problems. A New blade solved all.
How do I know if my mower blade needs to be sharpened?
A mower blade doesn’t need to be knife sharp, but the leading edge of the blade does need to be beveled and the face free from gouges. Examine your blade by turning your mower over on its side but always with the carburetor side facing the sky (prevents gas spill).
Wearing a glove, run your finger along the beveled blade. Are there large indentations or gouges? If the answer is yes, then your blade needs to be sharpened.
Can you sharpen a lawn mower blade without removing it?
You can sharpen a mower blade without removing it, so long as it is not badly damaged or worn. The best practice is to remove the blade from the mower, sharpen and then balance it.
Sharpening the blade on the mower runs the risk of unbalancing the blade which will cause the whole mower to vibrate.
Check out “Blade maintenance tools” here, they make the sharpening process a ton easier, or check out the Amazon link below.
Tools.This method is only suitable for relatively new blades. You’ll need a big flat metal file, move the file at 45 degrees with the bevel, and to finish run the file across the rear to clean the burrs. If your blade is heavily damaged or badly worn, this method isn’t suitable.
The “Mower blade sharpening video” covers the whole process both on and off the mower.
Should I sharpen or replace my lawn mower blade?
If your mower blade is more than four years old and has seen average use, then go ahead and replace the blade. Good quality blades aren’t expensive but note you will need a torque wrench to tighten the blade bolt to specifications.
Tightening a mower blade without using a torque wrench runs the risk of the blade coming loose or destroying the engine. I wrote a post about my torque wrench here “Best torque wrench for mower blades”
Unless your blade is in good condition, I’d spring for a new one. They’re not expensive, but you’ll need to buy or borrow a torque wrench.
How tight should mower blades be?
It’s important to tighten your blade to the correct specification. A mower blade may not be as tight as you might expect.
A blade fits on a blade boss (metal block) which is then fitted to the end of the engine’s crankshaft. A blade is designed to slip on the blade boss if the mower blade hits a solid object.
Over-tightening the blade will prevent the blade from slipping on the boss, and will instead bend the crankshaft and destroy the engine.
Check out the video on blade fitting, it covers torquing the blade to specification. You might find the video on using a torque wrench.
Can you sharpen a Mulching blade?
You can sharpen a mulching blade, it is sharpened in the same way as a collecting blade, best results are achieved by removing it before sharpening and balancing.
Which way do mower blades tighten?
A single-blade lawn mower blade bolt will be a right-hand thread. Viewing the mower on its side (carburetor side up). To tighten the bolt – turn clockwise. To loosen the bolt – turn anticlockwise. I wrote a post on a similar subject “How to remove stuck blade bolt”
Which side of the lawn mower blade is up?
All mower blades will have a lifted trailing edge. The lifted edge points upwards, to the underside of the lower body.
This side up
Do lawn mower blades need to be timed?
A single-bladed mower will not need to be timed. A twin-blade walk behind mowers like a Toro or some lawn tractors will need blade timing. The purpose of the timed blades is so the blades can overlap.
Overlapping blades help prevent uncut grass between the blades. If your blades can touch each other, then yes it’s likely you have a timed deck and the blades will need to be timed. I wrote a post about timing your mower blades here “Replacing timed mower belt”.
Timed Blades
What causes a lawn mower to cut uneven?
There may be several reasons why your mower is cutting unevenly, here are some of the more common reasons:
- Deck wheels are set to different heights (Walk behind mower)
- A bent/worn blade
- Uneven tire pressures (tractor mower)
- Deck needs to be levelled (tractor mower)
Should the front of a push mower be lower than the back?
A lawnmower deck should be level, front to back and side to side. All mowers will have a height adjuster, some will have a single lever, and others will have a height adjuster at each wheel. Level the deck by adjusting the wheel heights.
Level – Adjust all-wheel heights until the deck is level.
What does a high lift mower blade do?
A High lift blade has a trailing edge that lifts sharply upwards. This causes a powerful vacuum effect on the grass blades, lifting them upright before cutting them. The high lift blade is specially designed to collect grass and it does so really well.
An engine will need to be sufficiently powerful to drive a high lift blade, not all mower engines are. Check with your dealer before fitting a high lift blade.
Hey, I’m John, and I’m a Red Seal Qualified Service Technician with over twenty-five years experience.
I’ve worked on all types of mechanical equipment, from cars to grass machinery, and this site is where I share fluff-free hacks, tips, and insider know-how.
And the best part. it’s free!
Do You Need To Sharpen New Mower Blades (Beginners Guide To Blades)
In this post, we’ll answer beginner questions about lawnmower blades. And also what you must not do when changing your lawnmower blade.
In the future, if you need video help on inspecting, removing, sharpening, balancing, refitting, and torquing your mower blade, check out “Mower blade sharpening video”.
Do I need to sharpen lawn mower blades?
Lawnmower blades need to be sharpened regularly. A dull blade will pull and tear on your grass blades causing jagged tips. The dull blade stresses the grass and the damaged grass tips turn yellow. A sharp blade will cut cleanly which is healthier for the lawn, easier on you and your mower engine.
How often should mower blades be sharpened?
At the very least your mower blade needs to be sharpened at the start of every new season, and more often if your yard is stony or large. Setting your mower cutting deck to the lowest level will cause the blade to impact objects more often and will obviously need more regular sharpening.
Sharpen once per season, at least.
When should I replace my mower blade?
A mower blade should be replaced about every third to the fourth season. But it really does depend on its condition, a mower blade that cuts a small mature yard will last longer. New yards usually have rocks, stones, and debris that impacts the blade causing it to become dull and wear out quickly.
Blade wear – Check out the wear on this blade, this mower was having all kinds of cutting and bagging problems. A New blade solved all.
How do I know if my mower blade needs to be sharpened?
A mower blade doesn’t need to be knife sharp, but the leading edge of the blade does need to be beveled and the face free from gouges. Examine your blade by turning your mower over on its side but always with the carburetor side facing the sky (prevents gas spill).
Wearing a glove, run your finger along the beveled blade. Are there large indentations or gouges? If the answer is yes, then your blade needs to be sharpened.
Can you sharpen a lawn mower blade without removing it?
You can sharpen a mower blade without removing it, so long as it is not badly damaged or worn. The best practice is to remove the blade from the mower, sharpen and then balance it.
Sharpening the blade on the mower runs the risk of unbalancing the blade which will cause the whole mower to vibrate.
Check out “Blade maintenance tools” here, they make the sharpening process a ton easier, or check out the Amazon link below.
Tools.This method is only suitable for relatively new blades. You’ll need a big flat metal file, move the file at 45 degrees with the bevel, and to finish run the file across the rear to clean the burrs. If your blade is heavily damaged or badly worn, this method isn’t suitable.
The “Mower blade sharpening video” covers the whole process both on and off the mower.
Should I sharpen or replace my lawn mower blade?
If your mower blade is more than four years old and has seen average use, then go ahead and replace the blade. Good quality blades aren’t expensive but note you will need a torque wrench to tighten the blade bolt to specifications.
Tightening a mower blade without using a torque wrench runs the risk of the blade coming loose or destroying the engine. I wrote a post about my torque wrench here “Best torque wrench for mower blades”
Unless your blade is in good condition, I’d spring for a new one. They’re not expensive, but you’ll need to buy or borrow a torque wrench.
How tight should mower blades be?
It’s important to tighten your blade to the correct specification. A mower blade may not be as tight as you might expect.
A blade fits on a blade boss (metal block) which is then fitted to the end of the engine’s crankshaft. A blade is designed to slip on the blade boss if the mower blade hits a solid object.
Over-tightening the blade will prevent the blade from slipping on the boss, and will instead bend the crankshaft and destroy the engine.
Check out the video on blade fitting, it covers torquing the blade to specification. You might find the video on using a torque wrench.
Can you sharpen a Mulching blade?
You can sharpen a mulching blade, it is sharpened in the same way as a collecting blade, best results are achieved by removing it before sharpening and balancing.
Which way do mower blades tighten?
A single-blade lawn mower blade bolt will be a right-hand thread. Viewing the mower on its side (carburetor side up). To tighten the bolt – turn clockwise. To loosen the bolt – turn anticlockwise. I wrote a post on a similar subject “How to remove stuck blade bolt”
Which side of the lawn mower blade is up?
All mower blades will have a lifted trailing edge. The lifted edge points upwards, to the underside of the lower body.
This side up
Do lawn mower blades need to be timed?
A single-bladed mower will not need to be timed. A twin-blade walk behind mowers like a Toro or some lawn tractors will need blade timing. The purpose of the timed blades is so the blades can overlap.
Overlapping blades help prevent uncut grass between the blades. If your blades can touch each other, then yes it’s likely you have a timed deck and the blades will need to be timed. I wrote a post about timing your mower blades here “Replacing timed mower belt”.
Timed Blades
What causes a lawn mower to cut uneven?
There may be several reasons why your mower is cutting unevenly, here are some of the more common reasons:
- Deck wheels are set to different heights (Walk behind mower)
- A bent/worn blade
- Uneven tire pressures (tractor mower)
- Deck needs to be levelled (tractor mower)
Should the front of a push mower be lower than the back?
A lawnmower deck should be level, front to back and side to side. All mowers will have a height adjuster, some will have a single lever, and others will have a height adjuster at each wheel. Level the deck by adjusting the wheel heights.
Level – Adjust all-wheel heights until the deck is level.
What does a high lift mower blade do?
A High lift blade has a trailing edge that lifts sharply upwards. This causes a powerful vacuum effect on the grass blades, lifting them upright before cutting them. The high lift blade is specially designed to collect grass and it does so really well.
An engine will need to be sufficiently powerful to drive a high lift blade, not all mower engines are. Check with your dealer before fitting a high lift blade.
Hey, I’m John, and I’m a Red Seal Qualified Service Technician with over twenty-five years experience.
I’ve worked on all types of mechanical equipment, from cars to grass machinery, and this site is where I share fluff-free hacks, tips, and insider know-how.
And the best part. it’s free!
How Sharp Should a Lawn Mower Blade Be (For a Great Cut!)
Does a lawnmower blade really have to be sharp?
Grass of any thickness is no match for a blade, especially one rotating at 3000 rpm, no matter how sharp it is, right?
This article will answer some of the most common questions about lawnmower blades like just how sharp they should be.
So you can take your first step towards having a more beautiful lawn!
How Sharp Should a Lawn Mower Blade Be?
Generally, you want your blades to be sharp, but not razor sharp, about the sharpness of a butter knife. Overly sharpened blades tend to dull a lot faster and are a hazard to handle safely as well.
A sharp blade will cut the grass just as well as a razor sharp one. In fact if you sharpen your blade to razor sharpness you will have to sharpen it more frequently making your mower blade last less before you have to get a new one. It’s a fine balance between not making your blade too sharp fragile so it can actually do its job and having a blade that isn’t sharp enough. In this article we will see what difference does a sharp blade makes,what a sharp blade even looks like and if you need to sharpen new Lawn mower blades any further.
Do sharp mower blades make a difference
Sharpness does matter, think of it like cutting a carrot with a kitchen knife versus a plastic knife. A sharp kitchen knife will provide neat, quick and symmetrical carrot slices. A butter knife not only takes too much unnecessary time and effort, it’ll make sloppy and uneven slices once it finally manages to make a cut. The same principle applies for grass. A dull-edged lawn mower blade will tear up blades of grass rather than making a neat cut like a sharp one would.
Is mowing with a dull mower blade worth it
No, a dull blade could spell problems for your frontage. Now, if you believe that you have been cutting your grass with a dull blade, don’t panic. Mowing with a less-than-sharp blade a few times is hardly a death sentence for your lawn. However, doing it regularly over a long period of time can have negative effects on your overall turf health, according to The Wykles. In addition to making an ugly-looking, uneven lawn, improperly cut blades of grass are more susceptible to bacteria and fungus, which could lead to yellowing. Also if you are planning to start a Lawn Mowing business ,than a sharp blade is a Must have!
Do brand new lawn mower blades need to be sharpened?
If you are new to homeowning and are looking to buy your first mower, you might run across some conflicting information on online message boards about whether you should sharpen new lawnmower blades or not.
In general, no, you don’t have to sharpen new blades. If you purchase a lawn mower factory new and according to specifications, the blade should be ready to go. If you do feel the need to sharpen your new blades, you should make sure that the blade is properly balanced before you head out to work, since you don’t end up with a wobbly mower, as this could damage your mower in the long run.
John Deere mower blades
No New John Deere mower blades don’t need to to be sharpened. In fact John Deere has a self-sharpening blade on the market for 60-inch decks, so some of you with riding mowers may not even require sharpening at all.
Honda mower blades
Customers generally report that Honda blades are sharp enough to provide a clean cut as soon as they are purchased,so they don’t need to be sharpened (replacement blades also come cheaper than John Deere).
Husqvarna blades
No. In fact, Husqvarna specifically asks that you not sharpen their new blades. Their official website claims that “A new blade is precision designed and manufactured for excellent quality of cut and balance.”
Why are some new mower blades not sharp?
Sometimes, brand-new blades will have a coat of paint on the cutting edge that might need to be sharpened off for the best cut, but more often than not, this coat of paint is only thinly applied so customers don’t cut themselves taking a new blade out of the box, so it should flake off after you run the mower for long enough.
In general, check the mower’s instructions and the blade itself (carefully of course, don’t hurt yourself) if you want to play it safe. It also won’t hurt to give the new blade a quick test run in an inconspicuous area if you’re really not sure about its efficacy. However, if you are buying used or borrowing your neighbor’s mower, it’s a good idea to at the very least check the blade to see if it is sharp enough before you mow.
How often should lawn mower blades be sharpened
For a residential setting (that is to say, your front lawn), you should sharpen your blade twice a year, maybe more if you live in a temperate area with a long mowing season. But here’s a solid tip that I learned while working for Josh and Elise Wykle, the owners of Lawn Impressions, a great lawncare business in Mecklenburg, NC, when I was a teen.
If you notice something’s up with the way your mower is cutting, check to see if there’s anything wrong with the blade, even if it’s a bit early. Your blade might be too worn down, it might have sustained some damages, or it might be improperly balanced. It’s better to catch these problems early so they don’t cause sustained damage to your lawn or to your mower.
What should a sharpened lawn mower blade look like
A sharpened blade has a shiny and bright cutting edge (which is the slanted part, not the back part of the blade. Don’t sharpen the back part of the blade ). Also, when you are sharpening your blades, you want to make sure your blades are free of any major nicks or defects.
Remember, your blades can get damaged should you accidentally run over something hard like a root or a rock (or in my case last year, an old bit of scrap metal hidden in the overgrowth), and these damages can result in an uneven cut no matter how sharp your blades are. Now, smaller nicks can be eliminated with sharpening, but if you see something too major to be fixed when you’re checking your blades, or notice that the quality of your grass is not improving even after sharpening them, you should invest in some new blades.
When should I sharpen my lawn mower blade?
While, like I stated earlier, it’s a good idea to check on your blades as soon as you notice performance issues starting, you should sharpen your blades after every twenty-four hours of mowing. A pretty simple way of figuring out when exactly you have reached twenty-four hours is to time how many minutes it takes to mow your lawn, then divide 1440 (the number of minutes in twenty-four hours) by the number you got. This should give you a solid estimate of how many times you can mow your lawn before the blade needs sharpening.
Related questions.
How many times can I sharpen my lawn mower blade
This is a bit of a tricky question, since lawn mower blades come in a variety of sizes and thicknesses, and different yards could contain more or less obstacles for a blade to be nicked or dented on, which could then require more frequent sharpening. According to official specifications, you can sharpen your blade and as many times as you need, until more than a third of the blade’s original width is gone.
After this point, you need to throw it away. It’s a good idea to take a measurement each time you sharpen your blade, so you know when to replace them without having to rely on guesswork or your own memory, which, if your memory is anything like my own, is probably less than optimal.
How much does it cost to sharpen lawn mower blades
Once again, a bit of a tricky question. There’s a wide range of tools out there, but luckily, the price range is flexible enough that you can purchase a tool regardless of your budget. If you’re looking for the cheapest options, you could pick up a sharpening file for about 10 depending on where you look.
There are also whetstone attachments that you can purchase for your power drill for about the same price, although multipacks featuring replacement whetstones, blade balancers and gloves can cost somewhere around 15-20. However, if you have some money saved up, you could invest in a bench grinder. These can go for as cheap as 40 and as expensive as 2000, but some of the highest reviewed grinders out there usually cost around 130-330.
In addition to buying your sharpening tools, if you haven’t already, it would be wise to purchase other essential tools for blade sharpening. You need a vise clamp to hold the mower blade still while you sharpen it, and depending on the length of the vise, it should cost around 20-90. You should also pick up a lawn mower blade balancer, so you don’t accidentally throw off the balance of your mower and damage it. Some of the fancier balancers such as the Oregon 42-047 are a little over 100 if you have deep s, but the simpler models like the Oregon 42-100 are somewhere around 10, and some 15 whetstone multipacks come included with a balancer.
Lastly, while not essential, I recommend picking up the Arnold Blade Removal Tool while you’re at it. The Blade Removal Tool was specifically made to hold the blade in place while you work on loosening the nut with your combination wrench, and it can definitely save you some hassle.
What is the best lawn mower blade sharpener
There are plenty of gadgets out there that market themselves as the perfect blade sharpening tool. Two of the highest rated blade sharpening tools of 2020 are the Magna-Matic MAG-9000 and the Oregon 88-023. However, these also cost a pretty penny, the MAG-9000 costing a whopping 750 and the 88-023 coming in at about 430. The Wykles personally recommend a bench grinder for the job; not only are they the most efficient way of keeping your blades sharp, they also cost much less. I’ve provided a cheat sheet for some of the best reviewed of these grinders and their average below.
JET 577102 – 8-inch, 1 HP, Model # JBG-8A ~ (330.00)
RIKON Variable Speed Bench Grinder- 8-inch, ¾ HP, Model # 80-800VS ~ (200.00)
DeWALT DW758 – 8-inch, ¾ HP, Model # DW758 ~ (130.00)
Central Machinery Bench Grinder- 8-inch, ¾ HP. ~ (50.00)
WEN 4276 Bench Grinder- 6-inch, 2.1 Amps ~ (50.00)
It can be intimidating to tackle DIY lawncare for the first time, and just like any other long-term task, it has a lot of steps to follow. However, trying to tackle all those steps at once will overwhelm you. Becoming fluent with just one step at a time will help you not only remember everything better, but also become a skilled and natural homeowner. Just remember to stay sharp!
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.
Sunlight, rain and nutrient rich soil may not overcome the damage of a dull blade. The health of your lawn depends on a clean cut. Always start the season with sharp blade edges and a clean deck. A sharp lawnmower blade produces a clean cut through grass plants reducing stress and water loss. After the initial cut through the grass plant a sharp blade and quality lawn mower deck reduces the clippings into fine mulch. Small clippings return to the soil surface and feed your lawn. The tips recover quicker from the efficient cut and the fine mulch powers nutrients to the root system.
Renewing and sharpening blades is essential to lawn health. This article helps define a dull blade and explores the benefits of replacing with new and best practices when sharpening blades.
A dull blade leaves grass plants ripped or torn. When grass is torn or loses excessive water, the tips will turn yellow or white. A lawn full of dry, yellow grass is a clear indication that your lawnmower blade is damaging your lawn. A poor blade edge also leaves clumps of grass across your lawn. These clumps block the grass plants from vital sunlight and air. Excess grass clippings may also produce thatch between the soil and air. This effectively chokes your lawn.
Start the season with a sharp or new blade. Keep track of the hours or number of mows you perform. Typically, blades dull after 8-12 hours of use. Visual inspection is not ideal but any nicks and imperfections along the cutting edge demonstrate a dull blade.
Uneven wear, damage and debris will cause a blade to become unbalanced. Unbalanced blades may damage spindles, pulleys and belts. These components are typically far more expensive and more difficult to repair than simply sharpening or replacing dull blades. On newer electric mowers, damaged or unbalanced blades can quickly damage drive motors.
A brand new blade
Genuine factory blades (or Original Equipment Manufacturer) feature the optimal cutting edge both for quality of cut, efficiency and longevity. Lawnmower blades are designed to make a clean cut while remaining effective over a long period of time. For this reason, new blades are never razor sharp or even as sharp as a knife edge. The cutting surface is durable across multiple hours and withstands unseen hazards like small twigs, leaves and in some cases litter. Generally, a new blade may remain productive for 8-12 hours of use. For some homeowners this may be a complete mowing season while others will need to sharpen throughout the season.
Always replace blades with the authentic blades recommended and/or manufactured by the brand. Honda, Hustler, Spartan, Toro and all other brands feature proprietary blades. Using a “universal” blade will alter performance and may even damage your lawnmower.
Finding authentic blades is simple by searching our site using your model number. SHOP OUR BLADE KITS and find all the parts for your model with our Custom Search Tool (HOW TO USE SEARCH TOOL)
A Sharpened Blade
How a blade is sharpened is key to performance and safety. Our staff carefully sharpens and balances blades. These freshly sharpened blades will perform as well or better than a new blade. The cutting edge is so sharp that we coat blades in wax to protect our staff and homeowners when handling sharpened blades. This razor edge cuts through your lawn extremely well and our balancing techniques protect lawnmowers.
There are key differences between new and sharpened blades:
- Sharpened blades dull quickly. The razor edge wears quicker than factory blades.
- Sharpening a blade exposes the metal to oxidation.
- Blades should be carefully balanced during sharpening to prevent damage to lawnmower engines, spindles, pulleys and belts.
- Some blades should not be sharpened because of excessive wear or damage. Any nicks, chips, warping or rounded edges should be considered before sharpening a blade. These imperfections will make balancing the blade more difficult (as examples below demonstrate).
The first image is a blade with excessive chips and nicks. This blade has not been sharpened frequently and should be replaced.
The middle blade is bent. Striking anything in your yard often results in bent blades. Any alteration in the blade may damaged your engine or deck spindles.
The far image shows excessive wear. Eventually a blade must be replaced even if the blade is sharpened regularly.
Our Best Advice
I follow the rule of warm season holidays. I sharpen or install a new blade at the start of the season. I sharpen around Memorial Day, Fourth of July and Labor Day. You can also keep track of how long it takes to mow your lawn and create your own schedule based on sharpening every 8-12 hours of use.
Most walk power mower manufacturers recommend replacing blade annually. Riding mower recommendations vary. Many blades are thicker and may be sharpened numerous times before replacement is required.
You can drop off blades for sharpening any time. Our blade sharpening service takes only a day or two so your mowing schedule won’t be interrupted.
Removing your blade is pretty simple as in the examples below. Refer to owners manual for guidance on turning walk mowers onto their side (always disable the spark plug from the ignition coil and be aware that air intake must be facing upward when servicing your mower). Blades typically are secured with a single bolt and washer (Honda uses 2 bolts and washers).
Editor’s Note: This article was updated on June 16, 2022
