Lawn mower blade damage. How To Troubleshoot Lawn Mower Blade Problems (Explained)

Why Are New Lawn Mower Blades Dull? (Solved Explained!)

Did you just buy a lawnmower blade, feel the edge, and thought it was dull? I recently was wondering this myself. Why are new lawnmower blades dull I thought? So I did some digging and here’s what I found out.

No, new lawnmower blades are not dull. They are sharp but not to the point that they would cut your finger on the edge. A super sharp edge would just bend over in the first 5 minutes of mowing. Plus sharp blades are more open to damage from rocks and roots. Instead, new blades are sold with a solid edge ready to work. They cut slower and last longer.

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Are They Actually Dull Or Do They Come Sharpened?

No, new blades aren’t dull. They’ve been precisely sharpened to the manufacturer’s specs.

The seemingly dull edge is done on purpose. It’s sharp enough to last for 25 hours of mowing (about 25 weeks of mowing an hour each weekend).

It’s dull enough that it won’t get damaged as easily by roots and rocks. Hitting a rock with a Hyper-sharp blade will just bend the edge making it less effective. Ultimately super sharp blades die faster.

Why Lawn Mower Blades Are Like Blendtec Blades

Have you ever felt the edge of the blade in a Blendtec blender? I have. It’s dull. Or so it seems.

Why is that? Because they use a 2 HP engine that spins at 200 miles per hour. At this speed, it can break fruits and veggies down to individual cells.

How To SHARPEN And BALANCE A Lawn Mower Blade (The Correct Way)

If a Blendtec blade was sharp it’d simply get dull or possibly damaged while spinning. Then you’d have to replace the entire container as it comes fused with the blade.

The same thing is true for lawnmowers. Most push mowers are 2-7 horsepower. Many are just like the Blendtec blender. Just like the Blendtec that puts the tip of the blade at about 200-250 miles per hour.

Blendtec blades and push mower blades operate at 2 horsepower with the outer tip spinning at 200 mph.

Will you mow my lawn? Not really but it uses the same physics to cut.

Do Brand New Lawn Mower Blades Need Sharpening?

No, new lawnmower blades should be used as-is. We actually did a full analysis on what’s more cost-effective – replacing a new blade or sharpening the old one. You can read that article here to see the in-depth results.

The winner though – sharpening. Even at different assumed hourly rates for your time it was almost always better to sharpen the blade.

Both require you to take the blade off so you don’t save much time buying a new blade.

Better to sharpen it every 25 hours than replace it after 400 hours of use. That could be 10 years down the line.

Will Sharpening A New Blade Hurt It?

Yes, if the edge is too fine it could be nicked or damaged by rocks and roots. This will require additional sharpening. Each time you sharpen you whittle away the metal lowering the life of the blade.

If you buy and install a new blade just use it as is then sharpen it after a minimum of 25 hours of mowing. Check it before sharpening. If it seems to be mowing well and there are no nicks or damages, keep mowing even beyond the 25 hours.

The longer you wait between sharpening the longer the blade will last.

Can I Use The New Lawn Mower Blade Even If It Seems Dull?

Yes, just attach the new blade and start mowing. You should be able to go for 25 hours before you need to check it for nicks and scratches. Then check and sharpen as needed.

Remember, new blades aren’t dull. They are perfectly edged to maximize the time they can cut before needing sharpening.

Will A Dull New Mower Blade Kill Grass?

No, new blades are not dull. They are perfectly sharpened and ready to cut for the first 25-50 hours before sharpening is needed.

Even an old nicked dull blade that’s been running for 50 hours won’t kill your grass.

Instead of cleanly cutting grass tips a dull blade will leave the tips jagged. Plus dull blades might miss seed heads if they’re popping up. These can leave lots of tall stout seed stalks scattered throughout the yard.

When that happens just follow the videos below, spend about 1-2 hours sharpening your blade, and get back to mowing. The next time you mow those seed heads will be gone.

Is It Worth The Time To Sharpen A New Blade?

No, sharpening a new blade is not worth the time. It’s already perfectly edged and ready to cut.

Do not sharpen a new blade. You could damage it which would require more sharpening and even more of your time.

When Will a New Blade Need to Be Sharpened?

New blades need to be sharpened after at least a few hours of mowing. Typically after 25 hours, you should check the blade for nicks or damage then sharpen it as needed.

Tools Needed To Sharpen A Lawn Mower Blade

Use a 10 Inch File for hand sharpening. You only need 40-50 passes. We recommend this option as it’s more cost-effective than power tools. Plus you’re less likely to mess things up as you learn to file.

If you plan to use power tools you’ll need a power grinder instead of a file and you won’t need the vice grip as you’ll be holding the blade and running it over the grinder.

Power grinders can speed things up but don’t buy one just for lawn mower blades.

How To Sharpen A Lawn Mower Blade With Power Tools

Hi, I’m John Stephens, chief editor and writer for I’ve been gardening and raising animals for over 15 years starting with a small backyard plot in Northern Virginia where I grew corn, potatoes, squash, and using a high mulch technique called the Ruth Stout Method.

I also raised ducks and small mammals for meat and eggs in a movable pen similar to the ones used by Joel Salatin. I later moved to Colorado where I experimented with growing greens using aquaponics inside. I eventually added a microgreens setup and home sprouting operation. I’m excited to share everything I’ve learned plus more from the other local gardening and animal raising experts I know.

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How To Troubleshoot Lawn Mower Blade Problems (Explained)

Have you ever encountered a situation where your lawn mower blade stopped working properly, and you noticed that it started to cut the grass unevenly or poorly?

If yes, you might have wondered if it is possible to troubleshoot such a blade problem and if possible, how to troubleshoot a lawn mower blade problem.

Firstly, gather up all the necessary tools and materials. Then, look for uneven wheel adjuster or mower deck and replace the deck if necessary. After that, check whether the blade is installed properly or not and if required, install it accordingly. Next, check whether the blade is bent, dull or loose and replace it if required.

Keep reading this following article and learn the detailed way of troubleshooting lawn mower blade problems.

What Causes the Problem?

Often lawn mower users complain that sometimes they notice that their mower blade won’t engage or they could see rows of uncut grass while mowing with their lawn mower.

When your lawn mower’s internal battery is weak, not charged enough, or dead, you will encounter a blade, not engaging issues.

If you have not maintained the lawn mower blade sharpening or scheduled servicing properly, it’s obvious that your mower blade will turn dull or bent and if that’s the case, you will notice uneven cuts or rows of uncut grass like I mentioned earlier.

Lawn mower users have also mentioned noticing loose blades while they were having cutting issues and it can occur either due to overuse or lack of regular maintenance.

Such normal wear or tear issues of lawn mower blades mostly occur when the mower is getting older.

Steps to troubleshoot lawn mower blade problems:

If you suddenly notice that your lawn mower is not cutting the grass evenly or the cutting looks weakly done, it most probably happening due to a dull, bent, or loose blade that your mower has. In that case, you need an immediate, easy but effective fixing solution.

That’s why I have enlisted an easy and quick troubleshooting method in today’s article.

Things required to troubleshoot lawn mower blade problems:

Have a proper glance at the checklist of the necessary tools and materials for this task:

Step 1- Look for an Uneven Wheel adjuster or Mower Deck:

If your wheel adjusters are not all set to the same level, you won’t have a consistent mowing height.

Therefore, you need to check them accordingly, and in case of severe damage or wear issues, replace the defective parts as required.

Otherwise, clean them thoroughly and use WD-40 on them. Remember, a little amount of WD-40 can go a long way.

Also, inspect your lawn mower for damaged or bent mower deck, including any signs of excess rust.

While you are at it, remove any build-up grass from around and underneath the mower deck.

Step 2- Replace the Damaged Mower Deck:

If the mower deck looks damaged, you should replace it and before the replacement task, remove the fuel from the gas tank as well as oil from the engine.

Next, remove the control cable from the engine.

Then, remove the pull rope from the handle.

After that, remove the rear portion of the mower from the deck (including the rear housing, wheels, and handle).

Now pull the side of the deck out a little to remove these tabs from your mower.

Then, tip the mower up on its back and remove the front portion by removing the bolts.

Next, use a 2×4 through the side door on the mower to prevent the blade from spinning while removing the bolt.

Remove the engine from the deck by releasing these bolts.

Set the deck in the motor back down flat on your workbench to remove the rest of the bolts and take out the engine to put aside.

Lastly, remove the sight discard door.

Now, assemble the new deck on your mower by using the same steps but in reverse motion.

Step 3- Inspect whether the Blade is installed improperly:

It is not uncommon for people to accidentally install their cutting blade upside-down, but doing this will tear your grass rather than cut it.

Most mowers spin the blade clockwise that’s why you need to make sure your cutting edge is facing the same direction.

Thus, have a look at the blade to confirm it’s installed properly and if not flip it.

Step 4- Check whether the Blade quality is poor or not:

Inspect the sharpness of the blade and give it a quick sharpen if it is dull because a dull blade will also tear your grass rather than cut it properly.

A simple file can help you to get the job done, but a grinder will make it quicker.

A table grinder will help restore your blade but if you don’t have access to one, simply replacing the damaged blade with a new one is a Smart idea.

Be sure to sharpen the blade a few times per season to keep cut quality at its best.

You should also take this opportunity to inspect the blade for damage or wear like nicks or damaged or chips caused by rocks.

To learn the sharpening procedure in more detail, watch this video.

Step 5- Replacing the Mulching Blade:

If your mower seems underpowered or cuts the grass poorly, it might be the right time to replace the mulching blade.

First, tip the mower on its side to have clear access to the blade.

Then, bind up the blade with a piece of scrap wood and use a ratchet wrench to remove the single nut that’s holding the blade.

You can also see a metal spacer and the insulator, so remove them too.

Next, pull away the blade from the fan and install the new blade now.

While installing the new one, confirm you are pointing it in the right direction. Thus, look at the blade, you will see the “Grass side” mentioned, and this side should be towards the grass.

Now, install the blade onto the hub on the fan and then, reinsert the metal spacer as well as the insulator.

Performing such repairing tasks can be hazardous. Thus, make sure you have enough knowledge and expertise to perform them. Remember to first read all the instructions manual before operating, servicing, or troubleshooting it.

Frequently Asked Questions

How often should I inspect and sharpen or replace the Mulching blade of my lawn mower?

The blade should be inspected regularly and sharpened or replaced at least once per year for better mowing and mulching performance.

What causes the lawn mower Mulching blade to vibrate during use?

When the mower blade strikes larger debris, it nicks the blade and larger nick can cause such vibration during operation.

How to determine if my lawn mower blade needs to be replaced?

If you see sizable dents or if the lawn mower blade is bent, you can confirm that it needs to be either sharpened or completely replaced.

Final Verdict

If your lawn mower is also failing to deliver a perfect cutting finish and ruining your grass texture, take a moment to look deeper into the issue.

In today’s article, I already provided the easiest way to troubleshoot the mower blade problems. Initially, the entire troubleshooting process might seem a bit complicated, but eventually, you will be able to fix the issue in no time.

Thoroughly follow all the instructions to troubleshoot Lawn mower blade problems to get the best outcome.


Mow Like a Pro: How to Sharpen Mower Blades

Sharpening your mower’s blades twice each season helps maintain your lawn’s health and appearance. Having a sharp blade cuts grass blades cleanly, allowing them to recover quickly. It can also help reduce your mowing time. Read on and learn about how to sharpen mower blades like a lawn professional.

Blades with Normal Wear and Tear

During its lifetime, a mower blade hits rocks, branches, and thatch on your lawn that cause nicks, dings, and curls. Dull mower blades rip the grass blades instead of cutting them cleanly. Ripped grasses are more vulnerable to lawn disease infections. If your blade is in fairly good condition, sharpening it can be a fairly easy task. To sharpen, clamp your blade in a vise and run a metal file along its cutting edge. Ensure that you are following angle of the factory bevel. Always remember to disconnect the spark-plug wire before removing the blade or performing other kinds of mower maintenance. Sharpen the blade every two weeks to maintain your blade.

Badly Damaged Blades

Blades that are more damaged require different care. They should either be replaced or sharpened on a bench grinder. Take the blade to the professionals at a service shop. There, they will inform you as to whether it’s time to spring for a new blade or they will sharpen it for you with a grinder. If you have your own personal grinder, however, you can sharpen the blade yourself.

How to Sharpen, Balance and Change Lawn Mower Blades | How To Anything

To sharpen your own blade with a grinder, smooth out nicks by running the blade back and forth against the spinning wheel vertically. Doing this gives you a straight edge. It will be blunt, so next, support the blade on the rest plate. Then hold the blade at the angle of the existing bevel. Grind the blade’s length until its edge is sharp.

Balancing Act

Always be sure that the blade is balanced, as an off-kilter blade can damage your mower. You can purchase a plastic balancer at most local lawn-care centers for an affordable price. To use, start by resting the blade on the balancer. If one side dips down, it means the steel needs to be ground on that end—not from the cutting edge—in order to lighten it. After you have balanced the blade, it’s safe to bolt it back onto the mower. Now you’re ready to mow!

Questions? Call the professionals at Cardinal Lawns for advice or assistance with your yard.

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