My new lawnmower just arrived, but the blades don’t feel sharp enough to start mowing my lawn.
So I’m wondering, do brand new lawnmower blades need to be sharpened, why aren’t brand new lawnmower blades sharpened, and what is the right method to sharpen lawnmower blades.
I’ll also delve deeper and discuss how to know when lawnmower blades are dull, and when it’s time to replace lawn mower blades.
So, do new lawnmower blades need to be sharpened? The brief answer to this question is no, it’s not necessary to sharpen brand new lawn mower blades. New lawnmower blades aren’t dull, and are ready to use right out of the box. However, just like a knife, every homeowner should be aware that lawnmower blades should be sharpened regularly to cut grass at the right height.
Do Brand New Lawnmower Blades Need to be Sharpened?
You don’t have to sharpen new lawnmower blades, because they are already sharpened according to manufacturer specifications at the factory before being shipped.
The myth of sharpening brand new lawnmower blades stems from the fact that new blades appear dull, but the blades of these lawn power tools are pre-sharpened to a point where they can cut grass, but not cause injury to you.
Even though lawnmower manufacturers sharpen the blades for your safety, you can go ahead and sharpen them if you feel there’s a tangible difference in the quality of the cut.
When do Lawnmower Blades Need to be Sharpened?
Wondering when lawnmower blades need to be sharpened? Is it after a couple of hours of mowing or once or twice during the mowing season?
The good news is that you don’t have to sharpen lawnmower blades after mowing, but a rule of thumb is roughly after 20-25 hours of mowing or when they get dull.
Your lawnmower blades should be sharpened at the beginning of each new season, and more often if you have a large lawn.
Will Sharpening a New Blade Cause Damage?
Each time you sharpen a lawnmower blade, you shave some of the metal, which affects the life of the blade. If you buy a new lawnmower or install replacement blades, use the mower for at least 25 hours before sharpening the blades.
Clues that Your Lawnmower Blades are Dull
1. Uneven Cuts
Blades over time get dull due to wear and tear, and one of the most glaring signs of dull lawnmower blades is when they produce uneven cuts.
Pay attention to the grass when mowing, and if you notice the grass is somewhat chewed or if it’s covered with brown tips after a day or two, your blades are dull and could benefit from sharpening.
2. Examine the Blades
Tip the mower over to examine the blades, but with the carburetor side facing the sky (for a gas mower to prevent gas spill).
With safety gloves on, run your fingers along the blade, and if you feel any large indentations or gouges, your blades need to be sharpened. A damaged blade should be replaced with a fresh blade.
Can I Use a Lawnmower Blade Even if it’s Dull?
Well, can you use a razor blade if it no longer cuts your hair? Similarly, a dull lawnmower blade will not cut your grass to the right grass height or probably won’t cut the grass at all, and can also affect the visual appeal of your lawn, and the health of your turf.
The ragged edges of the grass caused by dull blades encourage disease and parasites to enter the grass, so mowing with dull blades is possibly the biggest mistake homeowners make.
Plus, the dull edges of the mower blade will pull at the grass, leading to torn blades rather than smoothly cut blades.
These grass clippings will also momentarily cling onto a dull blade before they rip or tear, which causes unnecessary stress on the mower and can lead to the short service life of the tool.
Benefits of Cutting Your Grass with Sharp Mower Blades
There are myriad benefits of using sharp blades to cut grass:
Do I Need to Remove the Lawnmower Blade to Sharpen it?
This depends on how badly damaged or worn the blade is, but I always remove the blade to sharpen it as it tends to be easier this way and doesn’t cause the mower to vibrate.
You can use a wrench or even your hand to loosen the bolt that secures the blade to the mower. My lawnmower features an upright and compact footprint, so it’s easier to access and remove the blade.
Speaking of which, when tipping your lawnmower to remove the blade, wear safety gear like gloves and eye protection, and refer to your user manual to ensure that you don’t saturate the air filter with oil.
Pro Tip: Elevate the lawnmower on blocks for easy access to the underside without tipping the lawnmower.
Here is how it looks like if tilted:
Lawn Mower Blade Sharpening Tools
Sharpening dull mower blades is easier than you think, and there are several ways to go about it.
- 10-inch file
- Eye protection
- Vice grips
- Bench grinder for a sharp blade
- Drill and sharpening stone for really worn blades
3 Ways to Sharpen Mower and Mulching Blades
Method 1 – Clamp and File – Easy Tool to Sharpen Lawnmower Blade
This method is regarded as the easiest way to sharpen a dull lawn mower blade. All you need is a flat file, and a blade secured with a vice.
Grind down any imperfections in the metal by applying pressure on the file until you achieve the shape of the existing edge. Repeat this process for the other side.
Method 2 – Use a Bench Grinder – Fastest Way to Sharpen a Lawnmower Blade
If you have a bench grinder in your tool arsenal, you can use it to sharpen a dull blade edge and entire lawnmower blade.
Get a good grip on the blade, and grind its edge against the spinning wheel of the bench grinder, and you’ll have a sharp blade within a couple of minutes.
Method 3 – Use a Drill and Blade Sharpening Stone
This method is similar to using a bench grinder and is much faster than hand filing.
Read my detailed article on how to sharpen a lawnmower blade?
How to Balance Mower Blades After Sharpening?
A lawnmower blade typically becomes unbalanced during the sharpening process, given that you grind more metal from one side than the other. An unbalanced blade rarely affects the quality of your cuts, but can cause wear and tear to the mower.
You can use a simple blade balancer to test the balance, and then trim the heavier side until the blade is properly balanced.
Now reinstall the sharpened and balanced blade in your mower, but be sure to secure the blade tight.
Still curious? Check out this video from “Brian’s Lawn Maintenance” about sharpening brand new mower blades:
Lawnmower blades fresh out of the box do not need to be sharpened, but over time will turn dull after approximately 25 hours of use. Sharpening a dull lawnmower blade is easy, and you can perform this task with a file, bench grinder, or sharpening stone.
Hi, Alex Kuritz here. Growing up I remember that my family had one of the best lawns in the neighborhood. Richly green and lush. I did a lot as I grew up in terms of caring and tending for not only my family’s lawn but also my neighbors. I can say I have years of experience, and I am here to share it with you.