To get the perfect lawn and keep your grass healthy it is vital to sharpen your lawn mower blade. Here’s how. Article and video instructions.
The Video. Sharpen your mower blade
There is also an easy to follow Youtube video on my channel to support this article.
It’s spring. The weather is beginning to get a bit warmer and the grass is starting to grow. Now is the time to sharpen your lawn mower blade. You may also need to sharpen it a couple more times throughout the season depending on how much you use your mower. Having a sharp lawn mower blade will help you achieve a great looking and healthy lawn.
The tools I use
- Scraper
- Spanner
- Clamp
- Metal file
- Angle grinder
All of the tools above can be found in our Amazon affiliate shop.
https://www.amazon.co.uk/shop/spendtimesavemoneydiy
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.
Thanks for reading and watching
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Like!! Thank you for publishing this awesome article.
My dad has been complaining for the past month that his lawn mower hasn’t been working as effectively as usual, and it’s been leaving his lawn taller and with a less smooth cut than usual. Your advice to use a metal file after clamping down the blade and to ensure you use multiple passes with even pressure would be helpful. I don’t think he has a good enough file, so maybe it would help for him to find a blade sharpening service so that the work is done by experienced professionals in order to avoid any mistakes or other problems.