Knowing how to sharpen lawn mower blades is vital to keeping your machine in top condition for years to come so that ultimately you can keep your lawn healthy too. Yard tools, especially the best lawn mowers, are often investment purchases that you want to last, so it's important to know exactly how to maintain them.
A lawn mower with dull blades makes mowing significantly less efficient and it can also be detrimental to the health of your grass as well. Even the very best gas lawn mowers or electric lawn mowers will suffer if their blades aren't kept sharp, so learning how to sharpen lawn mower blades correctly will give your mower a fresh lease of life.
The sharpness of a lawn mower's blade can greatly affect how easy it is to cut your grass, but a dull blade can actually make your lawn more prone to disease and less able to cope with extreme weather conditions. This means that prolonged dry spells or patches of heavy rain can leave your grass beleaguered, rather than flourishing into the lush, vibrant green lawn you're aiming for.
Here, we will take you through the best methods to sharpen lawn mower blades with step-by-step advice. This will leave your lawn mower blades good as new so that you can give your yard an accurate cut. If you're looking at giving your lawn mower a full MOT ahead of Spring and Summer, then it's also worth learning how to put gas in a lawn mower so your machine will be ready to use.
Why should you sharpen your lawn mower blades?
The most important aspect of mowing your lawn is actually cutting your grass with the lawn mower blades. If the blades aren't sharp, then they'll actually rip and tear the grass rather than scything through it neatly. These tears will weaken the grass and leave it vulnerable to disease and fungal growth, which can degrade the quality of your lawn.
It's also worth noting that even the best riding lawn mower will be difficult to use properly if it has dull blades. This can make the task of mowing your lawn longer and more stressful than it needs to be.
How to sharpen lawn mower blades
David Gower, chairman of the Lawn Association, says: “Sharpening is something of a skillset we’ve lost. A tool to sharpen lawn mower blades could consist of a simple file (or angle grinder if you are feeling a little braver) will take minutes to create a new sharp edge. And remember, even new blades don’t always come sharpened. But a great idea is to buy a spare blade, which gives you all week to sharpen before the next mow!’’
David Gower explains what happens when lawn mower blades are not sharpened: “Blunt mowing of grass comes down to many lawnmower manufacturers not being lawn specialists and often advise sharpening a blade with a service (once per year) is sufficient. It won’t be. When we cut or mow grass with a blunt blade it literally tears the grass blades causing the grass to turn dull at the end of the tips. Do this all over your lawn and you instantly lose the color in the lawn. It will then struggle to take in food and water and ultimately be unhealthy….’’
1. Turn off and remove
You can remove the blade to sharpen it, although it is possible to do it in situ. Whichever method you choose, ensure that the mower is unplugged if it is electric, or that there is no chance of the mower starting by accident (you may have to tape spark plugs for instance).
2. Position the blade
If you remove the blade, be sure to mark which is the top or bottom edge, so that you replace it the right way up. It won’t matter how sharp your blade is - it won’t cut if it’s upside down! The best way to hold the blade is by clamping it into a vice before you start work.
3. Start to sharpen
Use your file to sharpen from the top edge of the cutting blade (and remember the file will only cut on the push stroke - do not run it backwards and forwards). It should take no more than 50 strokes to get the blade sharp again - it would be quicker with an angle grinder, but unless you are very confident, you run the risk of damaging or overheating the lawn mower blade.
The lawn mower blades will have come from the factory with a specific angle on their cutting edge - make sure you keep to that angle each time you sharpen - it is usually between 35 and 45 degrees.
4. Replace the blade
When you replace the blades in your lawn mower, make sure that they are balanced correctly, or they may cause vibration and ultimately damage to your mower
Safety note: If you have a cylinder mower, it is best to leave sharpening to a professional.
How to tell when your lawn mower blade needs sharpening
It should be relatively easy to tell when your lawn mower blade is blunt, simply by looking at it. If there are visible dents, nicks or chips in the blade then this is a sign that it needs to be sharpened or replaced.
If you've recently mowed your lawn and the results aren't what you expected then this is also a great way to tell that the blades need to be sharpened. When lawn mower blades are blunt, the quality of the cut will be poor. Having sharp blades means that the cut will be precise and neat, so if your grass is looking messy and uneven right after cutting it then it's worth taking a closer look.
How often should you sharpen lawn mower blades?
David Gower says: “This is very much down to any individual and how nice a lawn you want. Grass obsessives should be doing this each week. For many, every two to four weeks will still be beneficial. It’s down to your own effort but never blame the tools when they’re your tools!’’
You should generally sharpen your lawn mower blades after at least every 20-25 hours of mowing (although doing it more often will certainly not hurt!). However, if you find yourself struggling to mow your lawn before this time frame is up, then it's worth sharpening them a little earlier.
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Knowing how to sharpen lawn mower blades is vital to keeping your machine in best condition for years to come so that ultimately you can keep your lawn healthy too. Yard tools, especially the best lawn mowers, are often investment purchases that you want to last, so it's important to know exactly how to maintain them.
A lawn mower with dull blades makes mowing significantly less efficient and it can also be detrimental to the health of your grass as well. Even the very best gas lawn mowers or electric lawn mowers will suffer if their blades aren't kept sharp, so learning how to sharpen lawn mower blades correctly will give your mower a fresh lease of life.
The sharpness of a lawn mower's blade can greatly affect how easy it is to cut your grass, but a dull blade can actually make your lawn more prone to disease and less able to cope with extreme weather conditions. This means that prolonged dry spells or patches of heavy rain can leave your grass beleaguered, rather than flourishing into the lush, vibrant green lawn you're aiming for.
Here, we will take you through the best methods to sharpen lawn mower blades with step-by-step advice. This will leave your lawn mower blades good as new so that you can give your yard an accurate cut. If you're looking at giving your lawn mower a full MOT ahead of Spring and Summer, then it's also worth learning how to put gas in a lawn mower so your machine will be ready to use.
