You’ll hear some people say you should sharpen lawnmower blades after every use. Others may point out that once a season is enough, while the rest maintain that you only need to sharpen them when they start to lose their edge. So who’s right?
You want the lawnmower blade to have an edge of 30-degrees or close. If the blade is too sharp, it will be more susceptible to damage and need to be sharpened often. If the blade is too dull, it will tear the grass rather than cut it cleanly.
This article explores some related topics, including how often you should sharpen your lawnmower blades and what tools you’ll need for the job.
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A lawnmower blade is sharp enough if it glides across the top of the grass. It should also not leave a windrow of uncut grass, have trouble cutting through a piece of newspaper, and make mowers hard to push and cause excessive stalling.
If your lawnmower is starting to dig the ground, it’s time to sharpen its blade.
Another way to tell if the blade is too dull is if it starts leaving a windrow of uncut grass. A windrow is a row of grass that’s been mowed over but not cut. This is a clear sign it’s time to sharpen the blade.
You can also try the “paper test.” Hold a piece of newspaper against the side of the blade while the engine is off. Then start the engine and slowly move the paper toward the blade. If the blade is sharp, it will cut through the paper. If the blade is too dull, it will tear the paper.
A dull blade also makes the mower harder to push. This is often accompanied by frequent stalling. It’s usually a sign that you’ve ignored multiple warning signs of a dull blade — in which case it’s time for a major sharpening.
A lawnmower blade can be too sharp, which is never a good thing. If the angle is less than the recommended 30 degrees, you will have to sharpen the blade more often, which will shorten its lifespan. This is because a sharp edge will get nicks and chips more easily.
A lawnmower blade that’s too sharp is also more likely to cause damage. It will slice through objects more easily than a dull blade. For example, if your kid forgets about the new sprinklers and accidentally runs over them while mowing, the sharp edge is more likely to damage the sprinkler.
The problem is that sharpening a blade to the recommended 30 degrees is hard to achieve without special equipment. Most people don’t have the necessary tools, so they end up with results that would’ve been much better had they gotten help from a professional instead.
New mower blades are already sharp enough to do the job. You may find the blades a little dull for your liking, but there is a good reason the manufacturer made it that way. If the blades are too sharp, it could sacrifice their relative durability.
You can sharpen your lawnmower blade, but it is not as easy as it sounds. And unless you have the right tools, you may end up with an edge that is too sharp.
If you’re going to sharpen your blade, you’ll need:
- A bench grinder
- A vise
- A honing guide
- Safety glasses
To do this right, you need to follow the steps below:
- Remove the blade from the lawnmower. This is because you need to access both sides of the blade.
- Once the blade is out, use the vise to secure it. Then, use the honing guide to set the angle. For most lawnmower blades, you’ll want to use a 30-degree tip.
- Start with the coarse wheel on the bench grinder. Grind slowly, and don’t apply too much pressure. You just want to remove the nicks and chips.
- Switch to the fine wheel once you’ve removed the nicks and chips. Again, grind slowly and don’t apply too much pressure. You’re just trying to smooth out the blade. Then use a honing stone to remove any burrs.
- Remove as little metal as possible. If you remove too much of the metal, you’ll end up doing more harm than good to the blade.
- Reattach the blade to the lawnmower. At this point, you should be good to go.
As you can see, sharpening a lawnmower blade is not a simple task. It’s something that should be left to the professionals. Unless you have the right tools and know what you’re doing, it’s very easy to get this all wrong.
If you’re not sure whether your blade is too sharp, take it to a professional and have them take a look at it. They will advise you on what to do next.
How Much Does It Cost to Sharpen a Lawnmower Blade?
The cost of sharpening a lawnmower blade ranges from $20 to $60 if you are taking your blade to a professional. This is because they have the necessary equipment and know what they are doing. If you try to sharpen the blade yourself, you will likely spend more money in the long run.
You should sharpen your lawnmower blade once a year at least, according to most experts. But if you mow your lawn frequently, you may need to sharpen it more often.
The idea is to keep the blade sharp enough to cut through the grass but not so sharp that it becomes prone to damage. I’ve already shared some of the signs of a dull blade earlier.
As I’ve mentioned, if you’re not sure whether your blade needs sharpening, take it to a professional and have them look at it. They’ll be able to tell you whether it requires sharpening or not.
It is possible to sharpen a lawnmower blade without disassembling it. But it is not as easy as it sounds. Unless you have the right equipment, it is very easy to damage a blade or give it the wrong sharpness.
On top of that, sharpening a lawnmower blade without disassembling isn’t recommended by professionals. That’s because it can be dangerous. If you’re not careful, you can easily cut yourself. But if you’re determined to sharpen your lawnmower blade without removing it, here’s what you need to do:
- Thoroughly clean the blade. This will help remove any dirt or debris that could dull the edge.
- Use a sharpening stone to grind the blade. Start with the coarse side and then move to the fine side.
You will end up with a sharp blade to cut through the grass. Again, be careful when you do this. You can easily damage the mower or hurt yourself.
Sharpening a lawnmower blade with a grinder is possible but not recommended. Grinders create a lot of heat and can damage the blade’s temper. If you must use a grinder, use a light touch and keep the edge moving to avoid overheating.
However, using a grinder is an easy way to damage your lawnmower blade and void the warranty. You should only do this on an old blade you plan to replace anyway.
If you damage an old blade, it’s not a big deal. But if you damage a new edge, you’ll have to pay for a replacement.
When to Get a New Mower Blade
There are a few instances where you’ll need to get a new mower blade. Here are some of them:
- The edge is damaged beyond repair. This can happen if you hit a rock or something else while mowing.
- The old one is too worn out. Over time, the blade will get thinner and thinner. Eventually, it will be too thin to stay sharp through summer.
- You can’t seem to sharpen the blade correctly. If you’ve been trying to sharpen the edge but it’s still not working, it’s time to give up and get a new one.
Most lawnmower makers buy ready-made blades and stamp their logo on them. It’s pretty common for two different brands to have the same blade. Finding a replacement should be easy and inexpensive.
If you have a unique mower, you may need to order the blade from the manufacturer. But even then, it shouldn’t cost more than $50.
A dull lawnmower blade is one of the main reasons your lawn looks terrible. It tears the grass instead of cutting it, and it can even damage your lawnmower. So, if you want a healthy lawn, you need to make sure your blade is sharp.
But how sharp should lawn mower blades be? Most experts recommend a 30-degree angle. But unless you have the right tools, it’s very difficult to pull this off. However, you can have a professional sharpen it for $20 to $60.
You might also want to read: When Do Lawnmowers Go on Sale?