Is it Better to Sharpen Lawn Mower Blades or Replace Them? (Solved & Explained!)

With a new set of blades, you can expect about 100 to 200 hours of work use, provided that you are sharpening regularly every 20 to 25 hours of use. After this period, it is best to replace the blades, unless you are using commercial-grade mowing blades. These can last up to 400 hours, in some cases, if properly maintained.

In the rest of the article, we’ve compiled the most commonly asked questions when it comes to sharpening and the overall lifetime and use of your mower blades. Stay with us and get the answers that you need to get the most mileage from your mower!

Does sharpening mower blades matter?

Yes! Keeping your blades sharp ensures that you will get the longest work life out of your mower blades and it also is the only way to keep the cutting nice and even. Sharpening should be done regularly and failure to do so will result in your blades tearing the grass, rather than cutting it cleanly.

This damages your lawn and also is bad for the blades, so regular maintenance in the form of sharpening is going to be a must.

Do replacement lawn mower blades need to be sharpened?

New and replacement lawnmower blades so not need to be sharpened initially, as they will come from the manufacturer already sharpened and ready for installation and use. This is a good time to check the blade with your finger – don’t worry, it’s not sharp enough to cut you.

By touching the edge, you’ll get a good idea how sharp the blade should be when you need to sharpen it for the first time – once you have used them for 20 to 25 hours of work use.

How much does it cost to sharpen a lawn mower blade?

This will depend on the vendor, but on average for standard mowing blades you can expect the cost to be anywhere from $5 to $15 per blade. Mulching blades may cost a little more and for commercial blades, it’s best to contact the vendor directly. These may run a little more, but you might be able to negotiate a deal for regular, scheduled sharpening. 

How long should mower blades last?

On average, provided that you are sharpening them every 20 to 25 hours, keeping them clean, and avoiding mowing in wet grass, then you can expect approximately 100 to 200 hours of work use from your mower blades until it is time for a replacement. With commercial grade blades, you can expect much more, up to 400 hours of work use in some cases.

Should you sharpen mulching blades?

Yes! Mulching blades do a lot of work, chopping those clipping down into smaller and smaller pieces, so you need to keep them nice and sharp if you want to get the best performance and work life out of your blades. This will require the same sharpening schedule as standard blades, meaning that you should sharpen them every 20 to 25 hours of use.

How do I know if my mower blade is dull?

If you notice that when you are mowing the cutting appears to be uneven or you are seeing small, uncut strips, then your blade may be dull or even damaged. Take a look at the blade itself to inspect for any dents, nicks, or even curling of the blades, and go ahead and sharpen them as well to see if this resolves the issue.

How do you know when you need new lawn mower blades?

If a blade is over 2 years old, it is definitely time to replace it, but there are other scenarios where it’s a very good idea. Extensive damage, such as curling at the tips, deep nicks that sharpening can fi, or visible bends in the blade are all good reasons to get a replacement before your lawn and possibly your mower get damaged.

How do I know if my lawnmower blade is sharp?

A lawn mower blade will feel sharp, but not sharp enough to cut you on the finger if you are tracing the edge. You want to feel the edge on new mower blades to get an idea of the perfect sharpness, but if you aren’t sure, a butter-knife edge is just about perfect in most cases.

 Avoid sharpening your blades to razor sharpness, as this will make them dull more quickly and the thinned metal will be prone to damage.

What’s the best way to sharpen lawn mower blades?

If you have one, a bench grinder is probably the fastest and most efficient means for sharpening your mower blades. Following that, you can get a handheld angle grinder for less than $60 and this will not only sharpen your blades quickly but if you can prop your mower up then you can likely sharpen the blades without removing them.

This is a real time saver, as filing can definitely take up a chunk of your day.

How do you sharpen a lawn mower blade without removing it?

While this won’t work will all mowers, some mowers give you enough access to the blades to sharpen them without removing them. You’ll need to put your mower up on some wood blocks or suspend it by another means that you have in your workshop so that the blades are accessible and not prone to move around.

Once you’ve done this, a handheld angle grinder will make short work of sharpening and you can get back to the job at hand!

Can a mower blade be too sharp?

Yes. Oversharpening blades is a common novice mistake and it is very bad for mower blades. When a mower blade is too sharp, the metal is thinner, and so nicks, dents, and bends become much more likely to happen.

The sharpened blade might initially cut very quickly, but the thin edge is going to dull fast. For best results, only sharpen to the same thickness as your blade with came from the factory.

What does a dull blade do to grass?

Dull blades tend to tear at grass, rather than cutting them evenly. This results in browning of the lawn and in some cases, the mower blades might even rip out the grass by the roots. Avoid this by regularly sharpening your blades once every 20 to 25 hours of use and by replacing them with fresh, new blades every 100 to200hours of work use.

What are two reasons mowing harms the grass blade?

The most common two scenarios where mowing can do more damage than good are when the blades are dull or when you are mowing too low to the ground. Mowing with dull blades can result in uneven cuts, tearing at the grass blades and eventual browning, or even ripping out the grass by the roots.

Mowing too low can cause clumping, which in turn keeps your grass from getting enough sun in those patches if you don’t take care of them, and by cutting your grass too low it will get warmer much more easily, so the sun can end up damaging your lawn from the reduced heat resistance.