How to Sharpen Lawn Mower Blades

You need to sharpen the blades of your lawn mower after using it consistently for a long time but sometimes you have to sharpen them if you are planning to use your lawnmower after a long time. It may get dull either due to striking some hard objects while mowing the lawn or due to rust in an idle situation.

So before sharpening the blades DIY, you must know how to sharpen lawn mower blades as it may need some technical skills. In this write-up, you will find brief information about different ways to sharpen the blades of your lawnmower.

Preparing for sharpening the blades

Before starting to sharpen lawn mower blades yourself you will have to be prepared for it. First of all, you should disconnect the lawn mower and its spark plug from the soured of power.

If you have a push mower, turn the lawn mower carefully to its side to avoid spilling of its oil on its air filter and carburetor. For riding mower or zero turn mower, you will want to use a car jack or mower lift to raise the front of the mower.

If you have a commercial lawn mower of any kind I would recommend only using a car jack with jack stands to raise the mower. This is because most most lifts have a weight limit. These mowers can be very heavy making mower lifts unsafe.

Note: Be sure to chock the back tires before raising the mower.

Now before removing the blades, you should mark its side facing downwards so that you can reinstall it in the right position. Now loosen the fastening bolt (an air compressor and air impact gun makes this very easy) of the blade by blocking it to remove it safely for grinding. Before grinding the blade you should clean rust or grass clippings from it by using a dry rag.

Sharpening the lawn mower blades in different ways

There are several different ways to sharpen your lawn mower blades. Everything from using a bench grinder to filing them by hand. There are also some ways to sharpen your mower blades without removing them. Below are some ways to sharpen them.

How to sharpen lawn mower blades by hand

While sharpening the lawn mower blades by hand you will have to clamp the blade safely on your worktop to work on it conveniently. In order to make cleaning easier after finishing the job, you can use old newspaper under your blade(s).

Before sharpening the blade by hand you must know how to sharpen lawn mower blades with a file as it is the only way for this purpose. You should run file along the cutting edge of the blade, striking it from its inside edge to its outside edge unless the edge looks clean and shiny. You should repeat the process after flipping up the blade.

How to sharpen lawn mower blades with a bench grinder

If you know how to sharpen lawn mower blades with a grinder then it will be a very time-saving process for you. But before starting the process you should take common safety precautions like wearing gloves, protecting your eyes and wearing a shirt with long sleeves to protect your arms, etc.

After taking all precautions you can use a bench grinder for this purpose. You will have to move the blade forth and back against the grinder wheel to sharpen it. But you should maintain the angle of the bevel of the blade as done in sharpening it by hand. You can also use a hand grinder for this purpose.

How to sharpen lawn mower blades without removing

If you want to sharpen the blade of your lawn mower without removing it then you can use certain products available in the market to put on your drill like sander belt etc. You can run your drill up and down on the blade. You should run it on both sides of the blade to maintain its balance. But to maintain the sharpness of the blades you should remove them after a couple of years to take them off for proper sharpening and balancing.

How to sharpen riding lawn mower blades

The blades of a riding lawn mower can be sharpened by hand as well as by using grinder after removing them from the mower, as discussed above in this write-up. You will have to follow all these steps carefully to get properly working blades without any additional effort.

A riding mower will take a little more work to sharpen the blades. The only extra step is to jack the mower up in order to under the take and take the blades off.

How often to sharpen lawn mower blades

The frequency of sharpening the blades of lawn mower depends on many factors including the type of mower and workload etc. If you are using a rotary mower then its blades should be sharpened after using it for 20-25 hours which can be once or twice a year for some people. But if you are using a commercial grade lawn mower then you can sharpen its blades once or twice a week.

While sharpening the blades of your lawn mower you should frequently dip into cold water to quench it otherwise the heat caused by friction can weaken or warp them. After finishing the grinding of the blades you should check their balance before reinstalling them into your lawnmower.

How long do mower blades last?

While sharpening your mower blades is very important there will come a time when you need new blades. Usually, mower blades will last about 100-200 hours. On some commercial mowers with higher quality blades they can last up to 400 hours.

Once a mower blade becomes too thin or has a bunch of jagged parts it will be time to replace it. You should be able to find your mower blades on Amazon for the best price. In the search bar, type in {your mower} + blades and you should be able to find them.

Wrapping it up

If you own a lawn mower it is vital to keep your mower blades sharp. This will allow for a quality cut each time and prevent from tearing grass. Dull blades and promote many types of problems in your lawn.

Do you sharpen your mower blades frequently? If so, which method do you use to sharpen them? Leave a comment below!