How to Sharpen Push Lawnmower Blades

One of the best aspects of having a push lawnmower is that it will sharpen the blades as they scrape over the cutting bar when you push the mower. But every year you should still sharpen the blades so they will continue to cut your lawn cleanly.

Here are a few steps you can take in order to sharpen the blades on your push mower.

The first thing you need to do is prop up your mower in order for you to turn the wheels.

Check the blades of the mower for nicks and burs in the metal. If there are any present you need to remove them by holding a flat file on the blade and then pushing it away from the edge of the blade.

* Look closely at the cutting bar of your mower. The bar should just be touching the blades for their whole length. A good way to test this can be to grab a wheel and turn it forward as you should hear a sort of whisper, as the blades will be passing over the bar.

If the bar is not aligned you can adjust it by using the screws that are at the end of the bar. There will be a couple at each end and it is apparent which screws will move the bar closer and further away from the blade.

* Now use your fingers or a small paintbrush and cover the blades with a thin and even coat of a type of car valve grinding compound. This compound can be purchased at many auto part stores.

* Grab a wheel and slowly turn it backwards so the grinding compound squeezes in-between the cutting bar and the blades. When doing this it will sharpen both cutting edges when they pass each other. Make sure that each of the blades is touching the bar when you turn the wheel.

You should make around 10 turns and putting more of the grinding compound when it is needed.

* Look closely at the edges of the blades. If they are sharp you can wash off the valve-grinding compound using a mix of soap and water.

Now you can test how sharp the blades are. Place a piece of newspaper in-between the blades and the cutting bar and turn the wheel in a forward motion. When the blade cuts the newspaper just like a pair of scissors would then you know the blades are sharp enough. It may take a few times of placing the newspaper in the right position in order for this test to work.


If the blades are very dull it may be a better idea to take it to a professional to look at. Because the blades sharpen themselves with a push mower the blades should never get very dull. If they are there may be a problem, as there can be too much space between the blades and the cutting bar.

Author: Jason Green