Push mower blades should leave grass that is cleanly cut with little or no tearing. Torn grass blades can lead to disease in the grass, so it is important to keep your mower blades sharp. Apart from sharpening your blade before the first mowing of the season, make it a habit to check the quality of the cut after ever mow. Once you start noticing torn blades of grass, it is time to sharpen the mower blade.
Removing the Blade
Allow the motor to fully cool.
Remove any gas left in the tank by using a hand pump to pump the gas out or by turning the mower on its side to allow the gas to pour out into a storage container where it can be reused once the blade is sharpened.
Turn the mower on its side. If you failed to remove the gas, it will come spilling out of the ventilation holes on the gas cap or possibly drain out from other places.
Remove the mower blade by unscrewing the retaining bolt in the middle of the blade. Use a wrench or socket to loosen the bolt while holding the blade with your other hand.
Place the mower back in normal position.
Sharpening the Blade
Secure the middle of the blade in a bench vise. If you don't have a vise, place the blade on a step with one of the cutting edges overhanging the step. Step on the middle of the blade to secure it. You could even place it in a similar position on a table top and hold it securely with your hand.
Take a metal file, and make a pass along the bevel of the blade from the body of the blade to the edge of the blade. Push mower blades don't need to be razor sharp, so you only need to file the bevel side and not the flat back side.
Continue filing until you have created a relatively straight and sharp edge. When the blade can cut a sheet of paper, the edge is sharp enough.
Repeat the sharpening process on the other cutting edge.
Install the newly sharpened blade by reversing the process used to remove it.
About this Author
Vance Holloman is a residential contractor and freelance writer living in Atlanta. Much of his writing centers on the expertise he has gained from two decades in the construction industry. His work has appeared in newspapers, magazines and numerous online sites, including eHow.com and "Auburn Plainsman." Holloman has a Master's degree in business from the University of Maryland.