Sharp lawn mower blades are essential for the maintenance of a healthy lawn. Blunt blades tear rather than slice, stress your grass, and make your lawn more vulnerable to disease. Check the warranty information that came with your mower before proceeding with a do-it-yourself sharpening job. Some manufacturers insist upon blade sharpening done by a professional or accredited dealer to maintain warranty protection. The frequency in which you sharpen you blades depends on several factors.
Lawn Size and Obstacles
If you are maintaining a large property your mower blade will need sharpening more frequently. Much depends on how long it takes you to complete your grass cutting and whether your lawn is relatively free of obstructions or strewn with fallen twigs or other debris. Mowing through leaves and sticks may not hurt your mower, but it will dull the blade more quickly. Mature trees with protruding roots may also be hard on your mower's blade edge.
Landscapers who use their tools all day, every day, often sharpen mower blades at the end of each eight-hour shift. For the homeowner, mowing hours may be translated into sharpening every four to six weeks depending on how often you mow your lawn. In some locales, mowing is a twice weekly endeavor. At the beginning and end of the growing season or during periods of drought, mowing frequency and the necessity of blade sharpening is reduced accordingly.
Nicked or damaged blades should be replaced rather than sharpened. A 45-degree angle must be maintained on the edge to ensure optimum performance. If your blade has worn to the point that a clean, sharp angle is no longer possible, it is time to invest in a replacement. Lawn mower blades are not that costly and it may not be worth the frustration that comes with trying to sharpen a blade that has outlived its usefulness.
A hand file held at a 45-degree angle and moved away from your body along the length of the blade is the simplest way to sharpen the blade once it has been removed from the mower and clamped into your shop vice. Alternatively, you may take the blade into a professional tool sharpening shop or into a dealership that provides servicing for your make of mower. Some power tools have sharpening attachments that can also help you do the job.