Mower blades will dull over time, which can have a negative impact on lawns and lawn mowers. Dull blades require more energy to cut and increase the wear and tear on your lawn mower. Over time, using less-than-sharp blades will begin to impact your lawn as well.
Examine the tips of the grass after you cut the lawn. If the ends appear to be jagged or shredded, it’s time to sharpen the blades. A poor cut will cause the plant to recover more slowly, requiring more time, nutrients and water to repair itself. It also gives the end of the leaf a brown appearance and can detract from the overall appearance of the lawn.
But remember: safety first! Disconnect the spark plug before working on the blades. Next, using the proper size wrench, loosen the bolt that secures the blade to the deck. Most mowers only have one bolt per blade. You might need a block of wood to wedge against the blades so that it does not spin. After you have removed the blade, inspect it for damage; blades that are bent or have large divots need to be replaced. If it comes to replacement, I recommend taking the old blade with you to the store to match up the length and size of the bolt hole.
Secure the blade in a vise before sharpening. Files and grinders will make short work of a dull edge. Carefully work the edge of the blade. You do not want to actually change the angle of the cutting edge, only make it sharper. Butter-knife sharp is all it takes to make a clean cut.
Reinstall the blade and get back to cutting grass. Sharp blades will increase the life of your mower and improve the look of your lawn.