To sharpen your lawn mower blade, you'll need a socket or wrench to fit the blade nut. Tough nuts may call for a breaker bar and/or a penetrating lubricant. You'll also need two clamps, a block of wood and, of course, an angle grinder with a metal grinding blade. Start by disconnecting the spark plug wire (Photo 1).
Mulching blades may have longer or curved cutting edges, and you may need several types of files to sharpen them. In some cases, you may have to resort to a 4-1/2-in. angle grinder to sharpen mulching blades. If your mulching blade is too difficult to sharpen, take it to a hardware store or a blade sharpening service.
With long-term use, the spinning blades under your lawnmower can gradually grow dull.. high speeds, potentially causing injury if you're not wearing proper protection.. Another way to sharpen a lawnmower blade is to use a belt sander.
3 Methods to Sharpen the Blade. When you're sharpening your lawn mower blade, the goal is to make the blade as sharp as a butter knife. A flat file is an easy tool that'll sharpen a dull blade (with the blade secured in a vice.) The fastest way to sharpen a lawnmower blade is with a bench grinder.
This Old House has the advice you need for sharpening lawn mower blades.. Roger Cook shows homeowners the proper way to mow a lawn. In this how-to .