Healthy grass needs a sharp lawn mower blade. In this article, we will show you how to sharpen lawn mower blades to keep your lawn looking healthy. A dull mower blade tears grass blades rather than cutting them, which leaves the grass vunerable to damage and disease. It doesn't cut evenly, stresses the mower, and turns the top of the grass greyish/brown. The size of your lawn and how often you mow will dictate how often your mower blade should be sharpened. You can always take your mower to a professional to do the sharpening, but it is certainly a feasible job for a do-it-yourself type.
Before you begin the task of sharpening your mower blade, you should drain the fuel from your mower into a container or run it dry from use. Always disconnect the spark plug before working on a mower. You should only sharpen a blade that is dull, but still in good condition. If the cutting edges are severely damaged or the cutting angle is not obvious or the blade is twisted, you should replace the blade with a new one instead of sharpening.
Tip: Keep a sharp, spare blade in case you need to install a new mower blade.
You should clamp a 2x4 between the blade and mower deck to secure the blade for removal. There is also a device you can buy called a Blade Buster that will lock the blade in place. Squirt some penetrating oil on the bolt and give it 10 or 15 minutes to do its work. Next, remove the bolt(s) with a socket wrench by turning counter-clockwise. Use a grease pencil to mark the bottom of the blade. Clamp the blade and use either a grinder or a file to sharpen the cutting edges. Sharpen the blade by moving the file toward the cutting edge with long, even strokes. You should follow the blade's original bevel as closely as you can.
An unbalanced blade cuts unevenly, causes a mower to vibrate, and sometimes damages the engine. You can get special balancing kits at most hardware stores or use a c-clamp mounted upside down on a countertop. Set the blade on the center of the device you are using and mark the lighter side. File on the heavier side and recheck the balance. Repeat until both sides balance evenly.
Put the blade back on the mower and twist each bolt until it is snug; then go back and lock each one down tight. Reconnect the spark plug wire and your ready to go.
