<p>How to Sharpen Your Lawn Mower Blade</p><p>1. Disconnect the ignition wire from the spark plug. (If it’s a cordless mower, remove the battery pack.)</p><p>2. Tip the mower onto its side to expose the retaining nut or bolt that secures the blade to the underside of the mower.</p><p>3. After removing the retaining nut or bolt pull off the mower blade, making note of which side of the blade faces downward. It’s important that the blade gets bolted back on in the same orientation.</p><p>4. With the blade removed, take a minute and scrape clean the underside of the mowing deck with a narrow-blade putty knife. Remove all caked-on grass, mud, leaves and other debris. Also, clean both sides of the lawnmower blade by first spraying with penetrating oil, and then scrubbing with a stiff-bristle brush.</p><p>5. Lawnmower blades typically have a cutting edge on each end, which are positioned on opposite sides of the blade. Each cutting edge is only about 3 or 4 inches long; it doesn’t extend the length of the blade. Clamp the blade in a vice at an angle with one of its cutting edges facing up.</p><p>6. Use the drill-powered blade sharpener. It consists of a round abrasive stone, flat sharpening guide, and ¼-inch-diameter steel shank. The stone has a beveled surface that grinds the ideal cutting angle onto the blade.Chuck the sharpening stone into a drill. Put on some safety glasses. Squeeze the trigger to run the drill at full speed. Slip the spinning sharpener over the edge of the blade. Be sure the dull cutting edge faces the beveled side of the stone, and the flat surface of the guide is against the rear of the blade. Slowly move the stone back and forth along the cutting edge using moderate pressure.After four or five back-and-forth strokes, stop and check the sharpness of the blade.</p>