Tips to help sharpen your mower blades

Dull mower blades are pretty rough on your lawn, tearing grass rather than cutting it.

By Observer Staff
| 9:14 a.m. April 2, 2015

Winter Park - Maitland Observer
Neighborhood

Q: How do I sharpen the blades on my lawnmower? — Cara, via email

A: Dull mower blades are pretty rough on your lawn, tearing grass rather than cutting it, which can turn the tips brown, weaken the grass and promote the growth of fungus.

Sharpening mower blades is something not everyone does routinely, but you should commit to sharpening them at the beginning and end of the mowing season.

Do you need to sharpen them mid-season? Professional landscapers sharpen or change their mower blades every 12-15 hours of mowing time (yes, that's every day or two), so it would depend on the size of your yard and length of the growing season.

Here's how to change a blade:

Lay down a plastic sheet or dropcloth to prevent oil drips and grass cuttings from staining the work area.
Disconnect the spark plug from the starter wire, remove the spark plug itself, and make sure the fuel cap is tightly closed.
Turn the mower on its side. Using a socket wrench, unscrew the center nut that secures the blade to the mower deck and any other connecting bolts or nuts. If the blade keeps turning as you try to loosen the nut, wedge a piece of wood between a blade and the deck. Remove the blade and brush off any dried grass clippings.
To sharpen the blade, check the angle of the existing edge. You'll want to sharpen in the same direction as that angle. Run a metal file down the blade at about a 45 degree angle. Or, use a drill with a blade-sharpener attachment.
Once sharpened, check the blade's balance by hanging it from a nail (or buy a blade balancer at the hardware store). If one end of the blade tilts down much farther than the other, file away more metal on that side until the blade stays horizontal.
Reattach the blade to the mower, making sure the blades angle downward. Tighten as much as possible, bracing the blade with the block of wood.
Attach the spark plug and wire, and turn the mower upright.

A great overview of this process can be found on YouTube at http://bit.ly/1xT2Kn8

HOME TIP: Worried that you'll forget which way to reattach a lawnmower blade? Snap a picture of the underside with your smartphone before starting the task.