Don't Sharpen Your Edger Blades, Replace Them Instead - Here's Why

While you can use a string trimmer as an edger, using a metal-blade lawn edger provides a cleaner look where your lawn transitions between lush green grass and hard surfaces such as sidewalks and driveways. As a tool we've invested money in, we would like to take care of it properly to ensure years of trouble-free service.

You may look at your edger blades and think they look dull and could benefit from sharpening. However, much like new lawn mower blades that come pre-sharpened, your edger blades shouldn't have a razor's edge. While a lawn mower blade needs to be sharp enough to cut blades of grass cleanly without tearing them, an edger blade is designed to rip through dirt and grass roots, and contact hidden debris such as rocks and concrete.

Edger blades will wear down with normal use. If they become damaged, chipped, cracked, or bent, or if they've worn down past their useful limit, it's time to change them. Still, some might think sharpening an edger blade is a good idea even if leading edger manufacturers like Ryobi and Stihl advise against sharpening them in their product instruction manuals.

There are a couple of primary problems with sharpening edger blades. First, it's difficult to maintain the blade's proper balance without special tools. If slightly more metal is removed from one end versus the other, the blade will be out of balance. The same is true for balancing lawn mower blades after sharpening them, but mower blades are longer, making them easier to balance (think of a tightrope walker holding a long pole for balance). An unbalanced edger blade can cause the tool to vibrate excessively and lead to worn components in the edger's drivetrain.

Another disadvantage to sharpening edger blades is accelerated blade wear. Edger blades come with blunt edges designed to take abuse, abuse that maintains the sharpness required for them to perform. The edge of a sharp blade breaks down faster, much like attempting to chop down a tree with a razor. An axe is a better tool because its edge isn't razor sharp, its edge is designed for slamming into the tree without rolling over or chipping. Attempting to keep an edger blade sharp would require frequently grinding a new edge that would almost immediately wear down as soon as it touched the dirt, an exercise in futility.