No More Files: Here's A Clever Trick To Sharpen Lawn Mower Blades

Belt sanders are a quick way of removing everything from paint to mower blade damage. But these are not the most precise or delicate of tools, and can be confounding to homeowners trying to sharpen their mower blades. Bryan Clayton, CEO of GreenPal, spoke exclusively with Hunker about the ins and outs of using this offbeat method of blade-sharpening, offering tips on choosing the right sandpaper and explaining when and how to use your sander.

"When I was first getting started in the lawnmowing business 30 years ago," Clayton explained, "I couldn't afford a proper angle grinder. ... I would sharpen my lawnmower blades with anything I could get my hands on and I used a belt sander a few times, and it can indeed work." To get the job done, he advises using a sanding belt in the heaviest grit, somewhere in the 80 grit range. It's an aggressive and quick operation, and as a result, you can expect to go through some sanding belts. Clayton also says you can expect to replace the belt after two or three sharpenings, and there are imperfections in the belt-sanding process. "What I found is that you can't get the nicks out of the blade, you can only get the surface dulling off of the metal, but if you do it once a week, it's enough to keep it sharp."

Sharpening once a week might seem excessive, and Bryan Clayton agrees that under normal circumstances, your lawn mower blades don't need to be sharpened as often as you think. "If you're a homeowner, you should sharpen your lawnmower every 30 or 40 lawn mowings, which usually means about once a year," he said. "If you're professional, you should plan on doing it every week."

That pro schedule works for weekly belt-sander sharpening as well. "What I like to do is keep a spare set of blades and just swap them out and sharpen them on the weekends," Clayton explains, but that's a lot of commitment if you're not a lawn care pro. "Ultimately ... you want to upgrade [to] a full-scale angle grinder with a grinding disc," Clayton said, "but a belt sander can get you by for a while."

Ultimately, a belt sander is a stop-gap measure when it comes to mower blade sharpening. With the right accessories, you can easily sharpen lawn mower blades with a drill, a rotary tool, or a bench grinder. Clayton is a fan of combining the belt sander with another commonly used sharpening tool, the angle grinder. "A belt sander is not the ideal tool," he said, "but it can work, especially in conjunction with an angle grinder. You get the rough stuff off with the angle grinder and put the finish polish on with the belt sander."