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While a common metal file is among the best tools for sharpening dull lawn mower blades, it’s a labor-intensive method that requires skilled hands for best results. But like many tasks in today’s world, there is a smarter way to sharpen your mower blades.

A specialized lawn mower blade sharpening machine, like the RBG712 bench grinder, makes easy work of sharpening mower blades, but its high price and limited alternative uses doesn’t make it the smart choice. An angle grinder is Harbor Freight tool that can sharpen lawn mower blades, but these can be dangerous in inexperienced hands and can remove metal quickly enough to ruin an otherwise serviceable mower blade very quickly.

Using a Dremel variable speed rotary tool with an attachment kit for sharpening outdoor gardening tools from Amazon is a smarter, safer way to sharpen your mower blades at home. Many DIYers already have a Dremel in their toolkit since rotary tools are useful for a lot of different things. In addition, if you already have a bench vise and some common-sized wrenches you have all the tools you need sharpen your lawn mower blades the smart way.

Before you can sharpen a mower blade you’ll need to remove it. Safely position the mower for easy access to the underside of the mower deck and secure it so it doesn’t fall on you. The method used for this step depends on the mower’s design, but don’t use a car jack. Next, it’s important to disable the mower so it doesn’t accidentally start while removing or replacing the blade. The procedure for disabling the mower is different for electric vs. gas lawn mowers — consult your owner’s manual.

Once the dull mower blade is on the workbench, inspect it thoroughly. Ensure the blade is straight where it should be and holds the correct form of a new blade. If any surface, including the cutting or trailing edges are chipped, worn away, or show signs of cracking it’s best to replace the lawn mower blade, or the entire set, whichever applies to the mower you’re working on.

Attach the sharpening attachment kit, or a suitable grinding stone to our Dremel. Guide the rotating stone along the cutting edge of the mower blade, maintaining the same angle originally ground into the blade and moving smoothly to prevent creating divots along the cutting edge.

Take as many passes as necessary to restore the edge, keeping count so you can match the other side for easier balancing later. A lawn mower blade needs to be butter knife (not steak knife) sharp to do its best work. Before reinstalling the blade, use a simple balancing tool ($5.99 at Amazon) to ensure it is balanced to limit unnecessary vibration. If the blade is heavier on one side, file off some additional material until it sits level.