Forget The Bench Grinder: Easily Sharpen Garden Tools With A Lawn Mower Staple

While any expert sharpener will demur and tell you that a whetstone and the tears of a unicorn are the only way to sharpen garden shears with integrity, the fact is that most garden cutting implements can be sharpened quickly and effectively (and often somewhat dramatically) with nothing but an angle grinder. The angle grinder is an ideal sharpener for larger tools like lawn mower blades, axes, hedging shears, and shovels, but it can handle most other garden tools just fine too. It's also very fast, which is a blessing and a potential curse.

It's critical to take every possible safety measure when working with a 10,000+ rpm angle grinder. It sharpens fast, but things can go tragically sideways fast as well. So, just as you should be cautious when bench grinder sparks fly upwards, approach the workpiece so that angle grinder sparks fly away from you — but not toward that pile of greasy rage in your garage. Likewise, be sure to wear eye protection and gloves, and keep your clothing out of the way. Your devoted writer has set his shirt on fire twice while cutting steel with an angle grinder. Fortunately, he was wearing the same shirt on both occasions.

You might balk at the idea of a guy who has set himself on fire more than once giving you advice on how to use an angle grinder, but he can certainly tell you what not to do. What you should do starts with clamping the tool or blade to be sharpened firmly in a vise. Unlike bench grinders, when using angle grinders and die grinders that are often pneumatic and powerfully and quickly sharpen mower blades and other garden implements, you should bring the grinder to a stable and secure workpiece. The larger the implement, the more true this is. Sure, you can sharpen your landscape edger fast with an angle grinder, but it would be hard to manage while swinging a four-foot-long handle around. 

Now, opinions differ about whether to use a grinding wheel or a flap disc when sharpening garden tools, and it might make sense to decide based on your experience with the grinder. More habituated users might do well with an aggressive grinding stone, while those who are likely to set themselves on fire might choose a comparatively tame 120-grit flap disc.

Either way, grind lightly. It's a seriously quick operation if done correctly; if done incorrectly in a rush, you might very well generate scrap metal. For some tools, like axes and hoes, you will need to sharpen both sides of the blade. Take care not to ever grind the flat side of tools with two jointed blades such as scissors or shears, as it will undermine the tool's ability to shear. Grind the beveled edge instead, matching the factory bevel angle as closely as possible.