How to Sharpen Electric Hedge Trimmers

Electric hedge trimmers make light work of shaping and pruning your shrubs, but they need occasional sharpening to keep them in prime condition. Sharp blades make shrub care easier by offering clean, efficient cuts that keep your hedges looking groomed. Read the owner's manual for your hedge trimmers to learn specific steps or product recommendations before following the standard sharpening tips.

You can usually tell that it's time to sharpen your electric hedge trimmer when it stops cutting well. Every cut the blades make also dulls them a little bit, eventually requiring you to sharpen them. When it's time to sharpen the blades, you might notice the trimmer grabs the branch instead of cutting it easily, or the cuts might be more ragged than normal. It's common to sharpen the blades after about 50 hours of use but watch for other signs of dull blades as well to help you decide.

Cutting through various bushes and shrubs can leave the trimmer's teeth covered with sap, resin, dirt, and other debris, which can interfere with cutting. It also makes it difficult to sharpen the blades if they're dirty and coated with gunk. Before you start cleaning and sharpening the tool, put on some safety goggles and work gloves to protect yourself.

Wipe the teeth with a soft cloth to dislodge any debris from them. Check the owner's manual for cleaning solution options if you can't wipe sap or resin off the blades with a damp cloth. Soapy water is usually safe to use, but you'll need to dry the blades well and lubricate them when you're finished sharpening the trimmer to prevent rust.

Before you start sharpening the blades, adjust the upper and lower blades so they're aligned. Use a flat file and align it with the angle of the cutting edge of the blade. You should only file in one direction, filing toward the cutting edge before lifting the file and moving it back to the starting position.

Continue this motion to remove just enough of the blade material to sharpen it. You shouldn't file off more than 5 millimeters of the material or you risk weakening the blade too much. Count the strokes you make with the file and use the same number of strokes for each blade to make them even and consistent.

Filing the blades sharpens them, but it can also leave behind burrs that you need to remove to keep the blades from dulling quicker. You'll usually find the burrs on the bottom side of the blade. A whetstone helps smooth off the burrs.

This step is easiest if you turn over the hedge trimmer. Lightly moisten the blades and use a swiping motion, following the direction of the tip as a guide. Repeat this on each blade to remove the burrs.

Your hedge trimmer is almost ready for trimming your hedges, but the tool needs a final cleaning. Use a soft cloth to wipe away the dust and debris from sharpening the blades and removing the burrs.

The final step is to lubricate the blades, which helps prevent rusting. Check the manufacturer's recommendations for the type of oil or lubricant you should use on your model. Using 3-IN-ONE multipurpose oil is generally safe for any hedge trimmer.