How to Sharpen Hedge Trimmers

Emma Loker Headshot - DIY Garden
Written by: - Gardening Expert
how to sharpen hedge trimmers

Hedge trimmers belong in every garden – they’re a must-have gardening tool. They’re perfect for getting rid of that scraggly hedge growth and cutting away branches that won’t play ball. 

With a sharp set of hedge trimmers, you’re unstoppable! But their blades don’t stay sharp forever – like anything else, they need tending to after a while. Blunt hedge trimmer blades reduce the tool’s effectiveness – the cut won’t be as clean, and you may find branches keep getting stuck. 

Here, you’ll find info on when and how to sharpen hedge trimmers. 

When to Sharpen Hedge Trimmers

A common mistake is to only sharpen your hedge trimmers when they’re blunt. But when it comes to hedge trimmers, prevention is better than cure!


Hedge trimmers should be sharpened after every 30-40 hours of use. But bear in mind, this varies between brands and hedge trimmer types. Now, this could be difficult to keep track of – I mean, who wants to keep a tally of their hedge trimming hours?

Instead, get into the habit of sharpening the tool at least once a month. When using your hedge trimmers a lot, consider increasing this to fortnightly. 

Sharpening Hedge Trimmers

Now you know when to sharpen your hedge trimmers; next on the agenda is how to do it. Well, there are two main approaches to this:

  1. Using a Mill File
  2. Using a Power Grinder

Let’s start with a step-by-step for using a mill file. 

Using a Mill File


Step 1: Get Out the Protective Gear

You can’t make use of your hedge trimmers if you get injured while sharpening them. Remember to get out your safety goggles and gloves before tackling this task.

Step 2: Prep Your Tool

Ensure your trimmer is on a flat surface where it won’t rock or fall. Next, remove the power source. Take out the spark plug from petrol hedge trimmers, unplug mains-powered ones, and check cordless trimmers are batteryless. 

Then, you need to align the blades. Using your hands, manoeuvre the blades, ensuring the top blades are in line with the bottom ones. If the blades are temperamental, pliers should do the trick!

Step 3: Sharpen the Topside Teeth

Hedge trimmers should only be filed in one direction – downwards. The blade becomes sharp on a downward stroke. Don’t touch the file to the blade on your way back up –  sharpening back and forth will blunt your tool even more.

To get just the right filing angle, check the specifications on your trimmers’ instruction manual. Keep your filing consistent, using the same number of strokes for each blade. Don’t file any more than 5mm, as this can reduce the blade’s structural integrity. 

Step 4: Sharpen the Underside

Once the topside teeth are sufficiently sharp, flip your trimmer over and sharpen the underside. Remember, work downward and don’t touch the blade when you’re lifting the file back up!

Using a Power Grinder


Step 1: Prep Your Tool

You need to prepare your hedge trimmers regardless of the tool you use. So get started by preparing your tool using the same method as step 2 of “Using a Mill File.”

Step 2: Protect Yourself

Although using a power grinder saves time and energy, it’s more likely to injure. So, take the necessary precautions! Gear yourself up with gloves, safety goggles and ear protectors. 

Step 3: Clamp it Down!

You don’t want the blades wibbly-wobbling all over the place when you’re using your power grinder. That’s plain dangerous! So make sure to clamp the blades down to stop any movement. 

Step 4: Switch On and Sharpen

Load your power grinder up with 80-grit sandpaper and switch it on. Keep the wheel parallel to the edge of the tooth and sharpen the topside teeth. Once you’re done on this side, flip it over and do the underside.  

Now, this doesn’t take very long. Resist the urge to carry on for longer – we know the damage oversharpening causes!

Final Note

Don’t wait till your hedge trimmers are on their last legs before sharpening them. Sharpen every 30-40 hours of use or once a month to be on the safe side. When it comes to sharpening, you’ve got two options: a mill file or a power grinder. 

Whatever you choose, gear yourself up with protective equipment and remember to prep your tool. Stick to a downward motion, and don’t sharpen on the way back up! 

Happy sharpening!

How useful was this post?

Click on a star to rate it!

As you found this post useful...

Follow us on social media!

Scroll to Top