Horticulture Magazine

How To Sharpen Garden Hedge Trimmers In 5 Steps

hedge trimmers being sharpened on a workshop table

For the avid gardener, maintaining your hedges with a hedge trimmer can be a rewarding undertaking, resulting in well-manicured bushes and shrubs that give your garden that landscaped look.

You can make your task easier, and achieve the best results, by keeping your hedge trimmer sharpened, so that it functions effectively. You should aim to sharpen the teeth as soon as they begin to seem blunt, or after every 30-40 hours of operation. Doing this yourself at home can save you time and money.

When it comes to sharpening your hedge trimmer blades yourself, there are two main ways to go about it. You can do it by hand using a mill file, or you can operate a power grinder. Filing by hand is a longer and more arduous process, but safer, whilst using a power grinding is quicker, but it is easier to over-sharpen and weaken the blades.

Here, we take a closer look at exactly what’s involved in each option, so you can choose the right one for you, and once again have a super-sharp hedge trimmer that’s ready to tame your shrubbery.

Option 1: Mill File

A mill file is a multi-purpose saw file that is used primarily for sharpening blades. If you want to sharpen your hedge trimmer’s blades by hand, it’s a good idea to invest in a high-quality one that will last for years to come. To sharpen your blades using a mill file, follow the below steps:

1. Wear protective clothing

Before you begin sharpening anything, it’s important to make sure you are prepared. As you’ll be handling blades, you should put on thick protective gloves, to help prevent any accidents or injuries. Even blunt blades can cause harm, so it’s best to be safe.

2. Prepare your trimmer

Again, before you begin sharpening, you should make sure your hedge trimmer is on a stable, flat surface, and that it is removed from the power source, to prevent accidental starting whilst you work. Mains-powered trimmers should be unplugged, cordless trimmers should have their batteries removed, and for petrol-powered models, you can remove the spark plug.

hedge trimmers disassembled and sat on wooden surface
Place your hedge trimmer on a flat, stable surface for sharpening

3. Align the blade teeth

It will be easier to sharpen your blades if the teeth on the top and bottom are aligned. You can do this by first pulling them towards each other with your fingers, and then using a tool handle to pry them fully into place. Once the teeth are aligned, you will be presented with 6 surfaces on each one to be sharpened – the 2 sides and tip of the tooth on the topside, and the same on the underside.

4. File the topside teeth

Once your teeth are aligned, you can begin the process of sharpening. Starting with the teeth on the topside, take the mill file, and align it parallel with each edge of the tooth. File in a downward motion, using smooth strokes, until the surface appears shiny – this is how you know it’s sharp. Repeat this for the sides and tips of each tooth on the topside of the blade.

5. Flip it over

Once you’ve finished sharpening all the teeth on the topside, turn your trimmer over and file the teeth on the underside. Make sure to only file downwards, and stop once the edges are shiny, to avoid over-sharpening. Once you’ve finished, add some lubricant to the blades to help them move smoothly. You’re ready to start trimming!

Option 2: Power Grinder

If you own a power grinder, and you’re confident using it, you can also use that instead to sharpen the trimmer’s blades. This method is quicker and less tiring than filing the teeth by hand, but you will need to take safety precautions and be especially careful not to over-sharpen. To sharpen your hedge trimmer with a power grinder, follow steps 1 to 3 above, then continue as thus:

4. Clamp the blades

Before turning on your power grinder, secure your hedge trimmer blades to your surface with a clamp, to prevent them from moving whilst you work. You will need to adjust the clamp in between sharpening to access all the teeth.

5. Wear safety goggles and earplugs

As well as your protective gloves, it’s vital to also wear safety goggles when power grinding, to protect your eyes from the sparks that will be generated. Ear protectors should also be worn to protect your hearing from the loud noise.

6. Sharpen carefully

When you’re ready, turn on the power grinder, and sharpen each surface of the teeth, making sure to keep the wheel angled parallel to the tooth edge. You can use an 80 grit grinding wheel for this purpose. It should only take a few seconds to sharpen each surface – make sure not to over-file, as this will reduce the strength of the teeth, and affect performance.

7. Flip it over

Once you’ve finished sharpening the topside, turn the trimmer over, re-clamp the blades, and sharpen the teeth on the underside. Complete the process of sharpening your hedge trimmer by wiping the blades with a rag and applying some lubricant.


Is it necessary to sharpen electric hedge trimmers?

Yes, all hedge trimmers, no matter how they are powered, should be sharpened regularly to keep their blades in good condition and allow the trimmer to function at its best.

Should you oil hedge trimmer blades?

It is a good idea to apply lubricating oil to hedge trimmer blades before each use, and after sharpening the blades, to allow them to move smoothly. You can use a general lubricant or one recommended by the manufacturer of your trimmer.

Where can I get my hedge trimmer sharpened?

If you don’t feel confident sharpening your hedge trimmer yourself, you can get the blades professionally sharpened at many tool stores. If you don’t live close to one, many retailers also offer a postal service.

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