This is one of the most common questions I get.
Yes, hedge trimmers can be sharpened and there are a couple of methods you can use to sharpen the blades on your hedge trimmer. You can use a mill file and sharpen them by hand, a Dremel tool sharpener, or you can use a power grinder which will make the process a bit faster.
I will show you how to use all of these methods. Regardless of which method you decide to use the first thing you will need to do is align the upper and lower blade on your hedge trimmer so they are in line with each other.
How to Align the Upper and Lower Blade
You are dealing with sharp blades so it is smart to put on some good gloves to protect your hands as you align these blades and do the sharpening.
I found the easiest way to align the blades is to start by hand. Simply press the two blades together and you can get them pretty close to being right in alignment that way.
To get that fine bit of alignment, you can take the handle of an old screwdriver. Put it between the blades and use it as a pry bar. The handle on the screwdriver will keep you from damaging the blades and they will move the blade to that distance to align them perfectly.
With the blades aligned you can see on each blade that there are two or three (depending on the type of the blade) different surfaces you need to sharpen. And if it’s a double-sided blade, we have the same surfaces on the back so there are a total of four/six surfaces that need to be sharpened per tooth.
How to Sharpen With a Mill File
Remove the bolts that hold the blades together and clamp them into a bench vice.
Run the mill file down each cutting edge. Ensure you keep the file at the same angle as the cutting edge.
Push the mill file toward the cutting edge and not back and forth. The file is designed to work this way to guarantee an optimum cutting edge.
Ensure you maintain the specified sharpening angle. You can easily find this in your equipment’s instruction manual. Continue this until the edge looks shiny.
Sharpen all the sides of each blade on each side. The blades have a wear threshold of 5mm, so ensure you don’t file away too much of the blade. The material may lose strength if you file away more than this.
Once you are done filing, wipe down each blade with a wet rag.
You can draw the cutting edges against a sheet of paper to test for sharpness. The blade should slice the sheet of paper if they are really sharp.
Lightly coat the blades with linseed oil before reassembling. This will help to preserve their lifespan and protect against corrosion.
If you want to see how it’s done, check out the video below. This or more or less how I’d do it.
How to Sharpen With a Power Grinder
This method is great if you are experienced with the power grinder, as it’s much faster than using a mill file. However, I wouldn’t recommend it for beginners. The reason for this is that it’s very easy to grind off too much material from the blade, greatly lowering its lifespan.
The video above also covers this method, so you can check it out if you are more of a visual type. Either way, here is how I’d do it:
Of course, whenever you use a power tool you will want to be wearing the appropriate safety gear – hearing protection and eye protection.
Start by clamping the bar of the hedge trimmer to a bench vice just so it doesn’t move around while you are grinding. With that secured, you can begin to grind.
Again, the same surfaces will need to be ground but now we will use a grinder instead of a file. You need to be careful to maintain that same angle while you grind. The grinder will work much faster than the file, so be careful not to take too much off the tooth.
Repeat this process for the opposite side.
To finish all you need to do is continue with that same process on each tooth all the way down the bar.
How to Sharpen Using Dremel
You can also sharpen your hedge trimmer blades using a Dremel rotary tool. Now you might be thinking, “But wait, how is this different from using a power grinder?“.
Well the main reason I recommend this tool is because it has an attachment specifically designed for sharpening the blades of outdoor gardening tools. These bits are a lot smaller than the disc of a power grinder, allowing for more smooth and precise movement.
Check out the video below to see it in action.
Make sure your hedge trimmer is clean before you start the sharpening process. Clean the blades thoroughly so no stone or grass is stuck on the blades.
Prepare the Dremel sharpening kit. Make sure you attach all the nuts and screws in the right position.
Wear eye and ear protective gear to protect yourself from grinding noise and sparks of light as too many sparks and noise can cause permanent damage. If you have a protective face cover, you can put it on. Sharpen during the day so you can see clearly.
Secure the hedge trimmer to a bench vice. In order to sharpen the blades, you need to clamp the hedge trimmer tightly so it doesn’t move while you are sharpening.
Switch the Dremel on and move it slowly to the blades of the hedge trimmer. To prevent over sharpening of the blades, apply light pressure. Use short strokes because long strokes cause unevenly sharpened blades. Be careful and make sure you keep your hand away from the grind.
Continue this process by repeating it for all the blades.
The Dremel tool sharpener will make your trimmer as good as new.
What to do When Your Hedge Trimmer is Not Cutting Properly
If the hedge trimmer isn’t cutting as good as they use to there can be various reasons for this. Here is how you can find and get rid of the cause. Take a closer look at the blades on the trimmer and the way it cuts the branches.
If the cut on the branch is frayed and uneven, it means the blades are blunt and you need to re-sharpen them. If you don’t want your gardening work to be interrupted you can try to sharpen the blades yourself by using the tips above. Just remember to keep the right cutting angle when sharpening the blades.
The Branches Get Caught Between the Blades
When trimming, if the twigs or branches get caught between the blades, block the blades, or prevent the branches from being cut, this is because the lower and upper blade have become detached. This is usually caused by wear to the blades spacers. In this case, you can arrange for the blade spacers to be replaced.
Benefits of Sharpening your Hedge Trimmer
I probably don’t have to tell you this, but there are a number of benefits to keeping your hedge trimmer in top condition.
Easy Trimming Process
Using a sharpened hedge trimmer will make your trimming process a lot easier. You will finish your task a lot faster, potentially saving you from sunburn during summer months.
Easy to Notice
It is quite easy to notice gardens or plants that a properly sharpened hedge trimmer was used to trim; they are usually very neat. Beyond that, trimming your shrubs with a sharp blade can help them heal faster.
They Last Longer
Sharpening the blades of your hedge trimmer on a regular basis will also increase its lifespan. You won’t have to spend extra money on replacement parts, and your tool will likely serve you for years to come.
Frequently asked questions
Can electric hedge trimmers be sharpened?
Yes. The blades of an electric hedge trimmer work the same way as the blades of a gas powered trimmer, so the techniques described above will work.
There you have it, my complete sharpening guide for hedge trimmers. I hope you’ve enjoyed reading it, and I’ll see you next time!