Whether you are a DIY knife sharpener sharpening knives at home, an avid bread lover looking for a way to sharpen your own knife or a professional local sharpening service, follow these steps for a great and fairly simple way to sharpen serrated knives, sharper than new!
Prep & PPE?
Safety goggles, respirator.
Assessing Your Knife
As a professional sharpener offering knife sharpening services in Halifax, Nova Scotia, I am often asked to sharpen serrated knives. These can be bread knives, tomato knives or serrated utility knives with the traditional curved scallops or various other shapes as well as knives with micro serrations like the eversharp knives.
This method of serrated knife sharpening will work on all of them with 3 criteria:
- The serrations must be in fairly decent condition that is to say no major damage like broken points and chips.
- The ridges that run to the points must be long enough to handle a little material removal.
- The serrations must be ground in from only 1 side of the blade, we will refer to this as the front with the flat side being called the back.
I’ve used a lot of different machines for professional knife sharpening services over the years and I do a lot of my sharpening on a 1×30 belt sander. These are efficient and safe for knives when used properly.
They are also affordable enough for the DIY knife sharpener or knife sharpening hobbyist.
This method will require a 1×30 belt sander with a ceramic 120 grit belt, a 400 or 600 grit belt, an extra fine scotchbrite belt and a felt belt as well as a buffing machine with a cardboard wheel.
Leather belts and hard felt wheels will also work.
Getting Started
To get started, it is important to look at and assess the knife, make sure it is in a suitable condition and does not require any regrinding of the serrations.
Next, you will need to fit a 120 grit belt to your belt sander, I use Klingspore and 3M.
Now the work can begin!
Step One: Initial Sanding
With the belt running, place the flat back side of the knife almost flat on the belt, raise it just enough to be sure you will not scratch the entire back of the blade. A gap of 1 or 2mm from the spine of the knife to the belt will be good. The lower the better. With low pressure and moderate even speed across the belt, get the knife moving sideways as soon as you touch down.
Repeat this step as often as required in order to form a burr down the entire length of the blade, from the inside of the scallops to the tip of the points. Check the back of the knife often to make sure you are removing the same amount of material along the length and that you have an even sized bevel forming.
You know you have successfully completed this step when you have a continuous burr and can no longer see or feel any flat points.
Step Two: Finer Details
The second step involves the exact same movements as the first with a finer grit abrasive, I like to use a Trizact A30 (600 grit) but a 400 or 1200 grit will work too. You will only need to do 2 or 3 passes to remove all the deeper scratches from the previous belt, again, check your work as you go. You should also notice that the burr is softer than it was before.
At this point the actual work is done and the knife is sharp behind the burr which must now be removed without damaging the apex. Knife sharpening only has 2 stages, create a burr and remove the burr!
Step Three: Removing the Burr
Fit an extra fine Scotchbrite belt to the belt sander and give 2 or 3 passes along the back as before. You will see the burr change and it may even start to flake off at this point. Now turn the knife over, angle it to match the angle that the serrations were ground in at and run it down the top corner of the belt, do this with very low pressure at a fairly fast speed, this will flip the burr to the back of the knife.
Repeat this step 2 or 3 times until the burr has flaked off almost completely. Even if you can no longer see it, there is still a tiny bit of the burr left.
Step Four: Alternating Passes
Using a buffing machine with a cardboard wheel or hard felt wheel and some green or blue compound, do a few alternating passes. First on the back and then using the corner of the wheel, on the front. Try to match the existing angles and use light pressure. The aim is to polish the burr off without rounding the apex.
Step Five: The Final Pass
The final step is to use a felt belt on the 1 x 30 sander. Using the same technique as with the scotchbrite belt, do a few passes each side.
Your knife should now be sharper than it was when you bought it!
Video Tutorials
For a video breakdown of this tutorial, watch this video:
To make your own cardboard wheel, watch this video to learn how to make it:
A Few Extra Tips
Remember that there is always more than one way to sharpen a serrated knife, this is my preferred method at the moment but as we are always learning and striving for perfection, things might change.
As such, you could substitute the cardboard wheel for a hard felt wheel or the felt belt for a leather belt.
You could even finish on a higher grit sanding belt and then move directly to a felt or leather belt, these methods will also give you sharp edges. I have found the most success using this sanding method.
At Maritime Sharpening, we offer knife sharpening services in the greater Halifax area. We also sharpen a variety of other tools. For more information, visit Services page.
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Stay Sharp!