Creating a convex edge using the Wicked Edge – method 1

Creating a convex edge using a guided sharpening system like the Wicked Edge is not too difficult with some practice. Basically it involves sharpening the blade at different angles, creating a multi-beveled edge. These edges are then blended together by means of stropping.

Multi-beveled edge

You can find more information on this on the internet:

Method 1: from most acute angle to least acute

The first method I applied was the method with which you set the most acute bevel first, then the next less acute one, then …  until you arrive at the least acute bevel (with the highest angle).

In theory this is the easiest method, because at every angle you create a full edge. This should be easy, because you should feel a burr when you have completed the edge. Once you feel the burr, you go on to the next less acute angle

Practice showed something different, mainly because it is extremely difficult (impossible for me) to feel a burr once you have completed an edge when you set this edge on top of another one with a difference of only one or a few degrees. Also, it is a very time-consuming method, since you have to recreate every edge using (as it appeared) low-grit stones and then use the whole progression again up to the 1600 stones.

The knife I practised on was a Global Santoku knife, made of a steel with a Rockwell hardness of about 57 HRC. I wanted to create bevels of 16, 18, 20 and 22 degrees. Starting at the lowest angle, I did so in that order.

First I created an edge at 16 degrees. To do so I went through the full range of stock WEPS stones: 100, 200, 400, 600, 800, 1000, 1200 and 1600 grits. See below for the result. I didn’t bother the top of the edge did not seem polished, since I was going to set other edges on top of it.


First edge at 16 degrees after all of the stones.

Then I tried to create a new edge at 18 degrees on top of the 16 degrees edge. I had read this should go very quickly, so I went for the 1600 grit stones. But no matter how hard and how long I tried, nothing seemed to happen. So I went back to the 1200 grit stones… nothing either. 1000, 800, only at 600 I started to seen something. But even with 200 grit stones the forming of the new edge went quite slow. So I took the 100 grit stones. And then it went fast, almost too fast. After only a few strokes I had set a new edge of 18 degrees on top of the older 16 degrees edge. It covered around 3/4 of the 16 degrees edge, which was about perfect. But only a few stokes more, and I would have wept out the 16 degrees edge.

The two photographs below shows both bevels; it is spread over two photographs, since the entire edge is slightly larger than 1 mm.  Note from the scratch patterns that I set the new edge using up and down movements of the stones, whereas I set the old edge using push motions.

New 18 degrees edge on top of old 16 degrees edge after 100 grit stones – top part.

New 18 degrees edge on top of old 16 degrees edge after 100 grit stones – bottom part.

I worked my way up all of the stones and below you can see the result after finishing with the 1600 grit stones at an 18 degrees angle. I tilted the camera about 45 degrees in order to capture the entire edge. As you can see, the new edge is nicely set at about 3/4 of the old edge.

New 18 degrees edge on top of old 16 degrees edge after 1600 grit stones.

Then I tried to create a new 20 degrees edge on top of the 18 degrees edge. Having learned from the previous edge, I did not start with the 100 grit stones, but with the 200 grit ones. But even then I almost managed to wipe out the previous edges… Nevertheless, after having worked up my way until the 1600 grit stones, the new edge came out nicely and at about 1/2 of the original 16 degrees edge (well ok, slightly over it…), as it should. For the new edge I used push strokes again, to make it clearly distinguishable from the previous edge.

20 degrees edge on top of old 16 degrees and 18 degrees edges, after 1600 grit stones.

It was time for the final bevel at 22 degrees. Having learned from previous experiences, I now started at 400 grit making up and down movements with the stones. This appeared to be the right choice as the photograph below shows: the final bevel nicely covers one 1/4 of the full edge.

22 degrees bevel after 400 grit stones on top of 20, 18 and 16 degrees bevels.

I continued polishing the new edge with the remaining stones. Below you can see the result.

22 degrees bevel after 1600 grit stones on top of 20, 18 and 16 degrees bevels.

Then it was time to turn the multi-beveled edge into a convex edge. I started stropping with 5 micron paste on leather strops  at an 18 degrees angle, which I thought would be nice to start with. However, even after about 100 push strokes per side, hardly anything happened. The 18 degrees bevel had somewhat blended into the 20 degrees bevel, but little had happened to the other bevels, as you can see below.

The four (three?) bevels after stropping at 18 degrees.

I decided it was time to strop at a 16 degrees and 21 degrees. And after about 100 push strokes per side at each angle, still with the 5 micron paste, I had obtained a nice convex edge.

Convex edge obtained by stropping the four bevels at 16 degrees.

Just for a more polished look, I stropped the edge also using 3.5 micron past (again, 100 push strokes per side at 16, 18 and 21 degrees) and the result is below. It may look like the edge is actually rougher than after stropping with the 5 micron paste, but that is not the case; I was simply able to focus better with the microscope, so it shows more details.

Convex edge after stropping with 3.5 micro paste.

All of this polishing resulted in a knife with a mirror edge. It wouldn’t easily shave arm hair, though.

A mirror edge.

3 thoughts on “Creating a convex edge using the Wicked Edge – method 1

  1. how could it be that it doesn’t shave arm hair easily with 18 degree angle with such a polished edge??

    • Good question. I suspect it’s the steel (Cromova 18). It gets a fine edge for a kitchen knife and it also takes a nice mirror polish (with 5K/10K Chosera’s), but it’s hard to get it shaving sharp.

    • As far as shaving hair it is a 22 degree edge. This edge has a lot of the strength/ durability of a 22 degree edge but the pass-through-ability of a 16 degree edge. So its a great configuration if your going through a carrot and contacting wood.
      Passing through is 16’s forte, contacting hardness is 22’s forte. Cutting hair is different.

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