Sharpening 31 vs 21 - share your experience

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rishma

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Jun 22, 2008
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I have never sharpened a 31 but I know if you don’t roll a 21 clip the bevel will widen at the tip. I was never very good at getting a nice even bevel on the 21 clip with my sharpmaker because I don’t roll consistent enough. It annoyed me. I don’t own a 31 except the gift I got my son for graduation, still in the box.

I saw this apostleP video where he indicates this is not an issue on the 31. You can see in this screen shot that the 21 is wide at the tip, the 31 is not. He uses a fixed angle system. I’ve always thought his 21s looked terrible.

CRK does not indicate they changed the grind for the 31. I asked and they said to sharpen them the same.

So, what has your experience been?
 
The only difference between the blade on the 21 and the 31 is the size and location of the detent hole. Tim Reeve has said as much. Far be it from me to disagree with the Apostle, but I'm not sure what accounts for his experience in that video. One could guess at a subtle change in the position of the knife on the Edge Pro table. All drop point Sebenzas thicken up at the tip. They will all develop a fat bevel on a fixed angle system unless care is taken to prevent it.

I use a Wicked Edge, but the principles are applicable to other fixed angle systems. When clamping a Sebenza, you have a choice. If you clamp the knife parallel to the spine, the angle at the tip will remain consistent but the bevel will widen. If you tilt the knife in the jig, the angle will widen at the tip but the bevel height will remain consistent. I suppose one could compromise anywhere in between. On the Sebenza 31 pictured below, the bevel width at the tip is just slightly narrower than on the straight part of the blade. I did this for reasons related to the factory grind on this particular knife. On a Sharpmaker, mimicking this requires some freehand skill, which I lack. Sounds like others have struggled with it, too.

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I never have had much luck with a Sharpmaker (I'm sure it's me); but I am skeptical that there would be an significant difference between sharpening a 21 and a 31.
 
I use an edge pro apex.


I have sharpened 3 21s and 1 31s. 2 of the 3 21s widened quite a bit near the tip. The other one was more consistent but has the polished blade so idk if that is a factor. The 1 31 i have sharpened is a little more consistent as well.

They are all quite thick at the tip, some just more than others.

I think that the narrower grind that some sebenzas have is unintentional. Though, i do wish they would just make them thinner at the tip
 
the tip definitely doesn’t thicken as much on the 31 as the 21. I never liked the sharpmaker on a CRK very much. Much easier either freehand sharpening or using one of my fixed systems and maintaining on a strop with Diamond emulsions. With S35VN I have to strop often
 
Interesting responses so far. The tip is either exactly the same on a 21 and 31 or the tip is not as thick on the 31 🙃

I do appreciate the discussion. I am sure someone will take a micrometer to their collection of 21s and 31s and solve this once and for all!
 
I have yet to have a 31, but I thought it had previously been discussed that the BTE thickness was deliberately more consistent to the tip on the 31's grind, IIRC.
 
While I am convinced this question has a simple, empirical answer...

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...it's actually beside the point of this thread. The Sharpmaker is a fine piece of kit, but it can't be a stand alone sharpener, especially if, like me, you lack the skill to follow the grind lines of the knife. You're probably best served by investing in a clamp based fixed angle system. This will allow you to create bevels that suit your fancy. As proof that the dreaded fat bevel can be avoided with correct clamping, I offer the following photos. The first two are a 21 and the last two are a 31.

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Modernflame said:
While I am convinced this question has a simple, empirical answer...

View attachment 2078045

...it's actually beside the point of this thread. The Sharpmaker is a fine piece of kit, but it can't be a stand alone sharpener, especially if, like me, you lack the skill to follow the grind lines of the knife. You're probably best served by investing in a clamp based fixed angle system. This will allow you to create bevels that suit your fancy. As proof that the dreaded fat bevel can be avoided with correct clamping, I offer the following photos. The first two are a 21 and the last two are a 31.

View attachment 2078046

View attachment 2078047

View attachment 2078048

View attachment 2078050
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Beautiful edges.
 
I saw on the CRK website where they have the "how to sharpen a 21" by rolling the blade on a sharpmaker at the tip. I don't have a sharpmaker, but I normally use an Edge Pro system. After reading that I am kind of concerned when I go to sharpen my 21. It would not be that easy to change the angle of sharpening along the length of the blade toward the tip. I use some other knives more than the 21s and have sharpened them before the 21s. I will have to take some care when I finally sharpen them.

I really don't want to buy a sharpmaker just to sharpen 21s. It is more of a maintaining system rather than reprofiling or heavy duty sharpening system.
 
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jjg6319 said:
I saw on the CRK website where they have the "how to sharpen a 21" by rolling the blade on a sharpmaker at the tip. I don't have a sharpmaker, but I normally use an Edge Pro system. After reading that I am kind of concerned when I go to sharpen my 21. It would not be that easy to change the angle of sharpening along the length of the blade toward the tip. I use some other knives more than the 21s and have sharpened them before the 21s. I will have to take some care when I finally sharpen them.

I really don't want to buy a sharpmaker just to sharpen 21s. It is more of a maintaining system rather than reprofiling or heavy duty sharpening system.
Click to expand...
Much of the concern about wide bevels comes from the Apostle P's YouTube channel. The dude is a sharpening genius and I understand why his opinions carry so much weight. It may be worth remembering that he sharpens Sebenzas at 16 degrees per side, which, at least in my opinion, is too acute for the knife's design. Sebenzas are in the neighborhood of 20 thousands behind the edge and seem to be comfortable being sharpened at 20 degrees per side. I personally will not sharpen a Sebenza any more acutely than 19. When I look at his Sebenzas, the entire length of the bevel looks too wide. Some people like to lay the edge back for cutting performance, but I find the standard geometry to be more than adequate for pocket knife jobs. I think the problem can be mitigated by choosing an angle in the 19-20 degree range. Even if you can't tilt the knife on the Edge Pro, you can avoid cutting so deeply into that thicker steel at the belly.
 
I just saw another video entitled TNG Ep 63 by Matthew Rowell and he did a much better job than Apostle P. I have never been a fan of AP.

M Modernflame Thanks for the suggestion on the angle! I think that is the key. :)
 
I usually go around 18 degrees per side on the Wicked Edge when sharpening Sebenza drop points. I've done 31s and 21s over the years and I'd say that there's not much difference in terms of the thickening at the tip. Maybe slightly less on the 31s, but you really only get a super wide bevel at the tip if you lay the edge back to closer to 15 degrees. I've always found 18 to be the sweet spot between getting good slicing performance and not removing a ton of steel, especially from the forward portion of the grind.

I'd add that Small Sebenza drop points, in my experience, are much worse about thickening towards the tip, and being thicker behind the edge in general. I like how the larges sharpen much better.

Insingos, on the other hand, whether large or small, Sebenza or Inkosi tend to have very uniform thickness behind the edge and also come in thinner behind the edge than the drop points, making them good candidates for sharpening more acutely. I've done 15 degrees on those on the past without the bevel looking super thick, and they definitely slice incredibly well that way.
 
Modernflame said:
Much of the concern about wide bevels comes from the Apostle P's YouTube channel. The dude is a sharpening genius and I understand why his opinions carry so much weight. It may be worth remembering that he sharpens Sebenzas at 16 degrees per side, which, at least in my opinion, is too acute for the knife's design. Sebenzas are in the neighborhood of 20 thousands behind the edge and seem to be comfortable being sharpened at 20 degrees per side. I personally will not sharpen a Sebenza any more acutely than 19. When I look at his Sebenzas, the entire length of the bevel looks too wide. Some people like to lay the edge back for cutting performance, but I find the standard geometry to be more than adequate for pocket knife jobs. I think the problem can be mitigated by choosing an angle in the 19-20 degree range. Even if you can't tilt the knife on the Edge Pro, you can avoid cutting so deeply into that thicker steel at the belly.
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I first noticed the wider bevel at the tip when I was sharpening using the sharpmaker. Not just on my sebenza, but other knives too. While trying to figure out what I was doing wrong I found the “how to…” instructions from CRK and came across the apostleP videos. I thought his bevels looked terrible, an exaggerated example of the problem I was having. Your point about him using a 16dps is spot on. Makes the problem even worse. I’m quite satisfied with 20dps.

halden.doerge said:
I usually go around 18 degrees per side on the Wicked Edge when sharpening Sebenza drop points. I've done 31s and 21s over the years and I'd say that there's not much difference in terms of the thickening at the tip. Maybe slightly less on the 31s, but you really only get a super wide bevel at the tip if you lay the edge back to closer to 15 degrees. I've always found 18 to be the sweet spot between getting good slicing performance and not removing a ton of steel, especially from the forward portion of the grind.

I'd add that Small Sebenza drop points, in my experience, are much worse about thickening towards the tip, and being thicker behind the edge in general. I like how the larges sharpen much better.

Insingos, on the other hand, whether large or small, Sebenza or Inkosi tend to have very uniform thickness behind the edge and also come in thinner behind the edge than the drop points, making them good candidates for sharpening more acutely. I've done 15 degrees on those on the past without the bevel looking super thick, and they definitely slice incredibly well that way.
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Good points. I have only had a small drop point and small insingo. I liked them both but the insingo is so much easier for me to sharpen. I gave up on the drop point. Not the knife’s fault. I’d like to try another drop point but I may have to wait until I can afford a better sharpening system.
 
rishma said:
I’d like to try another drop point but I may have to wait until I can afford a better sharpening system.
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That may be the best answer. For what it's worth, you don't have to buy all the bells and whistles for whatever system you like. With most of the respected brands, you can get good results with the basic kit.
 
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