Convex edges and the Wicked Edge

Hotshot10

Hotshot10

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My mother-in-law bought me a WE a few years ago, and I've been able to resharpen some of my knives quite well with it. I've been interested in buying a Fallkniven F1 or BKRT Bravo-1 for a while, but I'm not sure that I can use a WE to sharpen them. Given what I've read about convex edges, I don't know if the stone will actually reach the edge or if it will simply remove metal about a millimeter or two from the edge (see my diagram).

Wicked Edge.jpg

Does the "convex-ness" of the grind interfere with sharpening? I don't know how to phrase this question otherwise. Sorry if it's confusing.
 
Google "wicked edge convex edge"

Wicked Edge has a pdf on thier website (the second match on Google for me) that does a pretty good job of explaining convex edges and the Wicked Edge.
 
KME's version for convex is a curved guide rod. Not sure if something like that could be adapted to the WE since the rod appears to ride through the stone holder.

kme-convexing-guide-rod-1.jpg






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People are Strange, When You're a Stranger....
 
Hotshot10 said:
My mother-in-law bought me a WE a few years ago, and I've been able to resharpen some of my knives quite well with it. I've been interested in buying a Fallkniven F1 or BKRT Bravo-1 for a while, but I'm not sure that I can use a WE to sharpen them. Given what I've read about convex edges, I don't know if the stone will actually reach the edge or if it will simply remove metal about a millimeter or two from the edge (see my diagram).

View attachment 644468

Does the "convex-ness" of the grind interfere with sharpening? I don't know how to phrase this question otherwise. Sorry if it's confusing.
Click to expand...

Yes it does, which is why convex edges are duller...

I can just see archaeologists digging out one of our knives, and going:

"Yes that example has what was called a "convex edge", typical of the early 2000 AD period. There was a mystical belief in that period that it made knives cut better: We never found any drawings of that time, all of them being on electronic support, but we suspect they made drawings showing the convex lines drawn inside a V edge to support and perpetuate the notion..."

Gaston
 
Bark River claims you can maintain them with a leather strop, and sandpaper with a leather backing for sharpening, so I did one using strips of sandpaper attached to a leather strop...

7905fc4258c3b75261177aac6e1fdcac_zpscjjwci5g.jpg


... ended up with a nice defined convex edge. I used 'removable' double stick tape and sandpaper from 100 to 2500 grit, then stropped. Works if a convex edge is what you're after, but still want to use a guided sharpener. You can also sharpen the edge at multiple angles, then blend it with a strop, as mentioned in the pdf referenced above.
 
cbwx34 said:
Bark River claims you can maintain them with a leather strop, and sandpaper with a leather backing for sharpening, so I did one using strips of sandpaper attached to a leather strop...

... ended up with a nice defined convex edge. I used 'removable' double stick tape and sandpaper from 100 to 2500 grit, then stropped. Works if a convex edge is what you're after, but still want to use a guided sharpener. You can also sharpen the edge at multiple angles, then blend it with a strop, as mentioned in the pdf referenced above.
Click to expand...

That's a nice edge there. I saw the PDF, but that process of blending the edge looks like a PITA. The leather strop option is much more appealing.
 
Gaston444 said:
Yes it does, which is why convex edges are duller...

I can just see archaeologists digging out one of our knives, and going:

"Yes that example has what was called a "convex edge", typical of the early 2000 AD period. There was a mystical belief in that period that it made knives cut better: We never found any drawings of that time, all of them being on electronic support, but we suspect they made drawings showing the convex lines drawn inside a V edge to support and perpetuate the notion..."

Gaston
Click to expand...
Typical nonsense response that in no way contributes to the thread in anyway.

Op.
You can do a convex edge on the wicked edge if you sharpen in a tier of angles. Or sandpaper taped over a mousepad connected to one of the paddles. (Or on a strop like mentioned above)

A strop will work for along time thou.

Sent from my SM-G935V using Tapatalk
 
It aught to be possible leave the clamp open slightly, put in a block to elevate the spine so the angle is where you need it, shim the spine so it doesn't shift at the bottom of the clamp.

As the blade is rocked side to side it will hit along an arc. Might take some futzing to get right.


but we suspect they made drawings showing the convex lines drawn inside a V edge
Click to expand...

Well...that is how CATRA does it...
 
I'm not a mathematician, so drawing inside or outside doesn't matter. When sharpening though, you can go from outside where the stone contacts the steel.
 
Last edited:
Depends. From v to convex. Keeping apex angle the same, you grind/thin the back bevel and shoulder. However, keeping the back bevel or shoulder angle the same, the apex will be more obtuse. This is why some say convex is stronger..
From convex to V, you'd definitely reduce the apex angle. Imagine running straight line from shoulder to apex.
 
Chris "Anagarika";16222911 said:
Depends. From v to convex. Keeping apex angle the same, you grind/thin the back bevel and shoulder. However, keeping the back bevel or shoulder angle the same, the apex will be more obtuse. This is why some say convex is stronger..
From convex to V, you'd definitely reduce the apex angle. Imagine running straight line from shoulder to apex.
Click to expand...

I saved one of the many diagrams showing this (unfortunately, forgot to save who made it, sorry)...

 
cbwx34 said:
I saved one of the many diagrams showing this (unfortunately, forgot to save who made it, sorry)...

Click to expand...

I wish that eventually users would understand the red lines don't belong in that diagram...

Comparing the red lines and the black lines is pretty much like comparing a folder to a fixed blade, and pronouncing the folder superior in sharpness...

I had a knife professionally converted from the black lines to the red lines, a full height convex, and the 0-1 steel chipped and crumbled with astonishing ease... Even in its thinner condition, it did not really cut as spectacularly as its thinness would imply, because the initial apex aggressivity is always poorer on a convex...

Great for chopping free-hanging manila rope though...

Gaston
 
Megabassx7 said:
Why dont the red lines belong??
Click to expand...
Hi,
Because that is a thinner shoulder,
thinner than the blue convex
and thinner than the black V-edge
the blue and black are same height, and begin at same width (thickness),
the red convex is much much taller,
If you want to compare the red convex to a v-edge,
you'd have to draw a new one,
one with the same height, example
the green square is the metal you begin with,
the width/height,
convex will always be fatter than v-edge given same starting square
sTmvXvy.png
 
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