Edgepro sharpening question

K

kirko

Joined
Dec 4, 2004
Messages
497
Have a question regarding sharpening one of my large regulars... I sharpened the blade at 20 degrees. No problem in sharpening at all, very pleased. My question is that the actual edge becomes more wide towards the tip. Like on the flat of the blade, the edge is probably .5mm wide, and as is goes through the belly of the blade to the tip, it widens to about 1mm. Anyone else run across this? Its the same on both sides. Its normal i suppose?
-Kirk
 
Quite common, doesn't affect the sharpness at all. You can ignore it unless you're particularly anal about such things.
 
The reason this happens is because the steel gets thicker as the edge profile grind sweeps up towards the tip of the blade. In order to make the edge "look" symmetrical you would have to sharpen it free hand and be very good at it. I would stick with what you are doing as the Edgepro system is really very good.
 
If you want the exposure of the secondary bevel to remain uniform, you have to adjust the stone's angle of attack as you move along the blade. Or perhaps more correctly, you have to keep it from adjusting itself.

There are several potential variables in play, edge thickness being one of them, as ES says. Based on your description, my guess is that one factor in your situation is that you are increasing the distance from the stone's pivot to its contact point with the blade as you move toward the tip of the knife.

Consider a plan view of the EP and knife. The knife is resting on the EP's platen in its most advanced position (as you would begin sharpening). If you place the stone on the blade so that it’s parallel with the platen, it will fall just forward of the rear of the cutting edge. In that position, the stone is traveling on its shortest path = steepest vertical angle.

If you continue to sharpen toward the tip of the knife, without moving the knife, the stone has to travel an increasingly greater distance from its pivot point = decreasing vertical angle = increasing exposure of secondary bevel.
 
This isn't a problem for Spyderco and Fallkniven knives, since the blade thickness narrows toward the tip. The solution is to buy knives of the correct blade geometry in the future.
 
Thats what exactly what I did to mine. I had it on one of the lowest settings...:p I guess I shouldn't have used the benza as the 2nd test knife on the EP hahaha :o

DSC00561.jpg
 
I like that. it looks pretty wicked. mine edge isnt near that thick though, lol....
 
its because of this i hate sharpening system with rods and stones ... the sharpmaker keeps the angle consistant the whole run of the blade... it took a lot of work to beat the lansky out of me knives with the sharpmaker!!
 
Can anyone post pictures of their Sebenzas with Edge Pro Edges and what settings you guys used?

The Small Regular in the picture was done at the red setting (15) and I put it flat against the edge. You could say that the spine was raised a bit.
 
I forget what i set this as, I think 20 degrees. Then I stropped to a mirror finish.
seb_edge.jpg
 
I'm guessing you set it a the 21 setting? I think its the yellow mark? How did you set the knife flat on the surface? I had problems with the knife wobbling around...

BTW that edge looks great! !!!:thumbup:
 
How did you use duct tape? Could you please describe your process a bit more or maybe take a few pics? I would love to put your edge on my 21...
 
As of right now I am having my benza sit on the "flat of the spine."

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However, when I do that, the actual edge is sitting above the table.
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Thus, I must actually set the edge on the table, but this raises the spine from being flat with the guide, and now it wobbles around.
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In this picture, it is set at the 21 setting or the yellow mark. We can see that it is not even close to hitting the edge. So I can either keep it at the current setting and remove more additional metal, or go to the 24 setting and remove less metal....however at that setting I don't think I'll beable to actually maintain the edge on my sharpmaker (30/40) settings.

DSC00868.jpg


My main concern is I don't want to remove too much metal from the tip as my previous sebenza.
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This picture currently shows where the EP is hitting the tip at the 21 setting...
DSC00869.jpg


My other concern is how do you approach the other end of the knife where there isnt the thumb stud as a guide? I have even more trouble trying to keep this thing from wobbling.

DSC00870.jpg
 
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Initial testing results of the 21 setting (Used the polishing tapes to show where the EP is hitting).
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As I mentioned, I'm mainly concerned with the tip as I do not want to remove too much metal. I think the marker indicates that too much metal will be removed from the tip at the 21 setting(Not as extreme as my first sebenza)...any advice?
 
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