Edge not centered, can it be fixed?

W

Whelen Nut

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Jan 2, 2011
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So I bought a new knife. It's .25 thick and the edge isn't in the center towards the tip. I intend to put a convex edge on this knife and I will be using sandpaper to get me there however I'm not sure if the edge being off center will screw me over? If I want to make the center of the convex edge true what will happen? Should I waste my time trying to convex this (by hand mind you) only to find out that because the edge is off center it changes the belly sweep, tip or something of that sort?

I'm not sure I'm wording this right but I want to know if the edge being off center will negatively impact my desire to convex this knife.

If yes what are my options?

Thanks

Shot from the spine down
IMG_2061.jpg


Shot from the edge up
IMG_2064.jpg
 
They're just at different angles, when you sharpen it, assuming that you do it correctly, it will be fine.
 
I usually keep using it and sharpening it until it gradually returns to center. doesn't really affect use, especially on a 1/4" thick blade and the tasks it will do.
 
The edge being a bit uneven like that won't make any difference. When you sharpen it, that will even out, assuming you sharpen it properly.
 
I think virtually every edge I've looked at, when I've looked VERY closely, is somewhat asymmetrical, as in your pics. So long as the edge itself is clean & sharp, I've never worried about it too much.

Your edge, as shown, actually looks pretty good. And your pics are excellent.
 
an edge that is not centered is not good. It will influence it cutting characteristics a lot.
an extreme example of this is the chisel grind, which cuts totally different than a v-edge that is properly centered.

because the edge is not centered, the force distribution is different and it will be harder to make a straight cut etc.

It might not be bad for you, but in any case, it should be centered.
proper sharpening with a littlebit of attention to the off-grind will restore it to the way it should be.
 
There was another thread recently (forget what the original topic of it was), but the subject of asymmetrical blade grinds came up, in terms of how they affect the edge. It was pointed out, that the primary grind on many blades, to greater or lesser degree, is often asymmetrical as a whole, which does some odd things when the edge is sharpened. Wider bevels on one side of the blade, or 'wavy' bevels that tend to follow or highlight curves/bends in the blade or, as in this case, an edge that appears off-center.

Looking at the pics here, the blade profile (apart from the edge, beyond the bevels themselves) looks very similar to what was discussed there. Looks 'thicker' on one side, than on the other.

Also, from what I see in the pics, it looks like most of the visible asymmetry is at or near the very tip. The bevels further down, along the rest of the edge, look relatively good. Not perfect, but definitely very serviceable. And, as pointed out, it's something that can be gradually straightened out over time, during normal upkeep of the blade. It's not so extremely misshapen, that it has to be 'fixed' immediately, if at all. Focus on keeping the edge sharp, and I bet you'll be quite happy with it over the long run.

It's obviously ideal to have a blade and edge that are perfectly symmetrical, but I think 99.9% of the time, people aren't likely to even notice the very slight degradation in cutting performance. The very edge itself, if it's not truly sharp, will have a much more noticable impact in typical, real-world use (opening packaging, cutting up boxes, stripping insulation, field-dressing game, etc.). A cutting task that actually requires that degree of precision (perfect edge symmetry), would likely be done with a much more specialized tool, I'd think.
 
Whelen Nut said:
So I bought a new knife. It's .25 thick and the edge isn't in the center towards the tip. I intend to put a convex edge on this knife and I will be using sandpaper to get me there however I'm not sure if the edge being off center will screw me over? If I want to make the center of the convex edge true what will happen? Should I waste my time trying to convex this (by hand mind you) only to find out that because the edge is off center it changes the belly sweep, tip or something of that sort?

I'm not sure I'm wording this right but I want to know if the edge being off center will negatively impact my desire to convex this knife.

If yes what are my options?
Click to expand...

I neglected to address your original question in my earlier reply. For what it's worth, I have several knives that I convexed (from being V-grinds previously). None of them LOOK perfect, but they all cut beautifully. If there's any significant impact on convexing, it mostly comes down to appearance, in the end. You might notice, due to the 'thicker' looking bevel on one side vs. the other, that the end result will also look somewhat asymmetrical, UNLESS you go to great lengths to grind/sand more metal from the thicker side, to even it up a bit.

This isn't to say, that you still can't make it into an excellent cutter, when all is said & done. As I pointed out before, focus on the edge itself, making sure it's completely apexed along the full length. Use as much magnification as you've got; from your pics, I'd assume you've got that covered.
 
From the looks of your amazing pictures, it looks like the person who sharpened it pulled off as the tip approached and it is only very off center at the tip. This is actually quite common on mass produced knives that are sharpened by hand.

Honestly, I would use it (and I am QUITE picky about my edges). If that disparity really effects your use that much, I have a lot of other questions...the first would deal with the uses of a blade that is that thick AND must be centered perfectly.

This is an example of where I would not touch that factory edge...try it out first;)

Convex is nice, but why not try this one with the V first...it will give you data specific to that knife regarding the superiority of one shape of grind over another...

BTW is that a 5? Mine was quite off center from the factory and the edge grind started about 3/4 inch from the plunge! It was quite easy to fix though.
 
Thanks for all the comments. I'm not sure if you guys are pulling my legs about the "amazing" pictures but I just used a point and shoot canon powershot to take them. Nothing fancy that's for sure.

This is a SOD and it chops chicken carcasses in half very nicely.

The reason I wanted to convex it is because I do have water stones but I find stropping so much easier. I'll leave it as is for now I guess and when it's dull from doing things a SOD does I'll either put the sand paper to it for convex or fool with water stones.

I also find it easier to touch up a convex in the field than a v edge. That's just me though.

I'm not really to worried about one side being thicker than the other (not sure when that would ever matter on a SOD used as a camp knife) but more so about the edge not being circular like it is supposed to be on the belly but rather having a dimple or something of that sort due to convexing. I'm absolutely certain I'm not using the right terminology but I'm worried that if the edge is to far on one side that sharpening it to where it ought to be will sharpen away the metal that is to far on one side and leave a ditch, dimple where it used to be as there is no metal on the imaginary center of the blade.

I'm off to bbq some venison tenderloins.

Thanks for reading.
 
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No, I can assure you neither of your legs have been pulled. Those are some outstanding Pics.
Always makes a thread a little more fun with nice pics.
I concur that the minor asymmetry in your present grind won't have a negative effect on sharpening or just leaving it alone. My Acies was worse. I evened it up on the WEPS but I can assure you it was and is sharp as hell.
It was merely the aesthetic that bugged me nothing more.
 
unit said:
From the looks of your amazing pictures, it looks like the person who sharpened it pulled off as the tip approached and it is only very off center at the tip. This is actually quite common on mass produced knives that are sharpened by hand.

Honestly, I would use it (and I am QUITE picky about my edges). If that disparity really effects your use that much, I have a lot of other questions...the first would deal with the uses of a blade that is that thick AND must be centered perfectly.

This is an example of where I would not touch that factory edge...try it out first;)

Convex is nice, but why not try this one with the V first...it will give you data specific to that knife regarding the superiority of one shape of grind over another...

BTW is that a 5? Mine was quite off center from the factory and the edge grind started about 3/4 inch from the plunge! It was quite easy to fix though.
Click to expand...

They say that is why sheep herders wear those big rubber boots;)
 
Well I took it out as is and chopped a 2x4 with it. Wasn't all that great so I got some sandpaper and convexed it. It can actually cut paper now (which it couldn't before) and chopps much better now. Here are a few pics.

Convexed tip/edge
IMG_2082.jpg


SOD with smaller cousin RMD
IMG_2077.jpg


Just cause it looks cool. The coating seems finer on the SOD than the RMD.
IMG_2080.jpg


Cheers
 
Whelen Nut said:
Well I took it out as is and chopped a 2x4 with it. Wasn't all that great so I got some sandpaper and convexed it. It can actually cut paper now (which it couldn't before) and chopps much better now.
Click to expand...

Your new edge looks great! :thumbup: And the pics are excellent, too.

I've noticed, with every single knife I've convexed so far (10+), they all will glide through paper like laser beams. Makes push cuts almost effortless. I've really become a believer in the 'smooth, round shoulders' of a convex edge making for a lot less friction in slicing. Same holds true when cutting cardboard & plastic materials. These are prime attributes of what I'd think of as an excellent working edge.
 
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