Reprofile: What is it exactly?

singularity35

singularity35

Joined
Mar 1, 2010
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When I sharpen my knives at a more acute angle on my aligner is that reprofiling or is that just making a back bevel? Or does reprofile mean that I have to hit the whole secondary bevel?
 
Re-profiling is simply changing the geometry of the edge bevel. This is different than sharpening where your goal is to maintain the edge geometry.

I generally consider it "re-profiling" when I change the angle of the actual cutting edge, not just knocking the shoulders off.
 
As I've come to understand it, reprofiling is what happens if the existing bevel, from the edge to the shoulders, is completely removed & replaced with a new bevel (presumably at a different angle), or a complete change in the edge shape, such as from a V-grind to a convex.
 
Gotcha, so in effect, even if I use an angle setting in my DMT aligner which says 22-24 degrees but still doesn't hit the whole existing secondary bevel, then I am not actually reprofiling?
 
Well, you are re-profiling the blade, but not the edge. Re-profiling is just what it sounds like. You are changing the profile of your knife. The new thinner profile will slice through stuff easier. In fairness though, if you aren't taking off enough metal to enhance the perfomance of your knife, then I wouldn't call it "re-profiling" either. I would call it, as you said, "back-beveling". But if the object is to enhance usability I would call it re-profiing.

Reprofiling is not an uncommon practice, by the way. As old knives get "used up", it is often desirable to re-profile the blade down to a slimmer profile, so as to avoid a huge "shoulder" on the edge bevel.

What the other gentlmen are talking about is actually reprofiling the edge, which is true and fine, just not what I am understanding you talking about.

That's just my take on it. One can't change the functional geometry of the blade and not call it "re-something-or-other"....unless you want to. :D
 
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Perhaps I am off base?

I use the term "re-bevel" when I change the geometry of the bevel. This can include any of the following:
Changing a V-bevel to a convex
Changing a Convex to a V-bevel
Changing the angle of a V-bevel (perhaps taking a 30 degree inclusive bevel to a 20)
Grinding a bevel out to eliminate secondary bevels or micro-bevels (for example a factory edge that came with a primary edge bevel of 30 deg inclusive that has been touched up several times at 40 degrees thus creating a secondary "micro" bevel).

To me "re-profile", means you are changing geometry of the entire blade. If you have a saber-grind or hollow-grind knife for example, you must re-profile the blade if you want a full flat grind. Additionally, some will keep the general geometry but re-profile the blade so that it is thinner at the widest point for better cutting performance, or to achieve a zero grind (or at least something closer to zero than stock). As pointed out above, as a knife gets used up the bevel gets thicker and thicker shoulders. Some will re-profile the blade to reduce the shoulder width. Regardless, to me "re-profile" is understood as something much more involved than altering the area of the blade withing a few mm of the cutting edge.

As I said, perhaps I am wrong?, but I have adopted the view that you can re-grind a bevel or a blade. Re-grinding a bevel is a much smaller task than re-grinding an entire blade (thus re-profiling it). Admittedly, the lines get sort of blurry when your bevel starts to extend into a significant portion of the blade.

I am interested in what others think about this...
 
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unit said:
Perhaps I am off base?

I use the term "re-bevel" when I change the geometry of the bevel. This can include any of the following:
Changing a V-bevel to a convex
Changing a Convex to a V-bevel
Changing the angle of a V-bevel (perhaps taking a 30 degree inclusive bevel to a 20)
Grinding a bevel out to eliminate secondary bevels or micro-bevels (for example a factory edge that came with a primary edge bevel of 30 deg inclusive that has been touched up several times at 40 degrees thus creating a secondary "micro" bevel).

To me "re-profile", means you are changing geometry of the entire blade. If you have a saber-grind or hollow-grind knife for example, you must re-profile the blade if you want a full flat grind. Additionally, some will keep the general geometry but re-profile the blade so that it is thinner at the widest point for better cutting performance, or to achieve a zero grind (or at least something closer to zero than stock). As pointed out above, as a knife gets used up the bevel gets thicker and thicker shoulders. Some will re-profile the blade to reduce the shoulder width. Regardless, to me "re-profile" is understood as something much more involved than altering the area of the blade withing a few mm of the cutting edge.

As I said, perhaps I am wrong?, but I have adopted the view that you can re-grind a bevel or a blade. Re-grinding a bevel is a much smaller task than re-grinding an entire blade (thus re-profiling it). Admittedly, the lines get sort of blurry when your bevel starts to extend into a significant portion of the blade.

I am interested in what others think about this...
Click to expand...

I think I understand better now. Thanks.
 
I always think of reprofiling as changing the angle or the nature of the bevel; that is, taking a 15 degree per side V-grind to a 15 degree inclusive V, 20 degree inclusive V, convex grind, etc. I don't consider microbeveling or back beveling to be reprofiling. (Unless of course the back beveling is so extensive that all that remains of the original profile is a micro-bevel :) )
 
I don't have any problem at all in making a distinction between reprofiling the EDGE of a blade or, as unit described, reprofiling the entire blade. I think the term 'reprofile' can be applied either way. To me, it's about significantly altering the shape (geometry), but to lesser or greater degrees. The term 'profile' refers to the outline or shape of something. So, for me, 'reprofiling' just means that the outline or shape is being altered. That could be the shape of the whole blade, or the shape of the edge alone.

So, to unit, I don't think you're off-base at all (or wrong). I believe you're just thinking about it on the larger scale of the whole blade, whereas I'm applying the term to the edge alone.

That's my two-cent opinion on the matter... :p
 
I've used the term reprofile in a more general sense. Perhaps I should adopt the "re-bevel" term? I too would like to hear what others think.
 
Obsessed with Edges said:
I don't have any problem at all in making a distinction between reprofiling the EDGE of a blade or, as unit described, reprofiling the entire blade. I think the term 'reprofile' can be applied either way. To me, it's about significantly altering the shape (geometry), but to lesser or greater degrees. The term 'profile' refers to the outline or shape of something. So, for me, 'reprofiling' just means that the outline or shape is being altered. That could be the shape of the whole blade, or the shape of the edge alone.

So, to unit, I don't think you're off-base at all (or wrong). I believe you're just thinking about it on the larger scale of the whole blade, whereas I'm applying the term to the edge alone.

That's my two-cent opinion on the matter... :p
Click to expand...

Thanks for your opinion. I think it is a valid discussion and your interpretation seems logical.

I guess the term "re-profile" should be accompanied by a classifier. ("bevel re-profile" or "blade re-profile"). Sort of like "20 degree edge" needs to be classified with "per side" or "inclusive".

Leave it to a knife nut (me) to analyze the minutia LOL.
 
unit said:
Thanks for your opinion. I think it is a valid discussion and your interpretation seems logical.

I guess the term "re-profile" should be accompanied by a classifier. ("bevel re-profile" or "blade re-profile"). Sort of like "20 degree edge" needs to be classified with "per side" or "inclusive".

Leave it to a knife nut (me) to analyze the minutia LOL.
Click to expand...

Yes. :thumbup:

With regard to 'analyzing the minutia', that's why we're all here, right? That's what makes us ALL knife nuts! :D
 
unit said:
To me "re-profile", means you are changing geometry of the entire blade. If you have a saber-grind or hollow-grind knife for example, you must re-profile the blade if you want a full flat grind. Additionally, some will keep the general geometry but re-profile the blade so that it is thinner at the widest point for better cutting performance, or to achieve a zero grind (or at least something closer to zero than stock). As pointed out above, as a knife gets used up the bevel gets thicker and thicker shoulders. Some will re-profile the blade to reduce the shoulder width. Regardless, to me "re-profile" is understood as something much more involved than altering the area of the blade withing a few mm of the cutting edge.
Click to expand...

I've always considered that type of work "re-grinding", ala Tom Krein. When a blade visits the KMG, I'm grinding, not simply profiling the edge.

To the OP: As you can see there isn't really a consensus here. We just use whatever word works for us.

Phillip
 
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