Resharp -- Automated Knife Sharpening Machine at Stores

the cutting edge of a knife is (very) thin. when the edge is bent back&forth many times - typically by ‘aligning via a honing rod’ the edge breaks off.
just like bending a paper clip back&forth&back&forth - it eventually breaks.
the fatigue question is not anything I would expect from a knowledgeable sharpener . . .

I highly doubt the Resharp machine does anything about a ‘honing dent’ -
it uses lasers to track the profile, and follows the existing profile ‘no matter what’

I’m a “stoner” too; but some of the harder stainless out there gets old on the wetstone/oilstone. Why I buy knives I can sharpen quickly. But, I agree, stones the easiest for me and cheapest.

Pretty cool, Happy. Love this. My uncle carves wood and those nuts only use sandpaper for sharpening their precious cutting tools.

Yes… my grandfather taught my Dad (how to sharpen knives) and my Dad taught me.
None of my knives are expensive… I just touch them up on my whetstone when they need it.

It’s what started me in Kiwi knives. Bought one, used it, liked it; then, when I first sharpened it, it took just a few swipes and it was a razor again. Still have that first knife. $4

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Thanks for the explanation. Just to make sure I fully understand, you’re saying that, while honing, you’re applying enough force to repeatedly bend your knives’ edges like you would when intentionally trying to metal fatigue a paper clip to the point of failure? So, about how much of your edge breaks off?
Also, if you’re maintaining a regular routine of sharpening via EdgePro, shouldn’t that be removing enough material to work past the metal you’re fatiguing when honing? (Unless, of course, your edges are breaking off in chunks…)

Should I encounter a knowledgeable sharpener, I’ll be sure to test him with this line of inquiry.

In trying to goggle what “edges that have been over-ground (reverse curve) near the heel” (which I think I have on a boning knife) might mean, I found this.

I’m not sure he knows what you do for a living…

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He is a movie star.

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Less of a problem with a boning knife since most people don’t use the boning knife to cut against a cutting board, but this is particular problem with chef’s knife, especially the one with a traditional forged bolster. Borrow this image


I have seen this when I sharpened knives for friends.


Okay; thanks! This is what I was thinking of.

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the edge get ‘bent’ or ‘rolled over’ in normal use. the honing rod ‘straightens’ or ‘realigns’ the cutting edge. which explain why the knife ‘seems’ sharper but as the experts say, a ‘hone does not sharpen an edge.’
so yes - a hone ‘bends’ the edge comma back straight.

enough bending and the edge fatigues and breaks off - at first it is like ‘micro serrations’ but eventually gets more severe. a 10x loupe is sufficient to see the edge condition.

I judge the need to sharpen from use - I’ve noticed recently my 10" chef is still quite sharp on the ‘flat’ but the ‘belly’ has been worn down from ‘rock&chop’ use - so it needs a touch up…

Sadly, knife (and specifically knife sharpening) terminology is so imprecise and vague) that prople trying to use it get confused and talk over and past each other.

Eiron, a profesional knifemaker, knows this. Hence his gentle tweak about wire edges “breaking off”.

Edge geometry being what it is, burr edges (call them foils, wire edges, whatever you like) aren’t folded-over “normal” edges. They form via abrasion, specifically the kinds of abrasion that happen when we sharpen. Wire edges get “raised” on the stone or belt. This is what you feel under your thumbnail when the blade comes off the platen or stone.

What happens to this little flap? Well, many times NOTHING. It stays, invisible to the naked eye. This CAN be bent back and forth by “honing”, steeling, and even further "sharpening. That’s what most people are doing, and they’re not recognizing it. At best, they’re just staightening the foil, not aligning the bevels. So when the wire edge finally fatigues away in places the edge looks especially ragged under your loupe.

Much of this (both the formation of the burr and endless “honing”) would cease to exist if the wire edge was removed as a final stage of “sharpening”, or with a cutting steel or crockstick.

Bottom line: what is getting bent over is the wire edge, not the primary edge.

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I see. It does seem to be a overly sharpened and started to change its profile. My guess is that … because of how boning knife is typically used, this will have no determental effect. If oversharpening occurs for a chef’s knife or a santoku, then it can negatively affects a knife. I have seen this happened to my friends’ knives.

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The problem is there’s no clearance for the bolster. The only way to get into that hollow is with a round file, dowel rod, or a very tiny belt wheel or Dremel.

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You can still hit that area without touching the bolster by sharpening on a stone or on a belt sander. But now looking it closer, it does seem more like an intentional act. You think someone did this on purpose to try to improve the knife?

If you are referring to my boning knife, I was using a Chef’s Choice electric sharpener for many years. I don’t use it much anymore, but the last time I did, I noticed they cautioned the user to use the first part “sparingly”. I used to do two passes through the first and second part, and once through the third. No more than twice a year for the boning knife, probably less. That boning knife is probably 25 years old. I keep the other boning knife hidden from the rest of the household.:blush:

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Thanks for sharing.

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No. I think the bolster got in the way, and they kept on trying. The wheels on the consumer sharpeners are recessed for safety reasons, and this exacerbates the problem.


As others have noted, your boning knife’s edge is intentionally shaped that way. And yes, without the proper setup, it’s challenging to sharpen that portion of the edge in front of the bolster. If I get a boning knife to sharpen, I’ll ask the owner if they use it as a boning knife or a utility knife. 99%+ of the time they use them as utility knives, so I’ll sharpen only the straight edge and curved tip sections and leave the bolster section alone. Occasionally I’ll remove the bolster for them and turn it into an actual utility knife.

Here are a few before/after pics of what I often see. In this case I turned the full bolster into a partial bolster (at the request of the owner) so that the edge was easier to maintain in the future.