Size of edge resulting from sharpening?

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Mathias Z.

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All the knives I own came in an almost zero grind with very little edge (in size 0,1 to 0,2 mm). If I put them knifes onto the stones (1000, 4000 or 5000, >8000) it results in an edge that is bigger in size - up to 1mm. I would like to know if you aim for keeping the size of the edge at minimum or if you consider it normal for the edge to grow in size. From time to time I try to thin the knife in order to keep its geometry. How often would you thin your knife? How many strokes you consider ideal per side? Which stones do fit for kasumi finish? What do you use to thin out damascus cladding - so as not to destroy the finish? How do you consider the size of the primary bevel that resulted from sharpening my santoku? Do you have comparable pictures of your knifes showing the results of sharpening? Thanks.
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Benuser

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Rule of thumb for a general purpose chef's: 0.2mm thickness above the bevel; 0.5mm at 5mm from there; 1mm at 1cm.
 

Matus

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Are you talking about WIDTH or THICKNESS of the edge bevel?
 

ian

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I wouldn't stress out about the width of the bevel. On a wide bevel knife, I often do prefer a near `zero grind' with a microbevel at the edge, so if you also want the look of a tiny bevel, well, you can sharpen like that. (FWIW, I hate the term zero grind, even though people use it all the time here. The angle at the edge is not zero. I'd prefer just calling it a grind where the primary bevel is the wide bevel. Or perhaps a noncompound grind? Or.... hmm there must be a better term.) But a more traditional bevel would be fine too. For wide bevel knives, though, I think it's actually easier to sharpen in the way mentioned above. Namely, you're going to have to thin all the time anyway, and the above sort of removes one step in the process.

On the subject of thinning, just thin till you like how it cuts. Don't overthink it. Even if they're not doing a zero grind sharpening as above, many people thin slightly every time they sharpen --- in that case, you probably want to spend more time thinning (maybe at least twice as much... I don't know) than dealing with the edge, since it's harder to remove metal when there's more contact between the knife and the stone.

You will probably destroy the finish if you thin damascus. But it can be restored, more or less. Maybe some stones leave a better finish on it, but I don't know.

Your santoku looks fine. Don't stress.

Most people recommend natural stones for kasumi, but there are some synthetics that do pretty well imo. King 800 is often recommended, and the Gesshin 400/2000/6000 stones that I have also give you a finish with some contrast between core and cladding. Some others don't... e.g. my King 300, Chosera 800 and Gesshin 3k s&g remove all contrast. Not sure if this is something you can predict from the material or not. The ones above that produce contrast are softer and dish faster than the ones that don't, though. I am no kasumi god, though... quite the opposite.
 

Mathias Z.

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Are you talking about WIDTH or THICKNESS of the edge bevel?
I think about WIDTH of Bevel, the small, shiny band I see reflecting when I look at the knife. The WIDTH of the bevel usually was very thin when the knife comes new out of the smithery. I try to sharpen my knifes at 12 to 15 degrees, for big gyutos that is 9 mm to 10 mm that I lift the spine when sharpening. Should I aim for thinning the knife every time? What is your sharpening routine?
 

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Do not worry about the width of the edge bevel. Thin only when you start to feel that even a freshly honed edge starts to get ‘stuck’ in carrots or horizontal cuts on onions, or whatever other performance measure.
 

kayman67

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Adjust based on your needs and what you feel while cutting. There's no definitive answer. You already got great pointers above about pretty much everything important.

I sharpen knives for specific individuals in a specific way. Not all are the same as people like or need different things.
 

Benuser

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It's not about how many strokes, every knife is different. It takes as many strokes as it takes to get you where you going.
Don't flip sides before having reached the very edge.
 

inferno

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i almost never do zeros. they just dont hold up very well.

regarding the size of the edge/final bevel. well here i can do small or large. depending on what the knife is used for, and the steel/hardness.
Some of my knives have quite a small bevel at a low angle. typically aus8/white/blue/d2/vg10 steel.
but some of them have larger and longer sized bevels at higher angles. blue super/r2/srs15 for example since i find them quite chippy otherwise.

there is no right and wrong. just do what works for you.
 

ian

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Don't flip sides before having reached the very edge.
He migh be going for the no burr method?
Pretty sure he was asking about stroke counting for just thinning, and considering it separately from edge sharpening. As in, he's asking "how long should I spend sharpening at a lower angle than the edge, in addition to doing my edge sharpening." Anyway, the answer is ... until it cuts ok.

i almost never do zeros. they just dont hold up very well.
Zeros with a conservative microbevel seem to work just fine for me, but to each their own of course. I'm not chopping through many beer cans, though. :)
 

kayman67

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Pretty sure he was asking about stroke counting for just thinning, and considering it separately from edge sharpening. As in, he's asking "how long should I spend sharpening at a lower angle than the edge, in addition to doing my edge sharpening." Anyway, the answer is ... until it cuts ok.



Zeros with a conservative microbevel seem to work just fine for me, but to each their own of course. I'm not chopping through many beer cans, though. :)
So there are concerns for uneven thinning?
My bad.
 
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Mathias Z.

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For a wide bevel like the Santoku pictured I find it easy to thin a little but when it comes to convex grinds I really am not sure how I can thin the knife properly. Would I just adjust according to where I place my fingers and pressure put on the blades side? Is there an existing threat which explains in detail how to go about convex grinds - I really dont want to destroy that beautiful bevel Tosa San has put on that Ginsan knive. If I get the other comments right, I should not care too much about the size of the resulting bevel - as long as it cuts. Well - how true is that, but I have to say that knives are sharpest, when the size of the bevel is as small as possible, at least my experience - though fragile too. Maybe you could post some pictures of one of your knifes after sharpening - as a reference.
 

inferno

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almost all grinds are concave since they do them on 1m big waterwheels.

if you want to thin out then just fold the blade down lower than you actual edge angle. easy as that.

sure the blade side might not look as good after this.

then you have 2 options:
do nothing.
flatten the whole bevel and select your own finish on it.

most blades today are media blasted and while this looks cool when new. to get good contrast. this is not practical at home.

another option is finger stones. from narutaki stones or uchigumori stones.

i simply flatten the bevels off all my knives as soon as i get them. its easier that way imo. if the craftsmen could do it they usually would have from the factory.
i have no knives with factory finish on the bevels. its a part of the hobby.

the other alternative is simply taking the edge up higher and higher. up to you.
 

Mathias Z.

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Thanks for the reply, I meant concave not convex :). I think I will go with the try and have a look approach.
 

ian

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Are you sure you meant concave? Convexity is more common if your knife isn’t wide bevel. The convexity of a water wheel is only going to impart a slight concavity to the knife if you’re laying the knife flat against it, as in a wide bevel.
 

Benuser

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For thinning, start by removing the shoulders. Next step would be starting at the lowest level you're comfortable with. You may go even further, by applying pressure on the opposite side.
 

inferno

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Are you sure you meant concave? Convexity is more common if your knife isn’t wide bevel. The convexity of a water wheel is only going to impart a slight concavity to the knife if you’re laying the knife flat against it, as in a wide bevel.
all my knives that i have flattened, about 20 or so have been concave. the least concave ever by a large margin was a cheap 200€ hinoura. thats quality imo.
 

Mathias Z.

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I think that a slight concavity might help with food release, although on the other hand wide bevels also do the job. I don´t get your comment on the hinoura? Was it ironic or you consider their knives real good quality? Any idea where I can find a Tsukasa Hinoura Warikomi Kurouchi Gyuto 180mm to 210 mm? Thanks.
 

Benuser

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all my knives that i have flattened, about 20 or so have been concave. the least concave ever by a large margin was a cheap 200€ hinoura. thats quality imo.
Where is there any concavity, other than with wide-bevels?
 

ian

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Yea, I’m pretty confused. I’ve never had a non-wide bevel knife with a concave grind (other than Watanabes which always seem to come with a slightly concave strip behind the edge on the back side of the knife, although the front side of the knife is convex ground). Lots of knives have low spots, of course, but that’s different.
 

inferno

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Where is there any concavity, other than with wide-bevels?
Yea, I’m pretty confused. I’ve never had a non-wide bevel knife with a concave grind (other than Watanabes which always seem to come with a slightly concave strip behind the edge on the back side of the knife, although the front side of the knife is convex ground). Lots of knives have low spots, of course, but that’s different.
i meant on knives that looks like in the OP. i have only gotten 1 that was convex (masamoto kuro santoku), 1 almost flat, the rest have been concave.

i have also noticed that 2-3 flatground macs were actually slightly concave. i tried polishing the sides with stones, but i had to resort to sandpaper because of this.
 

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I think I understand what OP is asking bc I had the same question. Most knives seem to come with a microbevel edge out of the box. He's asking if he's supposed to stick with that edge, which means you'd be sharpening at a steeper angle right? Based on reading the answers, I guess it's up to the user but at some point you're going to have to thin, so when you thin that microbevel will get "taller" which is fine. Someone can correct me if I'm wrong.
 
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