# Thinning...?



## HumbleHomeCook (Nov 8, 2020)

Just curious what everyone's thoughts are on thinning.

Do you thin more or less with each sharpening?

Every now and then as you think the knife needs it?


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## adam92 (Nov 8, 2020)

HumbleHomeCook said:


> Just curious what everyone's thoughts are on thinning.
> 
> Do you thin more or less with each sharpening?
> 
> Every now and then as you think the knife needs it?


I thinning every time when i sharpening, make it easier to maintain the thickness


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## spaceconvoy (Nov 8, 2020)

tbh I keep telling myself I'll thin a bit during ever sharpening session, but end up ignoring it until it becomes a problem.


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## ModRQC (Nov 8, 2020)

There's thinning and maintenance thinning. Basically the same activity, but thinning is more involved since it's what you often have to do with a new knife - or one that's never been cared after this way. Of course, as long as you'll not have experienced the difference, you won't feel like it needs thinning if it is sharp enough. But I'd say more than 50% of J-Knives I've met so far needed thinning.

Maintenance thinning then can be done when you sharpen.


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## jwthaparc (Nov 8, 2020)

I'm always playing with wide bevel knives. Sometimes I thin just to have a reason to practice polishing... i think I have a problem...


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## ian (Nov 8, 2020)

If you care what your knives look like, you shouldn't thin with every sharpening, since then you'll scratch them up, and you def don't want to refinish every time. (Unless we're talking wide bevels.)

Otherwise, do what you want. I don't thin every time. I'd rather just sharpen until it's a problem, then deal with it.


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## adam92 (Nov 8, 2020)

I usually use 1000/2000 sandpaper with wood cork to clear the scratch from thinning everytime. Properly less than five minutes.


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## M1k3 (Nov 8, 2020)

Depends on the knife but not really. I'll maintain the knife on whatever I finished it on. Drop down lower when I can't refresh the edge quickly. If I notice the bevel becoming wider I'll thin. Or just use a really low angle to extend the time I have to thin.


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## ModRQC (Nov 8, 2020)

+1 for relief bevels as intermediary thinning while avoiding scratches. Easy to do as you sharpen. When the thinning and sharpening was done right touch-ups can carry things up for a while anyhow with surely 1-2 spare sharpenings before getting to the relief bevel stage.


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## Benuser (Nov 9, 2020)

I start any complete sharpening with the secundary or relief bevel at the lowest possible angle.


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## HumbleHomeCook (Nov 9, 2020)

Thanks for all the responses.


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## ModRQC (Nov 9, 2020)

Benuser said:


> I start any complete sharpening with the secundary or relief bevel at the lowest possible angle.



Would you say it's a performance requirement, or is it that you just luuuuv perfecting your consistency? 

BTW without @Benuser I wouldn't be where I am sharpening wise right now, so the question is part serious, part taunting.


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## ModRQC (Nov 9, 2020)

HumbleHomeCook said:


> Thanks for all the responses.



I'd be interested to know if you feel you've been answered, and what you took out of all the answers?


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## Leo Barr (Nov 9, 2020)

Any material that comes off the edge has to be equaled by the same amount above the edge otherwise the blade will get progressively thicker.
If deep cutting is needed the blade needs to be thin a fat sharp blade is only good for cutting pre sliced food.
You can have an incredible sharp edge but if there are substantial shoulders above it this will act as a brake the blade then becomes a splitter ruining umami.


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## HumbleHomeCook (Nov 9, 2020)

ModRQC said:


> I'd be interested to know if you feel you've been answered, and what you took out of all the answers?




Well, it seems something of a mixed bag but no one having very strong feelings either way. I like thin and am not overly concerned with looks but also don't want nice knives looking like garbage either. I've thinned a couple German knives and they performed much better but didn't look too hot.

I reckon at some point you have to do it regardless so I need to develop a good technique either way.


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## Benuser (Nov 9, 2020)

ModRQC said:


> Would you say it's a performance requirement, or is it that you just luuuuv perfecting your consistency?


1. I want to avoid thickening behind the edge. 






2. I want the right bevel to form one continuous arc with the right face.





So I start far behind the edge, at the the lowest possible angle, and only raise the spine little by little, until the very edge has been reached. With badly maintained, unknown knives I verify with marker and loupe to make sure the bevel is clean and I didn't overlook a microbevel. Then, and then only, I start doing the same on the opposite side.
It restores a former configuration, that has slightly moved upwards to the spine. Only to be done if you're fine with the previous configuration. Note this can be done with any unknown knife, splendidly ignoring angles, degrees of asymmetry, proportions and other imaginary concerns.


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## ModRQC (Nov 9, 2020)

HumbleHomeCook said:


> Well, it seems something of a mixed bag but no one having very strong feelings either way. I like thin and am not overly concerned with looks but also don't want nice knives looking like garbage either. I've thinned a couple German knives and they performed much better but didn't look too hot.
> 
> I reckon at some point you have to do it regardless so I need to develop a good technique either way.



There are ways to minimize scratches and rebuild a nice looking finish. The best your technique is, the less you'll have to intervene, but realistically, thinning at a very low angle will leave some haphazard scratches upward of where you want to work, except if a wide secondary bevel is already well defined on the knife, which allows more consistent work.

As suggested, you can use the relief bevel technique - find that angle where you don't touch the face, and have the widest possible bevel defined, and just do as you would do sharpening. If your angle is consistent, you can avoid scratching anything else than that bevel.

If not, once the thinning is done, a progression of sandpaper finishing with one just fine enough to reproduce the belt grinder pattern of the knife originally, going in the same direction than original pattern, works very well and doesn't take long.


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## ModRQC (Nov 9, 2020)

Benuser said:


> 1. I want to avoid thickening behind the edge. View attachment 102253
> 
> 
> 
> ...



I can see that if you want that particular geometry in continuity to the very edge, you don't have much option but to maintain it. My point was more towards someone that just thins "needle like" if you will, where when thin enough for at least 1-2mm behind the edge, there are a couple of sharpenings that can happen before having to maintain it.

Even in your case, you could probably get away with one sharpening, possibly at a slightly higher angle, and my question was aiming to see if, in your experience, doing that will really result in a difference in cutting you will feel as less performant.


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## Leo Barr (Nov 9, 2020)

Here is a picture of a carbon steel gyuto which has been fairly well used it is right handed so its about a 90/10 bevel


this is how I thin this was finished on Japanese Natural Stones


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## Codered (Nov 9, 2020)

Thin the knives you use as often as you can. It will teach you how to maintain your knives and also it will make you invest intro more stones, paste sand paper, finger stones. First time you will hate yourself for “ruining the knife” with all the scratches, and you will see that most bladeroads are univen and hard to make new again. Once you get pass this stage and buy some nice polishing stones and make your own finger stones and spend many hours polishing your skill, you will become more confident with making your own kasumi finish. The sooner you start the easier it will become in time. Note that kasumi you polish with stones, the rest of the knife you clean up scratches with 1000 grit sandpaper. Use tape to cover the bladeroad when you use sandpaper


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## ModRQC (Nov 9, 2020)

That’s a nice and clean relief bevel!


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## Codered (Nov 9, 2020)

Leo Barr said:


> Here is a picture of a carbon steel gyuto which has been fairly well used it is right handed so its about a 90/10 bevelView attachment 102280
> this is how I thin this was finished on Japanese Natural Stones


You should start thining from way up the blade to avoid turning the blade into an axe. The thining should be done 1/3 up the blade. It’s similar to the way barbers fade your hair. They don’t just trim close to the hair tips


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## ModRQC (Nov 9, 2020)

@Leo Barr leaves here the perfect pic sample of a relief bevel.

On the other hand, his knife being carbon, also shows the advantage of these: as @Benuser would probably put it, he doesn't concern himself much with overlapping scratches since the whole thing is gonna be hidden under the patina.


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## M1k3 (Nov 9, 2020)

As far as looks go for my own knives when thinning, I'll just keep going up in grits to my highest stone, then come back with sandpaper in the 400-800 grit range. Heel to tip. Usually takes less than 10 minutes to do both sides and leaves a decent matte finish.


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## Robert Lavacca (Nov 9, 2020)

I bring my knives into a professional kitchen daily. Some knives I do baby but i’m more concerned with how the knife cuts than if it has a kasumi finish on it. For example, my beater, a tanaka yo ginsanko 240 has a concave kind of faux wide bevel. I’ve thinned it lightly each time I’ve sharpened it besides the first couples times. Does it look great without the bevel being completely flat? No.. but it cuts just how it did when I first got it. Unless the knife is a serious laser I usually thin a tiny bit each time to stay ahead of the game.


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## Staystrapped (Nov 9, 2020)

That’s a nice bevel


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## HumbleHomeCook (Nov 9, 2020)

I'm not a huge Damascus fan but the thinning discussion sort of makes those "pretty" knives some what moot.


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## HumbleHomeCook (Nov 9, 2020)

This is a Wusthof that was my very first endeavor into trying to thin an entire knife, not just down by the edge.

I used sand paper and this is a picture of it "roughed" in and then sharpened on oil stones. I cleaned it up some more but it's still a little rough. And that's okay as this was about learning and producing a really slicey knife. Which I did achieve.

I'm now moving deeper into Japanese knives and stones so I really appreciate all the thoughts and input.


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## ModRQC (Nov 9, 2020)

HumbleHomeCook said:


> I'm not a huge Damascus fan but the thinning discussion sort of makes those "pretty" knives some what moot.



Then again, you could scratch the hell out of a damascus, polish it back to mirror finish, or any way that fits design, etch it to make the layers come out, and call it a day.


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## M1k3 (Nov 9, 2020)

HumbleHomeCook said:


> I'm not a huge Damascus fan but the thinning discussion sort of makes those "pretty" knives some what moot.


Depends on how much effort you want to put into it. Polishing damascus to highlight details is a thing....

Me personally, I use my knives for work, they will eventually get scratches at some point. I don't fret if my knives don't look factory new. I just maintain them so they don't end up trashed.


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## ModRQC (Nov 9, 2020)

You have to remember that these blades are first made, and they don’t come out perfect as they’re sold, they’re worked into it. Any finish on any knife is reproducible, but as you don’t have all their tools, sometimes you chose the simplest way that looks nice enough. Now if you can’t refrain from turning the knife all angles under direct light and be disappointed with your work, you’re not gonna get through this, but the deal is to look nice enough under most settings, and be better performers.

edit: or, as @M1k3 said.


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## Kippington (Nov 9, 2020)

When I sharpen I concentrate on removing as little metal as possible to keep the need for thinning down. Things like not trying to go for a honking great big burr down the entire length of the edge.
Sometimes I'll do a tiny bit of shoulder rounding but I generally only thin every 10 sharpenings or so. I have a belt grinder for that.




ModRQC said:


> But I'd say more than 50% of J-Knives I've met so far needed thinning.


Before my morning coffee I read this as "500% of J-Knives I've met so far needed thinning" and it blew my mind.


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## ModRQC (Nov 9, 2020)

@HumbleHomeCook ... if you'll forgive me for bringing your attention to this post...

Here's a Masahiro VC - carbon monosteel, and like any monosteel, a pain to re-finish so I do a botchy sandpaper job after thinning, whatever makes the deeper scratches fade most quickly to my eye goes...






because I know I'm gonna etch the full blade and have it look like this, with naturally blackened spots, and just looking like a patina of old:








Here's a Takayuki Damascus... One thing with a Tsuchime finish generally is that any scratch into it can be blended quite easily with sandpaper, since the surface is rougher to start with.

The Damascus layers were re-finished to high sandpaper grit, decent mirror finish, but I went quite fast about it... and I re-etched, not even using something strong like ferric chloride, but simple vinegar, which takes more time and is less spectacular. Under some angles, you can see the sandpaper scratches, and you can see the unevenness of the mirror polish I gave...









But under most settings...














And then again here's a Deep Impact... used the Cerax 320 to give a bevel finish... but as there were a lot of scratches upward of it, I taped off the bevel and gave a migaki-like finish with sandpaper, not going as fine as with the Takayuki for instance.






In the beginning I was scared of even having the tiniest of scratches from regular use. Then the necessity to work on my blades got me over that, but I was wasting a lot of time still not being satisfied, and not working correctly. I learned what goes, and what doesn't work so well. Now I kind of "botch" the jobs to the easiest way that looks okay, and keep happy.

And now, do you know what insults me most about a blade I need to refinish?

Those with stamped logo/kanji that you cannot save through a sandpaper progression. The only thing I don't like is removing the branding of a knife that's of value to me - even if that's a Victorinox. I still live with it. All my Victos are without logos but God do they cut to my likings. And I love J-knives that have a decently stamped engraving or truly engraved Kanji just because of that: you can refinish them all the way, and keep the maker's mark. It defines pretty well cheap knives from better one - those that have stamps which will vanish after a course of sandpaper, and those who live through many courses of sandpaper, and sometimes even look better when they become super polished by repetitive courses, making the stamp/engraving come out super nicely.


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## Robert Lavacca (Nov 9, 2020)

Pfffttt. My masahiro looks wayyyyy better 

I hated that knife at first. Bought for a real beater. I’ve beaten the **** out of that thing and it still is going strong. After I thinned the crap out of mine it cut so much better, easier to sharpen, and stays sharp. I even use a ceramic steel on it at work to keep the edge going. I love that thing now haha.


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## Kippington (Nov 9, 2020)

Robert Lavacca said:


> Pfffttt. My masahiro looks wayyyyy better
> 
> I hated that knife at first. Bought for a real beater. I’ve beaten the **** out of that thing and it still is going strong. After I thinned the crap out of mine it cut so much better, easier to sharpen, and stays sharp. I even use a ceramic steel on it at work to keep the edge going. I love that thing now haha.


Yeah those scuffs and scratches signify that the knife has been worked behind the edge, and it often indicates that a knife has been better looked after over one that still has shiny or factory finished surfaces.

I'm happy to have my personal knives looking like they've lost a fight with a pavement, so long as the knife performs how I want it. This one had no etch, it's just what the stone slurry did to the pattern.




Admittedly, with a bit of skill you can get even better results off a belt grinder, even at the same low grit.


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## Byphy (Nov 9, 2020)

Admittedly, with a bit of skill you can get even better results off a belt grinder.





Any tips on getting a nice uniform factory finish like you did w the HD here? You can PM me if it's not too much trouble, I don't want to derail the thread


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## Kippington (Nov 9, 2020)

It's simply running a slack belt down the surface. You can mess up the knife if you do it wrong, so there's definitely some steady-handed technique involved.
It's not my picture by the way, just an example of what it looks like.


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## Byphy (Nov 9, 2020)

Ok thats what I was doing some results better than others. Thought there was some magic technique haha

Thanks


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## CA_cook (Nov 10, 2020)

How far from the edge do you thin? Can you do it on regular stones? Why not just do an additional sharpening step at a very low angle, would that give an essentially same result?


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## ModRQC (Nov 10, 2020)

KKF science says: 0.2mm just above the edge, 0.5mm at 5mm from the edge, 1mm at 10mm from the edge.

Yes regular stones - coarser ones not to spend a day on it.

As for your last question it's been discussed a lot in this very thread, read carefully - see "relief bevel" and @Leo Barr pic.


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## ian (Nov 11, 2020)

ian said:


> If you care what your knives look like, you shouldn't thin with every sharpening, since then you'll scratch them up, and you def don't want to refinish every time. (Unless we're talking wide bevels.)
> 
> Otherwise, do what you want. I don't thin every time. I'd rather just sharpen until it's a problem, then deal with it.





adam92 said:


> I usually use 1000/2000 sandpaper with wood cork to clear the scratch from thinning everytime. Properly less than five minutes.



I suppose it's a good point that if you want a sandpaper finish and you are maintenance thinning on stones that are higher grit than your finish, it doesn't take long at all to refinish after thinning. I guess I was mainly thinking of fancier finishes, which take longer to reproduce. F**k, I like to think of myself as a hardcore user that doesn't care what his knives look like, but I think that may not be the case.

I think the real answer here, though, is that I never really do maintenance thinning on my own knives. I often do significant thinning when I receive a knife, but once I get it into a good shape, I always end up selling it before I need to thin it again.  No knife ever stays with me for more than a few months of home use. On customer knives, I will thin if it needs it, and then do a quick sandpaper finish, or a nicer finish if it's a nicer knife. 



Kippington said:


> It's simply running a slack belt down the surface. You can mess up the knife if you do it wrong, so there's definitely some steady-handed technique involved.
> It's not my picture by the way, just an example of what it looks like.



I always liked the spine to edge belt finish on Gingas, too. Looks nice in person.


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## happy_c (May 4, 2021)

Not sure if it's board etiquette to revive an old thread, but here goes anyway. As a newbie, I'm confused by the terminology related to thinning. From reading this thread and others, I'm getting the impression that proper blade geometry involves *three* bevels: The blade road below the shinogi line, which you thin every few years when it gets very thick; then another bevel below that, which you thin when doing "maintenance thinning" or "thinning behind the edge"; and finally another bevel below *that*, which you work on when "sharpening." Is this right, or am I grossly misunderstanding?

Sorry for any missteps in terminology, I'm still learning.


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## ian (May 4, 2021)

happy_c said:


> Not sure if it's board etiquette to revive an old thread, but here goes anyway. As a newbie, I'm confused by the terminology related to thinning. From reading this thread and others, I'm getting the impression that proper blade geometry involves *three* bevels: The blade road below the shinogi line, which you thin every few years when it gets very thick; then another bevel below that, which you thin when doing "maintenance thinning" or "thinning behind the edge"; and finally another bevel below *that*, which you work on when "sharpening." Is this right, or am I grossly misunderstanding?
> 
> Sorry for any missteps in terminology, I'm still learning.



Not all blades have a shinogi line or really distinct bevels at all. Sometimes the blade face is continuously convex all the way from the spine to the edge, except for a small microbevel at the edge. The distinction between maintenance thinning and repair thinning largely depends on personal preference. Imo, knives with a shinogi (“wide bevel knives”) work best when below the shinogi there’s a slight convex (“hamaguri”) blade face that terminates in a microbevel at the edge. To avoid making the microbevel a macrobevel, one thins the entire blade below the shinogi regularly, if not every time it’s sharpened, which is the traditional way. On knives without a shinogi, some people even do “maintenance thinning” over most of the blade every time they sharpen, aesthetics be damned.


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## ModRQC (May 4, 2021)

Take a basic geometry like a straight V-grind and you basically have two bevels; the faces going all the way down to the edge, and the edge bevel itself, assuming it’s not a zero grind.

Now a wide bevel: two bevels still, the V under the shinogi, and the edge bevel, assuming no zero grind. The faces in this case are no bevels per say.

Convex grind is the same: it could basically be thought like the V grind.

Maintenance thinning is what you can do as you progressively lose height in sharpening, thus bringing the edge up in the thicker part which you correct as you go; thinning is that it’s already quite too thick behind the edge and you need to remove more material - either an old knife never cared for properly (ie maintenance thinning), or any knife too thick from the start.


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## jwthaparc (May 4, 2021)

I do my maintenance thinning on the blade road. If you only thin right behind the edge, you will end up with a really jacked up geometry.


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## happy_c (May 4, 2021)

Thanks for the replies. I'm way too much of a noob to think about convexing and such, but it sounds like that if I want to thin my knife (which I do--25 years old and never been thinned, maintenance or otherwise, in all that time), I should aim to thin it all the way from the shinogi line down to the bevel of the cutting edge, right? If so, is there a way to avoid inadvertently rubbing out the shinogi line? I really want better performance but I'm worried about screwing up.

Edit: I've watched videos on thinning, including this one and others, but despite their high quality I cannot seem to wrap my head around exactly what should be going on.


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## ian (May 4, 2021)

happy_c said:


> Thanks for the replies. I'm way too much of a noob to think about convexing and such, but it sounds like that if I want to thin my knife (which I do--25 years old and never been thinned, maintenance or otherwise, in all that time), I should aim to thin it all the way from the shinogi line down to the bevel of the cutting edge, right? If so, is there a way to avoid inadvertently rubbing out the shinogi line? I really want better performance but I'm worried about screwing up.



Yes. Just keep the knife from wobbling when you’re working close to the shinogi and you’ll be fine. Keep finger pressure on the blade at all times and the geometry of the blade should prevent you from rounding the shinogi.


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## jwthaparc (May 4, 2021)

happy_c said:


> Thanks for the replies. I'm way too much of a noob to think about convexing and such, but it sounds like that if I want to thin my knife (which I do--25 years old and never been thinned, maintenance or otherwise, in all that time), I should aim to thin it all the way from the shinogi line down to the bevel of the cutting edge, right? If so, is there a way to avoid inadvertently rubbing out the shinogi line? I really want better performance but I'm worried about screwing up.
> 
> Edit: I've watched videos on thinning, including this one and others, but despite their high quality I cannot seem to wrap my head around exactly what should be going on.


Look up knifewear friday livestream with naoto. He does the entire thinning from beginning to end on camera, including polishing and everything. I'll link a good one in a sec. I recommend watching them live too, so you can ask him any questions you may have. Me and @HumbleHomeCook watch most of their streams. Very informative.

Edit


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## happy_c (May 4, 2021)

ian said:


> Yes. Just keep the knife from wobbling when you’re working close to the shinogi and you’ll be fine. Keep finger pressure on the blade at all times and the geometry of the blade should prevent you from rounding the shinogi.



Ah, if only my hand were as steady as I like to think it is …
I’ve got a couple of cheap knives I’ve been practicing in. Will probably try thinning one of them before I take a stone to the knife I’m attached to. They don’t have shinogis, though …


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## happy_c (May 4, 2021)

@jwthaparc , thanks for the tip. Would this one be a good place to start?


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## jwthaparc (May 4, 2021)

happy_c said:


> @jwthaparc , thanks for the tip. Would this one be a good place to start?


I linked that and one of the streams. Watch the short one first. If you need more information, watch the stream I linked. Like I said I also highly recommend watching live so you can ask questions as he does it. They stream every friday. I want to say 5pm central time.


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## captaincaed (May 4, 2021)

happy_c said:


> Ah, if only my hand were as steady as I like to think it is …
> I’ve got a couple of cheap knives I’ve been practicing in. Will probably try thinning one of them before I take a stone to the knife I’m attached to. They don’t have shinogis, though …


Starting cheap is the way to go, and taking little bites of the project, 20-30" per night, don't rush it. Ideally buy a new knife from your favorite retailer so you have one in the kitchen while you're doing the work! hehehe. 
Also, use a ~220 grit stone. Anything finer is too slow. The extra time you spend translates into fatigue, and then wobble. It feels like crap, but it's quicker and easier to clean up later than you might think.


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## jwthaparc (May 4, 2021)

captaincaed said:


> Also, use a ~220 grit stone. Anything finer is too slow. The extra time you spend translates into fatigue, and then wobble. It feels like crap, but it's quicker and easier to clean up later than you might think.


Yeah. My favorite for thinning was my shapton 120. Now I use my manticore. talk about removing material. It's a 60 grit, silicon carbide waterstone. Now most of the time I spend is just polishing it back up.


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## captaincaed (May 4, 2021)

Yeah, for heavy work, go coarse. Some knifemakers talk about starting with 36 grit belts for rough shaping.


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## happy_c (May 4, 2021)

I actually read in another thread that past a certain point, it’s hard to thin adequately without power tools to speed things up. I’ll see if I can get hold of a 220 grit stone, though. But won’t that scratch up the blade path terribly? Or do you go through the whole grit progression when you thin, same as for sharpening, before you refinish with sandpaper?


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## HumbleHomeCook (May 4, 2021)

happy_c said:


> I actually read in another thread that past a certain point, it’s hard to thin adequately without power tools to speed things up. I’ll see if I can get hold of a 220 grit stone, though. But won’t that scratch up the blade path terribly? Or do you go through the whole grit progression when you thin, same as for sharpening, before you refinish with sandpaper?



If you want it to look nice you're going to have to go through a full progression. You might have to use "finger stones" or high grit sandpaper.

Fortunately, I value function over form.


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## HumbleHomeCook (May 4, 2021)

happy_c said:


> I actually read in another thread that past a certain point, it’s hard to thin adequately without power tools to speed things up. I’ll see if I can get hold of a 220 grit stone, though. But won’t that scratch up the blade path terribly? Or do you go through the whole grit progression when you thin, same as for sharpening, before you refinish with sandpaper?



Also something to be aware of is soooooo many knives are not actually flat. They look flat but once you start rubbing them over an abrasive the hills and dips become readily apparent. It many cases it just isn't feasible to try to fully even everything out so I reckon that's where the finger work comes in for aesthetics.


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## Kiru (May 4, 2021)

I remember someone said to me it depends what kind of lazy you are, if you’re lazy to do a big thinning session, thin every time and vice versa


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## happy_c (May 5, 2021)

@ian — When you say that some people thin with every sharpening, I’m assuming they’re doing it with higher-grit stones, not pulling out the 220 grit or belt sander every time?


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## Mikeltee (May 5, 2021)

What kind of belt sander are you guys using? What advantage would one gain by using a $500 2x72 vs the $50 Harbor Freight one if they are only breaking it out every once and awhile? Sanding by hand, I would be afraid I'd cut myself and/or really mess up the edge? I feel as if I'd have more control once I got my timing down with a belt sander and it would take a fraction of time.


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## ModRQC (May 5, 2021)

happy_c said:


> @ian — When you say that some people thin with every sharpening, I’m assuming they’re doing it with higher-grit stones, not pulling out the 220 grit or belt sander every time?



It’s rather a question of steel. Starting higher grit with stainless, stainless clad, high alloy monosteel, will take forever even with just maintenance thinning on a stone not coarse enough. Semi-Ss, low alloys, carbon monosteels or iron clad, starting too low grit may result in removing too much towards what is needed.

Then of how: if I work towards a flat bevel, I start with a more agressive grit and a harder stone, when convexing, I prefer to buy time using a softer stone in between coarse and med. Any stone too fast and/or hard can all too easily create faceting when convexing.

Learning to balance needs out (experience will tell) is even more important than just a grit number. Then finding the stones that allow you to do your best work out of any circumstances is the graal.


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## kpham12 (May 5, 2021)

jwthaparc said:


> Yeah. My favorite for thinning was my shapton 120. Now I use my manticore. talk about removing material. It's a 60 grit, silicon carbide waterstone. Now most of the time I spend is just polishing it back up.


How are the scratches from thinning on the Manticore? Do you think they could be removed with a Shapton Pro 220?


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## jwthaparc (May 5, 2021)

kpham12 said:


> How are the scratches from thinning on the Manticore? Do you think they could be removed with a Shapton Pro 220?


I've never used the 220 so I couldn't say. They would definitely be removed by the 120 though. I use a coarse norton idia to get rid of the scratches most of the time, because it's the next coarsest thing I have.


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## kpham12 (May 5, 2021)

jwthaparc said:


> I've never used the 220 so I couldn't say. They would definitely be removed by the 120 though. I use a coarse norton idia to get rid of the scratches most of the time, because it's the next coarsest thing I have.


Thanks, might try that. I’ve been looking into getting a manticore for some heavy lifting thinning, but 60 grit sounded real low.


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## jwthaparc (May 5, 2021)

kpham12 said:


> Thanks, might try that. I’ve been looking into getting a manticore for some heavy lifting thinning, but 60 grit sounded real low.


It definitely is real low. Just make sure you have a normal low grit stone to take the scratches out. An atoma 140 could work too. I can say for sure my king 300 and cerax 320 are just a bit too fine to get the scratches out in a timely manner.


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## VICTOR J CREAZZI (May 5, 2021)

kpham12 said:


> Thanks, might try that. I’ve been looking into getting a manticore for some heavy lifting thinning, but 60 grit sounded real low.


I just ordered a Manticore and the scythe stone of the same abrasive.


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## HumbleHomeCook (May 5, 2021)

The Manticore is a beast.

Be aware, you may need to dress the surface to get it working right. Mine was so compacted it seemed almost slick. Some heavy scratching (read grinding down) of some screws and then re-profiling a thick Buck knife got it performing well.


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## VICTOR J CREAZZI (May 5, 2021)

Mikeltee said:


> What kind of belt sander are you guys using? What advantage would one gain by using a $500 2x72 vs the $50 Harbor Freight one if they are only breaking it out every once and awhile?


I have a 2 x72, but I would think that anything with speed control could be useful. I like to get down around 900 SFM when working close to the thin sections, especially at the tip


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## Benuser (May 5, 2021)

ModRQC said:


> It’s rather a question of steel. Starting higher grit with stainless, stainless clad, high alloy monosteel, will take forever even with just maintenance thinning on a stone not coarse enough. Semi-Ss, low alloys, carbon monosteels or iron clad, starting too low grit may result in removing too much towards what is needed.
> 
> Then of how: if I work towards a flat bevel, I start with a more agressive grit and a harder stone, when convexing, I prefer to buy time using a softer stone in between coarse and med. Any stone too fast and/or hard can all too easily create faceting when convexing.
> 
> Learning to balance needs out (experience will tell) is even more important than just a grit number. Then finding the stones that allow you to do your best work out of any circumstances is the graal.


In my l experience, you may very well use say a SG220 for thinning behind the edge with the least abrasion resistant carbon, without the risk of facetting, and obtain an nice convex bevel, in line with the face. And if facetting were to occur, I guess it's easily remediated within a few strokes. Just as simple as easing shoulders. 
That being said said, I don't use much pressure and like to create a bit of mud. And essential with the SG's: keep them wet.


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## Benuser (May 5, 2021)

I should have added that I had thinning as a part of a full sharpening in mind.


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## ModRQC (May 5, 2021)

Benuser said:


> In my l experience, you may very well use say a SG220 for thinning behind the edge with the least abrasion resistant carbon, without the risk of facetting, and obtain an nice convex bevel, in line with the face. And if facetting were to occur, I guess it's easily remediated within a few strokes. Just as simple as easing shoulders.
> That being said said, I don't use much pressure and like to create a bit of mud. And essential with the SG's: keep them wet.



Yes I can convex with a coarse/hard alright. Then again, with experience. This is the gist of the subject: from the OP standpoint and more broadly general approach. Excessive pressure being a common occurrence with beginners and all that. I just like to widen the scope in which one can look at thinning vs what job there is actually to do.


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## ModRQC (May 5, 2021)

Benuser said:


> I should have added that I had thinning as a part of a full sharpening in mind.



In this spirit, I probably should have mentioned that I had a polishing progression in mind, and convexing not just behind the edge but a whole bevel although the latter doesn’t change anything to what you said. Just for sakes of clarification.

Edit: and obviously, a full polishing prog is also way to avoid faceting as it would tend to correct as you go. But the general idea is: softer/muddier works best for at once polishing and convexing, and going very coarse not needed if the convex is already installed.

And bla bla bla... working on stones is such a personal thing and ongoing philosophy for me still. 1 year ago I had barely sharpened my first knife; thinking in terms of preferences of stones for the job is pretty much a 2021 thing for me.


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## whirlwynds (May 5, 2021)

Mikeltee said:


> What kind of belt sander are you guys using? What advantage would one gain by using a $500 2x72 vs the $50 Harbor Freight one if they are only breaking it out every once and awhile? Sanding by hand, I would be afraid I'd cut myself and/or really mess up the edge? I feel as if I'd have more control once I got my timing down with a belt sander and it would take a fraction of time.


A few things.

the Harbor Freight runs at 3450rpm which puts its speed way to high for most anything except hogging of steel for reprofiling. I know people do sharpen on these, but for fine knives i would not recommend it. the high speed can generate major heat and potentially ruin your blade. the 1" platten and contact patch make holding the correct angle challenging as well as having consistent contact across the blade. you're better off going with a stone and controlling the rate of abrasion. also if you touch that belt at that speed it will make quick work of your fingers as well, way more than one errant pass on sandpaper or a stone.

a 2x72 with speed control means you can run it in the right pocket for the speed of the activity and also have better angular control of the knife and target the spots for removal. it's really no different from a stone, but the belt moves instead of your arms and it happens about 10x faster.

to put it in perspective, if you have a 12" stone, one pass is 1 surface foot. let's say you can do 2 passes per second. that's 120 surface feet per minute. a low speed 2x72 will run at about 900sfpm, so about 7.5x faster than you can grind by hand. the harbor freight will run at approx 3600sfpm so about 30x faster.


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## branwell (May 6, 2021)

Mikeltee said:


> What kind of belt sander are you guys using? What advantage would one gain by using a $500 2x72 vs the $50 Harbor Freight one if they are only breaking it out every once and awhile? Sanding by hand, I would be afraid I'd cut myself and/or really mess up the edge? I feel as if I'd have more control once I got my timing down with a belt sander and it would take a fraction of time.



KMG 2x72. You can thin even the most hard case knives in a few minutes but.......

Assuming you are working to a zero grind or almost a zero grind, you really need a 2x72 with a variable speed control and fresh belts. Its doesn't take much to friction heat edges above their tempering temperature and soften the edge. A misting system or water dripper really helps here.

The $50 HF grinders don't come with VFD's and I've not seen a good solution to this. Without speed control....

If you have a bunch of spare change sitting about or have a way of making it pay for itself, a 2x72 is a great thing to have.


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## iandustries (May 6, 2021)

spaceconvoy said:


> tbh I keep telling myself I'll thin a bit during ever sharpening session, but end up ignoring it until it becomes a problem.



how do u know when its become a problem? I‘ve never thinned a knife before …


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## Bigbbaillie (May 6, 2021)

iandustries said:


> how do u know when its become a problem? I‘ve never thinned a knife before …


Really it's just preference for whenever you think your knife isn't cutting well anymore. You would probably notice it wedging in harder foods like carrots, if you hear a cracking sound when you cut a carrot, large or big, your knife could probably use at least a little bit of thinning. Most knives will probably give you some cracking, but a knife very thin behind the edge will just cut straight through with minimal cracking. Not every knife needs to pass this really, but it's an easy test. 

If you don't know what wedging is, it's when the steel behind the edge gets thick enough that it gets stuck in the produce above the edge, preventing your knife from cutting. Just imagine if you were trying to cut something with a sharpened doorstop (weird I know) but on a much smaller scale.


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## adam92 (May 6, 2021)

When I do thinning maintain with my R2 Takamura, I start with SG500, only behind the edge, when I do heavy thinning I start with SG220, I think harder stone is better, as not easily gouge. 
I usually stop at SP2k, sometimes SG4K. depand on what I gonna cut on that day.


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## jwthaparc (May 6, 2021)

happy_c said:


> I actually read in another thread that past a certain point, it’s hard to thin adequately without power tools to speed things up. I’ll see if I can get hold of a 220 grit stone, though. But won’t that scratch up the blade path terribly? Or do you go through the whole grit progression when you thin, same as for sharpening, before you refinish with sandpaper?


That is the whole reason you see the people here obsessed with jnats. Check the kasumi thread. 

Polishing a blade back up for me is a big part of the thinning process. I probably worry more about it than I should. It's sort of a skill that you build over time. I try to make my knives look as good as I can, just to see if I can do it.


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## stringer (May 7, 2021)

iandustries said:


> how do u know when its become a problem? I‘ve never thinned a knife before …



In a professional setting with randoms grabbing your knives, maybe 15 or 20 seconds. If you buy a gem from a god and you baby it you may never need to thin a knife ever.


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## happy_c (May 7, 2021)

jwthaparc said:


> That is the whole reason you see the people here obsessed with jnats. Check the kasumi thread.
> 
> Polishing a blade back up for me is a big part of the thinning process. I probably worry more about it than I should. It's sort of a skill that you build over time. I try to make my knives look as good as I can, just to see if I can do it.



I saw in Jon’s thinning video that thinning may cause food to stick to the blade more. Why is that? Is it blade geometry or polishing out the scratches or … ?


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## big_adventure (May 7, 2021)

happy_c said:


> I saw in Jon’s thinning video that thinning may cause food to stick to the blade more. Why is that? Is it blade geometry or polishing out the scratches or … ?



It's both and more.

If you take a full convex grind, then thin it at a flat, unique angle, you could wind up with an absolutely flat surface. Flat, smooth surfaces are more likely to stick. 

The surface also matters to an extent: a hairline or rough kasumi surface may stick less than a polished surface. 

It's a combination. I have a couple of knives that stick more than I'd expect given finish and geometry, and a couple that stick less than I'd expect given the same criteria. 

Basically, test it out! I've changed finishes on some of my own knives, basically operating under the idea that, with the exception of removing ku finishes, I can probably correct any change that I don't like. I smooth-sanded a damascus finish, then just re-etched it with hydroclorique acid. A mirror finish can be returned to kasumi with a litle work.


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## iandustries (May 7, 2021)

stringer said:


> In a professional setting with randoms grabbing your knives, maybe 15 or 20 seconds. If you buy a gem from a god and you baby it you may never need to thin a knife ever.



Thank you, this makes sense. I m in the camp of buying knives from God and babying them so hopefully, I wont NEED to thin a knife, but would do it as an experiment for fun like I did giving my Takamura Santoku a mirror polish


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## Grayswandir (May 9, 2021)

Bigbbaillie said:


> Really it's just preference for whenever you think your knife isn't cutting well anymore. You would probably notice it wedging in harder foods like carrots, if you hear a cracking sound when you cut a carrot, large or big, your knife could probably use at least a little bit of thinning. Most knives will probably give you some cracking, but a knife very thin behind the edge will just cut straight through with minimal cracking. Not every knife needs to pass this really, but it's an easy test.
> 
> If you don't know what wedging is, it's when the steel behind the edge gets thick enough that it gets stuck in the produce above the edge, preventing your knife from cutting. Just imagine if you were trying to cut something with a sharpened doorstop (weird I know) but on a much smaller scale.



Wouldn't anything around 1.5mm (at the spine) be fine and not cause this problem? I'm thinking 1.5mm where the blade meets the ferrule/bolster, after that the blade gets thinner as you travel down (distally) towards the point. I guess it depends on the product your cutting and how thick it is. If it's thicker then the heel of your knife, then I would expect the thinner the knife, the better, within reason?

I recall reading something recently (within the past month or two) about people polishing (and sanding) their knives to a mirror finish, apparently to help stop food from sticking to the blade. Someone said that a mirror finish actually makes the problem worse because it acts as a suction cup. By polishing away the tiny imperfections in the surface, there's no longer any way for air to get caught between the food and the blade, so the highly polished blade acts like a suction cup to whatever you're cutting. I don't know if this is really true or not, it just something I remember reading. Apparently there were a lot of people polishing the heck out of their Japanese knives to get that mirror finish, not only for aesthetic reasons, but to reduce food from sticking to their knives.

I know this is different then thinning, but I thought I'd bring it up as it is related to some degree.


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## Bigbbaillie (May 9, 2021)

Grayswandir said:


> Wouldn't anything around 1.5mm (at the spine) be fine and not cause this problem? I'm thinking 1.5mm where the blade meets the ferrule/bolster, after that the blade gets thinner as you travel down (distally) towards the point. I guess it depends on the product your cutting and how thick it is. If it's thicker then the heel of your knife, then I would expect the thinner the knife, the better, within reason?
> 
> I recall reading something recently (within the past month or two) about people polishing (and sanding) their knives to a mirror finish, apparently to help stop food from sticking to the blade. Someone said that a mirror finish actually makes the problem worse because it acts as a suction cup. By polishing away the tiny imperfections in the surface, there's no longer any way for air to get caught between the food and the blade, so the highly polished blade acts like a suction cup to whatever you're cutting. I don't know if this is really true or not, it just something I remember reading. Apparently there were a lot of people polishing the heck out of their Japanese knives to get that mirror finish, not only for aesthetic reasons, but to reduce food from sticking to their knives.
> 
> I know this is different then thinning, but I thought I'd bring it up as it is related to some degree.


Spine thickness isn't really what you are looking for, it's more of the thickness directly behind the edge. If you have a sharp edge but it's .5mm right behind the primary bevel, your knife will still cut poorly and need thinning. So regardless of how thin spine is, if your edge is too thick >1cm behind edge you will probably feel the need to thin.
Low grit finish will cause friction which will be noticeable while cutting but its definitely not like you need a mirror finish to reduce stiction. I usually only sand to 600-1200 grit and feel like that is totally fine.


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## Grayswandir (May 9, 2021)

That makes sense, I just remember hearing Murry Carter talking about thinning what he calls the secondary bevel on his knives (it seems like most of the knife industry calls the cutting edge the secondary bevel, I find that a bit odd, since it's the bevel that cuts things, go figure). 

I'm not sure if it was preventive maintenance, something you do over time, so as the knife's cutting edge slowly loses steel over time, the geometry between the primary and secondary bevels stay the same, or if it was done to aid in cutting? He talks about both things, so I guess both is the correct answer. He always says a thin knife slices better, but he was putting more emphasis on the secondary bevel in his knife sharpening videos in regards to thinning. You're talking about the the steel directly above the cutting edge, which is now something I'll keep in mind. 

I just bought a 250mm Gyuto (Shirogami #1), and it's pretty thin above the edge. It slices really well, and I guess that's the reason why (what you said).

Funny enough, I used some 2000 or 3000 sand paper to remove a little orange rust that appeared after making some sushi. Totally not on purpose, between the Kurouchi finish and the hamon, I accidentally created a semi-mirrored finish, so I decided to sand the entire length of the knife between those two points just so everything looked uniform. Shirogami #1 truly does take a wicked edge, it seems sharper then my Aogami Kiritsuke. It's already kissed me twice (I really need to pay more attention while handling these Japanese knives), nothing serious or anything, but I felt it. They're so light, it's easy to forget you have a dangerous tool in your hand!


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## stringer (May 9, 2021)

Grayswandir said:


> Wouldn't anything around 1.5mm (at the spine) be fine and not cause this problem? I'm thinking 1.5mm where the blade meets the ferrule/bolster, after that the blade gets thinner as you travel down (distally) towards the point. I guess it depends on the product your cutting and how thick it is. If it's thicker then the heel of your knife, then I would expect the thinner the knife, the better, within reason?
> 
> I recall reading something recently (within the past month or two) about people polishing (and sanding) their knives to a mirror finish, apparently to help stop food from sticking to the blade. Someone said that a mirror finish actually makes the problem worse because it acts as a suction cup. By polishing away the tiny imperfections in the surface, there's no longer any way for air to get caught between the food and the blade, so the highly polished blade acts like a suction cup to whatever you're cutting. I don't know if this is really true or not, it just something I remember reading. Apparently there were a lot of people polishing the heck out of their Japanese knives to get that mirror finish, not only for aesthetic reasons, but to reduce food from sticking to their knives.
> 
> I know this is different then thinning, but I thought I'd bring it up as it is related to some degree.






Very thin spined knives don't allow for as much convexity. Less convexity means more sticking. They are also less comfortable to hold if you are chopping all day. Nothing smarts like a split knife callous.

This is why we look for ways to make knives that are beefier where you need to hold it but still thin behind the edge

Geometry and surface finish are separate questions. After you alter the geometry with coarse stones then you have to decide what kind of surface finish you desire.


Grayswandir said:


> That makes sense, I just remember hearing Murry Carter talking about thinning what he calls the secondary bevel on his knives (it seems like most of the knife industry calls the cutting edge the secondary bevel, I find that a bit odd, since it's the bevel that cuts things, go figure).
> 
> I'm not sure if it was preventive maintenance, something you do over time, so as the knife's cutting edge slowly loses steel over time, the geometry between the primary and secondary bevels stay the same, or if it was done to aid in cutting? He talks about both things, so I guess both is the correct answer. He always says a thin knife slices better, but he was putting more emphasis on the secondary bevel in his knife sharpening videos in regards to thinning. You're talking about the the steel directly above the cutting edge, which is now something I'll keep in mind.
> 
> ...



If you want to see the knife's convex grind check it out by looking at the reflections on an angle off of some horizontal light sources like window blinds. I bet that your gyuto is ground more similar to the style we are describing than to a flat grind. It's all about balancing competing conflicting qualities and that balance is different for everyone. 

An axe has great food release but is by definition a wedge monster. 

A flat ground laser has very little cutting resistance on food. But the spine also has great cutting power on your skin. A split knife callous can really ruin your day. And flat ground knives are prone to stickiness and stiction. 

A typical asymmetric Japanese grind allows you to have convexity on one side for food release and strength, but a relief bevel on the other side to keep it thin behind the edge, reduce wedging, and increase stiction resistance.


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## Grayswandir (May 9, 2021)

> A flat ground laser has very little cutting resistance on food. But the spine also has great cutting power on your skin.



I take it you mean how using the knife all day (in regards to an uncomfortable spine), even the spine can wind up hurting you (bad ergonomics) because of the repetition involved, or am I misunderstanding you?

I'll have to take a few snaps of my Gyuto and see what you think. It looks like it's a flat grind, but to be honest, I haven't really given it a good, studious look up to this point. I haven't even owned the knife for a full month yet. I haven't had any problems with food sticking to the blade, but then I haven't really cut a lot of foods that tend to stick, like starchy potatoes, or even squash (which tends to be wet). So far I'm enjoying the knife. I'd really like to crush some garlic with the wide portion of the blade, but I've heard it might not be the best idea with white steel. The blade is pretty beefy, but I guess I'll think on it some more before I attempt it. If worse comes to worse, I can use the back end of the handle to crush garlic cloves, it works, just not quite as well as the widest point of the blade.


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## stringer (May 9, 2021)

There's no issue whacking garlic with any knife. Just make sure you are hitting with the part of the knife on the spine half instead of the edge half.

Here's what I mean by using horizontal light to look at the grind


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## stringer (May 9, 2021)

Here's one that's ground this way deliberately exaggerated my me on a very thick spined knife.

Here's the convex side




And here's the relief bevel side. You can see the difference







On some knives the relief side is even concave.
I talked about that here


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## Grayswandir (May 9, 2021)

Yeah, I'd make sure to thump the garlic on the side closer to the spine. I'll check out your video, thanks.


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## Grayswandir (May 9, 2021)

stringer said:


> Here's one that's ground this way deliberately exaggerated my me on a very thick spined knife.
> 
> Here's the convex sideView attachment 126425
> 
> ...




That's one funky looking apple man, I've never seen one of those before. I've been eating these awesome pears from Korea lately, they have a really delicate flavor and sweetness. They kind of taste a little like caramel, with the slight essence of cantaloupe floating around, they're really tasty and have a nice texture. Anyway, how do you get convexity using a stone? I'm thinking a strop would be handy to add some convexity, but I haven't really tried it, I'm just working off of theory.

P.S.,

I like your Sujihiki, that's the next type of knife I plan on buying, though I'm not in a rush or anything.


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## stringer (May 9, 2021)

Grayswandir said:


> That's one funky looking apple man, I've never seen one of those before. I've been eating these awesome pears from Korea lately, they have a really delicate flavor and sweetness. They kind of taste a little like caramel, with the slight essence of cantaloupe floating around, they're really tasty and have a nice texture. Anyway, how do you get convexity using a stone? I'm thinking a strop would be handy to add some convexity, but I haven't really tried it, I'm just working off of theory.
> 
> P.S.,
> 
> I like your Sujihiki, that's the next type of knife I plan on buying, though I'm not in a rush or anything.



Those red fleshed apples taste similar to a Fuji or gala but the red flesh doesn't oxidize or something. I forget the point exactly and I've only seen them once or twice.


But the key to getting convexity with a stone is finger pressure. There will be a natural convexing that occurs when you switch directions back and forth. You can focus that convexing with your finger pressure on the blade. Starting with the knife very flat on the stone working at first with your pressure focused on the middle of the face of the knife and then gradually shifting that pressure down to the edge. Then you add a micro bevel at the end which has the affect of accelerating the convexity toward the apex.


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## ian (May 9, 2021)

whirlwynds said:


> the Harbor Freight runs at 3450rpm which puts its speed way to high for most anything except hogging of steel for reprofiling. I know people do sharpen on these, but for fine knives i would not recommend it. the high speed can generate major heat and potentially ruin your blade.



Truth. I have burnt so many edges on mine. It's basically impossible for me to do any work near a thin tip without burning it.


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## ian (May 9, 2021)

Grayswandir said:


> I'm thinking a strop would be handy to add some convexity, but I haven't really tried it, I'm just working off of theory.



A strop will never remove enough metal to significantly affect the geometry. Sandpaper on a soft backing works, but you can also do it on stones like stringer says.


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## Benuser (May 9, 2021)

I have a Herder leather strop glued on hard wood. Rough side treated with 20 micron diamond powder. Yes, it does contribute to smooth convexity.


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## VICTOR J CREAZZI (May 11, 2021)

HumbleHomeCook said:


> The Manticore is a beast.
> 
> Be aware, you may need to dress the surface to get it working right. Mine was so compacted it seemed almost slick. Some heavy scratching (read grinding down) of some screws and then re-profiling a thick Buck knife got it performing well.


Did yours take a long time to ship? I ordered mine on the 4th and it still has not shipped. It seems a bit odd that you pay for priority mail and then wait so long for it to get into the mail.


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## branwell (May 11, 2021)

ian said:


> A strop will never remove enough metal to significantly affect the geometry. Sandpaper on a soft backing works, but you can also do it on stones like stringer says.



Hmmmmm. Here's an interesting article with SEM images of stropping without compounds








What does stropping do?


Stropping a blade on a clean (without abrasive) substrate achieves FOUR results: 1) REALIGNING THE EDGE Although a straight razor is made of hardened steel, the edge is flexible and malleable. Belo…




scienceofsharp.com





And with compounds.








The Pasted Strop – part 1


The primary goal of stropping is to reduce the edge width by increasing the bevel angle near the apex (micro-convexity). Abrasive particles (paste, spray, etc) are applied to the strop to increase…




scienceofsharp.com












The Pasted Strop – part 2


In part 1 of this discussion, a comparison of leading edge and trailing edge honing strokes was illustrated with examples from the Chosera 1k and the Shapton 16k hones. As described in The Honing …




scienceofsharp.com












The Pasted Strop – part 3


In the previous installment of this series, it was shown that (sub-micron) abrasive stropping produces convexity in the last few microns of the edge; this result was defined as micro-convexity. In…




scienceofsharp.com












The Pasted Strop – part 4


In part 1 of the series, it was shown that edge-trailing and edge-leading strokes on a hard, flat abrasive hone lead to entirely different processes for apex formation and refinement. The edge tra…




scienceofsharp.com


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## ian (May 11, 2021)

branwell said:


> Hmmmmm. Here's an interesting article with SEM images of stropping without compounds
> 
> 
> 
> ...



Sure, you can create a little bit of convexity near the edge, but I think the question was about creating a convex blade face. You can probably do that on a strop too, but it may take you a few years.

I always love those images, though.


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## branwell (May 11, 2021)

ian said:


> Sure, you can create a little bit of convexity near the edge, but I think the question was about creating a convex blade face. You can probably do that on a strop too, but it may take you a few years.
> 
> I always love those images, though.


Ohhh. My bad. Didn't read enough of the thread. That said, if you did try to convex a blade with a strop and it took years, you would be a master of epic proportions able to teach said skill and become a millionaire.


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## HumbleHomeCook (May 11, 2021)

VICTOR J CREAZZI said:


> Did yours take a long time to ship? I ordered mine on the 4th and it still has not shipped. It seems a bit odd that you pay for priority mail and then wait so long for it to get into the mail.



No but I've had mine for a long time. I don't keep up anymore but last I looked, Benjamin (owner) said they were slammed. He's a good guy so if you have any questions or concerns, I'd just try to contact him.


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## whirlwynds (May 12, 2021)

ian said:


> Truth. I have burnt so many edges on mine. It's basically impossible for me to do any work near a thin tip without burning it.


yeah pretty much impossible on fine belts. only advice I can give is water or ice bath dip first and start at the tip rather than at the heel. it'll give you a fighting chance.


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## whirlwynds (May 12, 2021)

here’s a well used shun I thinned down recently. Would you guys go more?


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## ian (May 12, 2021)

Yes


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## Benuser (May 12, 2021)

Rule of thumb: I would aim for a thickness of 0.2mm above the edge, 0.5mm at 5mm from there and 1mm at 1cm.


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## Brian Weekley (May 13, 2021)

whirlwynds said:


> View attachment 126825
> 
> here’s a well used shun I thinned down recently. Would you guys go more?




For my use I’d thin it a bit further. For a customers use I think it’s just about right.


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