Thinning...?

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HumbleHomeCook

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

BTW without @Benuser I wouldn't be where I am sharpening wise right now, so the question is part serious, part taunting.
 
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.
 
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.
 
Would you say it's a performance requirement, or is it that you just luuuuv perfecting your consistency? :p
1. I want to avoid thickening behind the edge.
sharpen4-4.jpg



2. I want the right bevel to form one continuous arc with the right face.
IMG-20180511-215023-BURST004-3.jpg


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


2. I want the right bevel to form one continuous arc with the right face.
View attachment 102254

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.

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.
 
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
 
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
 
@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.
 
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.
 
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.

3lvrlnI.jpg
 
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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.
 
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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