# Knife thinning



## lapointeus (Aug 9, 2016)

Do I really need to buy a belt sander? I tried thinning a Misono on beston 500 and don't feel like I got anywhere despite spending a lot of time. Do I need to thin laser since they are already so thin?

I ordered a Tesshu and am now nervous that I will need a belt grinder.


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## Mucho Bocho (Aug 9, 2016)

You certainty do not need a belt grinder. You could use a lower grit stone however. Contact Jon or Maxim or both. Also, patience grasshopper patience.


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## Matus (Aug 9, 2016)

You should only thin a knife when it is necessary. Every knife needs to be thinned here and then, but it is usually minor as long as you only want to keep the original geometry. If you want to do some more serious thinning, than I would strongly suggest to start with something like Atoma 140. I have recently significantly thinned a 225 gyuto and it took me about 3 hours on the Atome and them few more ours to get the scratches out (first with JNS 300 and than with a sanding paper from 120 to 2500 grit). I think 500 grit stone would be way too slow for such a work, but should work fine for 'normal' thinning behind the edge.


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## TurboScooter (Aug 9, 2016)

Did a Tojiro DP 270mm gyuto mainly on a Shapton Pro 320. For me it's not so much the thinning itself, but the refinishing that gets to me.

I obviously did mine by hand, so I'd say no you don't necessarily need a belt sander - but ask yourself what are you trying to accomplish, and in what time frame?


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## YG420 (Aug 9, 2016)

Is the misono mono steel? If it is, I've noticed it takes a bit more effort to thin mono than carbon clad knives.


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## lapointeus (Aug 9, 2016)

Yea. The Misono is a soft Swedish steel. I just can't seem to make it perform well. So should I just do a little thinning every time I sharpen? I hate the scratches it leaves on the blade. Makes them look terrible.


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## lapointeus (Aug 9, 2016)

Yea. The scratch marks look terrible to me, if that is what you mean by refinishing.


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## YG420 (Aug 9, 2016)

I like using the 80 grit c powder i think its called from maxim with a cork to refinish someknives. If its too bad I'd recommend sending it to Jon


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## LifeByA1000Cuts (Aug 9, 2016)

Just learn from my mistake (gladly not on something expensive): Don't use a cheap, new diamond plate.


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## Mucho Bocho (Aug 9, 2016)

I thin each time I sharpen, but I'm not looking to hog off steel, more like buffing the surface taking off maybe a micron or two from each side. My goal is to remove the bevel that's been created by stropping and create a new clean, grabby long lasting zero bevel with zero shoulders.

Then I strop between sharpening sessions. Some of my knives only need to be sharpened once or twice a year. With the advanced steels, HT and sharpening equipment most of us have, long pronounced grinding sessions are usually not necessary. 

Now if you have a blunt apex that's been abused and not maintained, then a grinder is a good answer. The reason the knife got to be a porka behind the edge is because it was not thinned each time it was sharpened.


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## Devon_Steven (Aug 9, 2016)

Mucho, what's this ' zero bevel ' concept? I noticed you used it in Matus's bunka thread as well.


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## Matus (Aug 10, 2016)

As far as I understand it means that there is basically no edditional edge bevel, or micro bevel. You just follow (during sharpening) the how geometry of the blade down to the edge. This means that you have effectively 'zero' (as possible as that is) thickness behind the edge and thus the aangle at the cutting edge is very accute. This affectively also means that with every sharpening you have to go relatively high up the blade to keep the geometry of the blade (effectively thinning just a tiny little bit every time). Mucho - did I get the right?


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## RDalman (Aug 10, 2016)

I agree with Muchos sharpening philosophy. With the addition of tweak for your own needs  &#128077;&#128077;&#128077;


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## Matus (Aug 10, 2016)

It really depends on the steel, HT, edge geometry and use of the knife though. If I would not use a micro-bevel on my Yoshikane Hakata SKD than I would get considerable microchipping very fast.


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## Mucho Bocho (Aug 10, 2016)

You're describing my technique exactly Matus. Not to say he is endorsing my approach, but Jon did agree that its a good approach (in most circumstances). 

Without a shoulder, your knife will perform significantly better too. I've come to this conclusion after trying and buying hundreds of knives. When I cut with knives that came with a MB, I could feel the shoulder resist moving through the food. When I cut with knives that came with zero bevels (Dalman, Yusuke, Konosuke, Kato, DT, Carter), I felt like I had more control and feedback. Some knives will not like a zero bevel, like Kono. Fuji W1 or Carter Muteki. For these knives after thinning/sharpening, I then just round any shoulder with the wet/dry sand paper when restoring the finish. 




Matus said:


> As far as I understand it means that there is basically no edditional edge bevel, or micro bevel. You just follow (during sharpening) the how geometry of the blade down to the edge. This means that you have effectively 'zero' (as possible as that is) thickness behind the edge and thus the aangle at the cutting edge is very accute. This affectively also means that with every sharpening you have to go relatively high up the blade to keep the geometry of the blade (effectively thinning just a tiny little bit every time). Mucho - did I get the right?


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## Krassi (Aug 10, 2016)

yep !
zero bevel rocks.. i give them some convex shape at the tip for more stability.. its also easier to sharpen if you just put it flat on the stone.


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## Nife (Aug 10, 2016)

Can you thus, lay the knife flat on the stone and sharpen with the blade flat to thin behind the edge? Could this be effective without hurting the performance and longevity of the knife. It is much easier to me to thin by laying the knife flat than by trying to hold an angle of between 5 and 10 degrees.


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## LifeByA1000Cuts (Aug 10, 2016)

If it is a tall bevel, with-kiriba style, I recently had that question well answered here ... on something with a gradual/convex grind, you will in the end turn the whole knife into a full flat grind (and probably make it structurally too weak and/or get terrible food release) this way.


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## Devon_Steven (Aug 10, 2016)

Thanks to Mucho and Matus for the explanations. I am mucho-matified (very satisfied).

This 'zero-bevel' approach is pretty much what I ended up doing with my 210mm Itinommon gyuto; my first J-knife and therefore the one that got all the practice sharpening.

Having said that, I don't do a 100 per cent 'zero-bevel' (shouldn't it be called primary-only bevel [or secondary-only, depending on your position on naming bevels]?) but allow my hands to 'wobble' a little when sharpening close to the edge so that there is a very small amount of convexing going on (for strength).

I ended up doing it this way because I felt that the micro-bevels I was putting on didn't do much for cutting performance, but a true 'zero-bevel' wasn't so good for edge-retention.

--

I added a 240mm blue#2 Tanaka gyuto to the stable a few months ago and note that that knife has rather pronounced convexing as it gets close to the edge. It cuts very well, so I am planning to be careful about not flattining this one too much.

However, I'd appreciate any advice based on members' experiences sharpening these (or similar) knifes.


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## Mucho Bocho (Aug 10, 2016)

Devon, Your right on. Having a true zero primary bevel would make a very thin piece of cutting steel. I'll give it a little bit of convexity with wet/dry sand paper when refinishing, but there is not a primary visible shoulder bevel when I'm finished.



Devon_Steven said:


> Thanks to Mucho and Matus for the explanations. I am mucho-matified (very satisfied).
> 
> This 'zero-bevel' approach is pretty much what I ended up doing with my 210mm Itinommon gyuto; my first J-knife and therefore the one that got all the practice sharpening.
> 
> ...


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## Badgertooth (Aug 12, 2016)

Devon_Steven said:


> --
> 
> I added a 240mm blue#2 Tanaka gyuto to the stable a few months ago and note that that knife has rather pronounced convexing as it gets close to the edge. It cuts very well, so I am planning to be careful about not flattining this one too much.
> 
> However, I'd appreciate any advice based on members' experiences sharpening these (or similar) knifes.




Mucho's explanation is great and what I am working towards with mine. And it's what I tried to articulate badly to a fella in a thread about thinning a Tanaka one or two up in the sharpening station. Thanks Mucho.



Anyone have any advice on how to get more cutting performance out of a Shig without murdering an S grind? Bear in mind food release isn't at the top of my list of priorities.


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