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Highest grit & amount of stones for carbon knives?

Sat Jul 12, 2014 2:59 pm

Hello cktg-community,

got a quick question about the number of whetstones one really needs for finishing carbon knives and how small/large the increase in grit between those stones should be. I'm pretty sure that my stone collection is a bit too small right now to get the most out of my own knives, so I thought I rather ask before I go on a shopping spree.

I neither cook nor sharpen knives professionally, guess that's something important to mention. I use my stones primarily to keep both my own and my family knives sharp, but I recently started sharpening a bunch of dull and beat up knives from a friend of our family. She ends up with fixed knives and I get both liquorice and more knives to practice my sharpening skills on...

What kind of knives do I need to sharpen?

- My family owns a a big block filled with various J. A. Henckels knives from the 5 star range, but only uses a small amount of them. They are stainless and most likely have a HRC rating of something around 55-56 HRC.
- My own small collection only consists of carbon steel knives. The German ones have a 58 HRC rating and the one real Japanese knife I have is made from aogami #2.
- I do intend to buy a carbon steel gyuto (either blue 1 or aogami super) from chefknivestogo somewhere in late summer/fall this year.

And what stones do I have right now?

- a low grit scythe sharpening stone (<150 grit), which I solely use on beat up knives to get rid of a heavily chipped edge or create a new tip, if the original one broke off
- a 400/1000 grit japanese waterstone. Good enough for the Henckels knifes...
- a tiny 6k coticule natural stone from Belgium (roughly 3x1.5 inches)

The 1k side of the combistone is a bit too coarse for my liking when it comes to my carbon steel knives, at least when it comes to finishing/polishing the edge. And while the coticules grit is high enough to give me that polished edge, its size makes it pretty much useless for anything bigger than a small paring knives and all my knives are bigger than that.

Which brings me to my questions:

1. What would a nice grit rate be to finish those carbon knives (esp. if I move up to a Blue #1 or AS gyuto)? 6k or 8k?
2. And is it better to directly move from the 1k to the final polishing stone, or would it be wiser to add another intermediate step using something like a 2-3k stone?

Thanks for the help and greetings from Europe

Re: Highest grit & amount of stones for carbon knives?

Sat Jul 12, 2014 3:17 pm

The Naniwa Green Brick would be a good stone to finish the soft stainless on. They won't keep an edge much better than that. http://www.chefknivestogo.com/naao2kgrbr.html
The Suehiro Rika 5k would be a good finisher for your carbons for now. A very good and popular stone that leaves a light polish and toothy edge. You may decide to go higher later but I would start here. http://www.chefknivestogo.com/suri50grst.html
You might consider a strop set to use after the 5k. http://www.chefknivestogo.com/haamstkit.html
This is enough to give edges probably sharper than you ever felt.

Re: Highest grit & amount of stones for carbon knives?

Sat Jul 12, 2014 3:46 pm

A +1 on the Rika. I love the edge I get off of that stone, and i find it really pleasant to use.

Edit: based on cedarhouse's comments below: I do have the Arashiyama 1K and it is certainly a fine stone. I don't find that it dishes too quickly, and it cuts well. I like it, but I don't have anything to compare it to.
Last edited by estayton on Sat Jul 12, 2014 5:36 pm, edited 1 time in total.

Re: Highest grit & amount of stones for carbon knives?

Sat Jul 12, 2014 3:47 pm

I like a 2-3x grit progression, so 1, 2, 4 or 1, 3, 6, or mix and match within that progression 1, 2, 6, which is my most commonly used progression.

Like Jeff said, the western stuff wont benefit from much more than the 2k Naniwa Green Brick. The harder Japanese stuff could go higher, but most on the forum work with finishing stones in the 4k-6k range. Some do go much higher, 8k+.

Something like the Arashiyama 1k, 6k stones with the Naniwa Green Brick for the western steels and as a midway between the two. I have not used the Arashiyama 1k, but I have both the 6k and the Naniwa and they are good stones. The Naniwa is a much softer stone.


I also really like my Shapton Glass stones. They are probably faster working and they are very hard, slow wearing stones, but they do not "feel" as good.


The Mr. Knife Fanatic set is also very popular, and I have not used it, but the set leans on the ability of the Green Brick to polish to a higher level of refinement than its 2k rating.


Jeff's recommendation of strops is also a good idea. Strops can be used between sharpenings to freshen an edge or at the end of a sharpening session to extend the level of refinement. I have used 1µ and 0.5µ diamond sprays on balsa wood with good results.

Re: Highest grit & amount of stones for carbon knives?

Sat Jul 12, 2014 8:39 pm

Sharpening beyond 6k for a Japanese kitchen knife is dubious. You loose the edge very quickly. If you want that higher polish you're better off stropping, as said before. 4k-6k is a good target final grit rating for your harder carbon knives. I have a Sanyo 6k that gives me a very nice polished edge and hasn't dished much on me at all. It has a very luxurious feel.

A 2k-3k before your 4k-6k would speed things up, but is by no means required, particularly if you grab a 4k stone. 1k to 4k is not a bad jump. If you get an 8k, you might really need that 2k-3k. As said before you can use whatever 2k you pick up as a stopping point for your German knives, but I personally finish my German knives on a Shapton 1.5k half the time these days and still get good results.

Shame the coticule is small. They really are lovely stones. They're a big part of why I can point to Belgium on a map.

Re: Highest grit & amount of stones for carbon knives?

Sun Jul 13, 2014 4:06 am

Guys, thanks for all the replies!

Regarding the German stainless steel knives: I don't intend to sharpen those with anything beyond the 1k grit stone I already have (and steel them once in a while to straighten the edge). They are sharp enough as they are for my mother, too sharp for my stepfather (guess who's the person who doesn't do much dinner prep in our household) and I stick to my own carbon knives, when it comes to dinner prep.

Regarding stropping: Right now I use a stable of newspapers as a last step (a trick I saw on the Korin knives YT channel), but I do intend to get a leather strop (coated with chrome oxide or polishing paste)

I'm going to recapitulate the recommendations:

1. Good finishing grit grade would be something between 4-6k
2. Anything beyond is overkill and one would be better of using a stropping leather instead
3. An intermediate stone (2-3k) helps speeding things up, but if one is patient one can live without it if necessary (=limited funds)

Did I get it right?

Re: Highest grit & amount of stones for carbon knives?

Sun Jul 13, 2014 8:33 am

Quite so. Depending on the 4k one needn't even be that patient.

Re: Highest grit & amount of stones for carbon knives?

Sun Jul 13, 2014 10:14 am

I would call it good with the Green Brick, it will handle all of the steels you have mentioned and more. It will also polish much better than it's rated grit giving a nice polished appearance and in many cases a edge approaching 4k or better.

I like it best after a King 1k or Shapton pro 1k but have used it very sucscussfully with a Chosera 400 which gives it a more toothy polished edge. I have used it in combo with a Naniwa Omura 150 grit too, you would not think it's possible but on softer steels it works to great effect.

Re: Highest grit & amount of stones for carbon knives?

Sun Jul 13, 2014 12:55 pm

"Did I get it right?"

Yup! :D

Re: Highest grit & amount of stones for carbon knives?

Sun Jul 13, 2014 10:38 pm

1-2k is all you need for the softer stainless.

It's a good thing to strop when finished on the stones regardless of the grit you stopped at. It just seem to helps "clean up the edge".
You can strop on newspaper draped over a stone, cardboard, blue jean material among other things until you get a strop set you like.
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