American vs. Japanese Grit numbers

Hello all,

I have tried looking this up on google and this forum to no avail. However I once read that there is a difference between the grits used in Japan and in USA. Something like a 4k Japan is like a 1k in the USA. I wanted to know because I have a 1k Lansky stone (http://www.google.com/products/catal...CH0Q8wIwCDgA#p) that I use to sharpen my survival knifes, is this like a 4k Japanese waterstone? (I know that in Japan they actually dont use grits sometimes, but have categories instead)

Would a chinese 12k stone (http://www.woodcraft.com/Product/200...fcode=05INFROO) suffice in keeping my razor sharp when it gets slightly dull? (I know the chinese stone is slow cutting).

Thanks and have a great day.

I'm not sure about the differences in grit between the US and Japan, but I'd imagine they dont vary that much. I'll certainly defer to the hone guru's on that one though..!

In terms of the C12k, that would make an excellent touch up stone for your razor. Once the razor dulls slightly, wet the hone and touch the razor up.

IIRC, the C12k is a pretty slow cutting stone so you could probably start with maybe 15-20 X strokes and then strop, test shave and see how the edge is. Then hone more if you need it.

What led me to believe there is a difference is:
"Japanese waterstone grades fall under three major groups: very coarse grits for fast removal of metal; medium coarse grits for refining the edge and removing the burr; and finish stones for the final honing and polish. These grades cover a range of 150 to 8000, and they don't exactly match up with U.S. grades. For example, the abrasive action of a 1000 grit Japanese stone is the equivalent of US 500; and the Japanese 4000, a US 1000.

In comparison to the Arkansas stones, the Japanese 800 grit is equivalent to a Natural Soft Arkansas; the 1000 to a Hard Arkansas; and the 1200 falls between the Hard Arkansas and the Black Hard Arkansas."

from: Japanese Waterstones - Their uses and care

What do you guys think of these stones? Anyone familiar with the 5k or 8k?

3-Piece Sharpening Set - eBay (item 360212223729 end time Aug-24-10 05:43:25 PDT)

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Originally Posted by airbus001

What do you guys think of these stones? Anyone familiar with the 5k or 8k?

3-Piece Sharpening Set - eBay (item 360212223729 end time Aug-24-10 05:43:25 PDT)

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This has been discussed repeatedly. Hi_Bud_GL evaluated those hones and found them to be acceptable.

The grit scale difference is real, though not as extreme as you depicted. That is, the Japanese 4k is not comparable to an American 1k to my recollection. I don't have immediate access to the scale at the moment but it's likely someone else will produce it shortly.

This is something I bumped into while trying to find J-nats with comparable grits.

So far, the grit rating seems to be close but as for the naming of the J-nat hones I'm unsure about. I emailed a gentleman that sells hones in Japan and his names for the hones are different but his recommendation for hones close to 1k US seem to be dead on with this grit comparison chart.

Scroll down to Grit...

Katana (Japanese Sword) Sharpening Guide

American hone numbers go like 1000, 2000 etc.

Japanese numbers go like 一千、二千。。。

Actually, try http://straightrazorpalace.com/advan...son-sheet.html

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Originally Posted by JimR

American hone numbers go like 1000, 2000 etc.

Japanese numbers go like 一千、二千。。。

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:roflmao
I just got to work, put media in the water bath to warm up, and then I read this. Thanks for starting my day out right!

Here is the last grit chart comparison sheet posted by Smokintbird some time ago and here is the complete thread that discusses it a year or so ago. Nice to subscribe to threads so you can find them when you need them. See thread tools for the drop down menu and hit 'subscribe'.:)

Just a bit of interjection here...

There is no science here, there is a ton of information that doesn't mean a darn thing UNTIL steel meets stone...

The type of grit, the binder, the release rate of the grit, the actual shape of the grit all come into play here... So take ALL the grit numbers with a large dose of salt until you try them yourself...

BTW when you add in Natural stones it really takes a huge hit to grit accuracy two different Ch12K's will cut differently...

Some Fun Huh???? :)

And this is why natural hones and barber hones do not have a grit rating--because it doesn't tell the whole story and they don't compare.

Have I mentioned the Chinese Hone is not 12K?
:soapbox:

Ron on a Roll gotta love it man.... :D

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Originally Posted by Utopian

Have I mentioned the Chinese Hone is not 12K?
:soapbox:

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PHIG FTW. I'm bringin PHIGgy back... yea.

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Originally Posted by Utopian

And this is why natural hones and barber hones do not have a grit rating--because it doesn't tell the whole story and they don't compare.

Have I mentioned the Chinese Hone is not 12K?
:soapbox:

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What do you mean by the Chinese Hone is not 12k? What would you rate it from experience?

Here is just a bit to occupy your time while Ron types more :)

http://straightrazorpalace.com/hones...nese-hone.html

Keep in mind this is just 1 natural hone

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Originally Posted by Utopian

Have I mentioned the Chinese Hone is not 12K

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Mine is. :D

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Originally Posted by airbus001

What do you mean by the Chinese Hone is not 12k?

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It means that when the quartz or whatever is the cutting media in that rock crystalized, the sizes are all kinds and nobody sorted them out selecting only the 12000 grit ones. Same is true for every other natural hone, the range of sizes is much larger than any industrial standard.

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Originally Posted by airbus001

What would you rate it from experience?

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I would rate them as slow cutting hones, some of them being significantly better than others in producing a sharp edge on a straight razor.
The grits in there are anything from about 1000 to 100,000.
How it behaves depends on how much of the big ones and how much of the small ones ended up in the particular piece of rock that you bought.

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Originally Posted by gugi

It means that when the quartz or whatever is the cutting media in that rock crystalized, the sizes are all kinds and nobody sorted them out selecting only the 12000 grit ones. Same is true for every other natural hone, the range of sizes is much larger than any industrial standard.


I would rate them as slow cutting hones, some of them being significantly better than others in producing a sharp edge on a straight razor.
The grits in there are anything from about 1000 to 100,000.
How it behaves depends on how much of the big ones and how much of the small ones ended up in the particular piece of rock that you bought.

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I repeatedly tried to multi-quote, which I have done in the past, but it did not work. Thus I am going to respond individually.

Gugi's thinking aligns with my own. If you compare my Norton 4k to my other Norton 4k to Gssixgun's 4k to JimmyHad's 4k, you would discover that they are virtually identical. Synthetic hones are made from screened uniform grit with a uniform ratio of abrasive and binder. Natural hones, like the Chinese hone, are ROCKS resulting from eons of geological forces acting on the particular strata of rock from which the hones are mined. Two hones cut less than a foot apart might vary dramatically in their constitution. In other words, if you compare my Chinese hone to my other Chinese hone to Gssixgun's Chinese hone to JimmyHad's Chinese hone, you would discover that they can vary dramatically. Short answer is that natural hones are rocks, and so they cannot be presumed to be identical

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Originally Posted by Philadelph

Mine is. :D

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Nope, yours is not 12k.
I'm pretty sure I bought my Boker 1056 from you and you honed that on a Chinese hone and given the quality of shaves I've gotten off of it, I'd rate your particular hone at 17.6! *
:D


*With the caveat that no Chinese hone can actually be assigned a grit rating!

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Originally Posted by airbus001

What do you mean by the Chinese Hone is not 12k? What would you rate it from experience?

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I hope this has clarified a little of this for you.
Individual rocks do vary in their cutting ability. Natural hones have grit of varying sizes.
Some of the components of the rock have cutting capacity and some of them don't.
Their ratios can vary.
The abrasive components of the rock may vary in their ability to produce slurry, which is the abrasive that has released from the stone and is suspended in the water on the hone. When the released abrasives, aka grit, are floating in the water they can vary in their cutting/polishing capacity based upon their shape and their friability. FYI, friability is the degree to which the grits break down into smaller pieces, effectively reducing their size, thus increasing their grit rating, and therefore increasing the fineness of the polish-ability of the hone.

I think that is technically correct definition of friable but I also tend to think of it in terms of hone's action. Arkansas/non-friable. BBW/friable. Or, simply the ability of the hone to release fresh abrasive.

Thank You everyone for your replies.