Thread: 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)

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)

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

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?

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