Thread: Japanese Grit vs. American Grit

Originally Posted by JimR

Please do, I'm keen to know...

Today I looked at the two side by side with my B&L 30x stereo microscope and I cannot tell them apart. I suspect that they are one and the same. .....but I may be wrong. Only 30x and I'm not an expert.

Originally Posted by JimmyHAD

Today I looked at the two side by side with my B&L 30x stereo microscope and I cannot tell them apart. I suspect that they are one and the same. .....but I may be wrong. Only 30x and I'm not an expert.

Well, it wouldn't surprise me. I mean, the same color in a color coded set would just be odd, especially coming from the same factory. I mean, how do they not mix them up?

Of course, the real test is in use...and your use tells you something different, right? Who knows. They're both good stones, let's just leave it at that...

Nah, who am I kidding? I NEED TO KNOOOOOOWWWW!!!!!!

Jim I do not believe that Japanese sharpening stones are re-labeled or recalibrated to suit the standards of another country.

16k Shapton is .92micrometer regardless of being JP version or USA.

when you switch between standards a bit of testing is all it takes. 8k norton is not the same as 8k naniwa, which may or may not be the same as shapton or king, or takenoko etc.

They are all different- as there is more to a sharpening stone than grit size.

try different things- if every stone cant fit into a niche- get more things to sharpen.

wait...what was the question?/?

Not to drudge up an old thread but I have a question about the micron to grit conversions. I'm going to get diamond pastes and I've decided to get 1 and 0.5.

Here's how Norton equates its stones to micron size:
3 micron = 8K
1 micron = they have no equivalent stone
.5 micron = 15K

Does anyone know which conversion is more accurate? If it's Joe's, then I'll get both 1 and 0.5 micron sizes. But if Norton's is right, then I might as well just get the 0.5 diamond paste. Thanks.OK. Here's the whole story.

I say 50K for .5 and 100K for .25, because that's what the diamond companies say. You can find a diamond paste chart at straightrazorplace.com.

In stone grits there are many standards. The two that concern us are the US and Japanese. The traditional US standard uses a screen, and if a particle passes through the screen, it's that size. In other words, grit size is the LARGEST particle in the mix. The Japanese use the average size. So, they will have twice the grit number compared to the US.

The US matches sandpaper, so a 2000 grit stone is like 2000 sandpaper, but the Japanese size for the same grit is 4000. The Norton waterstones like the 4k/8K use the Japanese system, so if you wanted to use sandpaper of the grit, it is really 2K/4K. A 15K grit by the US standard is .5 micron (30K Japanese), and 30K grit US (60K Japanese) is .25 micron.

When you see that a 15K is .5 micron, that's the US standard. For a waterstone it's 30K (see a Shapton chart).

In any case, you can rely on the numbers I gave you when comparing paste and waterstones. They're a combination of what the diamond paste companies tell you about .5 and .25 microns and the Japanese standard for waterstones, which Norton also uses for its waterstones.

The moral of the story is that you always need to know what system is being used for the grit you're looking at.

Originally Posted by hi_bud_gl

Not to drudge up an old thread but I have a question about the micron to grit conversions. I'm going to get diamond pastes and I've decided to get 1 and 0.5.

Here's how Norton equates its stones to micron size:
3 micron = 8K
1 micron = they have no equivalent stone
.5 micron = 15K

Does anyone know which conversion is more accurate? If it's Joe's, then I'll get both 1 and 0.5 micron sizes. But if Norton's is right, then I might as well just get the 0.5 diamond paste. Thanks.OK. Here's the whole story.

I say 50K for .5 and 100K for .25, because that's what the diamond companies say. You can find a diamond paste chart at straightrazorplace.com.

In stone grits there are many standards. The two that concern us are the US and Japanese. The traditional US standard uses a screen, and if a particle passes through the screen, it's that size. In other words, grit size is the LARGEST particle in the mix. The Japanese use the average size. So, they will have twice the grit number compared to the US.

The US matches sandpaper, so a 2000 grit stone is like 2000 sandpaper, but the Japanese size for the same grit is 4000. The Norton waterstones like the 4k/8K use the Japanese system, so if you wanted to use sandpaper of the grit, it is really 2K/4K. A 15K grit by the US standard is .5 micron (30K Japanese), and 30K grit US (60K Japanese) is .25 micron.

When you see that a 15K is .5 micron, that's the US standard. For a waterstone it's 30K (see a Shapton chart).

In any case, you can rely on the numbers I gave you when comparing paste and waterstones. They're a combination of what the diamond paste companies tell you about .5 and .25 microns and the Japanese standard for waterstones, which Norton also uses for its waterstones.

The moral of the story is that you always need to know what system is being used for the grit you're looking at.

This is a good question Sham.

I have lapping film that is labeled as #10000 grit with a micron value of 0.5

I also have lapping film that is labeled #15000 grit with a micron value of 0.3

Also the #8000 grit is 1.0 microns.

I know that these numbers are going to look wacky to a number of you but they are all packaged 3M lapping film that I bought here in Tokyo.

I was under the impression that 0.5 micron was in the Chromium Oxide range and was a mesh grit of approx. 30000 but mine is labeled #10000.

It doesn't affect my honing though. I get great edges off of them nomatter the numbering system.

i know i am confused about all this. what i am finding out now by using shapton 16000 is strange. makes me more confused.I have to do couple more testes to find out what is going on with shaptons,i have never seen anyone complaining about it. Everyone very happy with shapton 16000 .Lets see

Your statement about the Shapton #16000 is also a little puzzling to me.

I know many of the users here that have and use the shapton #16000 are extremely happy with the results (I don't have one nor do I plan to get one).

I have read the Japanese language Glass Stone pdf a number of times and what is puzzling is how the #16000 is rated so low for use with razors. It has the lowest rating in the chart, along side hones #1000 and lower.

Oddly the majority of the other stones are all mid range 'good/appropriate' for use with razors. But the 'optimal' hones in the glass series is the #3000, the #10000 (newly released) and the #30000.

It is just so puzzling as to why the owners of the #16000 laud its greatness when the manufacturer down plays it as appropriateness for use in polishing razors.

Don't get me wrong, I am a firm beleiver that the proof in is the pudding, and with all of the great results by chrisL and others who can argue its worth, but why the poor rating from Shapton...?