Thread: grit, grade, mesh, micron & finish

Originally Posted by hardheart

Stranger still, a hard black or translucent are said by some to create a shaving edge, while no charts I have seen on the web grades them any finer than around 2-4K

Under the US grit rating, that sounds about right. A translucent Arkansas is quite fine, it's estimated to be 8k JIS grit on our wiki, which agrees with my experience. Used dry, it's more like a ~10k stone (JIS rating).

yeah, but it was a JIS comparison, not CAMI. Very strange.

Someone told me that grit rating was not determined by particle size alone, that other characteristics of the hone were involved. I believe this to be completely false. The Norton and DMT are 8Ks becasue they use the mesh rating and have 3 micron particles. That has nothing to do with the binders, nickel plating, the fact that one uses diamond and the other doesn't, etc. Those 8Ks do not compare, nor do they have to compare, to glasstone, super stone, sigma power, gold stone, cerax, etc.

8 miles does not compare effectively to 8 kilometers. They are different measuring systems, but both measure distance. One is 60% longer than the other, the number '8' is completely irrelevant and denotes no similarity. I believe the same holds true for hones. The manufacturers simply cannot make an 'effective' grit rating. They don't know what you're sharpening, how you're sharpening, and they aren't collaborating to compare their finishes on some baseline material, angle, number of strokes, amount of pressure, etc. What is 'effectively' an 8K edge? One that matches a Kitayama? One that matches a G1 stone? One that matches a D8EE? They all say 8, which 8 is the 'effective' one? Mesh, JIS, something else? I like microns. Microns are microns. Once I know my 1K/4K progression in mesh is 14/6 micron, then I can effectively compare to JIS. Which would not be 1K/4K, because then I would be going 11.5/3 micron. Instead of a little less than half size, I'm progressing down to a little more than a quarter. Then I wonder why my stones seem slow, or the finish doesn't match.

I wish I was better at straight shaving, or had more honing gear so I could do more & better comparisons. I just rehoned my razor with the 4K King, 15 laps with a single layer of tape, no CrO after. I would like to compare this to Norton 8K since the particle size is the same. The shave was not great, but I am not a great shaver. My face is not raw, and I'd say I got about as good as a quick 2 pass with the Mach 3.

this is what meager fare I currently have - 4 diamond plates, 4 diamond cards, 1 diamond steel, 1 Fallkniven DC4, 4 naturals [aoto/kiita/Ch12K/mudstone] 4 Matsunaga King grits, 1 glasstone, 1 Norton water, 3 Norton oil-crystolon & india combos, 5 leather mounted on wood, 2 Spyderco rods, 1 Norton/St Gobain stick, 50 carats 0.25 diamond, small bottle HA 0.5 chromium oxide, small tub HA 3 micron SiC, 0.3 alox lapping film, awaiting 10K super stone

I am going to stop my participation in the old practice of referring to non rated stones by some number that really holds no meaning. Sal Glesser has stated that Spyderco will not provide a grit rating to their sharpeners because they can't. The man founded the company on these tools, not the knives, and he will only go so far as to call them medium, fine, and fine with surface lapping. They all have similar sized abrasive particles, they cannot be assigned a grit. Same with Arkansas stones. The diatoms all fell within a certain size (not the real reason), the abrasive their skeletons became will not differentiate in size from washita to translucent. Specific gravity can work for grading, but there is not grit measurement appropriate. I will not call them 800, 2K, 12K, or otherwise, because that means there would be a 'standard' finish provided at one of those 'standard' grits. There isn't. I asked what grit range a J-nat would fall under, just hoping to get an idea of how coarse to how fine they can go, but I will never be able to say that a kiita or asagi is 31,500 grit, or 43,782 grit.