Refined/Toothy & Diamond stone

[esoo]

So this is very likely a technique thing for me, but I need a little advice to see what I can here.

I have two 3K stones - a Shapton Glass 3K (SG3K) and a Naniwa Diamond 3K (ND3K). I know that 3K between brands isn't the same, so the ND3K is a finer stone than the SG3K (say more like a SG4K), but I don't think that is all the difference I'm seeing.

I love the refined toothy edge that I get off the SG3K. Follow it up with a few strokes on a 1u diamond loaded strop and it makes a very useful edge for me. Toothy, aggressive yet refined.

When I sharpen with the ND3K, I tend to get a much more polished edge with very little tooth. Gets nice and sharp, but seems to have very little tooth - almost like a polished the edge with a much higher grit.

Technique for both stones is similar, and I'm seeing these difference in results when I sharpen the same blade.

Any suggestions why I'm seeing such a difference in finish for what should be fairly close in grit? Steel is simpler carbons (A2, Blue 2, 52100, ApexUltra).

 

[Bico Doce]

When polishing with diamond stones the scratches don’t seem as deep compared to non diamond stones (purely anecdotal, no data to back this up). I wonder if that plays a role here?

 

[M1k3]

Diamonds are less aggressive at sharpening than Alox or SiC.

 

[dabes]

IME you need to apply more pressure than you would with Chosera/SG for bonded diamond to cut similarly.

 

[Bico Doce]

Shawn has this side by side Sic bs Cbn. Edge looks less toothy on the Cbn

 

[Rangen]

I have both of these stones, but I have not done a back to back comparison. Still, I have the impression that they produce similarly toothy results.

Maybe that impression is wrong; happy to check. However, I have a guess.

The Naniwa diamond stones are excellent, but the higher you go in grit, the more quickly they load up and become quite smooth and mild. You know that coarse conditioning stone that came with the Naniwa? Try using it vigorously over the entire surface, then rinsing and giving it another try.

If that doesn't do it, well, if memory serves, @stringer is using the 600 stone to get his toothy kitchen edges. IME it's more comparable to the SG1000 than the SG3000 though.

 

[Cliff]

Interesting -- I have JKI 1K and 6K. They are slower on most knives than, say, my Shaptons, but I find the 6K leaves a very toothy edge, feels more like a 4K. I have no idea why.

 

[ethompson]

Hmmm… I find my diamond stones to be faster than their synthetic counterparts, especially beyond 1.5k or so. I’ve also found that I get toothier edges from my 6k diamond than I recall getting from my 6k traditional stone.

 

[Cliff]

When I say slower, everything goes out the window with powdered steels, which is mostly what I use them for...

 

[esoo]

So as I said it may be a technique thing. I use a sweeping motion with what may be considered fairly light pressure. It has worked fairly well for me for my sharpening in the past.

Based on that it may well be a pressure issue for the diamond stone. I don't think it is a loading issue as I've had this issue from new and after cleaning it (which I have done multiple times)

One issue I have is that I don't have a "sacrifice" knife - something good enough that I'm not fighting bends/warps or weird grinds but cheap enough that I'm willing to waste steel to sharpen the daylights out of it as I better my technique. I'm working on solving that.