ceramic knives with the S G

[iSharpen]

This surprised me. Thoughts?

https://youtu.be/u1mMoXjHWcQ?si=gAGpWFrQJulJnGBt

Ken

Only just found this. Don't worry, it surprised me too! Here's a bit more info.

I had a long discussion with the owner of the knife before he let me try. I set the SG to to about 960 grit (the fine setting) using the 320 grit diamond plate and started VERY gently as I was aware of the chipping issue. I was very surprised when I saw that the knife seemed to be accepting the grind so I continued ever so carefully and gingerly. I was using a super soft touch, expecting the knife to explode but nope. I was able to take a fairly chipped edge and turn it into a decent edge by treating it like a normal knife.

I didn't deburr as I couldn't detect a burr and it seemed to slice paper where as before it was tearing it and was useless as a fine slicer. It wasn't razor sharp though and he was happy to take it away vastly improved. The chips (damage) weren't large but there we very visible and numerous. I wish I'd take a video before I started but I really didn't expect it to work and just started grinding it as he was there watching. It was only after I had achieved a result that I knew I had to share it on YouTube. The edge as presented resembled a misused global edge if that makes sense.

I assure you all there was no trickery and my surprise (although slightly bombastic and cringey) was genuine. I caught some flack in the comments but I can assure you it worked. My advise, start with a smooth wheel and push down only just enough to maintain contacts on the wheel but yes, the SG wheel can "sharpen" ceramic knives. I love the SG wheel.

A little info about the knife would help.

It was a Kyocera INNOVATIONblack® Knife similar to this although I don't remember a soft handle.
https://cutlery.kyocera.com/innovation-soft-grip-3-ceramic-paring-knife-black-z212-blade

[tgbto]

I sharpened the same knife this a.m. on a SB stone (edge leading)... and while I didn't spend a lot of time on it, I'm pretty sure I got a better edge... at least slicing thru some ad paper.

I don't know much about the physical properties of SG and SB. But I haven't yet had to true the SB, and in its current state I would say the surface is more even than the surface of my (several-times-trued) SG. Ie the RMS of the indentations is smaller. So you are using a harder, smoother medium than the SG, and it is logical that the blade would chip less. If you are abrading rather than microchipping on a smaller scale remains to be seen, and will depend on the relative hardness of this ceramic and silicon carbide.

[tgbto]

[Damn I messed up with the edits/post buttons]

I sharpened the same knife this a.m. on a SB stone (edge leading)... and while I didn't spend a lot of time on it, I'm pretty sure I got a better edge... at least slicing thru some ad paper.

I don't know much about the physical properties of SG and SB. But I haven't yet had to true the SB, and in its current state I would say the surface is more even than the surface of my (several-times-trued) SG. Ie the RMS height of the indentations is smaller. So you are using a harder, smoother medium than the SG, and it is logical that the blade would chip less. If you are abrading rather than microchipping on a smaller scale remains to be seen, and will depend on the relative hardness of this ceramic and silicon carbide.

[cbwx34]

The particles seem quite coarse. So it looks more like the edge is somehow getting microchipped away. It would be interesting if you could somehow get a microscope shot of the edge and the particles.

Today I dug out a 1200g CBN wheel and tried that.  Noticeable  difference in sharpness and edge smoothness, even vs. the SB wheel, and way better than the SG wheel.  And the water was cloudy with very fine particles in the bottom.  (Ignore the bigger "pieces" that's towel.)

You cannot view this attachment.

I'd say, from what you've posted, that this is actually the difference of abrading vs. microchipping the edge away?  Certainly a different result.

[3D Anvil]

Today I dug out a 1200g CBN wheel and tried that.  Noticeable  difference in sharpness and edge smoothness, even vs. the SB wheel, and way better than the SG wheel.  And the water was cloudy with very fine particles in the bottom.  (Ignore the bigger "pieces" that's towel.)

Interesting.  Did you sharpen edge leading or trailing?

[cbwx34]

Interesting.  Did you sharpen edge leading or trailing?

Edge leading.