Author Topic: 1st results for ceramic knife on diamond wheel  (Read 2223 times)

Offline Cyrano

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1st results for ceramic knife on diamond wheel
« on: July 19, 2018, 02:51:41 pm »
I sharpened a Kyocera ceramic chef's knife using the Extra Fine diamond wheel. I matched the factory edge angle of 25 degrees per side.

It required only three slow passes with very light pressure on each side to replace the entire factory edge with a new, clean, uniform edge. Although there was no burr, of course, the difference in scratch patterns between the factory edge and the Tormek's edge made it easy to see when I had removed enough material to form a new apex.

While the new knife edge looks great cosmetically, it is not very sharp. It measures c. 600 BESS, and it cuts printer paper with difficulty. To understand why the cutting performance is not good, I examined the edge under a microscope.

This image shows the edge at 200X magnification. On the left is the appearance under top lighting only, and on the right is the appearance when side lighting is added.



This focus-stacked image shows the appearance of the apex edge-on:



Based on this microscopic examination, I believe the edge is not sharp because micro-chipping has caused the apex to be rough and broad. I'm open to ideas on how to get a finer edge.





Offline Jan

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Re: 1st results for ceramic knife on diamond wheel
« Reply #1 on: July 19, 2018, 04:30:30 pm »
Cyrano, thank you for posting your results and beautiful edge images! :)

There is additional, very valuable information about ceramic blades on scienceofsharp.
https://scienceofsharp.wordpress.com/2018/02/24/ceramic-blades/

Jan

Offline Cyrano

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Re: 1st results for ceramic knife on diamond wheel
« Reply #2 on: July 19, 2018, 05:01:20 pm »
Thanks for the reference, Jan. It is very illuminating!

I look forward to the day when desktop SEMs are afffordable.

Offline kwakster

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Re: 1st results for ceramic knife on diamond wheel
« Reply #3 on: July 19, 2018, 05:18:24 pm »
A few years ago i did a review on various other forums of a Forever white ceramic knife, complete with resharpening/polishing.
If you Google on Forever SC-16WB ceramic knife you will probably find it.
Quality ceramic knives can get really sharp btw, as i show on the tomato in the two YouTube clips.

« Last Edit: July 19, 2018, 05:20:11 pm by kwakster »

Offline Cyrano

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Re: 1st results for ceramic knife on diamond wheel
« Reply #4 on: July 19, 2018, 11:56:14 pm »
A few years ago i did a review on various other forums of a Forever white ceramic knife, complete with resharpening/polishing.
If you Google on Forever SC-16WB ceramic knife you will probably find it.
Quality ceramic knives can get really sharp btw, as i show on the tomato in the two YouTube clips.

That's impressive work! You've set quite the bar for sharpening ceramics.

Offline Fernando

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Re: 1st results for ceramic knife on diamond wheel
« Reply #5 on: July 20, 2018, 12:22:47 am »
The ceramic knives also come in different qualities, one of them has been sharpened recently with the SG-250 that comes from the factory,
I know it's not the best option
I know that it is not optimal
But I still wanted to prove that just in one document I saw that even the aluminum oxide could attack the zirconium oxide, and they were absolutely right, even though it took a lot longer than with a conventional knife and that the knife did not have any defects in the edge, just needed to be retouched, sharpen it to 15 degrees per face, and I could return the edge, I usually do it by hand with a manual machine controlled angle and diamond stone to 1500 grain, but I'm glad to know that the SG-250 could with the task although I have clear that it is not the best option, also pass it through the leather wheel with the polishing compound of tormek, for a while, and also notice difference, the knife finally managed to recover the edge, is not a 10, but I definitely achieve a score of 8.5 cuts the paper very well, without effort.

This was just an experiment, I told myself, SG-250 is not designed for this task, but I did not want anyone to tell me, I just wanted to verify what could be achieved with this stone.
PS: it was not a kyocera, but I think that with the hardness of the ceramic 25 degrees per side is a lot, I sharpen them to 15 degrees with very good results.

I share an image.


« Last Edit: July 20, 2018, 12:33:35 am by Fernando »

Offline WolfY

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Re: 1st results for ceramic knife on diamond wheel
« Reply #6 on: July 24, 2018, 04:20:26 pm »
Year ago a client sharpened a knife with SG-250. he complained that nothing happened and there is probably something wrong with the stone.
I asked him to come in with the stone and knife.
When he pulled out the knife it was ceramic knife. So I put it on my T-8 with the SB-250 and it sharpened it perfectly.
Client went home with a new SB-250 stone :)

How is your experience with the SB and ceramic?
Giving an advice is easy.
Accepting an advice is good.
Knowing which advice is worth adopting and which not, is a virtue.

Offline Fernando

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Re: 1st results for ceramic knife on diamond wheel
« Reply #7 on: July 24, 2018, 05:09:10 pm »
Year ago a client sharpened a knife with SG-250. he complained that nothing happened and there is probably something wrong with the stone.
I asked him to come in with the stone and knife.
When he pulled out the knife it was ceramic knife. So I put it on my T-8 with the SB-250 and it sharpened it perfectly.
Client went home with a new SB-250 stone :)

How is your experience with the SB and ceramic?

I do not have the SB-250 so I do not know how the results are, but in the commercial videos of Tormek, they make it clear that the SB-250 is useful for sharpening ceramic knives, for now I have to extract the juice from the SG-250 and gather money to get the SB-250 or a diamond one,
The truth is I always have the dilemma of what would be the next stone I should buy, to have the best cost - benefit, if the SB-250, the diamond, or the SJ-250 to achieve those polished edges.
I want the SJ-250 more for pleasure than for necessity, I think, although I also think that with that stone I can sharpen the scissors of a stylist that generates good money, but at the same time I want a stone that can be used with any work including the ceramic knives , although these knives almost do not reach me to be sharpened.

It is a difficult decision
« Last Edit: July 25, 2018, 06:01:20 pm by Fernando »

Offline Ken S

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Re: 1st results for ceramic knife on diamond wheel
« Reply #8 on: July 24, 2018, 09:38:14 pm »
Fernando.

I would not recommend purchasing an SB at this time. Let the new diamond wheels actually come into use for a while and see how they compare with the SB.Tormek has not released any videos about the new wheels, and the coverage in the handbook is minimal. This is a big devision; we need better information.


Ken

Offline Fernando

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Re: 1st results for ceramic knife on diamond wheel
« Reply #9 on: July 25, 2018, 06:06:10 pm »
Fernando.

I would not recommend purchasing an SB at this time. Let the new diamond wheels actually come into use for a while and see how they compare with the SB.Tormek has not released any videos about the new wheels, and the coverage in the handbook is minimal. This is a big devision; we need better information.


Ken
am totally agree with you Ken

now I just bought the accessory RB-180 Rotating Base, "and" some PA-70 Honing Compound to have reserve.
I should arrive tomorrow,