which wheel for ceramic knives, and any special things?

[mysharpener]

Hi,

Up until now I've been telling my customers that I do not sharpen ceramic knives since I don't have a diamond stone machine.  B ut I've read here and there that the Tormek will do them.  I do NOT want to ruin a ceramic knife and have to replace it (my guarantee...if I ruin it, I replace it, thus I don't do things I'm not comfortable with or set up to do!). 

Jeff, which stone do I use...the new carbon one, or the original stone (I have a T-7, btw), and are there any other things I should know about sharpening ceramic kitchen knives? 

Thanks!

[Jeff Farris]

The SG will do the job.  Grade the stone carefully and work carefully.  SB will cut it faster, but I wouldn't buy one just for that.

[mysharpener]

The SG will do the job.  Grade the stone carefully and work carefully.  SB will cut it faster, but I wouldn't buy one just for that.

OK, now 2 follow-up Q's:

1.  "Grade the stone carefully..."  What do you mean?  What am I aiming to do that's special here?

2.  "Work carefully..."  What am I trying to avoid here?  What is unique about sharpening ceramic knives, what is likely to go wrong if I'm NOT careful?  It'll help me to do the job if I know why I'm being so careful...thanks!

[Jeff Farris]

Most people do not give the stone grader sufficient time or pressure to get the stone as smooth as possible.  When doing something delicate like a ceramic knife, I will stay on the stone grader for at least a minute, maybe a minute and a half, pushing down firmly.  The grindstone should feel like wet glass over its entire surface area before you start.

By "work carefully" I mean that you should check your work frequently to make sure that you are not over-grinding the material.

[jeffs55]

Since when does the SG stone do ceramic? Quote from tormek USA

The unique composition of the stone, together with the Stone Grader SP-650 gives you two different cutting actions in one stone. The Stone grader polishes the surface of the grindstone from its normal 220 grit to a finish that works like a 1000 grit stone. This is a great advantage, since you can do the fine sharpening* with the same setting of the jig as used for the initial shaping* of the tool. The Original Grindstone is the ideal choice when you want both efficient steel removal and fine finish in the same stone over a wide variety of materials, from carbon steel to high speed steel.

I do not see ceramic included. This question has been asked numerous times on this forum and there has never been a satisfactory stone. The "SG" has been around for years. It is the original stone, what has changed?

[Jeff Farris]

Jeff,

I bought a Kyocera kitchen knife specifically to check it out, and it cuts it just fine.

[jeffs55]

So, for how long has the SG stone been acceptable for use on ceramic? For years, you have reported it to be UNusable on ceramic.

[Jeff Farris]

So, for how long has the SG stone been acceptable for use on ceramic? For years, you have reported it to be UNusable on ceramic.

I'm not sure I know where you found that.  I just went over every post I could find on the forum that mentioned ceramic knives.  The first one I said I didn't know, and from then on, I've said that they could be done -- which is after I tested it.

I've also heard within the last couple of days from the factory folks that the new SB-250 works even better than the SG-250 on ceramic, though I personally haven't tested it yet.

[RJM]

Guys,

This ceramic knife sharpening is news to me! Is honing required?

Thanks,
RJM

[jeffs55]

Jeff, it would seem you are correct in your recollections. This is what stuck in my mind:
Now, having read that you actually used the SG stone on a ceramic knife, did you sharpen against the turning wheel or with the wheel turning away from you? Was the knife edge smooth? I am pretty sure that the honing wheel would have no effect on the ceramic blade, or am I wrong there? thanx
Matt Rabe

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     Ceramic Knife - need help!!!!!
« on: December 26, 2006, 11:19:54 pm » Quote 

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Someone has asked if I can sharpen a Japanese cermic knife?  Any tips?  Can I?

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Jeff Farris
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      Re:Ceramic Knife - need help!!!!!
« Reply #1 on: December 27, 2006, 01:24:00 am » Quote 

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Until someone comes up a with more intelligent answer, I'll tell you that -- I don't know. 

It may be harder than the grindstone, in which case, you won't be able to sharpen it.  On the bright side, if you try and it truly is harder than the grindstone, you won't do any damage to either one. I would grade the grindstone very smooth and try it.   

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[Jeff Farris]

Jeff,

I did it wheel turning into the edge, using the jig.

I had the stone very, very smooth and detected no burr, so I didn't try the honing wheel.  Sorry.  If I get a chance in the next couple days, I'll check it out.

[mysharpener]

Jeff, I looked at the ceramic knives you purchased to try out...I noticed that they come in black, as well.  If you sharpen a black knife, is it black throughout, or will it leave a silver edge on it? 

[Jeff Farris]

Mine was black throughout.

[thesharpeningguy]

I work part time at Woodcraft, and we sell ceramic knife kits.  One kit has a black blade and one has a white blade.  The black blades are more expensive.  When we called to ascertain the difference, they said the black blades were more wear resistant than the white blades due to the addition of carbon.  I just know both are razor sharp out of the package.
My $0.02

[aunsell]

  :-[Ahhhhhhhh PEOPLE, Ok here is a little education about Ceramic.

A ceramic is an inorganic, non-metallic solid prepared by the action of heat and subsequent cooling.[1] Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous (e.g., a glass). Because most common ceramics are crystalline, the definition of ceramic is often restricted to inorganic crystalline materials, as opposed to the non-crystalline glasses.

So in other words ceramic is basically Glass, or a form of it, so NO! it won't have a burr when sharpened, it won't bend, and yes it will brake if dropped!

Ok imagine this, taking a hammer to the top of your toilet, no it's not gonna dent it will shadder and you're gonna have a mess.

For those good ol boys out there that remember and use Crock Sticks, they are ceramic rods that are amazing for setting that final edge on a properly tuned Knife.

OK, as for sharpening a ceramic knife I would personally use the new black stone because I feel that the consistency of the abrasive is more even. I would have the stone turning away from the knife edge because you don't want any areas and flaws in the stone surfice to be jamming into an esentially glass edge. I bet that If you were to compare both methods under a micriscope you would see very small chips in the edge that has been sharpened toward the blade v.s away because of flaws in the stone.

Also a side note the cheaper the ceramic the more brittle it is,  The stuff at Woodcraft is really! Brittle, I work there to 

Hopefully I have enlightened a few 
Have fun sharpening, I do