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After a nice long vacation & a subsequent nasty flu it was time to go back to work, so i just finished refining the edge of this ceramic knife a bit further with 3 micron diamond compound on a Paper Wheel.

With my Victorinox loupe & strong floodlight the scratch pattern in the bevels is now very difficult to see, and the keenness of the edge has progressed just a little bit more.
For testing i sacrificed a few more chest hairs, and the edge is now able to whittle some of them in the direction of the hairpoint, while others are just cut completely through while the cut end jumps away.

One of the coming days i'm going to find out if a Paper Wheel with 1 micron diamond compound can improve the edge further.

The edge has now been refined with 6 micron diamond compound on a Paper Wheel and is starting to resemble milk glass.
Although the scratch pattern can still be seen with my Victorinox loupe, it's getting difficult for my cheap camera to do the same.
Pictures were taken on the exact same spot with the same floodlight, and you can click them 2 x.





The edge can now slice single layer toilet paper cleanly, treetop the hair on the back of my hand, and whittle a chest hair towards the root.

Reprofiling the edge on the Tormek silicon carbide stone turned out to be rather easy, as the ceramic material in this knife has good grindability.
I thinned the edge just a hair to an almost exact 25 degrees inclusive, en the time needed to remove the miniscule chips was about 10-15 minutes.
Afterwards i did a first refining step with 15 micron diamond compound on a Paper Wheel, and now the edge looks like this.
I took the pic using a bit of floodlight to showcase the scratch pattern a little better (if you click 2 x):



The now ever so slight convex edge can currently shave armhair in 2 directions.
Next step will be refining it further with another Paper Wheel with 6 micron diamond compound.

The knife has been used the last couple of weeks for cutting all kinds of food, and was checked each time afterwards for edge damage as well as the ability to shave some hair from my leg.
Last night with my Victorinox magnifying glass i saw for the first time multiple microchips in the edge, and it's hairshaving ability had also noticeably decreased.
These microchips aren't visible with the naked eye, and the knife still cuts vegetables, fruit, and various meats just fine.



However, since i don't like to continue working with a ceramic knife with a microchipped edge i will give it a new & somewhat finer polished edge in the coming week to see how that will hold up.
While microchips also act a bit like microserrations improving slicing ability, they are also stressrisers in a material that can't handle that aspect too well.

The last few days i used the ceramic knife in our kitchen for cutting various types of food: a lot of onions, tomatoes, smoked ham, Dutch cheese, mozarella cheese, mushrooms, paprika's, all for use in pasta salads which we eat a lot during summer.

I noticed a few things:

- Cutting up 5 to 6 large onions with the ceramic knife didn't induce teary eyes like it would have done had i used a steel knife.
Instead i could only feel a very slight stinginess.
- Slices of mozarella cheese stick noticeably less to the ceramic knife than they do to a steel knife, and also leave much less cheese residue there.

Both with the naked eye and using my Victorinox magnifying glass i could not see any change to the factory edge afterwards, and the knife can still shave the hair from my calf.

For people who like to read more about ceramic knives: http://www.myceramicknives.com/
(imo there are bits & pieces of info not entirely correct, but overall the site makes nice reading material about the subject)

On that same site there are also tests on cutting various foods and how it affects them: http://www.myceramicknives.com/my-30-day-test

On another forum i got this question:

"Looks like a nice knife. But would you expect the knife to become dull after cutting up a ciabatta and a box of cherry tomatoes ?
I have no experience with ceramic knives, so I am sorry if this sounds ignorant, but it would seem most or all kitchen knives with a decent edge would survive the ordeal ?"

This was my answer:

"Crusted bread is known to be able to chip hard & thin knife edges made from quality knife steels quite easily, and for much harder but toughness lacking thin ceramic knife edges it is even more difficult.
The fact that this Forever ceramic knife suffered just one extremely minor chip and was able to slice those cherry tomatoes the way it did tells me quite a lot already."

Cutting a large Ciabatta bread with a semi-hard crust into 4 sections on a good wooden cutting board provided the edge with 1 tiny microchip just in front of the heel.
That chip is only visible through my Victorinox magnifying glass (not with my naked eye), and the rest of the edge still looks and feels unharmed in any way.
I've already made a few cheap ceramic knives lose their entire sharp edge by doing this test, and i wanted to see how this rather coarse edge would do right from the start.



After this i proceeded with cutting a whole box of cherry tomatoes.
Even with it's light weight of only 83 grams i could pinch the end of the handle between thumb and forefinger, put the tip of the knife on the cherry tomato, and slice it completely through on the wooden cutting board just before i ran out of edge length.
The last tomato was cut as easily as the first.

This thread was already posted on several knife forums about 10 years ago, and recently i got a message from a forum member from one of these forums that all pictures had become invisible, so i re-uploaded all of them, and this time also to a larger size.
Apparently people are still interested in older threads like this one, so i'm now posting the thread on this forum as well.

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Some time ago while surfing the net i found a website with Catra test results for 3 different ceramic knives: two by the well known Japanese Kyocera brand, and one from another (and unfamiliar to me) Japanese brand with the name Forever Company.
Next to various types of ceramic knives the company also seems to make a host of other specialty kitchen knives from various space-age materials: http://forever-k.com/en/ceramic/
Anyway, the 3 ceramic knives were tested on wear resistance, and the (much) cheaper Forever knife seemingly won by quite a margin regarding that aspect:

http://socialcompare.com/en/comparison/couteaux-en-ceramique-mpo3v9w

Now i know that wear resistance does not equal edge holding (especially with ceramic knives), but who knows ?
Maybe they're on to something.
Since i sharpen ceramic knives for others from time to time (and the two tested Kyocera models have always ranked the highest for me in the edge holding department so far), i became a bit curious about the Forever knife.
So i ordered the exact SC-16WB model that was tested from a Japan based E-Bay dealer for 45 US dollars including shipping to the Netherlands, and yesterday it arrived:











Specs:

Ceramic knife for right handed use (non-logo side is flat, while the logo side has a wide saber grind and a 70/30 edge
Overall length: 10.9 inch (27,6 cm)
Blade length: 6.3 inch (16,0 cm)
Blade material: High Density Zirconia
Blade thickness: 1,43 mm
Thickness behind the edge: 0,61 mm
Factory edge angle: 26/27 degrees inclusive
Edge finish: rather coarse with lots of bite (my estimate: somewhere around a 1000 grit)
Sharpness: Can shave my arm- and leg hair with the growth, not against it.
Not a single microchip can be felt using my nail, or seen through my Victorinox magnifying glass
Handle material: black plastic
Weight: 83 grams

I'm going to use the knife the coming months for standard kitchen duty, mostly to see how that rather coarse factory edge will hold up.
When the time comes i will experiment a bit with resharpening and write about my findings in this thread.

This is the version of Blue Wonder i'm using for some time now:



I've tried several other products (among which a few other Blue Wonder products), and so far this seems to work best.

Blue Wonder also makes a degreaser which i haven't tried yet but plan to.

Generally, about one spray dose (~ 1 pull of the trigger) into the full water trough is sufficient.
Less water in the trough also means less Blue Wonder.

The trick is to use just enough so that it doesn't start to foam, which otherwise will obscure your view onto the newly forming edge & burr formation.
The water has to remain as clear as possible during sharpening, which also means thoroughly cleaning the water trough from time to time.

In contrast to aluminium oxide, SiC carbide grit is harder but also friable: in use the particles break down into smaller ones that will continue to cut & remove steel at a finer and finer level, until they break free from the stone surface which then reveals newer and larger SiC carbides.

For hand sharpening on wet & dry SiC paper (which has only one layer of SiC grit) this effect can be exploited by doing the bulk of the steel removal when the wet & dry paper is still fresh, and then continue using that same paper for finishing the newly established edge, as the grit continuously gets finer and finer.
This way i often do a completely new edge from start to finish using only (a section of) one sheet of 400 grit wet & dry SiC paper.
I also found that i could prolong it's useful life even longer when using a product like WD40, as this helps to protect the SiC grits from premature wear and clogging.

With the SB-250 stone i also use a detergent in the water, named Blue Wonder.
This product is thin like water, has a strong degreasing effect, it keeps the swarf in suspension for longer, and it acts somewhat like a lubricant.
In the US a good alternative might be Windex.

The right detergent does several positive things when used with an SB-250 stone:

- It helps to protects the SiC grit from premature wear.
- It diminishes the grabbing efffect of the stone (which is especially useful when freehanding)
- I helps to avoid glazing by keeping the stone surface clean & free from the build-up of swarf and/or a thin greasy film (which can inhibit the SiC grit from cutting effectively, especially when the grit gets finer)

I found that all of this together helps to keep the stone surface true for longer periods.

The brothers J&R Dodge owned two stores in the Netherlands in Amsterdam from 1820 up to 1884, where they sold high quality made in Sheffield knives as well as chisels and other cutting tools.
One store was situated in the Kalverstraat while the other used to be in the Leidschestraat, and both streets are filled with various shops to this very day.

The knife really is a delight to work with and it gets used at least several times a week for cutting various types of meat, as well as softer breads and large apple pies.
It's kept sticky sharp freehand on a DMT red.

Part of the ingredients for an old school beef stew:





Probably the best apple crumble pie we ever had.
(made by a Chef in return for sharpening two knives for him)

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I've already sharpened the knife on the Tormek SB-250 Blackstone and deburred it on the leather wheel, and from that experience i can say that the steel is quite hard (guesstimate in the 63-64 HRC range), the burr comes off in tiny bits instead of a long wire, and the resulting edge is armhair shaving sharp with an incredible amount of bite (even though the grooves from the (SiC) stone were polished away slowly by the 1.0 micron diamond compound on the leather wheel, as can be seen through my Victorinox loupe.
So far i've only used it to cut up 6 large tomatos on my Zanussi HDPE cutting board, but it is definitely going to see more kitchen use in the future.
After all: what better way to honor the Sheffield makers than by using the knife ?

Did you notice in the last picture the weld area that joins the double shear blade with what is likely a softer steel tang ?
I've read that is how many old Sheffield knives were made, and it is known as "the cutler's thumbprint".

These 2 pictures taken in 1869 show the J&R Dodge display, which was made especially for an international exhibition in the Dutch Paleis voor Volksvlijt exhibition hall in Amsterdam in the Netherlands.




Background on the building: https://en.wikipedia.org/wiki/Paleis_voor_Volksvlijt