Forever SC-16WB ceramic knife

[kwakster]

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.

[kwakster]

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.

[kwakster]

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."

[kwakster]

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

[kwakster]

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.

[kwakster]

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.

[kwakster]

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.

[kwakster]

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.

[kwakster]

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.

[kwakster]

Finally found the time to finish the edge with 1 micron diamond compound, and the edge can now whittle chest hairs towards the point along the entire edge and also slice a tomato quite well.

https://www.youtube.com/watch?v=q4YGGHltloU

https://www.youtube.com/watch?v=dP6fNB_obN4

Time to find out if and how this edge will hold up in our kitchen use,

[kwakster]

Since my last post i've been using the knife in our kitchen several times a week, together with with a reground Spyderco pairing knife for detail work.
Mostly cutting up onions, paprika's, mushrooms, various meats & cheeses and an assortment of other vegetables.
All cutting was and is done on an end grain beechwood cutting board that i oiled several times before i started using it a couple of years ago.

The sharpness has degraded from whittling chest hairs towards the point to whittling the same chest hairs towards the root, and through my Victorinox loupe i can see just one extremely tiny microchip (below the letter Y in the word "density" on the blade)
The chip is not visible with my naked eyes, but i can just feel it on my nail.

Will continue to keep using the knife.

[kwakster]

The knife is still being used in our kitchen in exactly the same way as described in my previous post, and the edge is still able to whittle little curls from one of my chest hairs towards the hair root.
(click 2 x for more detail)





Through my Victorinox loupe i can now spot 3 micro-chips, which can be felt on my nail as well.
However these are not visible with my naked eyes.

[kwakster]

Question from a member on another knife forum:

"After all this testing would you say benefits of ceramic outweigh the attention required, compared to steel ?"

My answer:

"At this moment i wouldn't say that, as i think ceramic knives in general haven't developed as far as steel knives yet.
Most of them are still too brittle and cannot be resharpened by the end user as easily as most steel types.

This particular knife however has proven itself to me already as an advancement over many other ceramic knives, as the ceramic material certainly has a much higher grindability (fact) and also seemingly a higher toughness (assumption).
While that toughness still isn't in the realm of most steel types i do notice a difference in use by much less edge chipping overall, and the chips that i see are also noticeably smaller (i need my Victorinox loupe to spot them).

What is however even more important in my view is that the ceramic material in this knife has a grindability that is more or less comparable to S90V steel, something i discovered when resharpening the edge on my Tormek T7, which is fitted with a silicon carbide stone.
In only a few slow passes i had a completely new edge.
(as a comparison: S90V steel sharpens like annealed 420J2 when compared to a Kyocera ceramic knife on the same stone)

Now from experience with other ceramic knives i've learned that the resulting edge needs refinement before being used (toothy edges are a no no on most ceramic knives), so that is what i did with the edge on this knife as well (with various diamond compounds), but in a later stage i plan to experiment with less refined edge types a bit to see how these hold up.

All in all more testing is needed to get a better understanding of how the current generation of ceramics in knives perform to have some benchmarks, as i think we will see much more improved types of ceramic in knives (and other articles) in the near future."

[kwakster]

The knife is still being used in our kitchen in exactly the same way as described earlier, but the edge has now lost it's ability to whittle one of my chest hairs towards the root.
I tried it multiple times on 3 different hairs, but the edge did not catch any of them even once.

The edge can however still shave the hair on both the back of my hand as well as on my leg on skinlevel, but i have to press the edge on my skin a bit or it will slide over the hairs without cutting them.
If i do that it will shave a patch clean.
It will also slice a piece of copy paper to confetti easily, so most non-knife people would still consider the edge to be very sharp.

Through my Victorinox loupe i can now spot 5 micro-chips, which can be felt on my nail as well.
However these are not visible with my naked eyes.

Will continue to use the knife to see how things develop and report back again later.

[kwakster]

The edge can now no longer cleanly cut the skin of most tomatoes, and on some types even downright sawing motions don't work anymore.
On onions i can feel that initial resistance cutting through the top layers, but on most other foods the knife continues to work well.
It also still scrape-shaves armhair and slices copy paper just fine, so most non-knife people would still call it quite sharp.

Although focussing with my new USB-microscope is still quite the challenge i did manage to take some shots of the current edge from tip to heel, to show the edge damage in the form of microchips as well as the sharpening scratches in the bevels.
My Victorinox magnifying glass had already showed me the larger microchips, but the smaller ones and the scratches which can now be seen clearly had always remained invisible to me.
It looks like i have jumped the other diamond wheels a bit to soon before finishing with the 1 micron diamond wheel, so apparently there is some room for improvement.