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Kyocera OK-45 4.5in Utility
Kitchen Knife Review

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Kyocera OK-45 4.5" Utility Knife

The only reason I've picked up this knife was my curiosity or interest in ceramic blades back in 2000. Before that I already had rather disappointing experience with Boker Titanium Delta, which also sports a ceramic blade. I already knew that ceramic composition differs from maker to maker and a simpler hint, Boker blade was black, Kyocera's blade was white ;) Anyway, I picked it up for 50$ which wasn't that bad for an experimental knife, considering that the price range of my current(2008) experimental kitchen cutlery varies between 200$-500$, that Kyocera Ok-45 was dirt cheap. On the other hand, 50$ isn't really cheap kitchen knife, for majority of people anyway, regardless of the income. Folks just don't spend that much on a kitchen knife.

General

 - Fit and finish were good. No visible defects or imperfections. Edge was evenly ground and pretty sharp out of the box. Although the knife did leave an impression of being very flimsy and I was rather cautious not to break it. Actually that isn't overrated because it is real easy to break your precious piece of ceramic cutlery by simply dropping it on any hard surface, be it a kitchen sink, marble countertop or simply a floor. In short, the knife didn't look very fancy or solid. Packaging was ok too.

Sharpening

 - Contrary to the popular belief and what ceramic knife manufacturers tell you it is absolutely possible to sharpen your ceramic knife at home, by yourself. However, it's not for the faint of heart. I've attempted sharpening this OK-45 blade couple years later. Like I said I didn't use it a lot myself, but it went as a present to my family, where it saw minor use mainly for veggies. Periodically I was inspecting it and in 3 months it was dull completely. After some email exchange between me and Cliff, he reassured me that it was possible to sharpen ceramics using mousepad technique. So, I've purchased load of micro-abrasive film starting from 15mic, then 5mic and finally 0.3mic plus some CrO (Chromium Oxide) powder which is 0.5mic and so the ceramic sharpening saga begun.
    Actually, in the beginning it was more like a torture. I'm not sure who got more tortured me or OK-45. By that time I was pretty good sharpening freehand and I was sharpening 100% of my knives freehand except when I needed very significant stock removal when I'd resort to trusty edge-pro. Even so, it was still a major problem to sharpen ceramic blade properly. it took me few days(!) to get the technique right and keep my hand steady enough to get the consistent angle. However, in the end I was glad I did it. Besides achieving an impossible feat for many, that is to sharpen ceramic blade it was a very good learning experience in terms of free hand sharpening, on mousepad and benchstone, yes DMT diamond benchstones work for ceramics too. Technique is pretty simple and no different from sharpening a steel knife. hold your hand steady and keep consistent angle, move from lower grit to higher and that's it. Few differences though. One is that the process is very slow. Second, you're never gonna raise a burr which you see on steel blades, so check the edge frequently. Three, because the process is so slow if you are not holding consistent angle it will show quite late and you might have to start the whole thing again. Thus, it is a very good idea to use magic marker to paint the edge to see where and how you are sharpening and repeat that during sharpening process as a control measure. One more caveat is that the aggressive abrasives with low grits won't work. The best you will get is bunch of chips. You can't use high pressure either, the same chipping will be a problem. Overall it's quite a hassle as you can see and benefits clearly don't outweigh obstacles. It's much easier to sharpen a steel knife which will get much sharper and hold that edge for shorter time on soft stuff. On harder mediums ceramics is hopeless. At least for now.
    There's a new hope in regards of sharpening ceramics - the Edge-pro Apex sharpening system. Now it has diamond sharpening stones. There's two types, fine and extra fine. Both are designed for ceramic blades. I've sharpened completely dulled OK-45 using Edge Pro apex in under 45 minutes. I can't say it was too easy, but overall, it is a lot better compared to hours on microabrasive films :)

Usage

 - The only place I have ever used that knife was my kitchen, and that wasn't for too long either. It did ok with vegetables, but for chopping veggies due to short blade it was no match for neither Global G-48 Santoku(review), nor for even bigger Global Forged GF-33 Chef's knife(review). Because it's ceramics the knife is very light and feels kind of awkward in hand. Takes some time to get used to it. Tried to use it as a paring knife, but again, too wide for that. All that isn't ceramics fault obviously, it's the blade geometry and length that makes this knife not so useful in the kitchen. Attempted bread cutting experiment failed miserably. I ended up with a 1mm long chip on the edge, besides it was really uncomfortable to cut bread with it. Again, blade too short. Basically, it just confirmed my opinion of utility knives being rather limited in the kitchen use.

Edge Holding

 - Per se it is very good on soft materials, before you encounter any dirt, and come incontact with the board. On harder mediums ceramic looses sharpness quickly due to micro and macro chipping. Sorry, no other way around, very hard blade, pretty much no toughness. Anther problem was that the edge wasn't as sharp as steel can get. It's not really possible to sharpen ceramic blades to the levels where a good still can be taken. On the other hand Cliff Stamp did get better results compared to stock edge, so did I after sharpening it myself.

Conclusions

 - In the end, microchipping is the plague of the ceramic knives. Not so sure if 1mm chip can be still classified as a microchip either. More like a macro chip. During later years of cutting with this knife, and thanks to the fact that I got a microscope to examine the edges more thoroughly, I was able to see the edge degradation after use on various cutting materials much better. Even though I use high quality, end grain cutting board all the time for vegetables, and that's the only stuff I cut with Kyocera ceramic OK-45 knife, still I did get microchipping and consequently dulled edge. Embedded dirt particles are main enemy of the edge. Leeks, potatoes, few other vegetables tend to have sand and dirt particles either in the skin, or between the layers of the leaves. Apparently the knife being in contact with the board also leads to chipping over the time. And bear in mind, endgrain boards cost quite a bit and they're not the most popular cutting boards out there, due to their price. Plastic, glass, marble etc, are obviously very damaging to any edge and ceramic knives will get their edges killed on those very quickly, but edge grain boards, hard rubber and other types are still less edge friendly compared to the end grain. In other words, chances of chipping ceramic knife on those is considerably higher than in my testing. Keep that part in mind when considering your ceramic knife. Simply put, even for me, always extra careful with delicate knives, with quality equipment and rather limited use of ceramic knives, it is very hard to prevent chipping and dulling and sharpening efforts are neither satisfying, in terms of final sharpness, nor justifying in terms of the time and energy spent on it.

As much as I like exotic steels and blade materials I can't really recommend a ceramic knife for a kitchen use. The only benefit being high levels of edge holding on extra clean soft materials in the air, is clearly overshadowed by sharpening difficulties, edge and knife fragility, inability to get extremely sharp edge and such. Besides, due to material tensile strength limitations, it's not too often that you see large ceramic knives and if you do they're that much more at the risk of breaking by accident of course. Edge chipping is different problem. For some strange reason bunch of ceramic knives simply suck for such everyday kitchen tasks as vegetable chopping and paring. Either blades are too short or too wide. No idea why that is. Small paring knife would be nice for fruits probably. Anyway, if you want to, feel free to try. Just remember, it will get dull with the use and then you're back to sharpening or knife replacement.

Specifications:

  • Blade - 114.30mm(4.5")
  • Thickness - 1.90mm
  • Width - 29.00mm
  • OAL - 228.60mm(9")
  • Steel - Ceramic 90HRC
  • Handle - Molded
  • Weight - 54.00g(1.83oz)
  • Acquired - 05/2000 Price - 50.00$

Last updated - 09/01/11