Usefulness of ceramic bladed folder

C

ceramicknife

Joined
Sep 28, 2006
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I would be very interested in comments or observations about the usefulness of ceramic blades in folding knife designs. Boker are the only ones, to my knowledge, currently selling ceramic pocket knives albeit at relatively high prices. My goal is to design & have manufactured a small 2" or smaller blade and a medium sized 3" or slightly smaller blade that would be suitable for pocket carry. I have launched a website showing these designs although I have yet to receive actual ceramic blade prototypes for trial purposes. Now is the time to get feedback in order to make sure I am on the correct path.

Phil
www.ceramicknife.org
 
I have a Ceramic Boker Delta. I has dulled over the years, and has a few tiny chips in the blade. Now i can't sharpen it myself. I can't find anyone local to sharpen it. And I don't really feel like spending the money to have it shipped back to the factory or to one of there sharpeners. So its now a very nice looking $200+ paper weight.
 
ceramicknife said:
I would be very interested in comments or observations about the usefulness of ceramic blades in folding knife designs.
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The main problems tend to be regarding durability, the very low grindability, and obtainable sharpness. You note on the website :

"Grain size <0.5um"

Is that a micron measurement? Do you have a reference, there is a shot of a ceramic blade in Landes book which he refers to as ZrO/AlO and the grain size is much larger, a lot are 50 microns.

Colog said:
Now i can't sharpen it myself.
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I reground a bunch of chips and a broken tip on several ceramic pocket knives on normal aluminum oxide belts for a 1" belt sander. You can sharpen them readily on most hones though it tends to be most effective on diamond abrasives. I never had much luck trying to get a coarse finish to be sharp, but it wasn't difficult to get it to shave at a high polish.

-Cliff
 
In my opinion they are only good for guys that do a lot of food prep with their folder. Otherwise I'd sooner carry an all titanium knife than one of those ceramic ones. I had a Boker Ceramic for years, but never really carried it. It never was that impressive of an edge from my observation but it basically stayed the same. The real draw back to ceramic is how brittle it is. You bang that blade, drop it, or put too much lateral stress while using it its history. Contrary to popular believe they can be sharpened but its a royal pain and they do chip if the abrasive you use is too gritty so use something finer.

STR
 
I don't want one , give me steel every time . EDC's get beat on , sometimes quite hard - not ceramic territory !

Chris
 
I have owned three different ceramic knives. As I owned and used them ten or so years ago there may have been improvements since then. Two were Boker folders; one was a white bladed Kyocera kitchen knife. It may be a matter of talent and technique, or just plain dumb luck, but I found them to be a nightmare to sharpen on my diamond stones, with a lot of edge chipping.

The Kyocera was very sharp and stayed that way for a long time. About 1" of the tip broke off due to a minor impact. Ever the glutton for punishment, I sometimes consider getting another, but the ceramic really did not have the toughness and flexibility needed to be a good cooks knife, at least for the way I use them.

The Boker knives (2" and 3"+) were not sharp out of the box; IMO dull and brittle describes them. Dull and brittle = useless. Sorry to sound so negative, but these two were a very disappointing experience.
 
Colog said:
I have a Ceramic Boker Delta. I has dulled over the years, and has a few tiny chips in the blade. Now i can't sharpen it myself. I can't find anyone local to sharpen it. And I don't really feel like spending the money to have it shipped back to the factory or to one of there sharpeners. So its now a very nice looking $200+ paper weight.
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The one and only reason why I don't own a ceramic blade. A Rockwell hardness of 62 is difficult for some folks to sharpen..... Ceramics typically have a rating of 90. :eek:

Laser sharpening, anyone?
 
I have had 2 boker ceramics, I still theoretically own one of them, but I sent it to a guy near me who claimed to be able to sharpen it, and he shortly thereafter closed up shop, and now I'm still trying to get him to return it... Anyway, I liked certain aspects about the Ceramic blade... but I think it has two weaknesses... Firstly, I don't know that they can get as sharp as a good steel, and second they aren't very durable at all... unfortunately. I'd be very curious what one could do with a blade made from 3/16s of an inch or thicker stock, and a fairly hefty grind, something on the order of the buck-strider 881. I'd like to see what one could do with such a setup. Also, perhaps the ceramic materials available today are tougher than their counterparts of a decade ago...
 
ohmyheckinslc said:
I'd be very curious what one could do with a blade made from 3/16s of an inch or thicker stock, and a fairly hefty grind ...
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Kevin McClung has such blades, he also uses a ceramic composite which are far tougher. They basically have small elemental additions which will act to prevent or reduce crack propogation. They are however still fairly brittle compared to steel.

-Cliff
 
I think the blade grind and profile need to be rethought for ceramic blades. Most I have seen are a typical drop point, and it seems like they have a problem with the tip breaking off. Perhaps a tanto shape or even a blunt sheepsfoot like the Spyderco Rescue would be better.

In my thinking, ceramic blades would be good for cutting tough fibrous stuff that would dull softer knives quickly, like bamboo or corrugated cardboard. Certain plants have silica particles in their cells that dull steel very quickly.

Ceramic might be good in very corrosive or wet environments, or where a non-magnetic and nonconductive blade is necessary. Underwater demolitions? Near CAT scanners or cyclotrons?

I know some surgeons keep a razor-sharp knife handy in case they have to perform an emergency surgery, like a tracheotomy, or so I have heard. They might like a razor-sharp, fragile, lightweight knife.

Karl
 
A scalpel is a knife handle, and an exchangeable bale. Plain and simple. It is NOT something fancy. The baldes dull very quickly, and are changed frequently.And the baldes are thrown out at the end of the surgical case. And disposable scalpels are also made, and you throw the whole thing out, knife handle and all..
 
Cliff Stamp said:
Kevin McClung has such blades, he also uses a ceramic composite which are far tougher.
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I did some googling, and didn't find much, either under his name, or the Mad Dog brand. Most of what appears to be available right now under that label are fixed blades made of high carbon, tool steel.
 
Colog said:
I have a Ceramic Boker Delta. I has dulled over the years, and has a few tiny chips in the blade. Now i can't sharpen it myself. I can't find anyone local to sharpen it. And I don't really feel like spending the money to have it shipped back to the factory or to one of there sharpeners. So its now a very nice looking $200+ paper weight.
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I believe the micron size of ceramic have become smaller than in the past AND the extra sintering under pressure to turn the blade black also results in a more even distribution.

The few technical reports I could find on sharpening indicate that unless you use above 1200 grit & preferably 1500 & up the edge will chip and you can not get a truly sharp edge. One neat way to touch up an edge was reported to be using a 3M diamond disc (flexible plastic) on top of cardboard or a mouse pad. http://www.physics.mun.ca/~sstamp/knives/ok_45.html scroll to the bottom of this article!
 
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