Janet Bostwick wrote:
> What's the deal with ceramic knives? I know nothing about them. They're
> touted as never needing sharpening and unbreakable. I'm not interested in
> buying any more knives, but I just want to know something more about them.

Ceramic *insert* cutters have been used extensively in the metal
working industry for some 25 years now, was only a matter of time
before ceramic kitchen knives would appear, but in fact it's only a
marketing gimmick... not only do kitchenware suppliers always looking
to turn a quick buck but the ceramis industrt as a whole is struggling.
Ceramic cutters withstand tremendous pressure, heat, and are virtually
abrasion proof, but they are brittle (which is why in industrial
cutting applications they are inserts), the thinner the cross section
the less they will resist chipping/cracking, ceramics are extremely
vulnerable when dressed to a fine edge such as a kitchen knife...
they'll stay at factory sharpness for a long time, just don't tap their
edge against anything harder than a carrot... you definitely do not
want to be carving around a t-bone. Industrial ceramic cutters do not
operate on the sharpness factor, in fact they are manufactured rather
dull edged, usually with a 1/64" radius or greater and no taper
whatsoever, often a negative rake is employed (whereas the two sides
forming the cutting edge meets at an obtuse angle, ie. greater than
90º)... they instead maximize pressure, heat, and abrasion resistance
for severing materials. And yes, ceramic cutlery can definitely be
resharpened, even reshaped (ceramic inserts are re-formed in the shop
all the time, but a diamond impregnated grinding wheel (wet) is
essential... one could probably do light touch ups at home with one of
those fercocktah diamond hones that idiots use to ruin perfectly good
steel cutlery... diamond hones were developed for dressing fully
hardened tool steels and carbides, not the relatively soft steel used
for cutlery, soft steel will load up with diamond particles and then in
use will continue to accellerate dulling itself forever, the loaded
diamond particles can never be removed... such a knife will literally
destroy itself and a knife steel... never switch a diamond honed blade
back to a knife steel. Ceramic cutlery can never be made as sharp as a
good steel kitchen knife, certainly not a carbon steel knife... don't
yoose think were that true the shaving industry would be hyping ceramic
razor blades by now. There really is no practical benefit to ceramic
kitchen knives (okay, the different grades of ceramic come in pretty
colors and are good for tiling your bathroom)... but for those
afflicted with chronic snobitis and with more dollars than brain
cells...

http://www.ceramicindustry.com/CDA/A...10,875,00.html

Sheldon Strop