I know steel is good,  but what kind of metal is "better" than steel?  like titanium or what,  whats the next step up from steel,  is it Damascus steel?

Jabames wrote on Dec 20^th, 2010 at 1:42am:

Steel is the best metal all around. modern damascus steel isn't any better than other carbon steels, and modern stainless steel is almost as hard as carbon steel. Some modern carbon steels are even semi-stainless. If you want a dive knife then plastic, titanium, or "cobalt-blue" alloys are inert and will not rust. All of these are less sharp than steel. Ceramics are sharper than steel, but they chip and break easier than steel too.

The real question is: Do I need something almost as good as steel for some funny reason, or do I have the wrong kind of steel?

Masiakasaurus wrote on Dec 20^th, 2010 at 6:01pm:


By what measure is this comparison between ceramic and steel made?  

I'd have to say the wrong steel is chosen for various reason quite often.  

Well, I am no knife enthusiast (far from it), but if you're talking about knives with blades under 6 inches, it would either be VG-10 or s30V. If it's between 6 and 12 inches, I heard D2 tool steel keeps a good edge. For swords and such, carbon steel (1080- 1050) works fine. The amount of carbon should vary, though. (Keep in mind that I am no knife expert, and I had completely forgotten about the existence of s30v until I started playing with someone's Spyderco Military. God, that thing shaves! I must have cut apart at least 10 issues of TIME before I was stopped.)

me2 wrote on Dec 20^th, 2010 at 9:54pm:

The two main ceramics used for making knives are both zirconia (ZrO₂), and both are rated at 8.5 on the mohs scale. They are composed of two crystal lattices (tetragonal and cubic) with "white" zirconia being more tetragonal and "black" zirconia being more cubic. The only real difference is that black zirconia is harder to make and is "rare." Kyocera sells black ceramic knives for almost twice the price of white ceramic knives, or at least they did when I bought my kitchen knives. Steels are rated between 5 and 6.5 depending on heat treatment, meaning that they are less hard overall. That hardness relates directly to sharpness when cutting harder materials, and the harder blades of ceramic knives hold their edge longer for the same reason. The right kind of pressure, though; will turn me into a liar. Push at 90^o to the edge of a ceramic blade and it will shear off thanks to the crystal lattices and it won't matter how sharp the edge is such it isn't attasched to the spine of the blade anymore. Ceramics chip and break easier than steel because ceramics are crystals (a relatively ridgid structure) while steel is a mixture of iron with trace impurities with make it less malleable and ductile. Even less malleable than iron, steel is still less brittle than a ceramic knife however. Long story short: crystals break and metals bend.
me2 wrote on Dec 20^th, 2010 at 9:54pm:
Agreed.

Wow, this is a very good thread! Very good questions and very good answers!

I think that sharpness is often very subjectively defined. I remember that when I first started learning to sharpen knives, years ago, what I thought was sharp was not even close to what I think is sharp today!

I would ask your question over on the Spyderco forum. Lots of knowledgeable people there -- not least of whom is Sal Glesser, the president of the company! (He posts and interacts frequently! It's like being on a forum with a celebrity!