Jiri,



I never said that 420 HC was great, I do not understand your commments to me on that one. Really, your "attack" (if that is what is was) seemed unwarranted to me. I posted two links, in one they compare 420HC to 440. In the other they compare some far better steels (440 being on the low side of performance) where 420HC doesn't even begin to make the cut (no pun intended).



I also did not mean to infer that you were stupid, I sincerely was wondering if you misunderstood the Timken data.



440A stainless still is higher in both carbon and chromium than 420 HC. I think you know the rest of this but just for clarification. What this means is that 440A will hold a better edge, even if slightly lower in actual hardness, as it isn't the iron carbide, but the chromium carbide that is INCREASING THE WEAR RESISTANCE. At the same time it is less tough, ie more brittle. 440C even more wear resistant than 440A (more carbon so more carbides are formed) it is also, for the same reason that is it more wear resistant, more brittle.



I can tell you from first hand experience that 420 HC is tougher than, 440A or C, 1095, D2, or A2. It also holds an edge worse than any of them. I own several 420 HC knives and they are fine for what I use them for, general utility. I know how to sharpen a knife so the fact that they dull relatively quickly seldom bothers me, and 420 HC sharpens up quick almost quicker than it gets dull . I hunt with either 440C or AUS8 knives though cause like PaulH I hate to sharpen knives in the field, I don't use a D2 knife though as I have found them too prone to breakage (and I am too cheap to pay that much for a knife and then break it because I pried a bit with it, or got it caught in a bone and twisted the edge too much).



I generally agree with you that 420 HC is a so-so steel for knives, BUT it is FAR better than 420 was (and there are a lot of older stainless knives floating around made out of 420).



For the record I personally am a big fan of 440C with a cyrgenic treatment (even though I am not sure how beneficial it is) with a final hardness around 57-58 Rc.



The largest cost of any knife is materials (that would be blade blank and handle stock). Now how that relates to what you and I pay is a completely other matter!



The Vickers tester is FAR better than Rockwell, and I think you know that!



Again this post is meant primarily for clarification (to make sure we are both understanding one another) and not to suggest that anyone is an idiot.



I hope this clears things up.



ASS_CLOWN

Wayne Goddard has some good information about knife alloys, cutting ability and edge retention in his books. Even if you don't plan to make your own knives, you'll be a much better informed consumer if you pick one up and leaf through it.

To an extent, the alloy is less important than the edge geometry and the hardening of the blade. The "best" knife alloy hardened to RC 53 will hold an inferior edge to an "average" alloy hardened to RC 58. If the geometry of the blade is off it won't cut worth a hoot either.

My idea of a good hunting knife is one made from a steel that will hold it's edge, and has the proper geometry and cut. I've never been able to do a good job sharpening a knife in the field when I'm tired and covered with goo. Why bring a blade to the field that will have to be dressed up when you can get one that'll stay sharp enough to fully dress an an animal or two?

All very interesting reading, and some excellent points. Keep 'em coming, I want to know as much as I can find out about all the various steels, their properties, and any advantages and disadvantages. It would be good to hear some commentary on knife designs also. Shapes, grinds, edge angles, blade lengths for differing jobs, etc.

Here's the article on the 3 properties of steel:

http://www.hocktools.com/steelrap.htm

It's geared towards woodworking tools but the properties still apply......DJ

ASS_CLOWN: Yes, I didn't understand. I don't know nothing about metalurgy. Nothing about steels, what you wrote me I know from my 15 . . . Yes man, little secret that harder mean brittle . . . you must really think I am stupid. That comparasion is not sipmly correct . . .

BTW I am studing at university, for now, I am Bachelor, my father have a little company, where we are lathe turning, milling etc., so please, don't make stupid guy from me . . .
and of course, my technical english is pretty good, much better than common english (level 6 at university)

Sorry if it sounds much ironic . . .
Jiri

BTW : Here, we use much more Vicker's test of hardness, than it is recalculated to Rockwell

But the point I had in my mind is: There are steel with the same or higher toughness, that are also a far better edge keepers. 420HC is not good in any way except price.

Few thoughts :

When you cut with knife, you need higher compresive strength with good wear resistance or toughness. I mean in non shock situations you would preffer the first one.

In semishock situations, like wood chopping or prising, you will prefer higher toughness or higher ultimate bendind strength ?

When you are chopping hard materials, like stone or metals, or you are trying to break the blade with hammer, then you need toughness.

Good steel MUST have good all of properties including hardness, which corespond to compression strength, toughness, wear resistance, bending strength and corrosion resistance, if it is important to you.


for example 440A is average or not bad in all of that properties, so it will make average knife, which will not be really bad in any property.

420HC is only (and it is not 100%) tougher than other low grade steels, and corrosion resistance is good, but other properties are bad, so it will never be a good knife steel, I mean if you would like to have at least average knife . . .


And about price, what part of price of knife is blade material and heat treatment. It is not much, of course better steels are harder to work with and need more expensive heat treatment, but . . .

I belive you understand my idea . . .

Jiri