Well I was somewhat worried at the time about all the stories of CPM 440V suffering massive damage (significant blade chipping) from high impact use and hitting hard objects like staples in boxes. I asked about this and mentioned that I may use a Military to slam into a 2x4 and more gently to cut another in half. I have to say how impressed I was with the performance, especially when you consider the first time round test was with the factory edge... thats 15% per side people
. How many steels will take moderate force blows into 2x4 without showing damage at that angle and STILL have world class wear resistance? Sure, second time round with a 20% per side angle and FULL force blows, the edge did deform somewhat, but on a par with what I expected many steels to do. I used the 10a Native to get a feel for this on one half of the 2x4 that was left to see how it held up. I have to say the difference was noticable, but hardly major on either knife. Very easy to fix and NO CHIPPING. It is my opinion that the reduction of Rc means Spyderco's CPM440V will roll more than chip. This is a good thing as it is a simple matter to re-steel it back, or even use a ceramic plate to strop it back... I have done this before, even the back of a larger fixed blade knife works well.
Now others would argue that a larger blade (fixed) would do all this without a problem or any damage, my M2 steel Nimravious laughed at this test. It did dull slightly, but did not wear down or roll at all. Two passes on a steel brought it to 80% full sharpness, two passes on the fine stone had it poping hair sharp.
I am sure Joe is better to answer the question than me, but from what I understand...
Toughness is the ability of a knife to resist impact and high stress damage without breaking down or failing. This might mean the blade is either unaffected or the material bends (i.e. the edge rolls, rather than breaks) rather than chip out.
Look here:
http://www.crucibleservice.com/cruts.htm
Wear resistance is the ability of a knife to hold a uniform and clean edge, that still cuts material when used a lot. It is often called edge holding, but as that is a combination of a number of complex factors. I will avoid those pit falls for now.
In simple terms, the harder a steel, the more likely it is to remain in 'shape' and not bend or lose its profile, thus edge rolling=blunt edge. However a hard edge will often fail in a big way when pushed hard, thus chipping out without rolling.
The difficult part is finding a steel and heat treat that works well as a tough steel and at the same time holds its shape well. If a steel does not hold its shape well, that careful edge you have made will flop about like a wet noodle or on the other side shatter like a ceramic edge is prone to The two are at oposite ends of the desire scales. Then you factor in the elements like Carbides and other ingredients and it gets super complex.
A number of steels, work better in the right size blade. What works in a small folder, i.e. CPM 440V, would be a poor choice for a very large and heavy hunting knife.
I, myself have ordered a custom blade in CPM 10V, it is a 10" fixed blade. Now the obvious question is why the heck did I do this, when CPM3V is a LOT tougher. The simple answer is CPM10V is tougher than M2 steel and my 4.5" M2 knife has taken a bashing without a problem. Secondly, I have been using a 6.25" 154CM fixed blade at a Rc 62-64 and even with a lot of chopping, have not had any significant edge break down, just the usual wear from use. So if 10V is a LOT tougher than 154CM and I am getting it at around 58-59Rc. I am confident that 10V will give me a reasonably tough blade with truely world class wear resistance! Oh and the angle will be 20deg per side, so not to weak or over sharp
Hope it helps!
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Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
[This message has been edited by The General (edited 05-29-2001).]
