Over the years I have had many opportunities to take part in several different venues of Knife combat training. Throughout my several experiences I have taken the training in a buffet style mentality. I take what applies to me and my own personal style and use it. What does not apply to me I throw away. The sad fact is that there is never a 100 percent solution. There are always so many variables. There are many excellent clinics, seminars and schools out there. Unfortunately the ones that I have attended always neglect the very most important aspects of Mortal Combat when dealing with edged weapons. They always touch on it yet never expound. What I am talking about is the Imperatives.

A brief evaluation of one of the newest blade steels that is starting to be used by custom makers.

In this short piece I would like to give a broad picture of what steel is composed of, and how it's made. Then in future discussions, I intend to get specific and look at various types, their composition, how they are hardened and produced, and several other items of interest.

Stainless steels, in one form or another, are almost as common as normal carbon steels that I have previously discussed, but again, few(many knife makers and enthusiasts excluded) know what makes a steel "stainless".

Actually the word stainless must have been a marketing tool originally used to sell the first tools and knives made from them ( other than industrial applications) because many steels which are  technically stainless will still rust in salt water. However, most stainless steels do a good job in water other than salt water.
So, what makes a regular carbon steel which is 98+% Iron(Fe) and highly prone to rust, stainless.

In a few words it is the addition of an element called Chromium(Cr). I have never seen pure chromium, but I was once told by an electroplater that the chrome plating we all have on our vehicles is actually an electroplate coating of copper(Cu), followed by a shiny silvery metal called
nickel (Ni), covered by another electroplate coating of chrome. According to him, chrome is a clear coat, put on as a top coating because of its tremendous hardness and see thru colorless aspect. It's like a clearcoat paint coating on many automobiles.
You might ask how much chrome do we have to put in the mix to get a stainless steel. The accepted percentage is 13%, minimum. This amount was no doubt arrived at by much experimentation and testing, and we will learn that all the other elements that go into steel today to make all the various specialty steels were also arrived at by just plain hard work on the part of metallurgists.
It is also important to note that the Chromium doesn't just make the steel rust resistant, it also acts as a hardening agent by forming carbides with some of the carbon present in the steel matrix. These hardening agents are what give blade steels their edge holding ability..Other elements also form these carbides, and they all help to make the steel superior in edge holding and other aspects.

Some tool steels, like D2, come close to being stainless. In D2's case, it has about 12% Cr, and that 1% difference between 12 and 13% sure makes a difference. D2 will rust! You might well say, "why not just add some more Chromium and cover your bases". The answer to that question is probably best answered by a metallurgist, but I can take a stab at it and say that a small change in % of any of the alloying elements can make a big difference in properties and performance, and adding more in this case may degrade the purpose of the steel.

Someday I will try to publish a composite table of all the steels I can find along with all the alloying elements present, and their percentages. These tables are available now from several sources, and my job would be to combine them into one complete table. I bring this up because, when you see this table, you will marvel at the strange percentages (some well less than 1%) of some of the alloying elements, and the sheer number of them that are in some steels. It's actually more complicated than that, because some alloying elements actually enhance others that are already present!
We have come a long way from the first stainless steels which were noted for their "mushiness, poor workability, and poor edge holding ability. There are many stainless steels now with series names like 300 or 400 and others, all with specific formulations to perform well at specific tasks..

One of the most popular stainless steels for knife building in the past, and still used, is 440C. It has an astounding 18% chromium along with a few other alloy elements. It is a "high" carbon steel in its own right, and has more than enough chrome to make the stainless classification. It holds an edge well and can be used in salt water if rinsed off at the end of the day. I notice that some manufacturers still make these knives for us as boat or dive knives.

I will close by saying that the quest for the perfect knife steel is still going on, but has come much closer to reality these past few years, and that will be the topic for another discussion.

Dr. K.

There are many articles, techniques and tools out there which purport to be "the" way to get the best edge on your knife. I should know because I have all kinds of real Arkansas stones, synthetic stones, diamond slabs, and ceramic rods, not to mention several sharpening system kits and copies of sharpening directions. In other words,  I have tried just about everything out there.

For many years I believed that you started with a coarse or medium sharpening stone and then proceeded towards the finer stones until you had a razor edge. I faithfully used 4 different stones in many cases, culminating with an utra fine diamond pad or black hard arkansas stone.

However, I noticed I had a problem. The blade edge would be razor sharp, would cut paper like a straight razor, but it wouldn't really cut anything substantial like it did when it came from the factory. I sat down one day and pondered the problem and came to a strange conclusion. namely that I might actually be sharpening the edge too sharp and smooth.

Time passed, with me still wondering what to do about my apparent lack of sharpening prowess, until something happened that made the solution to my sharpening problem jump out at me.  I bought a knife. Not just any knife, but a David Boye dendritic cobalt boat knife. This knife is special in its own right, but what was really special to me were the sharpening instructions and explanation that came with the knife.

In his simple intructions he mentioned just using a medium stone to sharpen the knife, but his explanation of why to use only a medium stone was what turned on the lights. You have to understand that David Boye is concerned with crystal structure and alignment of cutting carbides. That is why he uses special alloys and casts all his blades (as far as I know). He is looking for a lot of sharp "micro teeth" that will all line up at the edge and do the cutting/ripping at a microscopic level.

He came to the same conclusion I had-that you could oversharpen a knife edge to the point that the carbides couldn't do their job because( in my words) the teeth were all smeared too close together from oversharpening. This was a breaktrough for me. It all made sense then, especially if you hold a brand new and sharp factory knife to the light and rotate it to see the fine grind and sharpening lines of a really well done edge that you know works. You will see all the ridges go right to the edge to form mini teeth.That also explains why I have felt the edge of a some new knives and didn't think they were too sharp, but they still cut extremely well.

What does this all mean? Well, I would recommend that you try using just a medium stone as your final stone on your next sharpening effort. And, don't drag the blade laterally across the stone. Keep the portion of the edge being sharpened perpendicular to the direction of travel down the stone. I guess this would tend to negate the use of ceramic rods for heavier cutting applications, and I'm sure I'll hear about this, but this is effectively what the factories do when they sharpen a new knife in my opinion.

Dr. K.