The most basic division I am going to point out is fixed blade vs. folding knives. This one is pretty simple and self explanatory. Fixed blade knives do not fold, and folding knives do.
Fixed blade knives (provided they have a good tang) are much sturdier than folding knives. Even an excellent locking mechanism on a folder is not equal to a solid tang.
Less Basic Basics:
|This picture is to show the tang on my K. Tragbar|
|As you can see, according to this chart my knife has a rat-tail tang|
|The Svord Peasant Knife, an unusual style of folder|
Basic Knife Terms:
|This handy little diagram gives a good overview of basic knife terminology|
|Anatomy of a folder|
Basic Knife Shapes:
There are many many many knife shapes. There are a huge number of different special types of knife shapes, far too many to talk about here, so I will just focus on four of the most common among US knives.
The Clip Point:
|A clip point knife. A chose this image because it clearly shows the swedge on the clipped edge|
I have personally always been rather partial to Bowie style knives. Not for any particular reason, I just like the look of them. When I was a teenager I was all about the biggest meanest bowie I could get my hands on. As I got older I realized that I didn't actually use knives over 6" very much. And after moving to Seattle I found that I pretty much only even used the Tragbar while camping, since people in cities tend to get nervous around 6" fixed blades.
The clip point takes off the top of the blade near the tip which makes it more effective for piercing because there is less mass at the tip. This also makes the tip more fragile than some other styles. The clips can be flat or concave (but if they are convex then they are not clip points by definition). Often clip points will be swedged (or have a swedge) which is the unsharpened bevel on the top (sometimes called a false edge).
|The Fairbairn-Sykes Fighting Knife, aka the British Commando Knife|
I chose to use a picture of the Fairbairn-Sykes knife at the top because it is a 20th Century fighting knife design that was and is tremendously popular. The knife has been copied and adapted many times by many people. One of my favorite derivatives is the Applegate-Fairbairn Fighting Knife. The AF mainly altered two things, it gave the user more slashing ability and it changed the handle shape so that one would know where the edges were even in complete darkness (that's a little more tricky with the round handled FS). Plus the AF was adapted into the Combat Folder that my own Covert was derived from.
|The Applegate-Fairbairn Fighting Knife and the combat folder|
|The Spear Point design is so old humans didn't even invent it. This one was made by a Neanderthal.|
The Drop Point:
|A Drop Point knife made by Bob Loveless|
The Tanto Blade:
|Since Bob Lum was the guy who originally popularized this style in the US I thought I would show one of his before showing the American Tanto style. And I think this is a pretty knife.|
|And here is the knife that started the "Tanto" craze. The Cold Steel Master.|
The term "Tanto" is kind of a misnomer. Tanto just means short blade, and the short blades had many different configurations traditionally. What we tend to think of as the Tanto was popularized by Bob Lum (another Northwesterner, he was from Astoria Oregon). He made knives using a Japanese blade style that was designed for punching through armor. In the 1980's Cold Steel started producing their tactical Tantos influenced by Lum's designs, and the tactical Tanto craze was on.
I personally really don't like Tantos for the very scientific reason of I think they're ugly... So I don't really want to write too much about why I'm not fond of them. I also find the corner where the belly should be is not good for delicate slicing tasks, and the belly is the section of knives that I tend to use most. But my basic dislike of the style is aesthetic and emotional, so bear that in mind if you're thinking about a Tanto.
(One last thought on Tactical Tanto Folders. I cannot for the life of me understand why someone would want to use a folding knife to punch through armor, regardless of the tip. On a fixed blade this can make sense, but it is never a good idea to rely on a folding knife's locking mechanism to hold when you are punching through a surface designed not to be punched through unless you really don't like your trigger finger.)
Other Blade Styles:
There are endless variations on blade styles. There are also specialized knife types like Trench Knives, Karambits, Kris, Balisong, etc. that I am not going to go into here (though I will write a little bit about trench knives in the future). If you would like me to write about some specific topic or type of knife please mention it in the comments.
In lieu of writing about more of the common blade types I will just provide you with a link to A. G. Russell's glossary of blade shapes. This is a very informative page. It is worth noting that the blade styles listed do not include Drop Points or Tantos, I assume this is because the described blades are the traditional blades commonly used in US knives. Specialty blade styles like Nessmuks are also not described.
|The five most common grind types|
Scandi is short for Scandinavian. This is a sturdy blade geometry that tries to find a middle ground between edge stability and sharpenability. The main grind on a Scandi doesn't start until more than halfway down the blade. This means that there is a lot of steel providing overall strength to the blade. The main grind is flat and relatively steeply angled which means that there is a lot of metal right up to the edge, this helps prevent folding of the edge. the flat grind also makes this more easily sharpened than the convex edge.
In this case the grind is concave. This means that there is very little steel behind the edge. This makes the edge more delicate, but it also makes it much easier to sharpen. This also means that you can sharpen the knife many times before you get to a point where the blade is hard to resharpen. In my experience this also means that the blade slices through things easier because there is less resistance from the width of the blade.
The high flat gives you a shallower angle which makes sharpening and slicing easier than with the Scandi. This also gives you more metal behind the edge which makes the edge sturdier than the hollow grind.
The full flat is pretty much what is says. The whole blade is ground to angle down to the edge. This gives you an even shallower angle than the high flat, but provides less metal behind the edge.
The convex edge gives you the maximum amount of steel behind the edge. The drawback to the convex primary grind is that you are looking at fewer times the blade can be easily sharpened. Every time you sharpen a knife you take away metal. So on a convex edge you have a very sturdy edge that can take abuse, but can only be sharpened so much before it becomes round.
(On the knife I made that I showed at the start of this entry I put a convex edge on it. I actually did this because I don't know how to do a hollow grind, and it was on big wheel that was designed for working on heavy equipment. Since I actually made the knife for jointing moose the design wasn't a bad one, but I did not know that at the time. The other reason I gave it a convex grind is because I had made another knife before that I thinned out a lot to make it slice well, but it snapped as soon as I tried to chop something, so I over compensated.)
For further reading, here is an article by Joe Talmadge on Blade Geometry.
If you want to know more about blade geometry this is a pretty good video:
I am not even going to try to tackle this right here, right now, because this is a huge topic I understand very shallowly. I will however provide you with a link to A. G. Russell's Steel Guide a wonderfully comprehensive chart providing some basic info on composition and typical hardnesses for a huge variety of blade steels. A. G. Russell also provides an article about steels by Joe Talmadge. You can also look at the Wikipedia entry on Steel Grades.
So that about does it for me for this entry. I will write more in the future. Knives is a huge topic, and I am very much an amateur in the world of knives. But I hope that this entry might give you some basic knowledge to work with as you look at knives.
To wrap this up I wanted to provide you with a link to the very useful Glossary from A. G. Russell's Knife Encyclopedia.
I hope that this article has been worth your time. Please comment and let me know if there is anything I should write more about, and of course if there are things I got wrong or should be doing differently.
P.S. This entry focuses on non-kitchen knives, because kitchen knives are a whole 'nother ball of wax. I will say however, that if you want to spend a lot ($100 or more) of money on just one knife, maybe spend it on a kitchen knife. A good kitchen knife will see more use and improve your life more than just about any other knife.