Blade thickness?

[beretta40ss]

Ok guys, I don't know anything about blade thickness. Is this correct: the thinner the blade the sharper? What is considered thick and thin? Thanks.


Pros Cons
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[cpirtle]

Sharpness really has nothing to do with the thickness of the blade. It does have something to do with the thickness of the edge. The thickness of the edge is determined by the angle from the edge to which the bevel is sharpened. A lower angle generally allows for a finer edge and thus can be more sharp. But with a thinner edge there is also an increased risk for nicks and rolls.

Blade thickness comes into play when cutting material because a thicker blade will bind more than a thinner blade.

How thick or thin you like the blade will depend heavily on what you generally cut. I tend to like the thin blade of a slipjoint for most cutting tasks, but there are occasions when I went to put some leverage on the spine of the blade and do some more rugged chores where a thicker blade is going to hold up much better, not flex or not be in as much risk of breaking.

 

[STR]

Some guys prefer a thicker spine so the blade is stronger. Personal preferance is what it boils down to. That and what you use it for.

For me I like a nice thin 3/32 blade for my folder because I do some fine carving and detail work with it. So that just works better than say a 1/8 or 3/16" blade would even if it was honed down to say even thinner with a thicker spine. The spine keeps the knife from penetrating in some harder materials and will cause splitting instead of allowing the edge to cut.

For a nice chopper for camping and such a thicker spine would be the choice I would think so it would hold up. But hardness plays a part in how well it will endure too.

 

[Jeff Clark]

Sharpness is not as simply defined as you might think. Most people think of sharpness as the ability to easily cut materials. On the other hand what you often are interrested in is a blade that can easily cut all the way through a material. Cutting through thin materials or cutting a little ways into the surface of materials is a function of how fine the apex of the edge is and how acute an angle the edge is ground at. A fine edge that is honed thin right behind the edge will shave off those nice thin hairs and will pass those paper cutting tests with flying colors. It will not matter how thick or wide the blade is. If the material that you are cutting is somewhat stiff the thickness of the blade a bit further behind the edge becomes significant if the material thickness is of comparable dimension.

When you test sharpness by shaving hair the characteristics of the last .005" behind the edge are significant. If you are cutting .090" thick nylon weed wacker line the dimensions of the last .090" are critical. If you stab into the side of a double-walled carboard box and try and slice through the middle of the side you will get drag on the entire width of your blade. If your edge is sharp and honed to a reasonably acute angle the cardboard will slice cleanly almost regardless of the blade thickness. On the other hand a thick and wide blade will cause you tremendous effort to push it through the cardboard. This performance issue is not due to edge/sharpness effects. It is simply blade geometry interacting with material stiffness and geometry. If you are cutting a lot of material like this you want a blade that approximates the disposable box cutter blades. My grandpa's stockman pocket knife is great for that kind of cutting. Anything thicker than a large Swiss army knife blade gets to be a drag.

If you cut softer material like meat the blade thickness will not be big issue. If you slice or whittle material off the surface of something stiff the thickness won't cause drag, but it will make it harder to take thin slices. If you cut through the middle of something stiff like a crisp vetable it will take more force with a thick sharp knife than with a thin sharp knife.