What are the uses for really WIDE folder blades?

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maximus83

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Nov 7, 2011
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I'm wondering lately about the increasing number of folders I see with quite wide blades. To be clear, when I say "wide" I'm not referring to steel thickness at the spine, I mean the WIDTH of the blade measured from say, the edge to the top of the spine at the widest point.

Some years ago it seemed like many or most folders, with the Buck 110 serving as a typical example, did not have super wide blades. Today, we still have many narrow "pocket knife" blade profiles like the 110, but much more common is what I'd call loosely a "medium" width blade, along the lines of the many popular Spyderco models like the PM2. But now, it seems like I see a small but growing number of folders that have REALLY wide blades, much wider than most of us would typically use on a folder. Some recent examples: some from the CS Espada series, a large set of the Zero Tolerance models, the new Spyderco Lionspy and Yojimbo models, the Benchmade 755, the Kershaw One Ton and similar, a number of the lower-end Boker models, a number of the high-end models by Lion Steel of Italy, and on the list could go.

So my question: apart from aesthetic appeal, is there any cutting performance reason for having a really wide folder blade? When you think about the range of tasks you do with a typical folder, is the blade WIDTH ever really a significant consideration?

Part of my reason for asking is just curiosity--because I can't see a lot of practical reasons for a wide folder blade--and part of it is, I'm interested in the Spyderco Lion Spy.
 
If spine thickness stays the same, then increasing the width of the blade will decrease the interior angle opposite the spine. This means that the blade approaches the edge more gradually--which increases cutting performance. This is why a full flat ground blade will cut easier than a saber ground blade, even when the edge and bevel angles are the same.
 
I'm happy with a spyderco and my skinny flat small sebenza in my pockets. If I need more blade height, thickness, or strength, ill grab a fixed blade or crowbar.
 
I guess you could look at it from a grind perspective in that a full height flat grind on a wider blade should make for a stronger overall blade than a narrower hollow grind on the same stock while leaving the thickness above the edge the same. And can use it as a tactical spatula.
 
Cynic2701 said:
If spine thickness stays the same, then increasing the width of the blade will decrease the interior angle opposite the spine. This means that the blade approaches the edge more gradually--which increases cutting performance. This is why a full flat ground blade will cut easier than a saber ground blade, even when the edge and bevel angles are the same.
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So, I have a question about this. I agree that FFG grinds are often very performant, in fact I tend to prefer that grind on most of my newer blades. But here's the thing with a REALLY wide blade: even though it may seen to cut better due to the reduce angle (because it "approaches the edge more gradually"), don't you still have to slide a lot more total METAL through the object that you are cutting, which means more overall resistance, etc.? Not disagreeing with you, but just thinking this through, I guess this is part of the very question I'm asking about wider blades.
 
maximus83 said:
So, I have a question about this. I agree that FFG grinds are often very performant, in fact I tend to prefer that grind on most of my newer blades. But here's the thing with a REALLY wide blade: even though it may seen to cut better due to the reduce angle (because it "approaches the edge more gradually"), don't you still have to slide a lot more total METAL through the object that you are cutting, which means more overall resistance, etc.? Not disagreeing with you, but just thinking this through, I guess this is part of the very question I'm asking about wider blades.
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Try to understand it this way. Let say you are cutting through a very thick material, the thickness of the material is more than the width of the blade. If the blade is narrow, while the blade will be cutting, and the material create a suction behind the blade, leading to more drag and less efficient fluid dynamic.

The wider blade cut better is best seen the practice of "tameshigiri," or "test cutting" in Japanese swordsmanship. In the old day, it is only a part of a larger curriculum. But today, "tameshigiri" becomes a sport into itself. There are competitions where one try to cut the thickest material possible as well as trick cut, multiple cut of the same piece of target without the piece falling down. The result is that you see katana that is wider and thinner than traditionally acceptable.
 
nearly all spydercos save for a few that won't go past your fifth digit. spyderco is now close to designing a blade that's wider than it is long. ;)
 
maximus83 said:
So, I have a question about this. I agree that FFG grinds are often very performant, in fact I tend to prefer that grind on most of my newer blades. But here's the thing with a REALLY wide blade: even though it may seen to cut better due to the reduce angle (because it "approaches the edge more gradually"), don't you still have to slide a lot more total METAL through the object that you are cutting, which means more overall resistance, etc.? Not disagreeing with you, but just thinking this through, I guess this is part of the very question I'm asking about wider blades.
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Think of it in terms of the volume of the knife's cross section as determining the amount of material that must be displaced as the blade passes through a material. If you make a knife with a full flat grind with 1/8" stock that's 2" wide if will out-cut a knife made in 1/4" stock that is 1" wide.

This is an oversimplification in that the specific blade geometry and cutting medium will cause the amount of real displacement to vary, and the advantages afforded by weight during the cut, but it's a good rough way to think of the concept.
 
Same reason kitchen knives are fairly broad. Makes a wicked slicer with a FFG. I'm waiting to see if they do sprints of the Manix 2 XL. Put a nice, thin edge on that blade and it should slice like a dream.
 
these are fixed blade applications, mostly kinetic cutting with sectional density, not applicable to folders.
 
darkaether said:
these are fixed blade applications, mostly kinetic cutting with sectional density, not applicable to folders.
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Yes it does. Have you cut cheese? It is not a kinetic cut. The wider the blade, the easier it is to cut cheese. It is fluid dynamic.
 
maximus83 said:
So, I have a question about this. I agree that FFG grinds are often very performant, in fact I tend to prefer that grind on most of my newer blades. But here's the thing with a REALLY wide blade: even though it may seen to cut better due to the reduce angle (because it "approaches the edge more gradually"), don't you still have to slide a lot more total METAL through the object that you are cutting, which means more overall resistance, etc.? Not disagreeing with you, but just thinking this through, I guess this is part of the very question I'm asking about wider blades.
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Yes, but that can be improved with a mirror polish finish. Also I think the angle difference makes a bigger difference than the friction drag.

Consider the CS spike, which is a zero ground blade of maybe half an inch in width. Try cutting with that vs like a PM2. Total difference
 
MKP said:
Yes it does. Have you cut cheese? It is not a kinetic cut. The wider the blade, the easier it is to cut cheese. It is fluid dynamic.
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I'm rising above the juvenile jokes that popped immediately into my head. Cutting cheese...hehehe...
 
darkaether said:
these are fixed blade applications, mostly kinetic cutting with sectional density, not applicable to folders.
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Cross-sectional volume is still applicable to folders, even during fluid-dynamic cuts as the knife still has to displace that volume as it passes through the material. :)
 
I have wondered the same thing WRT wide blades. I like blades that have a keen point such as the Benchmade AFCK. I've noticed that knives such as ZT are becoming wider and wider, which blunts the tip a bit and gives a lot of belly to the blade. A lot of belly is good for a hunting knife but I'm not sure what else. I bought a Kershaw Blur to try out and it has sort of a medium blade- a bit wider with some belly but still a reasonable point. I still like blades a bit thinner though.

Someone mentioned Spyderco, those are sort of a special case. The spydie hole in the blade makes those blades wider without the corresponding increase in belly or blunting of the tip.
 
yes, and I've cut cheese with a wire of basically zero height and it works better than any knife because you don't have sticky blade drag. They aren't tall for any geometric reason, its for ergonomics or strength with thinner stock when a shorter blade would be more fragile than the designer would prefer.
 
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