Geometry: It Matters Most

[Eli Chaps]

I know such things come up frequently but why not another thread?

Edge geometry reigns supreme.

Yes, steel type, hardness, usage, and all those influences are factors, but in the purest sense, edge geometry still reigns supreme.

I wish edge geometry and steel-specific heat treatment, and their effects on each other, got way more attention than steel type. I believe steel type in modern production knives, especially folders, is as much marketing hype as it is a genuine "improvement".

Check out this video from @DeadboxHero :

And of course skill is a major factor in stuff like this, but so is a sharp, thin knife:

I know it is all relevant, and I know it can be complicated and steel type, heat treat, and geometry can all come into play. I'm not discounting or dismissing any of those things. I just wish the knife community as a whole would recognize and embrace blade geometry with the same vigor that they do the steel type.

 

[Night Rider]

I know such things come up frequently but why not another thread?

Edge geometry reigns supreme.

Yes, steel type, hardness, usage, and all those influences are factors, but in the purest sense, edge geometry still reigns supreme.

I wish edge geometry and steel-specific heat treatment, and their effects on each other, got way more attention than steel type. I believe steel type in modern production knives, especially folders, is as much marketing hype as it is a genuine "improvement".

Check out this video from @DeadboxHero :

And of course skill is a major factor in stuff like this, but so is a sharp, thin knife:

I know it is all relevant, and I know it can be complicated and steel type, heat treat, and geometry can all come into play. I'm not discounting or dismissing any of those things. I just wish the knife community as a whole would recognize and embrace blade geometry with the same vigor that they do the steel type.

Agreed ^ Blade Geometry should be the first thing one should consider when choosing a knife if you plan on actually using it to cut.

 

[Fixall]

I brought this up in another thread but still don’t have an answer (forgive me if it’s obvious).

With edge and blade geometry being more important to cutting than blade steel... Why do we prefer our folders to be made out steels that hold an edge for an incredibly long time but are a bit fragile/chippy (s110v for instance)?

Wouldn’t it make more sense to use an incredibly tough steel like Elmax or something and then thin the blade and edge geometry to the point that it is equal in strength to the thicker bladed s110v?

It seems like the greatly improved edge and blade geometry from thinning the stock would offset the loss in edge retention and cutting performance while keeping the blade just as durable.

What am I missing?

 

[Eli Chaps]

I brought this up in another thread but still don’t have an answer (forgive me if it’s obvious).

With edge and blade geometry being more important to cutting than blade steel... Why do we prefer our folders to be made out steels that hold an edge for an incredibly long time but are a bit fragile/chippy (s110v for instance).

Wouldn’t it make more sense to use an incredibly tough steel like Elmax or something and then thin the blade and edge geometry to the point that it equal in strength to the thicker bladed s110v?

It seems like the greatly improved edge and blade geometry from thinning the stock would offset the loss in edge retention and cutting performance while keeping the blade just as durable.

What am I missing?

This is not a direct answer to your question, but an answer in the spirit of the inquiry.

I've come full circle and am currently, completely infatuated with Case and various French and Spanish offerings. Obviously, steel type is not at the forefront of these products. But so many of of them have thin, slicey geometry, that I hardly care. They just keep cutting.

I'm equally currently fascinated with a Dexter Russell vegetable cleaver that I've been playing with. It's soft and yes it loses it's keen edge quickly, but I'm messing around with it's edge thickness and it still performs. Not at the levels of those seen in the videos, but still.

What @DeadboxHero is on about, is the marriage of all these factors. Starting from a notion that geometry is the most important and then finding the right steels at the right hardness for the right applications.

I'm a long ways off of that but I do know that I value edge geometry over all the rest.

 

[Wowbagger]

I just wish the knife community as a whole would recognize and embrace blade geometry with the same vigor that they do the steel type.

Yeeeeessssss.
First off I will say the first posts I made here after signing on was all about this.
E.G., how a plain old Swiss Army Knife Bantom could be reprofiled and sharpened to make ANY other knife look positively silly when cutting wire ties even and especially the larger wire ties. And not have a distorted or damaged edge at all afterward.

That said geometry will never be all that popular because what cuts doesn't look BA.
What cuts looks like a paring knife.

As far as heat treat we are, for the most part, at the mercy of the manufacturers.
There are customs out there but I'm not patient enough to wait for one even if I could afford one. Mostly I am talking folders.

Finally for the work I do M4 with plain old stock factory geometry that is on all of my other Para2s makes all the others including S110V take a back seat or just get pushed off the bus. I wouldn't change a thing geometry wise.

Do not underestimate what real tool steel can do compared to
yes-but-I'm-stainless
or
I-can't-hold-an-edge-but-I-make-a-good-saw.

 

[jaseman]

Blade geometry is probably the hardest of blade properties to quantify, especially from a marketing standpoint. Steel type, edge thickness, handle material, etc. are all very tangible. But geometry is a bit trickier to give hard data on. The type of steel used had hard data behind it that you can point to, and say this much of a certain element makes it more resistant to wear, or easier to sharpen, or what have you. Geometry on the other hand is subjective, and will effect how a knife feels when using it... and everyone's hand is different, and prefers a different feel, even if Avery subtle.

It's like cars. Horsepower, cubic inches, curb weight, and torque get all the bragging rights, either in commercials or on nternet forums. They are tangible things you can point to and say one performs better than the other. But they tell you nothing about being behind the wheel, and if the car handles well, is properly balanced, or just feels right in the seat of your pants.

Moving the belly just a 1/4" on a knife could change the whole feel. Changing the primary bevel just a degree or two can take something from a great slicer, to almost feeling like a wedge. But you can't really put hard stats to any of that like you can steel type. So people focus on things they can easily quantify - horsepower and Steele type.

 

[marcus52AR]

I've almost purchased the spyderco chapparal a couple of times.. its a little on the little side, but the blade is nice and thin. If they did a native 5 or manix 2 thin like that I'd buy both. A backlock manix with the brass mesh scales in thin CTS-XHP would be a cool knife.

 

[DocJD]

it can be complicated and steel type, heat treat, and geometry can all come into play. I'm not discounting or dismissing any of those things.

The final performance of a blade is dependent on all the separate factors that go into the making . It's more a "weakest link in a chain" phenomenon than that one factor is more vital than another . They all must work together .

Ironically , it is quite common to try to compensate for poor choice of steel and HT by making overly thick blades . So geometry suffers in the attempt to overcome improper steel / HT .

 

[Lapedog]

Basically the guys on the Traditional section have been laughing at us modern guys for a while.

 

[Lesknife]

Different Blade geometry is necessary for different types of uses. Slicers, choppers, bush craft, kitchen cutlery, and utility among many other uses. Also personal preference comes into play for instance my camping knife serves as an all around camp knife from cutting and preparing food slicing meat and making some kindling and feather sticks. It is a Buck 124 420hc hollow ground blade. Many people don’t like a hollow grind for bush craft or utility but it works great for me and Bucks 420hc is very tough. I do have some full flat grinds, full shallow hollow ground, saber, and scandi ground blades just for specific tasks but that hollow ground 124 gets a lot of use and no worse for wear. And I would hate to have only a thick scandi ground or convex grind knife for slicing sandwich meat.

My edc pocket knife is much the same except I have mostly s30v blades and now a couple of 20cv all hollow grind Bucks and for my work and preference they perform well beyond my expectations. So. I do believe the steel type and heat treatments are just as important for my liking.

I do believe in some things that all the hype has been over played and just how many steel types are being used now? I would hate to make a guess but at least dozens.

 

[115Italian]

Blade geometry matched properly to what the cutting needs are is important.
That’s not saying other characteristics of a blade aren’t important.

Blade steel type has nothing to do with taking a sharp blade and cutting something. That properly heat treated steel does matter to how long I can keep cutting.

I wouldn’t say one characteristic is more important than the other when rating the overall performance of a blade. There needs to be a balance. I think blade geometry is a kind of first things first. But from there a balance of other things start to come into play.

 

[dirc]

anyone with experience knows this - and it's the reason people keep raving about opinel & other thin geometry traditionals...

anytime I go camping or need a good food prep knife, I bring the opi #8 and my ultra thin mora 090 fillet (0.05" thick stock)

 

[eveled]

I brought this up in another thread but still don’t have an answer (forgive me if it’s obvious).

With edge and blade geometry being more important to cutting than blade steel... Why do we prefer our folders to be made out steels that hold an edge for an incredibly long time but are a bit fragile/chippy (s110v for instance)?

Wouldn’t it make more sense to use an incredibly tough steel like Elmax or something and then thin the blade and edge geometry to the point that it is equal in strength to the thicker bladed s110v?

It seems like the greatly improved edge and blade geometry from thinning the stock would offset the loss in edge retention and cutting performance while keeping the blade just as durable.

What am I missing?

There is a lot going on in a folder. If the steel is too soft it will wear rapidly as it interacts with the spring while opening and closing.

 

[skyhorse]

I'd say Buck is a production company that does a really good job taking all these factors into account while producing a knife the average working man can still afford.

 

[Dean51]

Basically the guys on the Traditional section have been laughing at us modern guys for a while.

When it comes to geometry, they have been laughing for a very long time.
A lot of the traditional folks will use nothing but simple carbon. So when it comes to steel you can laugh.

 

[Dean51]

I wish edge geometry and steel-specific heat treatment, and their effects on each other, got way more attention than steel type. I believe steel type in modern production knives, especially folders, is as much marketing hype as it is a genuine "improvement".

You are right steel is hyped in modern knives. When you can find a modern knife with good geometry and a modern steel, it truly is an a genuine improvement.

 

[jceckrosh]

I used to not pay any attention to blade geometry (or more appropriately, I did not understand that there was more to it than just a sharp edge). But I got tired of cool looking knives that struggled to cut cardboard or could not cleanly slice open a bag without pinning the bag down first in order to apply pressure.

Anyway, I am at the point now where I absolutely consider the geometry of the knife first. I have no time (or pocket space) for a knife that can't do what I need it to do.

 

[marchone]

Blade geometry is probably the hardest of blade properties to quantify, especially from a marketing standpoint. Steel type, edge thickness, handle material, etc. are all very tangible. But geometry is a bit trickier to give hard data on. The type of steel used had hard data behind it that you can point to, and say this much of a certain element makes it more resistant to wear, or easier to sharpen, or what have you. Geometry on the other hand is subjective, and will effect how a knife feels when using it... and everyone's hand is different, and prefers a different feel, even if Avery subtle.

It's like cars. Horsepower, cubic inches, curb weight, and torque get all the bragging rights, either in commercials or on nternet forums. They are tangible things you can point to and say one performs better than the other. But they tell you nothing about being behind the wheel, and if the car handles well, is properly balanced, or just feels right in the seat of your pants.

Moving the belly just a 1/4" on a knife could change the whole feel. Changing the primary bevel just a degree or two can take something from a great slicer, to almost feeling like a wedge. But you can't really put hard stats to any of that like you can steel type. So people focus on things they can easily quantify - horsepower and Steele type.

I agree 100%. Others here opined similar thoughts.

I used knives in my work every day for more than three decades. Steel is the last detail I look at. Blade shape for specific cutting purposes and handle shape for reducing fatigue are of paramount importance to me. In that way many of my knives, whether fixed or folders, tend to be similar in overall configuration.

I’m a dyed in the wool drop point fan though a couple of spear points in my collection of working blades have opened my eyes to them. What I can’t or don’t understand are clip points and compound tactical shapes. I suppose from reading that they work well for cutting through car doors and neutralizing mortal enemies. But those aren’t my daily uses.

I have an MBK Laconico EZC that chipped the first week I had it. I only used it for soft foods and the occasional cellophane-type packages. No hard plastic or wire staples. That’s in SV35N. Maybe it’s a bad heat treat. I don’t know.

 

[Dean51]

Last year I took some of my knives and did a little cutting test to satisfy my own curiosity. A pocket knife test not a bush craft/hard use test. It was a rainy day and I was bored. What I was looking for was how much pressure it took to cut a U-Haul box.

I have reground the Muskrat from .021 BTE to it's current .015. The Muskrat out cut all the others by a very noticeable margin. The Wasp and Barrage were close to each other. With the GEC a noticeable 4th place.
Notice all those knives were ground at 20 DPS, not what you would think of as a super slicy edge. The combination of thin behind the edge and thin stock does a lot to overcome the need for an acute edge angle.

Of the next 4 knives even though they were sharpened to 17DPS with a 20 degree micro bevel, there was a noticeable increase in the effort it took to cut the U-Haul boxes. You can improve a knife that is thick behind the edge but in use thick is thick.

The last knife was the Benchmade bone collector 15055-1, thick behind the edge and saber ground it sucked as a slicer.

1. What I found out is without a doubt geometry cuts. That's why I have a mini pry bar on all my key chains. The saber grind is the biggest hoax in the knife industry. Companies are putting out these beautiful saber ground blades with a nice swedge on the tip, all those angles look like facets in a diamond. They don't cut well but they're pretty and customers buy them. The knife companies are laughing all the way to the bank because they only had to grind half the blade, their labor went down and profits went up.

2. Steel determines how long a blade can cut. Simple low carbon steels don't cut as long as the modern more complex steels.

3. Heat treat determines how long a particular steel cuts. The saying goes you can't make a silk purse out of a sows ear. You can't take 1095 and make it a super steel, heat treat will only make it a better or worse 1095.

Take two samples of 420HC, from Case and Buck. The Buck edge will definitely out last the Case, Buck does 420HC heat treat better than any one.

There is no way Bucks 420HC will out last any of the D2 steel I have from Manly, Smith and Sons, Benchmade, Queen, Maserin or Ontario.

When it comes to heat treat some companies might run a steel soft so they have a more durable pry bar/hatchet. Or to protect themselves from customers who pry. Others may heat treat for edge retention but as long as you buy from a reputable company that advertises their HRC. You'll know what you're getting and heat treat should not be much of an issue. If a company doesn't mention their heat treat don't but it.

 

[pinnah]

What I can’t or don’t understand are clip points and compound tactical shapes. I suppose from reading that they work well for cutting through car doors and neutralizing mortal enemies. But those aren’t my daily uses.

I find clip points useful on the kitchen cutting board and for some wood working applications. The tip can get into a tight space that a drop point can't. The curving cut to clean out the punky middle of a pepper or deboning a chicken are two examples.

I've found they do require a lot more discipline though as they are much easier to damage.