Geometry: It Matters Most

[pinnah]

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.

I think one think Buck understand very well and does a great job of is using grinds to visually enhance a knife to make it more appealing looking. I think a great amount of that credit goes to Leroy Remer, who took the use of a hollow grind popularized by Loveless and then pushed it to the next level. In particular, I think we can thank Remer for advancing the curved, sharp grind lines on many Bucks like the 113, the Spitfire and Reaper. And I think the sharp, clean lines of the current hollow grinds used on the 100 series looks crisper than the older rounded shoulder hollow grinds from back in the 70s.

That said, I think thinner blades generally perform better for practically everything and I've found that thinning and flattening a standard Buck hollow grind transforms the knife to a super slicer. You get the super thin behind the edge and easy to sharpen benefits of Buck's great thin hollow grind with the benefits of thinner blade stock and no shoulder friction like you get with an Opinel, SAK or most kitchen knives. But, flattened hollow grinds won't sell well. They look boring.

 

[Alberta Ed]

Interesting point. I consider edge geometry to be as important as steel type/heat treat, though it doesn't get as much mention among the herd of knife nerds here, though I can't quantify all the factors. Buck found the magic all-round formula for the classic 110; in general, the thinner behind the edge, the better.

 

[Banter 247]

This topic is huge. So huge, that I’ve been trying to wade through it by doing relatively short videos breaking it into digestible pieces.

One of the key pieces to consider is that optimal geometry is relative to application. When the topic comes up, many people go straight to the fringes, and become champions for extremes. Every hard use knife has to be .19” stock with .032” at the shoulder, every EDC knife has to be .09” or under stock at .0000000000001” bte, etc.

That’s not always the solution.

Geometry is optimized two ways: by specialized application, or by finding equilibrium for your set of needs.

For example, I cut a lot of cardboard at work. I also cut a LOT of zip ties, plastic banding straps, and plastic packaging. Other materials, such as bonded leather or rubber pop up with varying frequency. So... for my work knife, I like something with a stable edge (not the same as toughness, though some overlap exists), with an aggressive enough edge angle and bte measurement to readily blow through cardboard and bite zip ties aggressively.

Stock thickness has virtually zero effect on what I do at work, so .16” is fine with good up front geometry.

 

[craytab]

I'm not sure it matters most. Blanket statements like this rarely hold water.

It is very very important though, ergonomics being right up there.

Right tool for the right job. Just like I'm not going to go delimb trees/branches with my cpk potato knife or my north arms trillium, I'm also not going to dice onions with my esee 5.

Given the task, many things go into the choice of a knife. If you choose wisely, you can get most of what you want.

If you don't exactly know what you will be doing with your knife, I'd error on the side of thicker.

 

[Eli Chaps]

I'm not sure it matters most. Blanket statements like this rarely hold water.

...

It's a fair point and one I readily concede. I reckon in my mind I was thinking that of all the factors, I think it is the mostest important. But then tried to explain that in no way dilutes or dismisses the other factors, to include steel type.

For sure, it all has to balance.

 

[Banter 247]

I'm not sure it matters most. Blanket statements like this rarely hold water.

It is very very important though, ergonomics being right up there.

Right tool for the right job. Just like I'm not going to go delimb trees/branches with my cpk potato knife or my north arms trillium, I'm also not going to dice onions with my esee 5.

Given the task, many things go into the choice of a knife. If you choose wisely, you can get most of what you want.

If you don't exactly know what you will be doing with your knife, I'd error on the side of thicker.

Standing ovation for the strength of this one.

When I do pre-review use evaluation, it’s specifically to observe ergonomics in use. 3 pillars for a great user: comfortable carry, good ergonomics in context, and geometry suited for the application(s) of the user. Ergonomics are frequently evaluated out of context, which isn’t ideal.

 

[McFeeli]

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.

Does this mean I get to laugh at everybody? Haha.

 

[Dean51]

Laugh away, I do when I carry my Shuffler.

 

[Shotgun]

Kinda. You need a good handle. That’s important. You also need a steel that doesn’t dull halfway through the job unless you just love sharpening.

I want it all.

 

[Danke42]

To me what matters most is balance.

Thin stock will cut soft materials better for sure. That why when I"m cooking I use kitchen knives and when I cut cardboard I use a snap off Olfa knife.

For some of the other stuff where I might have to twist or work the knife harder I like the thicker stock. Not pocket prybar thick but reasonable thick like Endura-ish.

 

[Banter 247]

Stock thickness is often vilified unnecessarily for (non-food) EDC use.

I often carry this Keen, which has .155” stock...

...and it cuts cardboard every bit as aggressively as this Chapparal...

...which has .09” stock.

Why? Because it’s the up front geometry that matters for this application.

 

[Mistwalker]

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.

I agree that sometimes swedged saber ground blades are often improperly done for the tasks they are marketed for by people who use those facets as marketing hype because of their sex appeal. The thing about a swedged saber grind is that it is not really optimized for cutting and slicing but rather to be good at penetration of tough hides in hunting applications or layers of tough clothing like khaki in tactical applications and have some spine strength to cope with lateral stresses in hard uses. For good hunting knives the thicker blades usually have hollow grinds to make them better at slicing like Buck has done for as long as I can remember with their saber ground and swedged hunting knives that in my experiences work pretty well for their intended tasks. I grew up with, and still have a couple of, Buck hunting knives. In tactical applications most companies who make actual tactical knives tend go with a flat saber grind to be less focused on cutting and more optimized for durability in tactical applications. As someone mentioned above, what slices well usually looks a lot like a paring knife and there are reasons for that, because no one knife can do everything well, that's why there are so many different styles of blade profiles and cross sections. Every well thought out blade design is nothing more than a series of compromises, and it is always on us to seek out the right combination of compromises to suit our needs. Always has been, but luckily today there are a lot more options out there. I live in the deep south where it gets hot and muggy and I sweat a lot in the summer, and I like salt water. For me I like a good stainless for corrosion resistance and that is more important to me than edge retention. I would carry a knife, fixed or folder, made of well done AUS8 or 440A before I would carry one made of O-1 tool tool in a salt water environment, so I usually look for great corrosion resistance first, blade profile second, ergonomics third, edge retention, and then prices, and compare from there to see which I will go with.

 

[marchone]

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.

If that works for you, great. I can't say I've ever seen a clip point in a commercial kitchen though.

I prefer a small drop point parer. I'll glove-bone a whole chicken with one in minutes.

 

[DeadboxHero]

Durability is thick

Cutting Performance is thin.

Behind the edge thickness plays a bigger role than stock thickness.

People confuse stock thickness with making something a slicer. While that is a component, it's about how much material is removed on the sides of the blade going down to the shoulder of the edge. That's what Behind the edge thickness shows you.

How thick or thin it is in the area that is doing the cutting.


If you use your knife like a knife than you should be rewarded with thinner geometry rather than suffer with a more wedgy geometry that reduces cutting ability for durability.

If you want it to twist, pry, scrap, chisel than you cannot go past 0.015"bte on even the best steel with the best heat treatment and the ultimate cutting performance is diminished.
So I'd rather just use the knife better and get the killer cutting geometry.
I feel this way in the context for knives

I like knives to be knives, axes to be axes and a crowbar to be a crowbar

 

[Mistwalker]

I like knives to be knives, axes to be axes and a crowbar to be a crowbar

I agree to an extent. I certainly agree that geometry doesn't get the recognition it deserves. I think it is likely because most people these days don't have the history of experiences with knives in multiple uses that would allow them to have a context for the subject which would in turn allow them make use of the data that is available on the subject. As far as geometry goes in my personal uses, I like my kitchen knives to be kitchen knives, and those are obviously going to error on the side of slice-y-ness. I prefer for my edc knives to be somewhat of a work horse that essentially plays jump rope with the line between slicing and durability, a higher grind mated with a little thicker behind the edge than some like because I do occasionally scrape and pry a little with them when doing mechanic work and it's the tool that is handy. I probably won't spend a lot of time slicing carrots with it, only now and again on camping trips maybe so the BTE really doesn't get debilitating for me. I like the knives I teach advanced knife use techniques and wilderness skills classes with to be of a materials that make them pretty durable for repeated uses well beyond what I would put a knife through just in general use, and not be too thin at the edge for the steel used. For salt water recreation, fishing, and harvesting fresh oysters on the spot, I like softer less expensive stainless dive knives in case I damage or drop it in deeper water than I can retrieve it from. Having been at ground zero for a few instances of all hell breaking lose due to natural disasters and some other intense instances in my youth that have created a need to E&E quickly, and using a knife in rather unorthodox and unconventional roles for traditional knives, I prefer for my contingency knives, and the knives I teach urban survival skills with, to have a little bit of pry bar and chisel in their make up. Just as in the 25 plus years I spent in the commercial construction and disconstruction industries, while there will always be crossover and improvisation simply due to time constraints, for the most part what I want a tool to do will be task dependent, which is why I carry more than one small knife on me at a time, that complement each other by each being better suited for different tasks.

 

[Danke42]

Durability is thick

Cutting Performance is thin.

Behind the edge thickness plays a bigger role than stock thickness.

People confuse stock thickness with making something a slicer. While that is a component, it's about how much material is removed on the sides of the blade going down to the shoulder of the edge. That's what Behind the edge thickness shows you.

How thick or thin it is in the area that is doing the cutting.


If you use your knife like a knife than you should be rewarded with thinner geometry rather than suffer with a more wedgy geometry that reduces cutting ability for durability.

If you want it to twist, pry, scrap, chisel than you cannot go past 0.015"bte on even the best steel with the best heat treatment and the ultimate cutting performance is diminished.
So I'd rather just use the knife better and get the killer cutting geometry.
I feel this way in the context for knives

I like knives to be knives, axes to be axes and a crowbar to be a crowbar

I kinda like twisting, prying scraping and chiseling; I am incorrigible in that.

I do try to be smart about it though and if I get it wrong I know it was me.

 

[Mistwalker]

I kinda like twisting, prying scraping and chiseling; I am incorrigible in that.

I do try to be smart about it though and if I get it wrong I know it was me.

Me too, even when it's only eating English walnuts

 

[marchone]

Try black walnuts. You'll need a replica Kephart for those. And a stout bludgeon.

 

[Pomsbz]

It shouldn't be that hard to make an equation which could give a 'slicey-ness' number. Factoring in BTE thickness, spine thickness and blade height. Plug in a few well known slicey and non slicey blades to establish benchmarks and you now have a way to compare slicing performance. I realise it would only be effective for FFG blades, other grinds would throw a spanner in the equation.

Now if only I was mathematical.

 

[Pasteur291]

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?

Then knife made by 3v but in quarter inch thick is still exceed