Does a thick blade make a knife tough?

[kbuzbee]

Okay, first, let me say upfront, I have no need of a TOUGH knife. Durable? Sure. But I use my knives, especially folders for light/medium duty slicing.

But I've read a number of threads recently indicating that a thick blade makes a folder "tougher". Really? I've never thought of the thickness of the blade of any folder I've owned as the weak part of the knife (well, excluding ceramics, perhaps) Even the thinnest were plenty stout enough to keep up with pivots, rivets and screws.

What happens to these thinner blades? Do they snap off when pulling them through a 4" Maple limb?

In a big chopping fixed blade with a full tang of solid steel, I can understand the correlation, but not in a folder. And I know there is generally a correlation when someone builds a knife with a thicker blade, they may well also put in stronger pivots, screws, locks etc, making the overall design stronger

Am I missing something? Does anyone really think a thick blade enhances the toughness of a knife in any way? Or is this more of a marketing thing? 'We're making a stronger knife so we're going to put a thicker blade in it so that looks stronger too'

This is not intended to be a negative comment to those who just "like" thicker blades. It can be fun to just hold that big hunk of steel in your hand. Just a question of the validity of this perception I've been reading more frequently, recently. It just doesn't make any sense to me.

Ken

[casey1]

thickness gives extra strength in prying... and other things you shouldnt do with a folder. it's benefits are that it does make the blade stronger, thick blades look very nice, and often times, in cases such as the Para 2, still slice extremely well. sometimes it's more about the grind and blade geometry than initial thickness. just my thoughts

[Ankerson]

Toughness has more to do with the steel, hardness and tempering process.

Take a thick blade and make it too hard and temper it wrong and it will snap like a twig, shatter or chip out very easy.

I have a K294 (A11) fixed blade at 64 HRC that is .010" behind the edge that is very tough due to the high compression strength of the steel at high hardness, it doesn't chip out even under very hard cutting through knots.

Toughness is a subjective thing really, how tough does a 4" folder really need to be?

One isn't going to be chopping with it that's for sure, you can baton with it, but that's not really recommended use for a folder, nor is prying for the most part.

So as long as the steel is good and the hardness is correct for the use of the knife and it's tempered correctly the edge shouldn't fall apart even under hard cutting tasks.

That's assuming good design, blade and edge geometry and the steel choice is fitted for the intended use of the knife design.

That said does one what to cut stuff with the knife and how hard does one want to have to work using the knife to cut with?

Folding pry bars don't generally cut very well, but they are in general strong for the most part depending.

[kbuzbee]

Toughness has more to do with the steel, hardness and tempering process.

And I get the need for toughness in the steel itself, just not the necessity for it to be thick as well.

Toughness is a subjective thing really, how tough does a 4" folder really need to be?

Exactly!

Ken

[jnichols2]

Ankerson,

I keep seeing the term "baton", but I'm not sure what it means?

[Ankerson]

Ankerson,

I keep seeing the term "baton", but I'm not sure what it means?

That's pounding the blade through something.

[The Deacon]

Depends Ken. While steel is important, I think it's safe to say that, for any given steel at any specific RC, a thicker blade will be tougher than a thinner one and, where at least some locks are concerned, the lock will have more surface area. I'll still take thinner over thicker because, like you, my needs put a premium of slicing ability and finesse, rather than brute strength. But still, if I knew my survival might depend on it, I'd grab my C95, not my Chaparral.

[zhyla]

One thing I miss about my Rescue was being able to pry on things with the back side of the blade. From a utility knife point of view it's really nice to have the full thickness of the blade there. I think most of the ~.125" blades are plenty thick enough in this context, but many (like the Native, for example) has a large part of the spine thinned out.

[kbuzbee]

But still, if I knew my survival might depend on it, I'd grab my C95, not my Chaparral.

That's a good point, Paul. But IF I had a chance, I'd probably choose a thinner folder AND a thicker fixed blade. Then again, we don't always get to make the preparations we want to, do we?

I guess my thinking originally was 'why is a blade that will out survive the handle by 15x better than one that will out survive the handle by 2x?' But maybe my ratios are off and a Stretch or Caly 3.5 blade will, in certain circumstances fail before the handle....

Still, I guess, for my uses, a thin blade will generally be my carry of choice.

Ken

[Blerv]

My philosophy is that the tool has to fit the job (or at least the person performing the job).

If you are a user who really uses knives hard having something more robust design is ideal. Perhaps you cut a metric ton of abrasive materials per day, then you would see a huge benefit with exotic blade steels. If you abuse the knife in question having an extra stout lock is a must.

Personally I have never broken a tip, broken a lock, or whacked-out a pivot to the point it had excessive play. I don't cut cardboard almost ever and always look for the tape on boxes to save my edge. That's just me though and why I generally aim towards slicers.*

*That said a thin slicer will still stand up to rugged use just not huge lateral loads. They seem to sharpen/fix better assuming they don't lose a tip.

[The Deacon]

That's a good point, Paul. But IF I had a chance, I'd probably choose a thinner folder AND a thicker fixed blade.

You and me both, Ken. I should have qualified my answer that way.

Then again, we don't always get to make the preparations we want to, do we?

True. However, in 66+ years I've yet to find myself in a situation where I felt seriously under equipped. Of course, that may be more a factor of lifestyle and luck than intelligent preparation.

[dbcad]

Good conversation......

If you take 2 theoretical Mules made with VG-10, one with a 3mm thick blade, one with a 4mm I would think the 4mm blade would be tougher given that the handles are equal. With folders you have liner thickness, pivot diameter, type of pivot, type of lock, scale material etc. coming into play. So blade thickness wouldn't necesarily give you knife toughness.

I would think that the Bradley is a "tougher" knife than the Superleaf in part because of those reasons.

One thing blade thickness definitely gives you is blade rigidity

[kbuzbee]

However, in 66+ years I've yet to find myself in a situation where I felt seriously under equipped. Of course, that may be more a factor of lifestyle and luck than intelligent preparation.

As you say, Paul, you and me, both. But lifestyle can't protect from the Zombie Apocalypse

Ken

[Evil D]

With a thicker blade comes a thicker and stronger pivot so the short answer is yes. There are other things to consider though like the type of grind and lock and how the pivot is designed and how big the pivot pin is.

[kbuzbee]

With a thicker blade comes a thicker and stronger pivot so the short answer is yes.

Always? I get that is generally true among better vendors, and I would expect it. I just don't see a reason why it HAS to be true.

There are other things to consider though like the type of grind and lock and how the pivot is designed and how big the pivot pin is.

Oh, I know, and I totally agree. My question was specifically about whether a folding knife would, in any practical way, be tougher just because it's blade was thicker. ie - take a Stretch, leave everything else the same and make the blade 2mm thicker... Is it "tougher" than the origional? I get the sense some folks think "yes". But maybe it goes back to your first point. People perceive/assume/know that a thicker blade means all the other components are stronger as well.... That may be the connection I haven't completely embraced

Ken

[chuck_roxas45]

Always? I get that is generally true among better vendors, and I would expect it. I just don't see a reason why it HAS to be true.



Oh, I know, and I totally agree. My question was specifically about whether a folding knife would, in any practical way, be tougher just because it's blade was thicker. ie - take a Stretch, leave everything else the same and make the blade 2mm thicker... Is it "tougher" than the origional? I get the sense some folks think "yes". But maybe it goes back to your first point. People perceive/assume/know that a thicker blade means all the other components are stronger as well.... That may be the connection I haven't completely embraced

Ken

That's a very good point you're making Ken. Take the Superleaf for instance. Massive blade with a flimsy feeling handle. It does look very beefy but I wonder how tough it really is.

[kbuzbee]

That's a very good point you're making Ken. Take the Superleaf for instance. Massive blade with a flimsy feeling handle. It does look very beefy but I wonder how tough it really is.

Thanks! For me, it's purely an intellectual exercise. A lot of things will have to have gone VERY wrong for me to care if my folder is "tough enough" Anything Sal has ever made will easily outlive me. But this recent trend of posts just got me wondering....

Ken

[chuck_roxas45]

Thanks! For me, it's purely an intellectual exercise. A lot of things will have to have gone VERY wrong for me to care if my folder is "tough enough" Anything Sal has ever made will easily outlive me. But this recent trend of posts just got me wondering....

Ken

I do drag my knuckles somewhat but I do enjoy discussions like these.

But I do wonder which will break first(with superleaf), if you really set out to break it. Will the blade break? Or will the liners go first? Or is the pivot gonna be the weak spot?

All intellectually of course because as you say, it would already be a really bad day when I put that much stress on a knife.

[Evil D]

Always? I get that is generally true among better vendors, and I would expect it. I just don't see a reason why it HAS to be true.



Oh, I know, and I totally agree. My question was specifically about whether a folding knife would, in any practical way, be tougher just because it's blade was thicker. ie - take a Stretch, leave everything else the same and make the blade 2mm thicker... Is it "tougher" than the origional? I get the sense some folks think "yes". But maybe it goes back to your first point. People perceive/assume/know that a thicker blade means all the other components are stronger as well.... That may be the connection I haven't completely embraced

Ken

With your Stretch example I'm gonna say definitely yes because the thicker blade means more meat in the lock itself because the lock bar will thicken with the blade. Mainly what you'll see are stronger locks/pivots and more strength laterally when twisting the blade.

[kbuzbee]

I do drag my knuckles somewhat

We ALL do that

With your Stretch example I'm gonna say definitely yes because the thicker blade means more meat in the lock itself because the lock bar will thicken with the blade.

Okay so the lock thickens and adds stability so I see where that will help. But IF (I can't stress enough how hypothetical this is as I've never caused a knife to fail, even cheap ones, let alone a Spyderco) the lock and blade were already stronger than say the pivot, it doesn't seem like the knife itself would gain any overall strength from beefing them up.

It has to be an overall design upgrade, being aware of what the current weakest point is (and IMO, Sal does a great job of doing exactly that) Just making a blade (and if requisite for mechanics, the lock) stronger would change the strength of the knife (assuming they weren't under designed, initially, of course)

Mainly what you'll see are stronger locks/pivots and more strength laterally when twisting the blade.

But again... generally? Or ALWAYS? You see where I'm going with this David?

Ken