Gerber Silver Trident

[Cliff Stamp]

I used the Mora 2000 as a benchmark on the cardboard cutting performance by the Silver Trident. I had actually intended this to be a comparison of a high carbide vs low carbide steel showing the benefit of all the carbide in 154CM because it sure doesn't help in regards to toughness / grindability, however that isn't what happened :

The blades started out similar, but the Mora 2000 quickly pulled ahead. 12C27mod which is the steel in the Mora 2000 lies very close to the carbon saturation line at an austenization temperature of 1100 C thus it has trace amounts of primary carbides. However 154CM has a very high primary carbide fraction (17.5% chromium rich) so it should have a massive advantage in stock tests of wear resistance.

(anyone has any wear tests on 12C27, 12C27m, 13C26 let me know)

However looking at the edges under magnification they were deforming and showing signs of fatigue fracture with stress lines running parallel to the edge as well as pieces tore out of the edge, more than ten times the size of the micro-teeth left by the 600 DMT hone. Thus the wear resistance of the 154CM was of no benefit as it was just cracking apart.

The edge angles used here are very low, 10 degree primary for both blades and the 15 degree micro was only 0.1 mm wide, about 0.001" thick. There was little evidence of direct impaction which makes sense, but checking periodically the edge progress from a slight wave and progress to visible deformation and then tear outs. This seems reasonable give the very low thickness of the micro-bevel.

(yes I realize high mag shots would be useful here)

What would be interesting would be to see if RWL34 has the same performance. This makes me wonder if this isn't the reason why CPM 154CM had a significant increase over 154CM in the Spyderco CATRA tests. Considering that people are in general more prone to lateral loads in cutting due to the variance of a human hand, it would be expected that a greater influence of edge stability would be seen. The numerical details can be seen here :

http://www.physics.mun.ca/~sstamp/knives/silver_trident.html#edge_retention

I am also interested in 12C27m vs S30V (ideally AEB-L vs S30V) so a comparison to the South Fork seems reasonable as well as of course ZDP-189 which I have been meaning to do. That will just take a lot of cardboard as I want to do at least five runs with each blade for about 100 m each to map out the secondary blunting state in detail. That totals to about 1.5 km of similar stock cardboard. I shuld maybe include a Spyderco S30V in there as well and ideally the Swamp Rat S30V as well and see if there is any significant difference among them.

-Cliff

 

[kel_aa]

I'm not very pleased with ATS34/154CM. 440C is much easier to work with. Can you make a guess as to toughness and "coarseness" of the two (relatively speaking) at 58-59?

Also, do you have any idea of the densities that the CPM steels are actually achieving? There is the argument that says they are losing quite a few percent from the maximum. I too think it is unlikely that the CPM steels are achieving the same density as other production methods.

 

[Sal Glesser]

(anyone has any wear tests on 12C27, 12C27m, 13C26 let me know)
-Cliff

Anybody out there with a 2" x 4" piece of the above steels, we can do a basic CATRA abrasion resistance on the 3 for comparison?

I'd be interested in the results as well.

I would also be interested in seeing how the PM version of 154Cm would compare?

sal

 

[Cliff Stamp]

The densities can be less, for example M4 has a density of 0.295 lbs/in^3 and CPM-M4 is 0.288 lbs/in^3. However is this actually void or just batch/manufacturer differences. The problem is no one actually tells you the variance you can expect in the measurements so it is not possible to make meaningful comparisons.

Powder steel is actually just small ingots forge welded together under high heat and pressure. I think if there were a problem with voids Landes would have noticed it when he examined the edges of knives of various steels. His position has been of size of carbide aggregates generally causing tear outs and not voids from what I have seen in his critism of S60V and similar stainless.

440C, has a significantly smaller primary carbide fraction, 12% according to Crucible, but it depends strongly on how hot it is austenized. Verhoeven notes that it can contain the primary carbides left from initial forming which make it a really coarse steel, unsuitable for knives.

440C is usually ran much softer than ATS-34/154CM, almost to the point where it can be machined readily by a file. Most people with high standard for sharpness like Clark tend to critize ATS-34/154CM. It was often tempered hot which induces a strong secondary hardening responce through the molybdenum which has lead some to critize that element for problems with ease of sharpening.

Some people like R.J. Martin and many other makers will critize one steel and praise another (ATS-34 / 154CM) even though they are near idential in composition because of the differences in how they are manufactured, or the tolerances used, induces changes in the purity of the steel.

-Cliff

 

[thombrogan]

You'd think at least the makers who strive for the ultimate performance would be curious; especially the competition guys. Ah well.

I've seen knives by Matt Lamey, Jimmy Fikes, and Maggie Fikes that suggest these concepts aren't foreign to performance-oriented artists.

 

[the possum]

I would not have expected this steel to normally be this brittle. Yet since the blade snapped so easily, I'm not surprised that there was also a problem with the edge breaking away. Is this similar to performance you've gotten from this steel in the past?

I've seen knives by Matt Lamey, Jimmy Fikes, and Maggie Fikes that suggest these concepts aren't foreign to performance-oriented artists.

And you may well be right, Thom. I don't get to shows to see the makers or their knives in person, so I'm only going on what I read in the magazines and here. I could understand that a competitor may want to keep a few secrets that give him a performance edge, which may be why they don't discuss it in detail.

And either way I'm betting that they've got things pretty much correct for what they want to do anyway, just through repeated testing & experience. With some designs, it's possible to nail the rotational centers exactly almost by accident. However, I'm still betting there is room for learning in at least some instances. A while back in Blade, in an article about competition blades, someone mentioned how they first tried making a light hollow ground blade with a heavy pommel to bring back the balance point. This indicates they did not in fact understand what the pommel was for, and I'm betting we'd be seeing more pommels on comp blades if they did. In another article (I believe it was written by our own Roger Pinnock as I recall) about Dan Farr's comp blades, he talked about the evolution process he went through, finally ending up with a lighter blade than previous models. So again, he may have ended up where he wanted to be, but what about if he makes a knife of a totally different size and design? Will he know how to apply the ideas again (I'm betting he would, just based on "feel") or will he need to make several prototypes first?

 

[Cliff Stamp]

I would not have expected this steel to normally be this brittle. Yet since the blade snapped so easily, I'm not surprised that there was also a problem with the edge breaking away. Is this similar to performance you've gotten from this steel in the past?

ATS-34 developed a reputation for being very brittle in Benchmades which ran them very hard and were rumored to use high temper to allow heavy grinding after heat treating which I never saw publically confirmed or denyed by Benchmade. EDI reversed with a different hardening, significantly softer than Benchmade and many users noted they could tell it apart by feel. There was a huge blow up a dozen years ago regarding how it is supposed to be heat treated with makers like Mayer noting that the low temper should be used while Engnath and many others argued that the high temper provided a more durable edge. Materials data does show a charpy loss during secondary hardening however it isn't trivial to extend that to edge behavior. I personally have seen similar brittle failures with other Bos hardened ATS-34 such as the Solution (Bos), and a WB fractured readily on concrete losing parts of the primary grind.

However, I'm still betting there is room for learning in at least some instances. A while back in Blade, in an article about competition blades, someone mentioned how they first tried making a light hollow ground blade with a heavy pommel to bring back the balance point. This indicates they did not in fact understand what the pommel was for, and I'm betting we'd be seeing more pommels on comp blades if they did.

This is a common perspective, consider :

"If the blade is very long, I tend to enlarge the pommel to put more weight at the rear of the tang. On most knives under 8" I can pretty reliably get the balance point to within 1/2" of the forefinger, without having to do anything beyond tapering the tang."

from :

http://www.bladeforums.com/forums/showthread.php?p=1143078&#post1143078

Note the focus of the balance is on the static center of mass perspective which is stated clearly and distinctly :

"IMHO, the point of rotation for all knife movements is the forefinger. The closer you can get to it with the balance point the lighter and more ALIVE the knife will feel. Once a knife gets beyond about 7-8" that's gets increasingly difficult and tends to move forward."

from :

http://www.bladeforums.com/forums/showthread.php?p=1255028&#post1255028

and :

"Unless you're using it for heavy chopping, IMHO the balance point should be as close to the forefinger as possible. That is the rotation point of most knife movements. Plus that is where the knife will feel lightest if it is balanced there."

from :

http://www.bladeforums.com/forums/showthread.php?p=1130234#post1130234

This is a very common perspective which is basically "use thin stock and keep the center of mass close to the forefinger". Note there lack of depth of discussion on strength of the user, tip mobility, vibrations during impact, power on the swing, static vs dynamic balance, etc. . There are ways to measure/quantify how the knife will "balance" in a general sense as they are based upon simple physical laws such as the inertial moments and the conversation of momentum (linear and rotational). It may very well be that they are well known to some makers who simply don't discuss them openly for the same reasons that few contend the overhype of steels.

It may be that a maker simply doesn't want to come out and say that all the static center of mass focused balance arguements are ignorant of a whole host of factors and are too simplistic a viewpoint and that you have to consider the strength and speed of the user when designing the "optimal" balance. It is similar with Cashen article on forging. Lots of makers will agree with Cashen's statements privately but how many will publically tell Fowler he is wrong and he is ignoring a wealth of materials science as illustrated by Cashen in detail in his public article on his "hype" page.

Mike Swaim discussed balance with regards to a khukuri vs machete some years ago in regards to vibration during impact. I never gave it much thought as I didn't personally see much of an effect. However recently I have been evaluating some knives in this light based mainly on comments by possum some time back and can see a massive potential for change which sweeps over large areas of performance, including heavy chopping blades and many others. I would say there is even more ability to enhance performance from a balance point of view as there is in regards to edge reprofiling / grit optomization.

-Cliff

 

[kel_aa]

ATS-34 developed a reputation for being very brittle in Benchmades which ran them very hard and were rumored to use high temper...
...while Engnath and many others argued that the high temper provided a more durable edge. Materials data does show a charpy loss during secondary hardening however it isn't trivial to extend that to edge behavior.

Does a high temper form huge precipitates? What is the argument that a high temper provides a more durable edge?

Can you make an analogy that precipitates in steel are sort of like a brownie with chocolate chips embedded in it? As the chocolate chips melt together and get larger, they fall out easier and all you are left with is the soft brownie?

 

[the possum]

I hadn't really intended to keep going off topic here, but I guess it's your thread anyway. That, and I just saw a post in the custom forum where someone was demonstrating how their knife balanced right in front of the guard...

If they want to use the knife that way, i.e., move it as a whole, that's their prerogative. But this may end up making things slower & more fatiguing in the end anyway. By swinging the knife as a whole, regardless of how little weight is out on the blade, they are gonna be moving all that weight way out there. But if the knife naturally wants to cock back so you can snap it around with the wrist, then that weight is no longer several inches out in front of your grip. It's right above it- which is where it's easiest to get moving at the beginning and end of a stroke. As an extreme illustration, hold a 20 pound sledge hammer by the end of the handle. Is it easier to hold it upright so the weight is right over your grip, or hold it out horizontally so the head is way out there?

It is similar... Lots of makers will agree with Cashen's statements privately but how many will publically tell Fowler he is wrong and he is ignoring a wealth of materials science as illustrated by Cashen in detail in his public article on his "hype" page.

Yeah. I ain't gonna touch that one with a ten foot pole. Even if I did actually understand the metallurgy well enough. I ain't gonna come right out and tell a maker they don't understand balance, unless maybe specifically asked or whatever.

 

[Cliff Stamp]

Does a high temper form huge precipitates?

Secondary carbides are *much* smaller than the primary carbides. For example, the primary carbides in the poweder CPM steels are generally < 10 microns but the chroimum rich secondary carbides in ingot AEB-L are < 1 micron, so it is a different order of magnitude. In HSS they are much smaller still as the carbides are mainly MC type. Essentially it is a time dependance, the carbides need really high temperatures and more time to coarsen and spheroidize which they get during the initial forming in the ingots and again in the annealing.

What is the argument that a high temper provides a more durable edge?

Experimetal :

"We just went through all this bs over on knife-list. ATS 34 has two
peaks in the tempering area. While the lower peak gives better
corrosion resistance, the higher seems to deliver a more durable
cuting edge. The higher draw also allows a knifemaker to machine
finish the blade with little or no chance of heating the steel to the
point where it will soften.
Practical experience is the final judge in hardening treatments.
While the mfr. will have their recomendations, folks who work with the
stuff every day may actually have more insight. I've had Mr. Bos
harden about 50,000 ATS 34 blades for me and have been happy with
every darned one of them. My customers report going through multiple
deer or elk without sharpening and I've only had two guys break blades
since 1976.
If you parrot the bs, you're not helping to solve anything."

Ref :

http://groups.google.ca/group/rec.knives/msg/526bf72384632c0f?dmode=source

The conflict over this was quite heated and it stemmed from people translating materials data into knife properties with no actual experience and a gross ignorance of the central issues. The arguement in general isn't well defined because what does a "durable" edge actually mean? Consider that Phil Wilson runs higher austenizing temperatures on his steels than normal and Crucible states this reduces toughness. However are his edges actually reduced in durability? Are the properties Crucible is using to make that statement actually relevant?

(no and no)

Knife edges in use tend to take damage even cutting really soft materials because the edges are really thin. While it is hard to bend 60 HRC steel at 1/4" thick it doesn't take much force to bend a piece of steel no matter how hard if the steel is just microns thick. Now consider the properties of really chunky primary carbides trying to stay stable in an edge which has a fraction of their size in thickness. What happens to a very knotty piece of wood if the knots are in a section you taper to *smaller* than the knot. Knots are in general much harder than the surrounding wood but if you make a bow and the tips are full of knots and you actually cut through them what happens when you draw the bow?

The same thing happens to an edge when you cut through the primary carbides and leave pieces of them remaining with nothing to hold them in place. Often if you go low enough in angle they won't even be cut by the abrasive, just like the knots in finely tapered wood they get riped out. The cutting edge meets the inclusion, the action/reaction force builds until it either generates enough pressure for the cutting edge to go through the inclusion or the inclusion tears free of the substrate. A lot of people naively assume since an abrasive is harder than carbides it can cut it, anyone who has worked with woods knows this arguement is false because even though the edge of a knife is far harder than a knot you can still tear knots out of the wood. Once again it is extrapolated knowledge with no experience and which is ignoring critical aspects.

What I think is happening is that when Phil soaks the steel hotter he dissolves more of the primary carbides, specifically the chroimum rich ones. This reduces in general the average size and volume fraction of the primary carbides and increases the edge stability making it less likely to suffer tear outs - this isn't a theory see again Landes/Verhoeven. So even though if you were to take a hammer and bash two pieces of steel heat treated his way and the lower temp way the lower temp hardening may in fact resist the hammer better, his way makes for a better cutting edge.

In regards to secondary hardening it is much the same issue. In general in wear on HSS in industry what happens on rollers and such is that the actual secondary carbides get torn out by abrasive scratches and the primary carbides are stable. However the mechanics of wear on very blunt surfaces does not translate well to edges at all and I think the opposite is seen which is why M2 does very well in knife edges even though it is full of secondary precipitates as are all HSS. Note if you take a HSS blade and draw the temper to soften it, the blade gets less durable and the teeth are easier to break off in cutting even though the impact toughness is much higher.

Can you make an analogy that precipitates in steel are sort of like a brownie with chocolate chips embedded in it? As the chocolate chips melt together and get larger, they fall out easier and all you are left with is the soft brownie?

The chips are more like the primary carbides, they don't hold the cookie together, they actually make it easier to break apart. The secondary carbides are more like the gluten stringers in the flour which can be "precipitated" by kneading which is why it is very easy to tear/crumble a muffin but bread is stronger because it has had a secondary hardening responce through kneading.

(this isn't an exact analogy as gluten will form stringers which are elastic in nature, secondary carbides are not)

By swinging the knife as a whole, regardless of how little weight is out on the blade, they are gonna be moving all that weight way out there. But if the knife naturally wants to cock back so you can snap it around with the wrist, then that weight is no longer several inches out in front of your grip. It's right above it- which is where it's easiest to get moving at the beginning and end of a stroke.

Damn, I thought I had this sort of at least roughly figured out, I didn't even consider the effect of the rotation effecting the linear inertial moment. This makes some of the things I have been doing lately make more sense. Specifically when I was using the Ratweiler vs Battle Mistress the Battle Mistress "felt" much faster. It felt odd that the lighter and more neutral balanced blade was actually "heavier" in hand but consider the effect the two motions can have on each other it makes sense. That is an interesting point to induce rotation so as to position the knife for maximal linear acceleration.

I ain't gonna come right out and tell a maker they don't understand balance, unless maybe specifically asked or whatever.

It is rare no matter how well you understand something that you know everything about it. It is very likely if you talk to someone of vastly different experience they will have information you do not and thus reveal vast areas of personal ignorance. You have to be pretty naive to expect to never be wrong so it is pretty inane to be concerned when it is pointed out. As for makers, being able to make a knife and actually knowing anything about how a knife works are also two unrelated areas of knowledge.

If you wanted to pick out a hammer would you ask a carpenter who uses them or a factory worker for Estwing? Would one of the guys making axes for Bruks actually know more than someone who uses an axe all day long? Did they in fact design the tools based on personal experience or just coping a design or just having artistic inspiration? There are knife makers I respect for their knowledge of how knives work but it is because they actually use them, that they make them is irrevelant to that issue. As well not everyone makes knives based just on performance and thus you can't look at most knives as a representation of the knowledge of the maker in that area even if they are so experienced.

-Cliff

 

[the possum]

Your second to last paragraph reminds me that I also have a lot to learn on this topic. I've about got that goldanged khukri alllllmost finished now, and it's still surprising me. So I don't mean to sound like some kind of pretentious authority figure here. Just trying to attract attention to a subject that has really changed my view on the way a knife should be designed.

Damn, I thought I had this sort of at least roughly figured out, I didn't even consider the effect of the rotation effecting the linear inertial moment. This makes some of the things I have been doing lately make more sense. Specifically when I was using the Ratweiler vs Battle Mistress the Battle Mistress "felt" much faster. It felt odd that the lighter and more neutral balanced blade was actually "heavier" in hand but consider the effect the two motions can have on each other it makes sense. That is an interesting point to induce rotation so as to position the knife for maximal linear acceleration.

I guess this is one of [several] things I was trying to get at a while back when I was comparing the handling qualities of a paring knife vs. a sword. I'm not very good at putting my thoughts into words though. The guys on the HI forum often say you should just use the knife, and it will tell you how it wants to be used. Does the knife want to rotate, or does it just want to stay straight out from your grip through the swing? That's the kinda stuff I'm thinkin' of here.

 

[kel_aa]

Note if you take a HSS blade and draw the temper to soften it, the blade gets less durable and the teeth are easier to break off in cutting even though the impact toughness is much higher.

So it is this due to too much secondary carbides coming out? Is the same argument being made against high temperings for ATS?

Benchmades which ran them very hard and were rumored to use high temper to allow heavy grinding after heat treating which I never saw publically confirmed or denyed by Benchmade.

So secondary carbides do not grow too much. Then what is the argument that a hotter temper will make ATS easier to machine?

 

[Cliff Stamp]

I'm not very good at putting my thoughts into words though.

I would not say that, personally I think it is more of trying to explain color to a blind person. Until you have some background/perspective then it is hard to see the point because some of the issues are simply too foreign.

The guys on the HI forum often say you should just use the knife, and it will tell you how it wants to be used. Does the knife want to rotate, or does it just want to stay straight out from your grip through the swing?

I think in general a lot of the time we tend to enforce viewpoints and preferences on tools often overlooking what they can offer. The far opposite is never a good idea either, putting designs on some godly platform where critism is seen as insulting. A balance between the extremes tends to be more productive in general.

So it is this due to ...

It gets weaker as the temper draws the hardness and the teeth just break off.The impact toughness is far higher but the strength becomes the critical failure point so the "edge" durability is lowered. I was using this as a general example of why you can't just argue durability=charpy, it is far more involved.

Is the same argument being made against high temperings for ATS?

Essentially yes, and it is flawed for the same reason. There is also another side issue of austenite transformation which will happen at high tempers but not in low ones for the high alloy steels and retained austenite can make the edge less durable and the blade body more durable. This is complicated by cryo which makes retained austenite a moot point.

So secondary carbides do not grow too much.

Not during normal temper times, if you keep them there they will but it is slow unless you really raise the temperature. This is why they are "high speed" steels because they will resist coarsening at temperature which is what causes the loss of hardness.

Then what is the argument that a hotter temper will make ATS easier to machine?

It isn't easier to grind however it can be ground hotter and thus you can press harder into the belts which drastically increases speed of sharpening.

-Cliff

 

[kel_aa]

As the angles are very low the edges are deforming and seeing fracture. This may be due to the coarse grain and heavy aggregate carbides of 154CM.

In your review of the Trident then, when you say heavy aggregates, you mean heavy aggregates of primary carbides, as in it wasn't soaked hot enough to dissolve them? And what would be the cause of the coarse grain? Tempered too hot/long?

 

[Cliff Stamp]

The grain is coarse by nature of the steel. The high alloy chromium wear based steels are especially bad in this regard in general. The primary carbides in D2 for example huge, easily 10 times that of finer steels :

I am being sloppy with grain here meaning it to refer to the austenite grain size and carbide aggregation. It would be possible to remove the primary carbides by high enough soaking but then you have to deal with the grain of the austenite coarsening, the effect on the hardening as all that dissolved alloy will induce massive retained austenite and of course it begs the question why did you have the alloy there in the first place?

Some steels work better than others at certain applications. You are usually better off picking an inherently more suitable steel when the standard heat treatments don't work very well because industry did design the steel for a purpose and has refined the heat treatements accordingly. Usually even if you do get it to work you end up having it be sub-optimal and vastly over expensive.

-Cliff

 

[kel_aa]

begs the question why did you have the alloy there in the first place?

Because many people get all giddy when they see CM154? That's a good steel, must be a good knife. The steel it self and the design non-withstanding, you can make the heat-treatment more suitable for the purposes of the knife than it apparently was, right?

I understand the how alloys can change the hardenability of the steel. Can you explain why alloys alter grain size?

 

[me2]

Just to let Cliff's fingers rest, I'll take a stab at the grain boundary size and alloy elements issue. Some high temperature carbides wont completely disolve at the austenizing temperature. These provide a barrier that the enlarging grain boundaries have to move around and engulf. Alloy elements not tied up in carbides can gather at grain boundaries. For the boundary to expand/move, these must cross the boundry, or be pushed along, which is more difficult than with the other iron atoms. Verhoeven has a good explanation in his book for bladesmiths and heat treating.

Cliff, does Phil have trouble with the higher temps disolving too much carbide and causing underhardening? I've read of it being an issue for D2 and other high Cr/C, but dont know about the newer alloys. Of course, Phil if you're reading this, then jump in any time.

 

[kel_aa]

Some high temperature carbides wont completely disolve at the austenizing temperature. These provide a barrier that the enlarging grain boundaries have to move around and engulf. Alloy elements not tied up in carbides can gather at grain boundaries...

But according to these high alloyed steels should be fairly fine. It has been said that M2 is fine, but I don't see how CM154 and D2 are not. I understand hardening through grain refinement doesn't lead to as much decrease in toughness, so shouldn't this de desired?

 

[Cliff Stamp]

The steel it self and the design non-withstanding, you can make the heat-treatment more suitable for the purposes of the knife than it apparently was, right?

In general you have to sacrifice too much of the other properties when you try to make a steel do something it wasn't really designed to do well and it is costly and more time consuming to work with. The only reason you in general would do this if you were forced to use it or simply had a bunch of it for free. The most common problems induced are too low a strength for a given impact toughness, or too low a grindability for a given strength.

... with the higher temps disolving too much carbide and causing underhardening?

This causes underhardening mainly because it shifts the martensite start and end points down and results in a high percentage of retained austenite. This isn't a concern if your end point in your quench is liquid nitrogen. Phil actually draws his hardness down significantly during tempering.

But according to these high alloyed steels should be fairly fine. It has been said that M2 is fine, but I don't see how CM154 and D2 are not.

You want a very fine dispersion of high temperature carbides to pin austenite grains, not really big chunky chromium rich ones which are 30-50 microns in size. You also tend to do better with small amounts of dissimilar carbide formers rather than an equal amount of the one type due to less aggregation.

I understand hardening through grain refinement doesn't lead to as much decrease in toughness, so shouldn't this de desired?

Generally you want to increase the grain refinement as much as possible and it tends to make pretty much everything better however it will lower hardenability. This is a point of confusion to some. A2 for example has a higher hardenability than 1095 because A2 can air cool whereas 1095 needs a water/oil quench. However with standard heat treatements 1095 is usually significantly harder.

-Cliff

 

[Knygathin]

The Gerber Silver Trident is NOT a bushcraft knife. It is not designed for battening, slicing potatoes, hacking in gravel stone, or bending and levering.

It is purely a tactical self defense weapon. Excellent for stabbing and slashing. Very deadly. Perfect weight and length for the purpose. That it would break on such encounter is extremely unlikely.

A fantastic knife!