ZDP - Wow its brittle!

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gull wing
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Postby gull wing » Tue Jul 06, 2010 2:26 pm

ZDP (for me) is just fine.
I dropped my Stretch ZDP on concrete, it went tip dpwn. There was very little damage, just a few little "teeth" showing (from tip to 1/4" down). To fix it I used my Edge Pro, reprofiled, and all is well.
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dbcad
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Postby dbcad » Tue Jul 06, 2010 3:45 pm

I agree that very hard is proportional to brittle. At work I called out a low carbon ground stock for use on a part, The engineer told the vendor to make it out a-2 and to harden it, don't know how hard. I had a pretty snug fit called out and when the piece was seated with a light hammer tap it promptly broke.
I've never called for an Rc of 65 though.....lol. :D

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Postby Johnny Boy » Tue Jul 06, 2010 5:19 pm

v8r wrote:Back in my Machinist days I found out that Tungsten Carbide lathe bits could be worked lots harder then HighSpeed steel lathe bits. The Tungsten could take off crazy amounts of material at a time, we are talking .250 or more off the diameter at high speeds, but the downfall to the stuff is if you drop that lathe bit the end would shatter.This is due to being super hard/ brittle. High speed steel on the other hand, you could drop and it would just ding it a little due to it not being nearly as hard
I hope this helps folks to understand that if It is super hard it will probably chip or break
Absolutely man. I am chiefly a welder but, I do a fair amount of machining myself. Like you said if I use a cobalt or carbide or whatever bit/drill it can take a lot more abuse than a HSS cutter. The harder tools hold a nice sharp cutting edge a lot longer than the softer tools but, like you said any dropping or shocking impact and that carbide cutter is in pieces.

The same can be said for any alloy really. IMO the best blade steels or alloys are a nice balance between toughness and edge retention. There is grain size involved in the equation as well. The tighter the grains or smaller the grains the sharper the material can be. Blades made for anything are designed (for the most part) to do a specific task.

OP if you are interested in learning a bit about the alloys spyderco employs I really recommend checking out their edge-U-cation located on the main spyderco website. It's very well done and will give ya a much better idea of application of allloy. Matter of fact according to the machinist handbook and edge-u-cation, steel by definition has no more than 2% carbon. Your ZDP-189 has 3% so technically it's not steel. I guess it'd be a ferrous alloy? I don't know because it's not something I work with at all. Anyways here's a link for ya http://www.spyderco.com/edge-u-cation/

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Postby Ski » Tue Jul 06, 2010 8:27 pm

marcus1 wrote: What is the point of making these statements. You could have simply stuck with "exhibited a known characteristic". Which, until now was relatively unknown to me... And it IS UNreasonable for anyone to criticize the way I have been in this thread. Be constructive, as most people here have been. To make flippant remarks helps no one!
I was not being flippant. My ring analogy was EXACTLY the same what you experienced with your blade damage. If you choose to take it as me causing trouble, that's your prerogative.

If you find my analogies to not be constructive, I'm sorry. I was just trying to aid you in being realistic about the capabilities and properties of "super steels"
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The Mastiff
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Postby The Mastiff » Wed Jul 07, 2010 3:05 am

I've been carrying and using ZDP since it was first introduced by Spyderco. I have well over a dozen Spyderco ZDP knives, plus several from another manufacturer.

I can't say I find ZDP to be brittle or weak in any way, shape or form. It is what it is. It's just like an O-1 knife. You might want to take into consideration that it's not stainless. If you have a knife with a needle tipped point you treat it the way you are supposed to by not prying, or using it as a screwdriver.

ZDP is an amazing steel. If you want 5160 toughness, get a knife made of 5160. If you want an extremely stainless/stainfree knife get a salt. If you want a knife that has ZDP's combination and balance of excellent wear resistance coupled with the ability to run almost absurdly thin, low angled edges to cut atoms in half than nothing else does it as well.

If you grind your knife like that common sense says that it just might break if you abuse, or even drop it. That doesn't mean it's brittle. That just means it's not built with the extra beef added on to take into account the occasional drop onto concrete.

A knife, like any tool can be designed for any job you might want.

It's really a simple concept. I like specialized knives. They are more efficient at doing their job than a jack of all trades knife. Some, on the other hand want one knife that can do everything they ask from it.

Nothing wrong with that. There are companies with designs to make almost everybody happy

I have seen when people get mad at a design that isn't what they percieved it to be. We had a guy here that was indignant that the millie couldn't take, and wasn't reccommended for prying. His argument was that anything called a "military" should be indestructible.

No amount of reasoning could convince him. The fact that the paperwork warned against prying was irrelevant to him. People posting comparisons of the Millies slender ( but strong) blade with sharp "splinter picker tip" compared to knives more designed for what he stated he wanted went over his head. He would not, or could not accept that tools are designed with certain jobs in mind and no one design could do everything. Especially one that costs...$ XXX.XX

Steels, as advanced as they have become are certainly the same way. ON top of that, the grinds used, as well as the heat treats and final hardness all contribute to the knifes final acceptance, or lack of it.

Of course the internet, and forums like this have a certain amount of influence on products. If there are products that get labled as "brittle", for instance, some will accept this as canon and in turn repeat it as gospel whether it's true or not.

A few years back the "problem" with S30V was a prime example. A large percentage of folks were convinced that S30V was "chippy". Somehow defective. The most common diagnosis by "experts" was "poor heat treatment".

It wasn't any more chippy than any other high vanadium stainless. When the knives did chip a lot of it had to do with how they were ground, and to what grit.

Despite that the "common knowledge" of the time had it being heat treat problems because it was difficult to treat just right.

Crucible tested knives. Information was given to industry users that needed it. Fixes made, and the problem, such as it was virtually disappeared.

To this day rarely a week goes by on certain forums still repeating as facts the problem with S30V steel chipping.

The fact that it's a very high quality, consistant and high performing steel tends to get overlooked even to this day. It's actually a very good, high performing stainless steel, consistent from batch to batch more so than some "tool steels" even. A 4% vanadium stainless cutlery steel is no joke. When I was a kid it, like ZDP 189 was inconcievable in fact.

Regards, Joe L.
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chuck_roxas45
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Postby chuck_roxas45 » Wed Jul 07, 2010 6:34 am

I guess you're referring to me. My point was not that I wanted to be able to pry or whatever else you think I wanted the millie to handle. My point was that you tried to convince me that The tip of the millie was robust enough. I just could not accept that what I was seeing as thin and fragile was as strong as you made it out to be. I did not get all bunched up at what the millie is incapable of but rather I just got tired of being told something other than what my eyes were telling me. I love my millie, it is one of my two favorite knives among my few. I just can't accept that the tip is hard use.

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Postby Blerv » Wed Jul 07, 2010 1:45 pm

This forum is a wealth of knowledge. They range from industry leaders and sages to the ignorant.

Personally as someone closer on the spectrum to "ignorant" I appreciate insight from these individuals.

A belief or opinion isn't required to be accepted. It should be assessed and filtered through common facts and decided on. That way the person can respond instead of "reacting" to a statement.

Emotions should be checked with Ego at the door. Something I work on every day and still need a ton of help with. :)
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The Mastiff
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Postby The Mastiff » Wed Jul 07, 2010 2:35 pm

I guess you're referring to me
Chuck, the incident I was referring happened about two to three years ago. I'm sure not going to tell you that your opinion isn't as valid as anyone elses, or you're not allowed to think differently from the "norm".

The incident was more of a hit and run complaint from somebody who wasn't part of our community, and didn't want to be. He was more here to put people and Spyderco down rather than make a valid point, as you were.

No offense meant to you Chuck, and I apologize for the misunderstanding.

Joe
"A Mastiff is to a dog what a Lion is to a housecat. He stands alone and all others sink before him. His courage does not exceed temper and generosity, and in attachment he equals the kindest of his race" Cynographia Britannic 1800


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Postby dbcad » Wed Jul 07, 2010 2:39 pm

I hear you Blerv...thumbsup!! I work on the same thing myself :)

Sadly hard steel hitting hard steel acidentally almost never seems to have a positive outcome. Have done it inadvertently with axes and hatchets, but I've been lucky I haven't done it to my knives.

I've read Spyderco's ZDP knives have a 65 Rc. I don't know any steels commonly used in industry that can take that kind of hardness without becoming stupidly brittle.

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Postby chuck_roxas45 » Wed Jul 07, 2010 4:36 pm

The Mastiff wrote:Chuck, the incident I was referring happened about two to three years ago. I'm sure not going to tell you that your opinion isn't as valid as anyone elses, or you're not allowed to think differently from the "norm".

The incident was more of a hit and run complaint from somebody who wasn't part of our community, and didn't want to be. He was more here to put people and Spyderco down rather than make a valid point, as you were.

No offense meant to you Chuck, and I apologize for the misunderstanding.

Joe
Ok Joe, my apologies.

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Postby jezabel » Mon Jul 12, 2010 12:19 am

The Mastiff wrote:
A few years back the "problem" with S30V was a prime example. A large percentage of folks were convinced that S30V was "chippy". Somehow defective. The most common diagnosis by "experts" was "poor heat treatment".

It wasn't any more chippy than any other high vanadium stainless. When the knives did chip a lot of it had to do with how they were ground, and to what grit.

Despite that the "common knowledge" of the time had it being heat treat problems because it was difficult to treat just right.

Crucible tested knives. Information was given to industry users that needed it. Fixes made, and the problem, such as it was virtually disappeared.

To this day rarely a week goes by on certain forums still repeating as facts the problem with S30V steel chipping.


Regards, Joe L.
Joe,
I have to admit that I have problems with S30v chipping. I own three Syderco's in S30v , a Chinook III, Mini Manix & an SE Native. If I recall correctly these particular knives all carry production dates circa Aug '08. While I have managed to put all my other Spydie's with CPM D2, VG10, CPM M4, CPM 440V & CPM S90V) to great use after I've gained experience with these steel's strengths and weakness's.

The same can't be said for CPM S30V. With my S30v blades it's almost like they chip if they're asked to cut anything other than soft fruit (Yes I am exaggerating). I've experimented with different sharpening techniques, grinds and levels of finish etc... but to no avail. Unfortunately these disappointing experiences have left a bad taste in my mouth, so much so that I longer entertain the idea of purchasing any more S30V knives.

I don't know if I've had the bad luck of a less than acceptable batch of S30V produced in '08 or if that's just how S30V is?

For me S30V's now a case of Once bitten, twice shy :( .

Jez
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Kicking_yourself
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Re: ZDP - Wow its brittle!

Postby Kicking_yourself » Sun Oct 11, 2020 8:03 pm

So this happened. The blade snapped completely in two. https://twitter.com/kicking_urself/stat ... 19618?s=21

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Re: ZDP - Wow its brittle!

Postby JRinFL » Mon Oct 12, 2020 8:35 am

Kicking_yourself wrote:
Sun Oct 11, 2020 8:03 pm
So this happened. The blade snapped completely in two. https://twitter.com/kicking_urself/stat ... 19618?s=21
You need to contact Spyderco support about this. They will want to know how the knife was being used when it broke, among other things.
Used to be JR in CT with a much earlier join date. :rolleyes: :spyder: Native in 440v was my gateway Spyderco! :spyder: Wharnie for the whin! Friends call me Jim. As do my foes.

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Re: ZDP - Wow its brittle!

Postby Wartstein » Mon Oct 12, 2020 8:59 am

Kicking_yourself wrote:
Sun Oct 11, 2020 8:03 pm
So this happened. The blade snapped completely in two. https://twitter.com/kicking_urself/stat ... 19618?s=21

Welcome to the forum! :)
How did this happen? And how long have you been owning/using the Endura?
Top three going by pocket-time: Endura 4 in VG 10/Micarta-scales; Stretch 1 in VG 10; Endura 4 in HAP 40

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Re: ZDP - Wow its brittle!

Postby bearfacedkiller » Mon Oct 12, 2020 9:26 am

How did it break? What were you doing? I would probably be kicking myself too!

What do you hope to achieve with this post? We will help if we can but this looks like a question for spydercos warranty department.
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Re: ZDP - Wow its brittle!

Postby Thunderpants » Mon Oct 12, 2020 9:31 am

A dab of superglue and it'll be ready for ebay...

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Re: ZDP - Wow its brittle!

Postby Larrin » Mon Oct 12, 2020 9:38 am

That is an odd location for a break to occur. I am also curious what the knife was doing when it happened.
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Re: ZDP - Wow its brittle!

Postby Evil D » Mon Oct 12, 2020 9:40 am

Definitely not a steel I'd pry with, not even a little. I also wouldn't say it's brittle either, just very hard and not very forgiving.
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Re: ZDP - Wow its brittle!

Postby Accutron » Mon Oct 12, 2020 10:33 am

What's this dark spot right here?

Image

I can't tell if it's a speck of rust or just dark from the lighting angle, but it looks very much like a speck of rust. If so, then you had some sort of stress crack in the spine prior to the actual breaking incident.

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Re: ZDP - Wow its brittle!

Postby JohnDoe99 » Mon Oct 12, 2020 10:41 am

marcus1 wrote:
Sat Jul 03, 2010 4:55 pm
I know I read somewhere on here that for hardness you sacrifice a bit as the steel can be more brittle, but wow, didn't think it would be that noticeable in my Spyderco ZDP Endura :(

I dropped my knife and it hit another metal tool, and the tip lost a nice chunk (The tip was still there, it was the edge that had a chunk out of it... sorry didn't think to take a picture before I fixed it).

I've dropped my G-2 Endura many many times over the 12+ years I've had it and all it has is a bit of a bent tip :)

So either this was just one really unlucky drop, or ZDP is really brittle (IMO).

Good thing I have the diamond stones for my SM... got it back in shape in no time (and perhaps a tear or two later ;) )
It is that brittle. I chipped mine good once just by using too much pressure when I was reprofiling the edge on an india stone to grind out an earlier chip.

S30v, s110v, and the rest aren't far behind either, if at all.


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