Testing the new Dendritic Militaries

C

Cliff Stamp

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In reply to Sal's post :

http://www.bladeforums.com/ubb/Forum20/HTML/001147.html

here is a place to hash out the testing methods for the new Militaries. Basically from what I have read of the Dendritic materials thay are supposed to cut really well and not be difficult to sharpen. I have heard however that they are rather fragile, that the 440C version tends to chip and the Cobalt indents fairly easily. The Cobalt also has high corrosion resistance. These are the positives and negatives so it should be a good place to start.

-Cliff
 
For testing these knives, we should first establish a reference point. I believe that the best reference is the current offering of the Military in 440V. This will allow testing the material properties with all other variables held constant, ie, blade geometry, handle, edge geometry, etc. From here, edge retention, ease of sharpening, brittleness and other characteristics could be studied without respect to field use. The second round of testing should establish results from field practices, as often is discovered, lab testing does not always tell the whole truth.

jj

[This message has been edited by jeffj (edited 03 September 1999).]
 
Dang, jeffj beat me to it. I'd like to see a 440V military and an endura go through the exact same tests as the BDC or BDS militaries.

Independent of the military, I'd love to see a controlled test of the supposed micro-teeth that BD* has. Finish all 3 knives at the exact same grit and then cut something that only toothy edges cut well -- like ultra-hard poly rope. Report how many slices to make it completely through.

More tests to follow after this thread is more filled out!

Joe
 
in the overall useability relm, im going to want to know how this stuff holds up to salt brine, sand and other abrasive/corrosive stuff i work around.

"can i cut a poly brine line buried in sandy dirt without killing the blade the first time?"

 
oopse, forgot to check the sig box on that one.

the other thing is, when i get done digging in the dirt, i need to open heavy gage plastic bags neatly, so itl have to have some edge left.

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'Till next time,
Rich the kite guy
 
Cliff - thanx, good start. What I'm after is the best all 'round test for any knife.

A test that would anwser all of the questions one might ask. I already see a few. Ultimately, I would like to end up with the "universal knife test". This is the best place to devise such a test, IMO.
sal

[This message has been edited by Sal Glesser (edited 03 September 1999).]
 
Ah, if this is a more general knife-testing discussion, here's my take.

First, you have to test against a well-known control. I always use an endura for 4" bladed knives. It's the best bang for the buck. Those expensive knives should be able to outperform a $40 endura -- but many can't.

Whittling is a good test of shallow edge penetration, which depends on the thinness at the very edge. Blade geometry further up doesn't matter as much on whittling -- a very thick-spined knife will whittle well as long as its edge is nice and thin. More importantly, whittling a piece of pine for 5 minutes can be tough on your hand. It brings out every little hot spot on the handle. So it tests both shallow penetration and handle ergonomics.

I try slicing in both soft rope and very hard. Soft rope tests slicing combined with push-cutting which is a very common use. But if the edge geometry is incredibly good, you can completely push-cut through, and that's even better. For example, my good slicers slice easily through soft rope, but the Calypso Jr. push cuts through even more easily. Hard rope tests slicing and especially edge toothiness. Slicing hard rope for a few minutes will also raise any handle hot spots, and it's a different motion than whittling so it'll find different handle problems.

Zipper cutting through cardboard gives you overall geometry feedback.

Stabbing test in something like a phone book tests shallow point penetration, but more importantly handle safety on stabs. Stabbing into something softer (e.g., squash or pumpkin) tests deep point penetration.

All of these tests I feel are things I might reasonably do in real life. Whittle, cut rope, cut cardboard, zipper cut, slice, push cut, stab.

I've done various tests for edge durability for folders, but still haven't quite settled on anything.

That's it for now

Joe

 
The Universal Knife Test, at least from a manufacturer's standpoint, <EM STYLE="color: maroon;font-style: normal; font-weight: bolder;">begins before the knife is even made</EM>:

"This is the broschyre description [but it will have better illustrations]: Would you buy the knife based on this; Would you want to handle it next time you visit the knife shop?"

"Now let's pretend we're in the shop. This is a prototype/mockup, so it doesn't cut [very well], but you can handle it: Would you pay for it right now; Would you go home and think about it and return to purchase it next week? (Note that this actually takes a week to test...)

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Urban Fredriksson
www.canit.se/%7Egriffon/


[This message has been edited by Griffon (edited 04 September 1999).]
 
Okay, going further ...

Beyond well-controlled "lab" tests (garage tests really
smile.gif
), a period of uncontrolled "field" tests are needed. Carrying the knife around and using it for random needs for a month allows the reviewer to assess the clip, the draw, the opening, and carryability in different kinds of clothes. Beyond that, although we try to simulate all real-world use in the lab tests, there are always other interesting uses that come in with daily carry. A one month daily carry test is a must!

Okay, some further thoughts on edge durability. I sometimes use the common brass rod test. But the thing that bothers me about that test is that unlike all the slicing and ergonomic tests I outlined above, the brass rod test does not really simulate anything I actually do in real life.

Something that might work better is hacking with the folder into medium-soft wood. I don't really hack with my folder in real life either, but a test like this does do a better job of developing real life stresses, like edge impact and slight torquing. A specific light torquing test, where the final edge bevel is stuck into soft pine and lightly flexed out, might make sense also.

My hesitation in all this talk about edge durability is that although I feel there's a real need for edge durability testing, I'm not satisfied I've done enough research to see a real correlation between the tests themselves, and real use. I'm almost convinced, but not quite.

Joe
 
seems to me the diffrence between the real world and the lab is the combination of events that happin together. not everyone cuts clean new rope on a daily basis, in fact most of the line i encounter either now or back in my marine construction days was heavily fouled with something or another.
how a knife works in a high stress situation with a wet gloved hand in sandy salt water while trying to cut barnicle incrusted line is clearly a whole diffrent world to its preformance in a lab.



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'Till next time,
Rich the kite guy
 
in another thought, not everyone is that hard on knives, but even then life comes into play.
new g-10 seems to hold in my pocket and slow my draw over "worn in" scales of the same material. also, how do you lab test lock performance with a days worth of pocket crud in the works?

i further agree that a benchmark for comparason needs to be set, but comparason to a favorite carry knife might be useful also. if youve worked with a spyderco disenbowler for a year and a half, you know what it will and will not do. a benchmark in some ways is only as useful as a users familiarity with that knife.

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'Till next time,
Rich the kite guy
 

I think that in real life situations the best test for a knife would be things that each of us do on a daily basis. My wife and I both use Spydercos on a daily basis depending on which model we have on us at any paticular time. In our profession we will cut boxes that have been wrapped in tape, cut various types of rope, cut rubber hoses, strip electrical wire, cut nylon banding straps, etc. I have even used mine to cut up sod squares and prune shrubs.
I have one of my customers that works with us who uses his Endura to scrape old paint from pipes to determine what the pipe is made out of, cut metal banding straps, open small crates and just about anything he can find for it to be used on. I hope that these examples will be useful.

Bobby
 
Joe T.'s last post, wherein he mentioned chopping into wood to test an edge's resistance against impact and torquing stresses, brings to mind one of my favorite tests: cutting through hardwood dowels. I normally do this in conjunction with lots of whittling. Rather than simply chop through the dowel (3/4" oak or something comparable) I actually push-cut and slice my way through it. You have to push really hard, rotating the dowel as you go, carving out a deep groove all the way around until the dowel breaks.

Although this doesn't test impact resistance, it does correspond fairly well with real-world cutting applications: a person who lacks a saw might actually want to cut through a stick in this manner. The heavy-pressure push cutting required to cut through an oak dowel approximates other kinds of hard cuts I've had to perform on occasion: cutting through chunks of beeswax, for example, or cutting firm, sticky cheese, where you have to bear down on the handle about as hard as you can.

Cutting through a hardwood dowel is a great test of the knife's handle ergonomics as well as intermediate-term edge holding and geometry.

David Rock

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AKTI Member # A000846
"Never carry a knife shorter than your schnoz."


[This message has been edited by David Rock (edited 04 September 1999).]
 
Thanx, some really great input. It would be nice to find a way that we can view a common list that is added to and changed as the tests are refined. Any ideas other than Email. If it is to be Email, we will need an "onsite" contact in R & D and an "offsite" contact. These two will make sure that each of the others in the "team" for that project are kept up to date...daily.

I believe that there are probably far more forumites interested than would be possible or practical to include. The test itself will make it difficult or impossible for some, due to the time or material requirements. There is also the possibility of rotating. In the design area, we're dealing with paper and drawings, but in the actual testing, much will depend on the number of production prototypes it is practical to make. Again, some rotation may be neccessary.

The difficulty will be in the persistance and discipline required to follow through to completion of the "systems" to make it work.

The lab stuff we can do. We have edge testers and breaking machines and we set up for "Q" fog corrosion tests.

What I feel we need is the educated opinions of those that spend a fair amount of thinking energy to the "perfecting of the "thing". This is how designs evolve and refine anyway.

I would at this time like to separate, as mentioned earlier, design and development.

Spyderco R & D Offsite "concept to design" group

Spyderco R & D Offsite knife development group.

On the design end, we would have;

Purpose of the design
What it must do
What it must not do
Size(s) of the design
Materials
The actual offsite field test

In the field test;

Edge geometry in performance. As Joe suggested, tests that show effectiveness of edge gometry and ergonomics (hot spots) in the same test. Cardboard, whittling, even the rope cuts would show this valuable info.

Carry comfort is important. Slicing, stabbing, mabe a "twist" test.
Lock defeat, ease of unlocking as opposed to accidental unlocking?

So far, so good. Need more ideas and more details on "how to". What is important to have in a knife? What is important to avoid?
Need a coordinator.
sal
 
Another test I do, when it makes sense for the particular knife I'm looking at, is put on a kevlar glove, pour liquid soap on the knife, and do some good hard stabs. Does the handle protect your hand under slippery conditions?

I guess the overall philosophy is:
1. Lab tests that are easy to reproduce by anyone and are measured against a benchmark, and that real-world performance as much as possible, given the design objectives for the particular knife.
2. A month-long real world test, to hit everything else.

We want tests to show cutting efficiency, blade durability, lock safety and durability, ergonomics, carryability and drawability. When a single test covers several of these at the same time, that's good.
 
Another test not mentioned that would be nice to add to field testing (especially for folders) is maintainablility. Some questions that the test might cover:

How easy is the knife to break down and reassemble in the field?

Is the knife locking mechanism easy to defeat under less than ideal conditions, that is, when muddy or wet?

How easy is the knife to clean?

Is the pivot protected and/or easy to clean?

How robust is the locking mechanism, that is, how many ways can the knife lock mechanically fail under poor conditions? What kind of use can I expect? 10%, 50%, 90% use when there is a lost/broken spring, Bent stop, etc.

jj


[This message has been edited by jeffj (edited 05 September 1999).]
 
I've purposely avoided volunteering to be the coordinator despite the fact that every fibre in me is screaming to volunteer, because I seem to have gotten a lot of cool knife jobs, and I wanted to give someone else a chance to volunteer. But if someone doesn't volunteer soon, I'm jumping at it!

Joe
 
I'd be willing to take a stab
smile.gif
at coordinating this type of thing I think we should also run the BD* up against something with a non-stainless blade, EDI Genesis in A2 if they're out already.
Aaron

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amacks@nist.gov
Don't forget to pay your taxes...they eventually become my knives:)

 
I forgot to add my piece of testing: Cutting thin straight lines in thin plastic, ie gel. I have to do this often in the theater, and it is very difficult with many knives because the playtis is pretty tough, but so thin that it's hard to get a good clean cut with out damage.
Aaron

------------------
amacks@nist.gov
Don't forget to pay your taxes...they eventually become my knives:)

 
Sal :

Ultimately, I would like to end up with the "universal knife test"
Click to expand...

I think you can get general catagories, which I have been doing as of late, but specifics need to be decided based on the knife in question. Doing similar things with my Bill Moran Featherweight and Busse Battle Mistress would not be that sensible.

It would be nice to find a way that we can view a common list that is added to and changed as the tests are refined
Click to expand...

That is rather trivial :

http://www.physics.mun.ca:80/~sstamp/knives/testing_military.html

I can keep a running list like that if desired. I will be in and out the next few days but should be back on schedule and checking in on a regular basis next week.

As it exists currently. The page is only a sketch drawn on suggestions here. If desired I can fill it out and put it into a more readable form. Suggested format for the outline, should it be listed in terms of specific tests and what they cover or the reverse?

-Cliff
 
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