How to test for different types of knives?

[Patrice Lemée]

This came about in a thread in the Customs forum when the discussion veered towards what level of performance was expected of knives that had a very small chance of being used. The consensus is that it needs to perform as well as the maker is capable making it do so. That led me to ask about how to test for other types of knives.
I mean we all know the classics cutting tests but what testing is needed for let's say a Persian dagger?
Or any other type of knives that doesn't fit in the "cutter" category.

 

[JParisi48]

If I were to buy a custom show piece that probably wasn't ever going to see use, I would still expect it to perform reasonably well for the particular style's intended use. I don't know much about Persian daggers, but IMO you should test it for its intended use and it should be able to perform. Say if you were making an art dagger for the MS test, test it before you did all of the detailed work to make sure it was solid and reliable. Whatever else you add would just be for asthetics. If you watch the Journey to Master videos of Kyle Royer you will understand what I am trying to say. BTW your Persian dagger is very nice

 

[james terrio]

I mean we all know the classics cutting tests but what testing is needed for let's say a Persian dagger?

Stabbing Persians?

A knife that's not a "cutter" (or stabber, as the case may be) is not a knife. It's art, or decoration, or something... I do not understand the supposed confusion over this topic at all.

 

[Patrice Lemée]

A knife that's not a "cutter" (or stabber, as the case may be) is not a knife. It's art, or decoration, or something...

Sorry, I meant cutter in the sense of a large bowie or camp knife. Of course if it doesn't cut it is not a knife.

I do not understand the supposed confusion over this topic at all.

I am confused James. You mean you are confused about the confusion? Or is it the supposed confusion? Cause if I say I am confused, how can it be supposed confusion? Isn't it real confusion?
Very confusing!

 

[Rick Marchand]

You are asking how to test a dagger, kerambit or beheading sword for its intended purpose WITHOUT testing it FOR its intended purpose, right? I say that a maker who is worth their salt should be capable of making a decent performance knife before dabbling in other "less inclined to be used" styles. I don't see the need to test such pieces if the maker has a good reputaion for quality.

 

[Patrice Lemée]

But Rick, I see mastersmiths (or people without the MS but equally capable) still put their knives through thorough testing even thou as you say, it's probably a given that the knife will perform flawlessly.

 

[Rick Marchand]

You see mastersmiths testing persian daggers and other specialty styles? Then why are you asking how to test? I'm not trying to be a smart-aleck.

Perhaps I am confused as to what you are asking.

I test my knives all the time for cutting, edge retention and construction integrity. Once in a while(especially if I tweek my HT or use a new steel), I test to destruction. I did a LOT of destruction testing in the beginning. I'm at the point now, that as long as I keep my equipment working properly, the quality is there.

 

[Frank Niro]

Would you expect your current Bone Collector to perform as well as some made in a manner for actual use? You did not even intend to make it so it did when you started did you? There is a lot of side tracking being done to convince people that a knife is only supposed to do one thing and that is to cut. Compare art in the painted picture world. There are so many pictures that to many look rediculous or even totaly foolish but to others reach out and overcome some of the viewers. I feel and have stated many times that "art" knives serve a function and that is of "beauty" . So if it is a knife with little or no apparent functioning purpose why try to make it into what it's not? Frank

 

[james terrio]

Sorry, I meant cutter in the sense of a large bowie or camp knife. Of course if it doesn't cut it is not a knife.

I am confused James. You mean you are confused about the confusion? Or is it the supposed confusion? Cause if I say I am confused, how can it be supposed confusion? Isn't it real confusion?
Very confusing!

I understand your question better now. When I think "cutter", I just mean "cutting whatever it's meant to cut", not always a camp knife. Sorry for my confusion

I do agree that with a certain amount of skill, experience and knowledge, a known maker can surely be counted on to make a quality, performance-oriented knife - even one that's an unusual design - with a very high degree of certainty that it will perform as intended. Without necessarily testing it, and with no regard to how extensively it's embellished. :thumbup:

I'm at the point now, that as long as I keep my equipment working properly, the quality is there.

That's true. But still, one way to check to make sure one's equipment is working properly is to performance-test -- or even destruction-test - a knife occasionally. Besides, it's fun and whether it's really needed or not, clients like to see it. It builds confidence and sales in a very cost-effective manner. We trust Ferrari to make a fast car... but we still want to see them prove it.

I feel and have stated many times that "art" knives serve a function and that is of "beauty" . So if it is a knife with little or no apparent functioning purpose why try to make it into what it's not? Frank

I agree, and that's where my initial confusion came from. There's no need to performance-test a knife that's purely intended to stay in a glass case. But there are lots of knives that straddle the line between "art" and "tool", and do extremely well at both.

 

[Rick Marchand]

That's true. But still, one way to check to make sure one's equipment is working properly is to performance-test -- or even destruction-test - a knife occasionally. Besides, it's fun and whether it's really needed or not, clients like to see it. It builds confidence and sales in a very cost-effective manner. We trust Ferrari to make a fast car... but we still want to see them prove it.

I don't think that performance testing the knife is a valid way to calibrate equipment. Of course, in extreme cases(like a TC being hundreds of degrees off) it will show... but if you have to deflect your knife 90 degs or make 500 cuts through manila to make sure your kiln is working right, I see a problem. Do heavy testing while you experiment and gain experience in your method, then with properly calibrated equipment, testing can be performed less frequently.

 

[james terrio]

I don't think that performance testing the knife is a valid way to calibrate equipment.

That's true. It's certainly not anywhere near as accurate as proper calibration of a kiln or hardness tester.

I do think that p-testing is a valid way to check procedures in general -- I should have said that instead of "checking equipment" -- in much the same way that known industry standards for steel YZ at hardness ABC may or may not be optimal for the knife I make, and/or the one you make. I don't dispute that an experienced maker can, to a very large degree, "set and forget" most if not all procedures and equipment, assuming as you say that they've been tested previously and are well-maintained.

Either way, it's still fun though.

 

[Patrice Lemée]

It sounded so simple in my head.

You see mastersmiths testing persian daggers and other specialty styles? Then why are you asking how to test?

No Rick I don't so that's why I ask.
I hear from collectors that they are expecting a blade capable of a high level of performance with all types of knives they buy. So I thought that is was a given that the makers of these knives also perform tests on their blades. But I've never seen it discussed so that is why I asked.

James, I am glad that I was able to clarify things a bit.

There's no need to performance-test a knife that's purely intended to stay in a glass case.

I thought so too but again, from a collectors point of view, they seem to expect a blade capable of performing regardless.

Would you expect your current Bone Collector to perform as well as some made in a manner for actual use? You did not even intend to make it so it did when you started did you?

Yes I would Frank, that's why I've already tested it mainly for balance and will do so for cutting as soon as I get it sharpened. Even though it was not meant to be a workhorse, it was always meant to be a fully functioning Khukri. Sorry if I did not make that clear.

 

[Patrice Lemée]

Let me try and simplify this. I was wondering what sort of appropriate testing is or could be done for these:

Persian or other type of Dagger
Fighter
Karambit
Push dagger
Small hunter/skinner (if you don't have a supply of deers handy)
Folders

Just thought it would be interesting to come up with a specific set of tests for each type (and others if you think of some).

But I am obviously over thinking this and way off track.

We now return you to your regular programming.

 

[james terrio]

I thought so too but again, from a collectors point of view, they seem to expect a blade capable of performing regardless.

I should clarify again... by glass case or wallhanger I mean like a Hibben Klingon design. No one's going to take those camping or EDC them (well maybe someone would). But the ABS bowies and hunters that dominate C&H definitely could be used on a hunting trip, and could be tested the same way a plain unadorned knife of a similar design would be.

 

[Frank Niro]

Pat, I can tell you right now that your kukri will be only an okay chopper with that thick hollow grind. However, it won't cut anything like one that a true kukri does with the type of grind they have. As well, once you get past that thick "edge" the cut outs in the blade will make for good catchers, and restricters of movement. On the other hand you did want to dress it up and I believe you have done that very well by making it a very interesting and well done. Frank

 

[JayGoliath]

Pat,

I'm thinking more on the field of application and then only concentrate on different grinds and profile.
Opps...i'm just a noob.

 

[tryppyr]

I'm beginning to wonder if there's a question beneath the question being asked. As was pointed out previously, all knives are intended to cut, but there are different types of cutting and different knife designs to achieve those results. A knife designed for stabbing won't be the same as one designed for slicing, chopping, or sawing. Likewise, one designed to hack through greenery won't be the same as one designed to hack through bone. They may be similar, but not the same.

Obviously, a rope cutting test doesn't tell you how well a dagger will penetrate ribs and damage vital organs without chipping or snapping. When daggers were in active use, they were expected to penetrate some forms of armor (e.g. leather, silk, etc).

The Persian dagger is another thing alogether. How was it used? Was it primaily a throat slitter? A limb remover? I guess the thing to do is to clearly state what it's supposed to do. What is it supposed to cut? What stresses is it supposed to endure?

With a dagger I think the most likely point of failure would be the pointy tip. This is where the blade usually takes the brunt of impact. I wouldn't expect a dagger tang to get a ton of lateral pressure, since the stabbing motion is front to back. Likewise, the sharpness of the blade (and thus edge retention) is less significant for a dagger because it generally isn't a slicing tool. Moreover, since lateral forces would be minimal with a dagger, the tang is less likely to be broken too. Maybe with a traditional dagger you test by stabbing a plank repeatedly and see how long it takes for the tip to break off.

Persian daggers may be different in that they might have more of a slicing purpose than a stabbing purpose. But the methodology for determining how to test it would be similar... think about how it should be used, define the points where performance matters (and test those), and isolate the most likely points of failure (and test those). If they are more about slicing, then typical edge retention tests would be called for.

 

[Patrice Lemée]

James, I agree. What I was thinking of if the types of knives that can't be tested like the bowies and hunters are, but are not pure display knives like a Hibben you mentioned.

Frank, thanks for the good words. The hollow grind is only for the grind on the backside of the blade. Front is a flat grind. Even though I don't expect it to compete with a true Khukuri I would still be disappointed if it ended up just an ok cutter. Now you know what I'll do next when I have time to work on it.

Jay & Greg. Yes, grind, profiles, field of application and how it test for it all.

But the methodology for determining how to test it would be similar... think about how it should be used, define the points where performance matters (and test those), and isolate the most likely points of failure (and test those).

Thanks for laying that out clearly. Good starting point. I think I will start working on that and come back with a better researched question in the future.

Thanks again for all your help folks.