Fällkniven knife breaking test results

Sergiusz Mitin

Sergiusz Mitin

Joined
Nov 25, 1999
Messages
1,499
I just have visited their web site, this could be interesting - scientifically properly performed knife strength testing. Not everyone knife manufacturer does such tests and even if does - not publishes.

Worth to look: http://www.fallkniven.com/test.htm

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Sergiusz Mitin
gunwriter
Lodz, Poland
 
Very interesting Sergiusz, forgive my ignorance but did the F1 snap at only 85.5 Kg loading? I own one and I am a little surprised to learn this.

Iain
 
Hmm, it is a very discussible question to say "only 85,5 kg" or "a whole 85,5 kg"... You should be a hell of man if you are weighting more
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But regardless from is it a lot or few - simply compare these data with another comparably sized knife strength. Think it would soothe your disappointment
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Serg..
Your right, the F1 is incredibly strong for its size..
All the Fallknivens performed excellent..]
Check out the A1.. 242kgs.. Awesome eh..
 
Sergiusz
You said it!, until I hear otherwise I won't be swinging my 90 Kg
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(or anybody else's)on the handle of my F1, although I didn't buy it as a rock climbing peton. I've emailed Fallkniven for the simple version, I'm still suspicious I've missed something obvious. Unless I go on a diet I'm going to have to buy an A1 (it will hold me and my rucksack)

Iain
 
Originally posted by Sgian Dubh:
Very interesting Sergiusz, forgive my ignorance but did the F1 snap at only 85.5 Kg loading?
Click to expand...
I don't think that's "only" for a stainless knife that size.

And don't look just at that number, check how far it bent before breaking: 55mm (more than 2 inches).

And as for strength, the more relevant number is the one called "Böjmoment" ("bending moment"?) which makes clear that if you had a crack you could put the whole blade into, you could load the handle a lot more, as you'd have less leverage <small>(just like it would take less force to break off just a small part of the tip)</small>.

I leave it to someone else to convert it into ft lb.
 
Looking at the test configuration I was trying to see what knife application it would most closely model. It does not model sticking the blade in wood or a slender rock crack well. The two locations which contact the blade are further apart and more rounded than I would use to model levering in a crack. What we have here is closer to a "crowbar" test than other things we've talked about on the forum. When I look at it that way I find it a very useful test.


[This message has been edited by Jeff Clark (edited 06-12-2000).]
 
Jeff, I think this test simulates nothing, it is simply the data for comparison with other manufacturers knife strength.
 
Guys,
Firstly can I say that I was not knocking the F1, I own one and I'm very happy with it.
I emailed Fallkniven and got the following reply which is helpful. Please note the reply was posted back almost immediately, what a company!

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Dear Iain,

thanks for your interest in this important matter. It´s not easy to describe torque or bending moment and most people don´t understand about Joule (J), lever (m) and power (N). For that reason we transposed the breaking load (N) into weight (kg) in order to try and offer any kind of understanding of the graphs.
The most important figure is the bending moment (bojmoment) as it adds the length of the knife which was bent or as we call it, the lever.

These are the complete figures for the F1 knife:
The breaking power was 835 N.
Lever length was 0,109 m
And so the breaking/bending moment is 91 Nm or 91 J (joule)

You will understand about this matter if you check the figures for the WM knife. It seems like that knife is stronger than the F1 as it broke at a weight pressure of 88,4 kg. But, if you add the length of the lever, you´ll get this result:

Breaking power 870 N
Lever length 0,064 m
Breaking/bending moment 56 Nm or 56 J

Now it´s easier to understand that the F1 knife is much stronger than the WM knife since it could stand a much larger bending moment before it broke.

But, if you want to hang free with only a hand on your F1 knife, you should stick it into the wall as long as possible in order to make the length of the lever as short as possible. What will happen if you use a longer lever is that either the knife will break or the wall will break since you´re getting so much stronger with a longer level. Those who claimb mountains know extra much about this matter. Maybe you remember the old physical thesis:

Power x Distance = Energy
N m Nm (J)

We layed out these english text pages on Friday, knowing very well that we still had some words and matters to translate and to explain. The americans and some englishmen, e g, don´t understand about kilo and meter and we will see if lbs and foot will make the graphs better understandable.

If there´s things you still don´t understand about the test and the graphs, please don´t hesitate to get back to us again.

Best regards

Peter Hjortberger, Fallkniven AB
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Nice one Peter, I hope that clears things up for all you Americans and some Englishmen out there...
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Lang may yer lumn reek!
Iain
 
Friends, some data for comparison: the engine of small - medium car develops torque moment somewhat about 100-150 Nm.
 
Peter, very glad to see you making this information public, I hope it is a trend that other makers will follow.

-Cliff
 
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