What knives to take for bushcraft course

TLM said:
Stiffness and strength are totally different concepts.
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Stiffness is the resistance to bending, or stretching, or rotation (torsional) strength is the measure of the break point for those deformations, both are related to the bending moment, but the relationship in knives is more complicated than in levers and beams because when a person judges strength and stiffness they don't actually go by the force they apply they go by how much effort it takes to do so, these are not the same thing.

Consider for example a fairly routine task, press/stab the point of a knife into a stick to pry out a u-nail. As you press down on the handle the knife starts to bend, as the stiffness of the knife increases it will bend less under the same force, as noted in the above, when comparing the two simple cross sections we are talking about here (rectangle vs triangle) there is a very large increase in stiffness for the same area.

Now, if the stiffness is decreased (move from a flat ground to puukko) the knife can be bent to such an extent that the force changes from being mainly wrist driven to being driven from the shoulder, when this happens the effort required by the user descreases and thus you can easily exceed the strength of the knife, thus there is a large connection between stiffness and strength in knives.

It even goes beyond this because for a lot of prying tasks, if the knife bends past a certain point it becomes unable to actually exert a prying force because of extent of the bend, thus you can apply a very large force to it, but have it actually do little prying work, thus its strength in regards to handle the necessary prying load is very low and thus again very dependent on stiffness.

In the equations which develop bending such as the strength of a beam, similar to the end deflection, you end up with a square power of the thickness because the area moment is divided by the thickness because the strain / stress is dependent on the thickness, however in use by people this is counteracted by the dynamics of the force which isn't constant and tend to make the strength go above quadratic, in many cases it is so large it is even above cubic.

There is a point though that there should be a distinction made between using the terms to apply to the loads required or that of the individual or to the task, and I was sloppy about making this separation in the above. These are of course related, but I would argue the latter two are what is critical because knives are of course used and judged by people so in the end this is obviously what matters.

As for the relationsips being complicated for various shapes, we are not talking about highly convoluted surfaces, just a triangle and rectangle and the moments are known and in fact easy to calculate anyway, and the origional point is that in regards to stiffness and strength the puukko grind is an inefficient one compared to a flat grind thus if you are looking for those qualities in a survival knife you choose the grind accordingly.

In regards to the F1 as a bushcraft/wilderness knife, I asked Fallkniven about this, Peter made some comments about the design here :

http://knifeforums.com/forums/showtopic.php?tid/752325/

Peter also speaks well of puukkos for wood working, but just has an appreciation for other qualities including strength, different people, different methods.

-Cliff
 
khimbar said:
If you're going out to real woodland take the ones you're happy to lose.
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Khimbar, welcome to BF. Just as an FYI take a look at the original date for the original post. It was in 2005. I have made this mistake before as well.
 
Seams like a good reason to buy a new knife or two. What ever you take it's the skills you learn not the knife you use. If you use a knife not suited to the task it should made the technique that much better. Have fun.
 
there is a ray mears knife made by alan wood on ebay for £225 dated 16/11/06 same price as rays woodlore shop , but without the 20 month wait
 
225 pounds for a knife?!?! You can buy a really good rifle for that. I guess I don't have my priorities straight. Buy a frickin Mora knife and get over it. Then buy some more knives.

This is like listening to a bunch of teenage girls trying to decide what kind of bellybutton jewelry to wear before they get laid. (not that I would know anything about that) Thanks, I'll go to Whine N Cheese. (but thanks for the discourse, it's been enlightening ;) )
 
Someone bumped my old thread ;)

I'm having a bushcraft type knife made by Fred Carter. It's looking very promising so far. 225GBP is too expensive for the Ray Mears one if you're not a collector IMHO. Better spend that or less on a custom one that will fit your needs perfectly and will make a great user.
 
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