Various edge types for chopping/batoning

[eyeeatingfish]

I was thinking about the various edge types in batoning and the various steel types and how some can sustain chopping and batoning well. Not so much for axes, but more large camping knives like the Busses and Ranger knives.
Then i started to think visually and it seemed that in many cases or chopping/batoning through a material that isnt too flexible that the very edge of the knife doesnt play much of a part past the initial whack. I created a diagram to illustrate my point. Yes i do realize that wood can bend some but wood will often split when you are trying to cut it lengthwise and i think the amount it bends would not be significant for the diagram/point.
Excuse the poor diagram.

It seems that once the edge goes into the wood and splits it a little bit the tip of the edge doesnt really touch the wood anymore, rather only the sides. In effect it seems that the walls of the knife are prying the wood apart by pushing outwards on both sides. As i started to look at it i noticed that some edge types were more likely to have higher drag because of more surface touching the wood. Flat grind seems to have the most potential for creating drag from the wood while a taper grind produces the least. The taper grind seems like the only drag would be at the section where the edge starts a new angle.
The red circles are meant to indicate where the knife would be touching the wood/creating drag on the knife.

So what this makes me wonder is how important is the steel really? Is it still important for the first whack?
It also make me wonder about the tests where people baton a knife through fire wood. Is the knife steel that great, or is it really just that the edge geometry of the knife keeps the sharp edge of the knife away from the wood?

Obviously a super hard or super soft steel would have problems on the initial whack though. Everyone see what im getting at though?

Thoughts?

 

[Cliff Stamp]

Is the knife steel that great, or is it really just that the edge geometry of the knife keeps the sharp edge of the knife away from the wood?

Yes, the edge just cuts a little initially, after that the wood pops apart. The edge is stressed mainly if it hits knots or powers through the wood into the ground.

-Cliff

 

[eyeeatingfish]

Yes, the edge just cuts a little initially, after that the wood pops apart. The edge is stressed mainly if it hits knots or powers through the wood into the ground.

-Cliff

So then what role do you think the steel actually plays when doing those tests where they split wood then shave their arms?

 

[jzmtl]

I wonder would it help if you put a layer of ultra high molecular weight plastic (think plastic cutting board) on the blade. They are self lubricating and strong enough people put them on vehicle underbody armor plate so they can slide over rocker easier than steel.

 

[Macchina]

You are assuming that wood is 100% inflexible, when wood actually bends a lot. according to your pictures, the pivot of the split is at the very bottom of the log, which means that the wood would split immediately upon penetration. I believe the wood actually conforms to the shape of the point until the split is made wide enough (by the top of the axe bit) to cause the wood to split. I've noticed from experience that a convex edge is far superior to the other edge types because it slides easily and promotes splitting instead of sticking. As far as steel goes, you need a sharp edge to penetrate the wood deeper and allow the thick part of the axe/knife to do the splitting. A dull edge will compress wood in front of it and stop, a sharp edge will penetrate deeper and cause the split because the thick part of the axe/knife is now in the wood and applying horizontal force to the split.

 

[eyeeatingfish]

I figured that given the batoning people often do in tests the flexibility wouldnt be an issue. A knife blade only 1-2 inches wide, i dont think a 6-8 inch diameter log would flex enough to really grab the whole blade.
Maybe im wrong, ive never batoned through thick wood.
I can understand how a much longer 4-6 inch axe blade would mean more length for the wood to flex though.

You really think a convex is the best for batoning? I would have thought the concave or the taper edge for least amount of contact.

 

[eyeeatingfish]

So then does the steel only play a role on the initial whack?

 

[Gossman Knives]

The edge plays more of an important role when chopping. Edge sharpness really doesn't matter much when splitting. Think of a maul and splitting wedge. The wedge is not sharp like a knife. A convex grind will seperate material better then a hollow or flat grind but any will work.
Scott

 

[johnwaynesandw]

I am not sure if it helps, but here are a few pics of batoning. These were taken a few months ago, but I hope it show how the edge meets up with the wood.









Thanks,
John

 

[Cliff Stamp]

So then does the steel only play a role on the initial whack?

Pretty much. I have done a lot of splitting with a GB Maul with a very fine edge vs a hardware store maul with a blunt one and concluded quickly that you want a fine edge to start the cut, especially on difficult wood. You will not notice it on a few rounds, but spend a few hours and the difference will stand out. Of course it only takes a file+stone to sharpen any maul, you don't need a Bruks to get a nice cutting edge for the start of the split.

-Cliff