Little claw :
Before the blade is embedded in the wood, if you hit the spine centrally over the material to start the cut, surely the handle/pivot is not part of the equation (except maybe their inertia- which could be neutralised by unlocking the blade)?
Yes, there is little torque here, however the shock could still be an issue, depending on the nature of the lock. With a simple mechanism like the Sebenza this isn't a factor, and what you would mainly be concerned about would be avoiding any lateral impacts which would twist the blade and thus effect the handle pins and the blade washers and such, so just go slow and don't do caveman smashes with the baton.
if you split wood with a folder, doesn't choking up and supporting the handle as close to the pivot as possible (i.e. over it) minimse the leverage on (and therefore the damage to) the lock?
Yes, ideally you want it to be basically a chisel cut right through the wood. This is why just as you mentioned you start off on the blade centered. However as you progress you end up having to beat on the tip, this will then cause the blade to rotate down unless you oppose it by pressing down on the handle. The knife can then start to experience a bend in the handle depending on if you have the strength to press down right next to the lock or not. The torque will be similar regardless of where you press, but it is easier on the lock the closer you get to the handle (and the harder on you).
On thick wood the impacts might have to be high enough so that vibration might be very uncomfortable. If this becomes a factor you might want to start looking for another piece of wood. However if all there is on hand is junk knotty dead woods, then at least take the time to wrap the grip. As well get in a position where you can lean into the handle with a locked shoulder. This will allow you to use your body weight to keep the blade stable and not have to just press down as
this is a *very* weak plane of motion.
In general the tighter you can grip the wood the easier it is on the knife.
Solid questions raised.
Once you get a fire going, bring in your firewood so it can dry out. Once it is dry protect it in case it rains. Once a fire gets going, usually it can handle wet wood (though poorly), and unless wood is very scarce and you need to maximize its use, you can just burn the wet wood, and even large pieces by letting the fire dry them out and section them.
-Cliff