Good stuff, Jed. Wedges do wonders.
. On the other hand, as an arb I have very little experience stacking wedges. My wedges are usually crappy and don't stack well and tend to twist while driving them, which could turn me into a fast runner.
Jed, I figured out one day that if you bury a wedge in a bind, you can back-chain the mushroom off. If its not tightly held, the wedge can fling out forward, though.
Mushroomed wedges are BS for stacking.
I'm an odd duck to use a maul over an ax. When I started out, that's what I had, free. Actually, I like to be able to hit both wedges simultaneously, sometimes. Over two years of an ax, pounding over trees in the parks, didn't really sway me strongly to buy an ax, though I was eyeing one the other day. Gear geeking. Depending on your back-cut height, either really low or high, you can get the ax head/ handle to be oriented 90 degree, more or less, allowing you to strike both together. Its helpful when you hit one, and the other slides out, negating the lift.
Lots of wedges spreads out the force, and seems to me to work a lot better than one wedge/ one pair. If you've got a shitty tree, like hollow cottonwood, you are not putting as much compression force focused on the hinge fibers. If you have sapwood rot, like pouch fungus/ popcorn fungus on dead/ declining doug-fir, spreading the force as much as possible is important to not blow out the back of the back-cut, and have it start moving backward.
If a stack starts to slide out, its good to have multiple pairs of wedges to hold it up.
If a backleaner sits down on your wedges, with a lot of wood compression, closing the kerf, you can bore-cut a slot perpendicular to the hinge (typical wedge orientation), and create a slot to set more wedges, one at a time.
If a stack starts to slide out, its good to have multiple pairs of wedges to hold it up.