I regularly use a machete to clear brush. I must be using the wrong technique for the tool ... or the wrong tool given my technique. In order to maximize the speed of the blade, I rotate my wrist forward before it strikes wood. This causes the pommel to dig into the lunar pad (bottom face opposite the thumb) and quickly blister it.
Shown here is my starting grip:
And my grip at the end of a stroke:
Is there a better tool for cutting brush, or maybe just a better grip, given my hand size and strength?
Amendment: If I don't break my wrist it feels like I'm "hacking" with too light of a tool. Blade speed is much lower, and so much less work is done with each stroke. If I were to not break my wrist I could use a much heavier tool: A much longer blade, or a blade at the end of a long handle, which would give the same blade speed and power per stroke without having to break my wrist. But what am I describing? A pike? (And then there's the question of what to do when I have to pack the tool into the wilderness....)
Second Amendment: I also realized that if I don't break my wrist I can't reach a lot of brush: If I keep the blade at a right angle to my arm then I have to bend to hit anything lower than 3 feet off the ground, and I have to wade further into the brush to reach more central branches, which is an often thorny proposition!