The LeverAxe was designed by Heikki Kärnä in the forests of Sipoo in Finland. Faced with the arduous task of clearing his property of Spruce Pine to build a home, he spent a lot of time chopping and thinking about chopping wood. Heikki realised that forcing a thin wedge through a piece of wood wasn't the most efficient method of splitting it and the idea to create a lever to split the wood was born.
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Levers vs Wedges
Levers and Wedges are both tools that, in the case of an axe, translates a downward striking force into a sideways splitting force:
A wedge is a static simple machine and the split can only be as wide as thick end of the wedge at it's deepest point. The main problem with this is that as more wood is in touch with the wedge, the greater the energy lost as friction and the more likely the blade is to stick in the wood.
On the other hand, a lever is more dynamic simple machine and provides it's sideways force by rotating. As it doesn't rely on travelling through the wood to split it, it loses less energy to friction and won't get stuck.