Instructables member Bart Goemaere is a man of genius. In the past, we examined his boomerang axe, which is a throwing axe that returns to you if your miss your target. Now he's back with an essential survival tool: the Bayonax.
Recently, there was heavy flooding where Goemaere lives in northern France. He had to drive home, but a tree had fallen across the road he had to travel on.
Goemaere had only his metalsmithing tools and survival knife with him. He didn't have a saw or axe. But he found a solution: Goemaere wrapped duct tape around his knife and a hammer, giving his knife greater leverage and weight in a swinging motion. 15 minutes later, he had cut up the tree and unblocked the road.
Now he's offering a more finished version of his improvised tool. For this Bayonax, Goemaere cut the head off a cheap carpenter's hammer, then secured a knife to it with twine. You can find complete instructions on how to build your own here.