To make an improvised stone ax or hammer, first find a stone that has a shape that will allow you to lash it securely to the handle. A stone with a slight hourglass shape works well. If you cannot find a suitably shaped stone, then fashion a groove or channel into the stone by "pecking or knapping," repeatedly rapping the club stone with a smaller hard stone.
Next, find a piece of wood that is the right length for you. A straight-grained hardwood is best. The length of the wood should feel comfortable in relation to the weight of the stone. Finally, lash the stone to the handle using on of the techniques shown in the above figure. The technique you use will depend on the type of handle you choose.
There are many good videos on YouTube that show you how to knapp stone into knives, arrow and spear tips and ax blades if you are willing to take the time to learn.
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