The axe, or ax, is an implement that has been used for millennia to shape, split and cut wood, harvest timber, as a weapon and a ceremonial or heraldic symbol. The axe has many forms and specialized uses but generally consists of an axe head with a handle, or helve.
The earliest examples of axes have heads of stone with some form of wooden handle attached (hafted) in a method to suit the available materials and use. Axes made of copper, bronze, iron, steel appeared as these technologies developed. The axe is an example of a simple machine, as it is a type of wedge, or dual inclined plane. This reduces the effort needed by the wood chopper. It splits the wood into two parts by the pressure concentration at the blade. The handle of the axe also acts as a lever allowing the user to increase the force at the cutting edge (try using an axe head without a handle and you will see what is meant) - not using the full length of the handle is known as choking the axe. For fine chopping using a side axe this sometimes is a positive effect, but for felling with a double bitted axe it reduces efficiency.
Generally cutting axes have a shallow wedge angle, whereas splitting axes have a deeper angle. Most axes are double beveled, i.e. symmetrical about the axis of the blade, but some specialist broadaxes have a single bevel blade, and usually an offset handle that allows them to be used for finishing work without putting the user's knuckles at risk of injury. Less common today they were once an integral part of a joiner and carpenter's tool kit - not just a tool for use in forestry. A tool of similar origin is the billhook with short handle and long blade it can be used for tasks where an axe is unsuitable. However in France and Holland the billhook often replaced the axe as a joiner's bench tool.