There is a pretty good body of published material on axes. hatchets and the version of them used in the "indian trade". Most of the iron hand-axe/hatchet/"tomahawk" were functional tools for wood working/chopping splitting. They tended to be rather wedge shaped since a thin parallel sided blade tended to get stuck in the wood. Of course they had other functions and roles as well; including ceremonial and as weapons.
Some forms were developed to fit those roles but were derivative of the woodworkers hand axe. there was a form, sometimes called the "missouri war hatchet", which had a thin flat parallel side blade with a large triangular shape and a very small handle socket. then there were spike and pick versions used as naval boarding weapons, spontoon heads and pipe heads, but all came from the wood working hand axe.
Most of the early designs used a tapered "adze-eye" socket that depended on centrifugal force and impact to keep the head tight. the parallel sided socket with a wedge is a later development if my recollection is correct.
the tool in question does not in my opinion, fit the form of a typical historic "trade axe". while I am sure it would make a very functional weapon. the lack of taper to the blade cross section, again in my opinion, would make it an awkward tool for wood working and the spike on the back would make it even more difficult. the eye design makes it look later as opposed to earlier in my opinion. Unfortunately its a lot easier to opine about what it is not than what it is.
