Looks pretty good. I started some of these quit sometime back after not wanting to spend upwards of $300 or $400 on one. I was originally going to use the heaviest Estwing claw hammer they make and beat the head into the blade and the claw into the spike. After scratching that idea I was going to use the carpenters hatchet but ended up going with the Estwing Riggers axe because of the longer handle. I have an older Estwing carpenters hatchet in the works now along with about a dozen heads from various makers of the "carpenters" style hatchet's. For anyone looking to do this who is planning on adding the spike, cutting or grinding the hammer head is basically the only way to retain the original handle. I beat mine out in a forge and even though I was carefull to only heat the hammer head and keep most of the heat in that area, the handle started to melt. Im sure this would also be the case with the stacked leather handle as well. One advantage about using the riggers axe is the added length keeps the rubber handle a little cooler when working the head. The handle is pretty easy to remove and I ended up wraping and dipping mine when I was finished.
Here are a few pictures of when I was working on it. This is the first one I done and the later ones were easier after you get the hang of it.
Ill post up some pictures of the finished product soon.