Hammer I made for my kid, based it off the hammer from the game God of war Ragnorak

Rescale as you see fit

I've included a whole model and one split into 3 pieces for convenience. the handle broke on mine so i was able to replace it, it should fit together fairly snug and if not, theres glue. 

If the handle breaks depending on the scaling you chose, a drill bit is a good way to get the handle out of the pommel or the hammer head and not having to reprint everything. (if you print in 3 separate pieces)

I did PLA Pro but PETG, ABS, or TPU would probably be better options or a combination of them.