Hello everybody! :)
I've uploaded two .STL files regarding the two parts of a hammer: the handle and the head. Unfortunately I have not printed them yet, but I give you the right dimensions of the parts (taken from Cura):

• Hammer Head (X,Y,Z in mm): 112.95x36.45x38
• Hammer Handle (X,Y,Z in mm): 16.42x180.51x28.06

So, if you want to make it with different dimensions, you can scale the .STL files with Cura. Let me know about mistakes, suggestions or improvements I can do. Enjoy!