I need to know....You hit the starter with the hammer and it started. Dumb question, did you give the starter a good whack again to see if it would crank again?
I'm sorta thinking a solenoid problem. My Bosch solenoid would sometimes act like this. The contact that bridges from the cable side to the starter side would not make a good connection. Cleaned up the contact and it would work fine for quite a while.
Just a thought,
Tom