my old man was faced with this very same dilema about two weeks ago. Anyway the nut was locked solid and with the help of a cold chizel he tried hammering it off. He ended up slipping and hit his wrist watch with the hammer instead. It drove the wrist band into his radial artery.
With a subsequent spirting of blood and a few choice words the old man put pressure directly over his wrist and said to wifey - need to go to the emergency dept. Well by the time he got there. The bleeding had stopped and he was able to return home.
Silly fool. I think he ended up taking the nut off.
But let that be a lesson to everyone, dont use a cold chizel to remove the nut
andrew