thread size on ball joint nut?

my son has a 91 nissan sentra and he replaced the half shaft doing so when he was tearing it apart he coundnt get the ball joint to pop loose, so he put the nut back on and beat the lliving tar out of the nut, of course when i came home he could not get the nut back on. anybody know what the thread is on the balljoint, hoping to get it at hardware store locally,thanks for any input guys, chris

not sure but you could just replace the ball joint. chances are the ball joint threads got compressed and mushroomed from the pounding. or you could buy a ball joint and steal the nut and return it. or if your honest, buy a ball joint and take it into the hardware store to get a nut.

checked in the FSM and it doesnt list the nut size, like slide said it would prolly be best matched up at a hardware store when you take the bolt in