Isn't this a job for a stud extractor?Roof rack mount on a vivario van.
Bolt is chopped off. Can't grab stub from above to tru to loosen nut.
I have tried drilling but can't seem to jam nut to stop it spinning...
Luckily it's for The middle rack rail but would like to get all four rails mounted.
The way i would go...junior hacksaw and cut from the top of nut while holding bolt below with long nose pliersCan you maybe glue it in with araldite from the top, then thread either a junior hacksaw blade or coping saw through the gap in the bracket. Clip the blade into the frame of the saw and cut it off.
For an earth connection drive a small mild steel wedge against the nut to lock it and hold it after welding.