I had actually removed the nut by grinding down as close as I could to the thread and used a couple of off centre heavy hits on an old chisel to get it loose.
I could then get the nylon and spread the nut enough to get over the "bad" thread. Once off, I had a couple of goes with a triangle file in an attempt to re-groove some of the burred thread, but if I don�t cut it off, will probably need to invest in a re-threading die. Reducing it by about 6mm would line it up with the top of a tightened nut.
I thought this may have been a more �common� issue with the non-gentle use of utility Victa�s in the past, hence the query.
Mark
