Emailed Woodmax about this. They called me up the next day to explain that if one cuts a slot in the end of the stud it can be held and tightened with a wrench. Also they explained that the lock nuts used from the factory have a metal insert and not nylock type. All of the new chippers are coming through with nylock nuts this year.
Woodmaxx Power equipment Limited are very good people to deal with very customer service oriented.
Fred