Using a torque wrench is a great idea for those who have had a limited mechanical background.........even those who do are a bit suspect.........for one who has worked on diesel engines, trucks or heavy machinery will almost certainly strip most threads on a Vincent........whereas those who spent their life as an aircraft fitter, will probably under torque everything, so things will fall off.......... The front bolt/stud in question should be done up tight, and then backed up with the two 3/8 BSF locking nuts........BSF threads are a medium fine thread, look at torque figures for similar sized unified bolts between the UNF and UNC thread forms and this will give you some idea of where to aim for.