“ Hammer and punch have ruined many a cush drive nut. Oh, the innocence and naivety of youth.”
I know this mainshaft nut issue has been discussed to death, but I have to disagree with Swarfy here. I’ve been using a hammer and drift on these nuts for over 50yrs and have no intention of changing. Why? Because it’s really the only way to ensure that nut is tight.
The idea of torqueing it seems attractive, but how do you lock the engine? If you restrain it by the sprocket, your torque reading is instantly meaningless, as the cush-drive is now fighting against you. And is 65 ft/lbs enough anyway? That’s a figure normally associated with a 7/16” nut / bolt. The mainshaft is around 7/8” if I recall (not in my workshop at present to measure) and that would accommodate more like 200ft/lbs. Granted over time the nut doesn’t look as pretty as it was when new when using the impact method, but at least you know it won’t come undone.