RD,
For the record, because I am neither the most expert member here with regard to every possible A7/A10 nuance, and probably 100th in line for best machinist, I started my recommendation by saying I thought Swarfy had it about right. Here is part of what he said (with date and time, for your reference):
Re: Fixation from the spindle of the front wheel
« Reply #23 on: 10.06. 2020 10:23 »
Quote
Lippi. The crankshaft has a left hand thread on the oilpump drive, so the locking nut used here, part 67 643 could be used to fit on the end of the wheel spindle as it is the same thread.
Do not remove metal from the fork leg, just turn down a few mm from the large diameter on the spindle so that it fits further into the wheel hub, and the spindle sticks out a little bit more to take the nut. The thread showing is not enough to take a nut safely.
Swarfy's idea is, turn down the large plain diameter of the spindle so the thread sticks out further, then, put a washer and LH nut on what now sticks out. The PLAIN sleeve (be it oilite or steel, doesn't really matter) does nothing but stabilize the lateral or up and down movement of the spindle in the leg hole. As I see it, no threading is involved, no abrasion occurs and less wear than an oilite bearing would see when it's actually working as a bearing.
I also threw in that obscuring the lever hole should not matter with this fix.
Even though I'm a crappy machinist. I think I could have completed the job in the time we've spent talking about it. You could have done the same, with lunch and a smoke thrown in.
Richard L.