[StephenB]

This may muddy the waters a little but I just took apart the vernier on the 610 I'm working on.  Its similar if not identical to Stephen's. It had the ball loose from the shaft just as Stephen's appears in the first photo.  After getting all the old grease off and packing with new, I put it back together without affixing the ball to the shaft just to see what would happen and all seems to be working well.  Can't explain it but ....

KHHHHAAANN!! 

What keeps the fine-tuning shaft from sliding out?  From what I can tell, the attached small ball-bearing held on the radio side of three large ball bearings by the three large ball-bearings is what keeps the shaft in place.  Also, I was thinking that it was the friction between the end of the fine tuning shaft/small ball bearing with the three large ball-bearings and the coarse tuning shaft that allows it to turn.  This blows that theory!

On the other hand, there's no arguing that it didn't work before and that now it does.  I'm not sure what I'm doing differently.

Stephen.