John, wouldn't a tube cause more problems, if it's length is not super precise?

I was asking about tolerances on the bearing fits, as I'm not quite sure how ACs are normally fitted. I've seen interference fits mentioned a few times in technical literature and I can understand that on the bottom bearing, but should the top bearing be an interference fit as well? the bottom can be easily pressed against the shoulder, so that's not an issue, but I guess the top should simply slide over the shaft? if so, isn't there a risk of the shaft rotating within the top bearing inner ring? I guess preload would create friction between the top of the inner ring and locknut / cap, but is that enough?

Regards,
dsc.