Re the bearing nut.... I flushed mine by soaking it in a bath of parraffin, then a bath of wd40, before blowing it out and dumping it in a bath of ISO68 way oil.
After that, wipe down, fit to faceplate and spin to max RPM on the lathe for a couple minutes to get oil where it needed to be.
Wiped it down again afterwards and it has always been as smooth as silk ever since.