Thanks everyone, this is why I asked. And thank you Bernard, I had no idea that you should lubricate before pre-load.
Yes I had not finished installing everything. There was no pre-load and no lube in there when I heard the sound. I went ahead and actually pressed everything together, lubing up the bearings with the proper oil and then setting some pre-load with the bearing take up nut. Everything is much much quieter, however I CAN still hear the a sound with the same characteristics as before, only much quieter. I went back to the video I had and if I listen very carefully it sounds like I can hear it too. At this point I'm not that worried about it, the spindle feels smooth. Once everything is buttoned back up I'll be able to make a judgement if I need to replace the bearing. Yeah it will be a PITA to take the headstock apart again, but guess what, I've got a lot of experience in that! :lmao:
As long and arduous as this re-hab has been I have to say I have no fear anymore of tearing a complex assembly apart to fix the darned thing. Not to mention I have an intimate knowledge of every last set screw, spring and woodruff key in this lathe.
In the long list of issues this lathe has lets add another one. At some point the woodruff key that was holding the backgear on the shaft had been sheared off and the shaft got super chewy and galled. I had a hard time even figuring out where the original key way was. Since the shaft was shot in that location I didn't feel bad attempting to re-make the keyway with a Dremel grinding wheel. I think it will work as a temporary fix, but I'd eventually like to remake that shaft as well as the countershaft spindle.
Which leads me to another question. What kind of material should I use for these shafts? I was thinking 1045 Cold Drawn TGP Precision Shafting would be the right thing for this application.
Anyway, the re-hab continues...
Oh, on a side note, don't bother painting your headstock until after you pressed everything back together, I'm going to have to touch up quite a few scratches!