From "Re: Continuing lathe chatter (from people now, not the lathe)" posted 4 June 2008 by Joe Gwinn:
> >> >> Mine may not be truly equivalent, since mine has three belts
> > >> >> applying stress to the side of the shaft. But I get what feels like
> > >> >> a
> > >> >> 3:1 or perhaps 4:1 ratio of starting force vs moving force. It
> > >> >> pegged
> > >> >> the force gage which I was able to find -- at about 1.5 KG applied at
> > >> >> a
> > >> >> point 3.125" from the center (on a chuck jaw at the OD of a 6-1/4"
> > >> >> chuck.)
> > >> >
> > >> > Ah! That sounds exactly how it now feels like when turning the
> > >> > spindle
> > >> > by hand. It sounds like I did not over-tighten it.
> > >>
> > >> O.K. Note that when I had the spindle out to change belts, I
> > >> tightened it until it fit the manual's spin test. But after using it a
> > >> while, it developed chatter. I had to go back, overtighten the collar
> > >> on the back, and then loosen it and re-tighten it after I had set the
> > >> bearings properly. :-)
> > >
> > > Hmm. I may have to do much the same, as the spindle bearing was
> > > probably too loose for years, and may need to re-adjust to its new
> > > circumstances.
> >
> > Perhaps -- but I think that I simply didn't pre-tighten over the
> > spin test point, when I should have. A bit of use pushed the bearings
> > deeper into their mounts.
>
> I perhaps may see the same effect. The bearings in my 5914 may well
> have walked a tad out of their mounts, and will now walk right back, > under pressure.
This does seem to be happening, and rather quickly at that. It has become noticeably easier to turn the spindle by hand. I don't plan to do any adjusting just yet, instead waiting to see how much it will loosen by itself.
Joe Gwinn