From " 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