Jet Spindle Sander Runout Problem

[Bernie Kopfer]

I have a Jet JBO-5 spindle sander about 4 years old with perhaps a couple of hours of use. The spindle shafts display about .020 runout according to the dial gauge I use. This is consistent with all the spindles. It is particularly noticeable with the larger size i.e. the 3" sleeve. The wood gets sanded but the chattering is hard to take and very annoying. I have a old cheap Ryobi that is smooth as glass compared to this unit.
Before I talk to Jet I would like to know if this problem has plagued anyone and what solution they have. Thanks