What comes to mind to me. The fan has to come off the shaft
(might be dificult).

Take a ball berring that's larger than the shaft hole in the
center. Drill a counter sink on the end of a shaft. Put the
ball berring on the end of the shaft, and the fan on the
ball berring. Ends up looking like a crude lamp shade.

That should give you a rough idea which is the heavy side.
Similar to balancing lawn mower blades.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Karl Townsend" wrote in
message
anews.com...
I got so much help on my sprayer, I'm trying again...

Full time investigation and part replacement has me working
on this theory
of the problem cause: The squirrel cage fan is out of
balance. It is barely
detectable because the fan has a 2" solid steel shaft and
some serious
pillow block bearings mounted solid to a beefy frame. At the
resonate RPM,
this imbalance feeds on the slack in the drive line. Any
system upset causes
the fan to become unstable and it lurches back and forth.

I've called around and not found a place to dynamic balance
something like
this. Are there any home brew methods? Or other suggestions?
Its built so
solid I don't think I'm looking for a minor imbalance.

Karl