As wetsailpat has identified don't be displeased with those belts.
If the spindle turns smoothly/freely and you don't notice any lateral play when you grab the collet end of the spindle and pull it back and forth (motor off and unplugged) then clean her up and make chips if you find that you are unable to get the tolerances you want then you may have to do something more. Then you will have to identify the problem.
Run her at slow speeds initially, until she gets warm. Listen carefully does she purr, grind or whine?
Nice Score!!
Daryl
MN