SO3: Imperfect circles?

Anyone using a S3 have experience in cutting circles? I’m cutting thick acrylic and need to make a PERFECT circle. I managed to cut the circle and of course right away looks and made the assumption that it’s perfect but once I set it on it’s spindle and bearing, and spin it, it has a wobble to it. It’s not oblong or oval shaped, it has 2 ovals in it, (excuse my explanation) like one oval on top the other while one oval is rotated 90 degrees.

Here’s my process:

I bolt the acrylic to the waste board in the corners ( through the stock piece)
I zero the machine at the center of the 12x12" piece of acrylic
I would either start the cut by drilling the center hole with a .25" bit, wait until the machine is on it’s track to the diameter cut, pause the job, and fasten a bolt through the center hole for when I completely cut through piece for assurance i don’t chip an edge.
OR I would drill my center hole using a drill press or the machine and start the job after the center hole has been made, i would zero the machine by inserting the bit into the .25 hole and then start the job.

Now…i do not have a dust shoe (yet) and chips are sticking everywhere. I’m constantly sucked them up and cleaned the rails as much as I can as it was cutting.

Do you think this could be caused by build up on the v wheels? Because there was some build up after I finished. Should I tighten the belts SUPER tight? I found a very good and affective way to tighten the belts (one man job) in which I’ll post tomorrow with pics btw.

Unfortunately, I only have one piece of acrylic at this time, I’ll be ordering a couple more but i’ll practice on MDF in the mean time.

Please see: http://www.shapeoko.com/wiki/index.php/Calibration_and_Squaring_the_Machine and http://www.shapeoko.com/wiki/index.php/Shapeoko_3#Squaring_the_machine

As well as: http://www.shapeoko.com/wiki/index.php/Materials#Acrylic

And http://www.shapeoko.com/wiki/index.php/Climb_vs._Conventional_Milling