I built a small electronic turntable with the following components: 1- Arduino 2- Sparkfun easy stepper driver 3- Stepper motor 4- Servocity set screw hub. 5- Thrust bearing from mcmaster-carr (square turntable, found here http://www.mcmaster.com/#swivel-plates/=eltxix) 6- Perforated pieces of acrylic attached to both sides of the thrust bearing. I attached the set screw hub to one side and tied down the motor to the other side. The set screw hub is attached to the shaft of the stepper.
The problem I've been seeing is that even with nothing on it, after a quarter of a rotation or so the thrust bearing will start making noise and get stuck. I am not sure but it looks as if the bearings may be getting "squished", probably from some misalignment. The motion overall is not nearly as smooth as when I make the same connection with no thrust bearing. I tried getting a much more powerful stepper motor as well (this one: http://search.digikey.com/us/en/products/PG20L-D20-HHC0/P14334-ND/2417058, 450mNm torque), but the problem is still there.
Do you have any idea what could be going on here, and a good way to fix this?