Notes:

• 3/04/2019 - added a new base Version2 file that replaces the original base file and eliminates the need for the bearing retainer component. This greatly simplifies the design. Just insert the skate bearing from the bottom of the new base now.
• The small hole in the ball cup along with the four small holes in the base provide for a pin to be placed through the holes providing stationary use of the ball cup.
• If the nut seems too tight, scale it by about 1.008% in Cura or your slicing software when generating the GCODE.
• There is only one ball bearing spacer defined in the .stl file. You should flip the spacer over on its flat side and create 7 copies in Cura prior to generating the GCODE.
• The Base, Ball Cup and Ball Bearing Spacers should be printed with 30% infill. All other components should be printed at 100% infill.

Links to the site to purchase the skate and ball bearings:

• http://www.vxb.com/8-Skateboard-Bearing-608Z-Shielded-p/sk8zz.htm
  
• http://www.vxb.com/100-1-4-inch-Diameter-Chrome-Steel-Balls-G25-p/kit8593.htm
  

You could also attach a base plate to the top and use it as a "Lazy Susan"

Comments welcome and appreciated.