Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4123628.
UPDATE 2-7-2020 - After playing with the plug version I thought it was a little wobbly for my taste so I thinned out the bottom rung a bit to make it sit closer to the base(s) and not wobble so much. Filename is - Plug-Thinner-bottom-Final.stl - for the thinner rung. It does work better IMO but the first one still works also. Playing around with the idea to incorporate the bearing into the plug but that would have to really be printed perfect or it would make getting the bearings rolling really hard so I doubt that is going to happen...maybe, but doubtful. Hoping this is the last update for this.
UPDATE 1-25-2020 - So I thought about it and figured I would make a version without the big insert so I created a plug and made the cup holes bigger to accommodate it. You will have to use the new cups for the plugs if you want the plug version...I have not printed the plug in vase mode as it needs to be a little strong as you will be able to tell with how tight everything fits. Shove the bearing into the plug...don't be shy as it is a tight fit. Push it in the whole way. now shove the plug into the hole on the bottom of the cup..again it will be tight. I left a lip on the plug in case someone needed to put a dab of super glue around the edge to hold it to the cup without interfering with the bearing. Thats it. The cups do wobble a little more due to the raised lip holding them off the base a bit further. You can cut the hole larger on the original cups if you don't want to print new ones! Hole should be about 23.4mm to make a really tight fit. I posted a make of this so people would get updated to the new design. Still use vase mode on cups!!!! The plug uses 1g of filament (again Cura said that so its close...) so the same as the insert, just takes up less room in the cup.
BOTH DESIGNS WORK FINE!!! it is just to give everyone a choice (Where is Neo or the Oracle when you need them to tell you that you already made the choice you just have to understand why).
So being poor and looking to save money on filament, I decide to do these in vase mode to see what would happen. It worked...mostly. There was of course a hole for the bearing but because vase mode has no top it was open, so I made a small insert that spins down inside to cover the bearing...easy peasy!
I used parts from everybody it seems to do this lol I included all the stl files I used. Hopefully that is ok. If not, let me know and I will delete yours from this post.
Again being cheap I did not buy bearings, I printed them. the bearings fit inside the opening at the bottom of the cup just fine and they spin just fine too. If you are concerned about the bearings staying in place then you could glue them into the hole in the cup but I don't seem to be having any problems at all.
So just print the cups in vase mode - whatever settings you like, up to you. I used .2mm with just 2 bottom layers and ran them at 100mms on my Ender 5. Then print the inserts - I included the reverse one also just incase you did not know how to do that in your slicer - and use the same settings as the cups. When done just turn them over so the open side is down and let them twirl to the bottom of the cup to cover the bearing and keep anything from sticking in it and jamming it up. You don't have to use them but I didn't like the bearings being sticking up like that if I put pencils or pens in it.
Of course the base still needs to print normally.
In cura it said the normal cup would take 105 grams of filament and take 11+ hours to print at .2mm. Vase mode is 23 grams and 1 hour 45 minutes. The inserts are 2 grams and take 13 minutes each. You can print 4 of them in vase mode with inserts for the same (little less really) filament. Did I say I am cheap and poor :)
Have fun!