This is a remix of emmetts gear bearing http://www.thingiverse.com/thing:53451

It should make a nice 16014 bearing for the turn table of a Ciclop 3D scanner. 110mm OD 70mm ID and 13mm thick.

Due to the large size it can be quite tricky to get the bearing to 'crack' initially and get all the parts rolling. I cut two disks of wood approximately 80mm diameter and then used them to clamp the inner race in a vice. I put a wrap of double sided foam tape on the outer race to give me some grip and then pretty much thrashed, twisted, yanked and swore at it until it broke free. Not the most elegant method, but I did get there in the end.

I found once you get the bearing turning, the best way to get it running really nicely is to submerge the whole bearing in water and spin it quite a few times. As the gears wear in they make a fine plastic powder which tends to stick to the teeth and make lumps. By running it under water the fine powder gets washed away leaving you with a nice free running bearing. Once its running nicely, apply a thin film of oil in the gears before installing it.

Even with the bearing running quite nicely I found my stepper motor was still struggling to turn the platform. If you also have this problem try my geared platform: http://www.thingiverse.com/thing:1243069

I have included my open scad script, the only changes from the original are a few tweaked values and making the hole in the center round not hex.

https://www.youtube.com/watch?v=bgW5GS3llfc