Dome Rotation Basics
The club's preferred method of dome rotation has been proven to be efficient, reliable and simplistic: A specially selected lazy susan bearing, with a diameter that is slightly smaller than the diameter of Artoo's dome (< 18"), is mounted to the frame. Here is a picture of the ABS Woodcraft bearing mounted to my frame:
<click image to enlarge>
More specifically, the stationary or non-rotating portion of the lazy susan is bolted to the top plate of the frame. On the rotating portion of the lazy susan,the threaded ends of four tall #10 screws are inserted underneath and upward through custom drilled holes are secured in place with nuts. These screws that stick upwards serve as an alignment pins when dome ring and support ring are stacked on top of the bearing. Just picture a 3 layer cake, with the lazy susan bearing as the bottom, the dome ring as the middle, and the support ring as the top layer of the "cake." Washers are used as spacers between the bearing and the dome ring to adjust the dome height just enough so the dome ring does not rub against the body. Mounted on the frame is a motorized wheel that contacts the surface of the inner side of the bearing and when the wheel turns, the bearing and the dome rotate in unison. (this covered more in detail in another discussion) Easy right?
Choosing a Lazy Susan
Picking out a bearing was pretty straight forward as there were only two options at the time: Woodcraft or the gold standard, Rockler. This lazy susan was the second item purchased for the project and it is was not cheap! Trying to save some money, instead of going with the preferred aluminum Rockler bearing, I opted to go with the PVC version from Woodcraft. Not only was it was seven bucks cheaper, there were no shipping charges since there was a Woodcraft store local to me, which I was able to pick up. Here's how the two compared, based on the advertised descriptions:
Brand Material Size Weight Capacity Price
Woodcraft PVC 17 5/16" 220lbs $54.99
Rockler Aluminum 17 1/2" 330lbs $61.99
According to these specs, the Woodcraft bearing seemed plenty adequate to support a light weight styrene dome.
Installation
