Here's the pro answer. It looks odd but it's made to do exactly what you seem to be looking for.

The thing shown below has a capacity of 50 pounds and costs $150. Masonite tops and steel tops are available in sizes from 8" to 17" in diameter. Or call them and find out what else they have.

I'm pretty sure that if you don't buy it at this price, you'll spend twice this much in time and energy coming up with a suitable substitute. For the top alone, it would easily take a couple of hours to plan, purchase, and fabricate it. If you have scrap material, it will take less time, but will it be nice and round? Will the mounting holes be in the right position the first time?



This is at [Link: xyzdisplays.com]

Capacity: 50 lb
Standard RPM: 2
Clockwise Rotation

Their other categories are
Rotating Display Turntables
Rotating Ceiling Motors
Wall Mounted Display Turntables
Battery Operated Turntables & Motors
Skeleton Display Turntables