Build a CNC rotary table? (longish)

[jcolley]

I have been keeping my eyes out for a good buy on eBay, but I don't hink I am going to find one. I am looking for a fairly low profile rotary table, somewhere between 8" and 12". I want to use it mounted horizontally on a small scale 5-axis machine.

I really like the ones that Parker-Daedal have listed on their site, but apparently, so do they...

So, my question is...what about designing and building my own CNC rotary table. I have several high end brushless DC servos surplus, but am more worried about the mechanics of the table.

- Cross-roller bearings? or would a pair of large angular contact bearings suffice?
- Worm gear drive? Is it possible to buy (e.g. MSC) a good set of worm gears to make a backlash-free drive system? Or would some other sort of drive system be more desirable/feasable?


These are just a few things to get rolling in the right direction, but any input would be appreciated. Oh, and if you know of any other similar rotary table which are precise and affordable, please, let me know.

Jim