How to build a CNC rotary table

Has anyone added CNC capability to an import 6" rotary table? I like
the idea of having a setup similar to the Sherline rotary table where
you can enter data through a keypad device. I guess I could also
interface the stepper motor with a PC and use software to control the
table. Has anyone done this before? I have not taken the leap to
converting my mini mill to full CNC yet but maybe someday. For now I
just want to do the rotary table. I saw the pictures of K8JBL's
rotary table, that looks like what I want to do.

Thanks,
Jamie