If you search, there are some Youtube vids of the conversion of a Harbor Freight mini mill to CNC and that might give you an idea of what to do. You may have to custom make some of your parts. I would think that you're gonna need some idea of whether or not your existing lead screws will work with the CNC motors. If they will work great, if not you'll have to find replacements. Seems to me that's the first place to start.