I have an X2, which I am upgrading the base on with a larger table. I plan to CNC it right from the beginning, so I plan to build it all ready to go. I am in need of advise when it comes to getting ball screws for it. The X axis is roughly 18", and the Z axis is 12".

Here are some pictures:
Click image for larger version.  Name: Mill Vise 05.jpg  Views: 87  Size: 68.1 KB  ID: 117149
This is the factory mount of the X axis.

More of the X axis:
Click image for larger version.  Name: Mill Vise 06.jpg  Views: 88  Size: 86.9 KB  ID: 117150
I can see how to make and attach a ball screw to the end, but what do I do about where the ACME screw goes though?

The Y axis:
Click image for larger version.  Name: Mill Vise 07.jpg  Views: 80  Size: 75.6 KB  ID: 117151
This pokes out the back of the base so being over 12 is not an issue.