What is the max size of a part that can be machined on the Micro Mill....without moving, repositioning, or anything.

The mill has a maximum motion limit of about 7.5" in the X, and about 4.5" in the Y. But in reality you don't want to do a lot of work at the far extents of the table motion because unless your gibs are really tight you'll have some play in the table.

I do all of my work in a pocket thats about 6" x 3.5" and that works fine.

Thanks,
Looks like my work I need to do is going to be right at my Y limit. How much more usuable would the Y extend kit get me?
Kinda need 6 x 6 or close.