I am just wondereing where you think the best place for ballscrews is on the gantry. I am looking for accuracy and obviously I would like to keep cost down, but I don't want to cut corners if one way is significantly better than the others. I am planning on using thompson type linear bearings, the pillow block and round shaft type

one Ballscrew under the table in the center linear bearings on the top of the table

one ballscrew under the table in the center linear bearings on the side of the table

two ballscrews one on each side of the gantry connected by belt

two ballscrews, one on each side with individual motors

On both of the two ballscrew ideas the linear bearings would be raised, so that the y axis basically sits on the linear bearings, and the shafts would mount on top of the raised surface. On the single ballscrew ideas, the linear bearings would be on the table with a raised gantry

I plan on making a cnc router for routing plastic and aluminum, that is 48x48.