Re: L3viathan's Steel Router
With epoxy make sure you pour a good thick layer, about 1/4" to ensure self leveling.
You will need to pour your epoxy pads much bigger than the rails due to meniscus.
Consider bringing the table rails in a little, so that the table is supported not just on the edge.
By having your table support beams on top of the other beams you have to have a taller gantry, which means more flex. I would suggest a single plane bottom structure.
If you want to cut 4 foot, you'll need rails longer by how wide the Z axis is. E.g 54" rails to cut 48" (8" wide z).
7xCNC.com - CNC info for the minilathe (7x10, 7x12, 7x14, 7x16)