Hi all, I need to build a huge "CNC" like machine to cut shipping containers. It does not have to be super accurate, we are shooting for 1 mm. Additional challenge is that the machine must me mobile to be moved from construction site to the next. So far the idea is to create two "sledges". A horizontal running on tracks secured on the floor with concrete footers and the same concept vertical secured on the horizontal sledge. The floor rails would be 12 feet sections, so can be unmounted and transported. The sledge with the vertical rail would also be 12 feet, so also transportable. So far we are working on the base tracks. We are thinking of 1x3 x 0.12 square tubes with 3x3 (we have those left over) sleepers. Same would go for the vertical. Challenge currently is what wheels to use to run on the tracks ? It should be "cheap". Metal Casters seem not to work, not exact enough. Bearings are to expensive for something big enough and at least 1 inch wide. The idea is to have 12 wheels on each sledge, 4 on top, 4 on the sides and 4 on the bottom so the sledges run fully locked on the track. Any thoughts ? Anybody build a big machine yet ?