Why you cannot just bolt rail or gear rack to tubes

[BTA Plasma]

Here is a good example of cleaning up a frame on a CNC machine. The first pass will often show the lack of parallelism of the tubes. If you want a SUPERB CNC this is a requirement. Parts made on a modern Star Lab under an optical comparator have proven that Star Lab CNC's have knocked it out of the park.

[weldguy]

A picture says a thousand words. Impressive that you machine the table sides true before installing the rails. i think most would like to do that but don’t have the equipment to do it.

[SegoMan DeSigns]

A video on the truing of the milling machine rails would be fun to watch.