What is the cost of these compared to the thomson's or a thk style linear guide? I imagine they are less, but not by much. What I'm getting at is maybe since you are investing heavily in this machine, maybe aluminum would be a better choice for your framing system. Two 80/20 1530 sections and 10 square feet of 1/2" precision plate would not cost much, probably less than 125.00, and eliminate your flexing problems entirely with the same rails and a good design. Then youd have a machine more capabl that would last forever and take much more abuse, or use. Just something to think about.