Syliavski I am sure you will find the solution. Your mind is sharp so I don’t worry. The only think I want to say is that some times we stack and we become maniac with some specs off the machines that we build. I would be the last one to talk here as I haven’t finished a machine yet. That doesn’t mean that I don’t have an opinion. So I think that the solution to your problem is more than obvious. It is #1 that you suggest. Go on with shimming. As I have read here in the forum many people use only shims. Why it would be such a big problem for you to use shims only in a small area ( near the bridges). Also have in mind that all these people who have already use the epoxy method, may never compare the straightness of the epoxy against a straight edge. The first introduction of that method that I saw here in the forum was Jonathans machine. But this machine ( as your first one ) was smaller. The scale is very important. Even a 3000mm straight edge may have (0,01%=0,3mm loss at accuracy ) I don’t want to introduce my self as the clever who knows everything. Most of the people here in the forum wouldn’t imagine the problem that you come up against. The only positive is that you give us a good lesson unfortunately by spending 200 euros. This is life. This is they way we learn, by making mistakes. No one could blame you. I think go on with shims is the best way to continue. For sure there is a solution about the epoxy method at this scale but if you want to find it you must pay. The most common characteristics that the DIYselfers have I think are stubbornness and persistence. We think that we can solve any technical issue and that make us some time loose time and money. It is useful some time to make a step back, see the things more clear and then go on again. I am no talking as an expert or as an experience constructor, I am talking as a friend ( even if I have never see you, you have helped me and that gives me the right to consider you friend ). Keep going