Made a little more progress. Starting to get the hang of Fusion 360 a little. Screenshot below. Integrating the ball screws is going to be interesting. I had thought out most of the frame and rails in my head, but the ball screws will really have to be squeezed in there, especially on the X/Z carriage assembly. I may have to find a way to have those carriages machined so they are not simply flat plates.
Peter,
I'm not sure why brazing would be better than welding? The steel tubing will most likely not be sufficiently flat for mounting linear rails from the factory, so it seems that even if I were to braze the frame I would still need to do a machining or epoxy leveling operation at some point? I would like to simply have the frame stress relieved and machined, but I don't think that makes financial sense when you consider the quality of the other components I'm planning on using. As long as I don't do any more welding or removing of material after I complete the epoxy leveling process, I don't see a reason why it would matter whether the frame was internally stressed or not?
I agree that the epoxy leveling seems finicky - I have seen a number of threads where it did not go well. I think the key will be to do some testing prior to the actual leveling pour(s) on the frame.
You are right about getting everything nailed down in CAD. I'm just impatient and want to start buying steel, haha.
Thanks for the comments; they are much appreciated.
David