Thanks Ryan, it is funny how things sometimes turn out not to be as you would think (i.e. thicker walls being better…)
So yesterday afternoon I dropped back into the steel supply and set 2 pieces of 20’ 1" tubing (they didn’t have any pieces cut so I could only look at the 20ft sticks w/out buying something to cut it) … results are this - at 20’ the .090 had slightly less sag (not much difference, but hands down a winner in that regard) … Although I still wonder that when it comes to a 3’ x 2’ machine frame the sag should be 99% eliminated on that short of a run and I suspect that really most tubing would be fine for a build size that small. I would like to be able to work w/aluminum as i’ve seen others do so with good results, which is really why i’m wanting to go a little ‘heavier-duty’ than EMT. I guess what I’ll do at this point is just build the machine with .125 and if it seems to underperform compared to what others are getting i’ll maybe swap out for some .090 , .060 or EMT. I suspect that this will work fine though with what I have.
Ultimately i’d like to probably build the low rider and keep an MPCNC for smaller / aluminum projects … (the desire to stiffen everything up was in pursuit of larger build volume, but I think the simple and easier answer probably is just 2 machines )
My only hang up with the low rider is garage space … i’ve been toying with modifying the design very slightly so I can turn the machine up at a 60 degree ish angle and put it against the wall similar to a Maslow design, but with much better accuracy and more complete design of the low rider… Maybe i’ll post more about this idea in another spot on the forum, but i’ve got a few thoughts on how I might achieve this. However, one area where i’m totally guessing is the X stepper motor … i’m wondering if a Nema 23 upgrade would be strong enough to pull the router up said 60 degree slope while cutting through wood? maybe 2 -23’s or gear reduction? I think it’s solveable problem, i’m just guessing at what would be sufficient for the first iteration. I’m working on MPCNC now, and I suspect i’ll learn a lot which would help with the modded low rider concept and take some of the guess work out.