Well, I thought I was almost finished with the design phase, but... I wasn't.
I went back to check my deflection calculations, and found I had forgotten to update the overall weight, post-router-motor-upgrade.
No matter, I'm well into the redesign, and it's actually a lot better. (Much more similar to other machines I've seen here, as well.) Note the new steel/aluminum I-beam Y-axis rail. (2" x 0.5" cold-rolled steel bearing members/caps, with a 5" x 0.25" aluminum anti-compression web. Strong enough, I think.
)
Of course, drive-system wise, everything's in the wrong place at the moment, so don't pay attention to those.
I'm also going to do the Solsylva thing, and raise the X-rails with some MDF structures. Sturdier/easier than trying to extend the gantry columns, to recover the Z travel lost by reorienting the Y-axis rails. It will also reduce the amount of belt I need.
Lastly, I measured the side-loads generated by a Dremel milling through aluminum, taking off 0.0625" per pass. Maxed out at ~10 lb. side-force, in the direction of the pass. Granted, this isn't a 1 HP router, but it still gives me something. Also, given a 1 HP motor, spinning at 35,000 RPM, driving a 0.25" dia. bit, the absolute maximum side-load generated by the bit (in terms of grabbing the material and trying to roll along it) is ~15 lb.
In light of these numbers, I'm designing for 30 lb. side-loads, w/ deflections of less than 0.005". (Roughing passes, basically.) Since the primary use of this machine is still foam milling, this is definitely overkill, but it will allow me to use it on plywood and what-not, if the need arises.
~Luke