Well here goes... Aluminium frame router design

[CharlieRam]

Well I'm back I had a play with that spreadsheet and decided to stick with my unconventional layout, the reason being is I have used calculations based on 35mm thick steel plate, this is the 20mm thick plate plus the 15mm thick spacers, I was thinking of gluing and screwing them together but I am not sure if this will give the same results as a 35mm thick plate with a recess machined for ballscrew.

Anyway, the figures from that spreadsheet give me roughly .65 micron deflection, the conventional is slightly better at .19 microns but a lot worse at full extent with 10 microns but if I reduce my cutting depth to just 100mm by raising the bed and spindle by 50mm then I get .19 microns across the full cutting height!

I am a bit stuck at the minute though, am trying to figure out how to drive the X ballscrews from a single centrally mounted motor but leaving the ends of the M/C open for any job overhang I may need. It seems like I may need a lot of pulleys to guide the belt but I am not sure it is a very elegant solution, Any Ideas or am I just going to have to go with twin motors?

I do want to add a 4th axis at some point and I don't want to go silly with the spend on adding unnecessary motors and drivers if they aren't needed, speaking of which, I have drawn the base up now and I'm thinking of having a go at welding but last time I tried that it looked like pigeon shit! How much should I expect to pay to have one fabricated?
I have added some more sketchup images, the steel parts are colored blue.
As before I look forward to your criticism/Acclaim
Thanks, Charlie

EDIT. Also checked the gantry sides stiffness using the calculator using height to top of gantry as 235mm but it assumes the 20mm plate is not braced, Mine has plates on the back bolted to the bearing block plate, the gantry plate and also the gantry beam so can I just reduce the length in the calculator so it reads full length minus the brace plate giving me a total height of 103mm to give a realistic figure?