Giant 20' x 3' x 2' router build

[routercnc]

Charlie,

It's a very unusual machine and I can't quite work out which bit will be which, so the question you've asked about motor sizes is probably proving difficult for anyone to answer.

But be aware that you can move a fair amount of weight with a 3Nm Nema 23 if you give it enough voltage as the ballscrew gives you lots of mechanical advantage. Don't rush out and buy 34's until you posted the final design sketch of the finished moving parts as you'll get a more definitive answer.

Your earlier question about pulley ratio on Z is also tricky since your Z appears to be quite long. Lots of designs are just 1:1 on a 1605 ballscrew for Z. But your travel (if I read the design right!) is quite long so this mught not be your best option. Again, a picture of the overall finished design would get a better answer from the forum on that question.

The wooden template motor bracket looks OK as a concept (assume ~20mm ali in the finished design?). Probably get away without triangulating back to the extrusion. But you'll probably need to recess the underside of the motor mounting area to raise the stepper and leave enough shaft sticking out the top. Also the ballscrew end might also need some pocketing on the top to clear the pulley / grub screw access.