Well here goes... Aluminium frame router design

[CharlieRam]

Well... I'm at a bit of a crossroad in my design, I have altered the Z axis to the conventional method which should please Jazz! but the machine is now 1004mm wide by 1400mm long with overall cutting area of 620mm x 1100mm and I'm now thinking do I need it that big?
The original idea was to have a machine capable of machining soft metals or even steel if it could cope but I also wanted it to be big enough to machine 600mm wide sheets of MDF so I could machine my arcade cabinets, the problem is I would need a machining area of 1800mm lengthways to produce them in one cut but I am now thinking should I make a smaller machine with say a cutting area of 400mm x 600mm for aluminium and possibly steel (Is steel doable or a definate no go?) and when that is built, use it to make parts for a dedicated mdf/wood router that would take the full length sheets at a later date, This machine could hang of the wall with a slight incline to get over the space issue.
I am also thinking that 1610 ballscrews with 1.8 deg steps will only give a resolution of 0.05mm, If I built it for metals and plastics then 1605 ballscrews could be used bringing the resolution down to 0.025mm.
What are your thoughts on this?

One other thought, If I only have a cutting width of 400mm would I get away with a single ballscrew, if not, what is the maximum width I could get away with or is it just better to go with 2 when machining metals?
Cheers, Charlie