First steel diy CNC router build

[JAZZCNC]

If you want to mainly cut aluminium on this machine then you really need twin ballscrews on your Y axis (X in my world). Even with using steel the gantry will still rack when cutting aluminium or harder materials. Also like Jonathan mentioned the distance between rails on your X axis is too great so either increase clearence or lower the gantry height to bring closer together.

Regards the twin ballscrews then use single motor and join them together with timing belts and pulleys. Use 10mm pitch and gear 2:1 ratio to give same resolution as 5mm pitch but at same time increase torque.
This way it's Win win you get around the racking issues give flexabilty to machine because you can fine tune with differant ratios or increase speed if required with simple pulley change.
Less electronics to go wrong and slight saving on cost's. Motors perform smoother and better due to less resonance affects and with a All steel machine resonance can affect motors quite a lot, esp if using cheap drives.! . . . . This brings me onto Drives.?
Don't buy cheap drives with a steel machine because of resonance, paying that bit more for digital drives will pay back big time in the long run. You'll get much smoother performance from motors but more the point they deal with resonance much better which will drive you crazy and give a very rough running machine if you do encounter it.!

If your dealing with Chai ask him for a price for Profiled linear rails and you may get a pleasant surprise.?