Hello every one

I would like to build a cnc with a bed size of 1200*1200mm or 4ft*4ft due to the cost of parts in Australia what would be the best way to build a machine with out spending mega dollars

Would 25mm (1') 1500mm (5ft) 900MPA precision ground rod be able to support a machine of this size with out support blocks? I was going to run the C type linear bearings but they are $100 each over here

BTW I would like to be able to cut aluminium

Cheers
Shane