Brand new newbie

[njhussey]

Your aluminium base at 50.6 kg isn't that much of a saving in terms of weight over a steel base frame. My base is 1300 x 700 and I'm making it out of 4mm thick steel. The calculated weight of mine (from the steel stockholder's data book) is 74.4kg and the cost of the steel (I've got 1m of 50x50 box, 2.5m of 50x25box and 4.9m of 100x50 box left over for other projects from the 7.5m lengths I purchased.) is £95. If your mates can weld then steel is much easier to weld than Aluminium and much cheaper which I'd have thought is a driving factor?

How are you thinking of connecting the ballscrew (if you're thinking of one central one) to the gantry sides? You'll need to raise the box up on legs (additional weight and cost) to do it with that layout?
Can you not use a steel base out of 3mm thick steel (to save weight) like the below?