Well here goes... Aluminium frame router design

[CharlieRam]

Little better but still not what I had in mind if your seriously wanting to cut aluminium. Check out the forum for machines with base frames with sides raised and rails sat on top. This design is more router biased and it will cut aluminium no problem but not with the same abilty as machine aimed directly to do this.

When you say ability, do you mean accuracy or chatter or what?, I did see the designs where the gantry sat directly on box section but I was trying to keep the footprint down to a minimum (Lack of space!) and I thought the angle brackets would give less flex than a box section, obviously not though. Would it help if I were to increase the size of the angle plates or would you still say box section is the way to go.
I will look at the Z axis, I never thought about doing it that way but now when I think about it, it makes sense thanks, I would prefer just ally for the base but its pretty damn expensive for a sheet that size, I will look into ply.
Thanks, Charlie