For a 2 x 3 foot machine you will end up with a serviceable, if light weight, frame for your machine. Use plenty of angel braces and gusset plates to supplement the normal bolting approaches for 80/20. Do take a conservative view on how all the pieces are bolted together though.
Other wise you could easily make the rest of the machines frame from this material. If you read my other threads I suspect the major weak spot on most DIY machines is the gantry beam, so my preference would be to see you use something entirely different there. The only way it might work would be to laminate three or more of these extrusions together and face it with some tooling plate. Given that I wouldn't use this material either way for the gantry beam as see it as a bit magical for such use.
The only real question is do you have enough to build a rigid frame? If not it may pay to sell the material and buy something different. I don't generally recommend aluminum T-Slots for a number of reasons but a big one is the cost of the materials so if that is out of the equation then You can put it to use. I'm thinking about build a cnc and have available some Series 30-3060,Would this be strong enough for a 2x3' wood cutting cnc router? what size for a gantry?If you have it available and it is in good condition, it is hard to beat free.
