Anyone have some patience for basic 'dumb' questions

[lrubin28]

If you don't like dumb noob questions, please just move on to the next post...
I don't know a hell of a lot about t-slot or how to build a good, precision cnc (I've been reading what I can find time for). I got a fair amount of aluminum extrusion that was being tossed at work - some 80 x 80, 40 x 40, a bit of 40 x 80, and some 20 x 20 (all mm). I think it's Misumi but I can't tell for sure. I'm attempting a small (18" x 22") desktop machine, with a fixed gantry, and I'm not aiming for the type of the precision that most people on forums seem to go for. This is for relatively light stuff, and just to see if I can do it, although if I can get it to work for aluminum that would be a bonus. I don't have access to any machining or metal tools, welding etc. I cut 4 base pieces from 80mm x 80mm which I think should be rigid and sturdy enough for a small desktop machine. I have a few questions if anyone feels like answering one or more of them.

1) Regarding the table - could I just connect a bunch of 20 x 20mm t-slot, side to side? If so, what's the best way to connect side to side? Is it to drill holes through the slot and put bolts through, attaching to nuts in the next piece, over and over with different spacing? Or I've seen 2 hole connector plates on eBay, which I don't love. Any other choices?
2) For the fixed gantry - I was thinking of using 40 x 80 pieces on the 2 sides of the frame, with the vertical 80mm face against the 80mm horizontal bottom. What would make sense to connect the two sides with at the top? It seems that 40 x 80 wouldn't work because the 40mm wouldn't be wide enough to mount the axis? Should I use 80 x 80 for the top? Or maybe for the whole gantry?
3) For the x axis I have supported rod with bearings. I don't suppose there's any 8020 type connector made for supported rod ? I guess I can mount them on top of 40 x 40 pieces if there's no connectors?

Thanks in advance!

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[routalot]

I suppose you could connect a series of sections side to side.Equally,you could use three lengths of the 20X20 across the machine to act as supports beneath the top layer of extrusions,in the manner of joists, and it might flex less.For the gantry,don't fall into the common pitfall of only seeking rigidity in one direction,most of us expect to cut in any direction at the same speed and that requires equal stiffness along and across the gantry.A sufficient amount of triangulation is what you should aim for.You can achieve a lot with no more than a hand held drill-if you work carefully and it gets even easier if you can get to use a pillar drill.Best piece of advice I can give is spend ample time planning before cutting a single piece.