Well here goes... Aluminium frame router design

[CharlieRam]

Does this bed design look better? It is still made using 1 off 80x40x4mm 7.5mm long and 2 off 50x50x3 7.5m long steel.

I keep going back to my bed design and I'm wondering, for a novice welder (zero experience!) will I need to add adjust-ability into the X rail supports, I have allowed for 5mm thick epoxy but I am just a bit concerned about welding the frame only to find it is twisted or out of square?? If I were to make the X box section bolt on to the bed frame rather than welded would it be strong enough and would I be able to skim the 80x40 seating face acurately enough to bolt the rail directly without the need for epoxy.....I think what I am asking is 'how flat does the seating face need to be? less than 0,01 or is it more forgiving than that?
Also if I go the epoxy route I have read people say drill and tap after applying the epoxy, could I do that with a standard drill or would I need something like a magnetic drill press? I was thinking to drill and tap the holes and coat some bolts with molten wax and then fix them in place before pouring the epoxy, would that work or not?
Cheers, Charlie