design choices when the budget will not stretch?

[wilfy]

i'll give my answer from a noobies perspective.

welded steel framed gantry... i dont know if i'm understanding this wrong, but i see plenty of alu profile gantries even on here there are people using profile frames

20mm alloy z and y axis, again not sure if i understand right, but if you mean the mounting plates then yes i'm looking this way myself and think it's needed

water cooled 2.2kw spindle and vfd, personally i've not dug deep enough yet to find the answer to the power needed for most operations, but my understanding is if you dont start water cooled then you will end up here anyway, but as i said the power at 2.2kw is something i feel might be something you can compromise on, personally i'd been looking at 1.5kw

m542 drivers and 50v power supply are both things i feel come down to your personal preference. your desire for speed will have alot to do with how much you want to spend on drivers and psu... me personally i keep telling myself i'm going to keep cost down by staying with cheap drivers.. the reality is that i will more than likely want to upgrade to better motors once i realise what i should have bought.. hey i might even get to the stage before i even buy my first motors..

1610 ballscrews, now personally with loads of reading i'd already decided ballscrews were going to replace that original thought of using threaded rod.. however i'm not sure what the difference is between 1605 and 1610 yet and how they will apply to myself

20mm supported rail is pretty much a given for the size of table i'm considering and maybe table size is what decides whether you go supported or not, the arguements here for supported rails really do make it hard for you to consider anything but them

variable height table is something i never even considered i suppose a trade off would be to build a low table with the intention of packing it out everything you did any work that needed it raising, but then i imagine alot of our work is like this therefore i'll personally not even consider this yet