Looks like its going to be a nice machine, clean design well done, was probably always asking a Workbee for to much in what looks like 20mm plate :), still they don't look that bad at all to be fair, and good job at making the Delrin plates first in order to then make them again in ali, the plan worked :)

Probably didn't really need to double on on the Linear rails for the Y, have you set one rail up and then used that as the datum to align the other 3 rails from or not got that far yet? I ask to let you know (don't know if you already know), adding a second rail like that (from what I understand) doesn't really add much of a performance gain vs the cost or...

Having the rails doubled up like that (so close) adds a margin of required sophistication when installing the rails, in short - if you don't dial them in to be on the same planes as each other, the bearing blocks/rails could* be working against each other in their linear movement and thus causing premature failure (wear) even if Hiwin quality.

No criticism only constructive feedback, your doing a great job keep up the good work

P.S Welcome to the forum, thanks for joining and sharing your adventure.