First time build - Steel Frame CNC Router

[examorph]

Hi Boyan, thanks for the advise. I looked at the design again and the main areas I think may cause me some headache are lining up the x axis bearing supports with the gantry sides (as clearances are small) so guess there will be a lot of back and forth with the hand file for this, and another area was the ball screw bearing support depths on the x axis being difficult to line up without a mill, so I reduced these in width and made them into spacers with thru holes instead (nut/bolt onto box section), allowing me to again skim them down easily with a file if required.

Also, I noticed that I could extend the rails on the x axis all the way along the box section and reduce the length of box section to better utilize the full length of the ball screw, so the X axis rail is now 1050mm. Front hard stop was easily added with a bit of 50 x 50 box section but for the back, I used 10mm plate as anything over the back face would get in the way of the belt. Not sure if this will be enough?
Attachment 17469Attachment 17468Attachment 17470
For the carriages, should it be 'ZA' pre-load? Also how do you define the longer carriages in the part reference and what is the length of these so I can double check the models please?