To mount the linear rails in a consistent fashion I printed a set of alignment blocks. They lock into the 2020 and 3060 rails for the MGN15 and MGN12 rails to ensure consistent centering. These are specially sized for milled extrusions (which are ~ .4mm narrower on the mounting surface from the middle point of the extrusion).
These blocks will keep the centering consistent down the length. Mount the rail on the extrusion, lightly tighten the screws so you can still adjust the centering, and then move down from one end sliding the alignment block screw to screw.
Test print updates:
Finished printing and checking the Left X-Carriage. Had to make a handful of small tweaks to adjust screw spacing and insets, but otherwise it’s good to go. (excuse the shoddy print quality, I switched to a .3 nozzle and need to keep tweaking the slicer settings for it)
Also I am starting to inventory the screw lengths and counts for each part. For a BOM but also just so I know 🙂