Was busy at work so the CNC building had to be postponed a bit.
The epoxy batch I mixed was not mixed enough so the eopxy didn't cure correctly. I removed all of it with my heat gun.
I proceeded to make a new batch. This time I didn't bother to make a form to save a little bit of epoxy; I made a form to level the full width. Still used two bridges.
The batch was good this time.
I waited a couple of days then proceed to drill holes using a jig I machined on my old CNC.
With the holes done, I proceeded to tap everything with M4 thread.
I aligned one rail with my straight edge then roughly adjusted the other with the first one a reference.
I tested with ballscrew block for any interferences and there's none.
Next step is to micro-adjust the rails spacing with a dial indicator to make certain that there is no binding.