Bearings and rails took an hour of so going back and forth with a run out gauge to make sure they are dead on parallel. Once done they are tightened down and I'm moving to position the ball screw. After a lot of thought I went with a somewhat unorthodox design for the Deep Z axis. Rather then run the screw done the center I opted instead to run it to the side. This allows me to keep the two load bearing members as close together as possible. Considering the stout construction of this axis due to its unusual reach I see no problem with mounting the screw off center. It's got a 19 inch inch Z travel. Grin