[greenene]

I notice that most gantry designs that use supported shafts do not use end shaft mounts for additional support---just like in the case of usupported shafts. Is it fair to say that if shaft mounts were added to the build, the static and dynamic load of the shaft would increase significantly. Or is it insignificant.

[ger21]

The open bearings are the limitiing factor with round supported shafts. If the shaft is able to move, then end supports would help, But I would expect the bearings to have play in them before the shaft ever moves.

[greenene]

So you are essentially stating that the normally spaced bolts used to affix the support structure is more than adequate---bearings notwithstanding.