So, keen to get some feedback on the Z Axis.

Nothing too controversial except for the use of concrete. The concrete will be formed around the spindle with a few mm spare and then once the concrete is set, the spindle will be installed via a plate at the bottom and then DWH forming epoxy (the liquid version of the stuff I used for the rails) will be cast around the spindle. This means that the spindle (it needs to be planned so it can be removed from the bottom) will be a 'press fit' into the concrete. The aim of this is to both strengthen the Axis (Axial and Radial) however absorb vibration and improve the Z Axis overall.

The concrete will be around 39 litres which makes up a weight of around 90 kg.

Thoughts / comments / concerns?