When the spindle was out I started looking at some play in the Z direction.

One major contributor was the Z ballscrew end fixing wasn't done up, so it was only weight and a bit of friction stopping the spindle moving up and down.

There is still a slight bit of play, which appears to be at just one of the crosswise linear bearings (round 25mm unsupported). There is a miniscule grub screw that is already quite tight. This transforms to both vertical and longwise play at the tool so is more of a problem for my 2.5D work.