Thanks for the feedback david - It does look a lot more rigid now. I'm working on the z-axis now but unfortunately am away at work which makes things difficult!

I have thought about just buying a CNCRP or readymade Z axis and bolting it on to my machine. What are your thoughts on this route Vs designing my own? I'd be looking at two hgr20 rails on the carriage, with the blocks on the z-plate. with a ballscrew between them. I'm just not sure I can make it as tidy as the CNCRP one. Can a smaller diameter ballscrew be used due to the short length?

You say thicker aluminium is the way to go, what thickness would you recommend for each of those plates? especially the one that bolts to the bearing blocks and the gantry riser? Aluminium is my preference because I can cut it on my shapeoko3 at home, and don't need to get it done at a machine shop.

Thanks again