Kitwn, I have considered it, but I like a good excuse for building another machine!

Thanks Dean. I'll just make sure to keep things well oiled to try and keep the dust flushed out.



What are the good build threads to look at for inspiration?
So far I've found that 45x90 is the recommended profile for the gantry, then what looks like 15mm plate for the major components.
What kind of spacing are people aiming for on the linear bearings?

I'm currently trying to decide whether to have a single underslung ballscrew for the long axis, or go for twin.
Single means the entire length of the bed will be unsupported (probably not that much of an issue?)
Twin means I can add triangulation, but I'm thinking a couple extra lengths of box over the length would probably give as much support as I'd need.

My current thoughts would be, aim for 8" clearance between gantry and the frame. That will give room for a work surface, and the carriage assembly, leaving about 6" useable clearance, and aim for Z-axis travel of 6-7".
Aim for 24" cross travel, so probably gantry rails will be about 32" to give plenty spread on the linear blocks.
Then aim for 48" of gantry travel, so again rails would need to be about 54" long.