For those who have been following and are considering building their own, I found another open source build platform similar to Makerslide mentioned earlier. It is called Open Build V slot.
This is also available in Australia http://openlab.com.au/
If you join the openbuild forum, you can download CAD models (including Solidworks) for every component.
It is a bit cheaper down under than Makerslide and a wider range of components is available plus heaps of videos on youtube.
I had to go to my plastic supplier today so I could not resist picking up a metre of 25mm dia Acetal (Delrin) rod and deviated past my bearing shop on the way home. The plastic cost $10 and is enough for 60 or so wheels. The bearings were $5 each because the only ones they had in stock were SKF brand. With a bit more searching, I am sure I can get them for $1 a piece. I've got some hex brass that will do for the eccentric wheel spacers.
Anyway, I thought I would have a go at making some wheels based on their plans. I figure I have to plan out the job so I turn up a set of 4 or 8 at a time so they are all identical dimensions which I can use as a matched set on a given axis. I thought I would turn all the v shaped surfaces first, cut the first bore, part each one off and finish off the bore on the reverse side.
I also finally got around to firing up a Nema 23 on my Arduino via a Gecko 10 x micro stepper and it leaves the little polou driver for dead! I am not sure If I will get any more, but I thought I would use the bigger stepper and the Gecko on the Z axis as there is more weight to move.
I still have no idea what a DIY home made printer will look like yet, but it would be cool to say you machined every part! Hopefully it will have a build volume of 12" x 12" x 12"
I think I will blame Tin and this thread for the $20 I wasted today...