He's added a fourth axis

[Smiler]

Ref the angular contact bearings, I'm not really sure. I think the way the big boys do it is to pair a set of single row angular contact bearings opposite each other, and preload them, either next to each other at the chuck end (as a matched pair, with a simple roller at the other end of the shaft), or preloaded along the whole length of the shaft (a non-matched pair, one at each end). I reserve the right to be proven wrong.

I've done it pretty much as per the video to be honest i.e. an angular contact bearing behind the chuck with a thrust bearing the other side of the plate and preloaded them, a simple bearing holds the other end of the shaft. Works really well for router use and I suppose it would work for light engraving on Aluminium but I'd never try machining, I'd convert a rotary table for that (Mr Kip was kind enough to donate a stepper adaptor for such use).

I'll tell you what was REALLY nice about this project. The fact I designed the plates and cut them on my macine and all the bits, bearings, stepper etc. just fit first time, no filing, no drilling larger holes because one was .25 of a mil out because the dot punch slipped, everything just fit and lined up. I know it SHOULD do that anyway but I still find it all amazing and it was worth doing just for that glow you feel when it all goes to plan. My mate at work Kenny has been doing CNC lathe for many years, most at RR, and he says he still gets the same kick when the bits all just slot together first time every time. Wonder if others do :)