High speed spindle for pcb making

Hi!

Im looking for additional info about Dave Cowden's high speed spindle.
I was reading about this design here:
[blog.reprap.org]

More photos here:
[www.flickr.com]

Some more additional questions for Dave:
- How many pcbs are you making with it? So how durable is it?
- The cpu cooling fan can support this (high) speed? (50-90k) How the skate bearings are wearing out?
- Can you post some additional photo (from inside) or design drawings (or technical schematics) of the spindle?
- I dont really understand the tool holder, how are you changing the milling bit?
- How robust are the pvc tube? It does not affect the overall robustness or durability?
- Please post some photo/video of the overall machine when milling

Any more info is really appreciated!

It would be interesting to see if we could print everything but the turbine axle for one of those things out of ABS.