Homebrew PCBs

Hi Guys

For the fellows who are mechanically machining their own PCB's, what is 
the choice of Spindle Motors?  How do the RotorZip units work for this 
application compared to using the Dermal units?  I was never very 
impressed with the bearings in the Dermal Grinders.  They don't seem to 
last and get loose rather quickly.  Interested in your thoughts on this 
matter.  Thanks for the help.

Regards

Bill