Homebrew PCBs

Now I have never built a CNC anything and I am not overly mechanical.  
Right that is my qualifications out of the way...

I was thinking about high torque motors to drive a linear thread and I 
thought about those really cheap cordless drills.  That is idea pt1.  

Now of course you need some sort of feedback for the position, the 
normal way would be to put a shaft encoder on the drive.  My thinking 
is that if you used a linear encoder then you would get absoulte 
positioning thereby negating the need for backlash compensation.  Now a 
quick look around ebay reveals that linear encoders are not cheap.  So 
has anyone used optical mice for a linear encoder? (idea pt b)

Here endith todays musings.

Mike