CNC Conversion for Education

I have been a machinist all my life and just recently a senior high
school manufacturing teacher. Because of all the school budget
cutbacks, I want to try to convert existing conventional lathes and
vertical mills to cnc. The schools do not have the money to either
convert these (quoted around 6,000) or buy new cnc machine. I wanted
to put together an engineering package which is based on current
school curriculum so that machine shop teachers on limited budgets
could follow these plans in order to convert their equipment as a
class project during the semester. Has anybody out there converted a
full size lathe or vertical mill to cnc--at a resonable cost--say
around 1,000 dollars? What size, i.e., holding torque did you use,
and whose controller, drivers and software did you use? I have many
old 486s lying around so I wanted to use turbocnc for the software--
it's Shareware. I fear that if someone does not take this kind of
action (reasonable conversions of conventional lathes and vertical
mills) that manufacturing high school programs will whither away to
purely simulation and model building programs--Manufacturing teachers
have the equipment and rather than sell it, let's convert it and give
our students and our schools something more than simulation and model
building.
Thanks
Darrell