How do People Find Used CNC Machines That Are Worth Buying?

[JimDawson]

The thing is, learning about running a machine would not make me capable of checking out a used one. It would probably help me reject machines that were hopeless based on obsolescence, however.

I would argue that there are no machines that are hopeless based on obsolescence, only machines that are hopeless based on mechanical condition. Control systems and motors can easily be upgraded to modern standards, and this can be done at a reasonable cost. When looking at a machine I am only interested in the mechanical condition, if the controls are still working then that's a bonus. You obviously have the skills to do a controls retrofit if needed.

I know a small amount about CNC. I actually turned a mini lathe into a CNC lathe. Then I found out it was pretty useless without ball screws. Basically good only for wood, and who needs CNC for wood?

If anyone else is considering a lathe conversion, my advice is to forget it. The lack of versatility is a dealbreaker. A mill is the only way to go.

There is a way, but that's a subject for another thread.