Hello, everyone. Great posts! If I may add my own observations.. I have been a Tool Maker for over 35 years. tango1niner is spot on about learning basic machining skills..including bench work..learning how to file and fit parts.
When the CNC machines started to come into our shop in the late 70's, all the new hired apprentices were given extensive training on them. Some became very proficent. BUT..if a critical part on the production line had broken..and it was handed to one of these fellows in three or more pieces..and told they needed a new one NOW!...they were lost. You see, they were only trained in setting up the machine by given math data for a particular job.
If any hand filing were needed for fitting, they were lost. New technology is nice..but a master machinest using just simple hand tools is hard to beat!