I use sophisticated milling machines at work every day.  That’s my job.  It basically involves moving parts in and out of the machine while the machine itself does the actual cutting operation.

Even though I have worked with these machines for many years, I still have to rely on my set up guy to maintain it – for example when to replace the cutting tools.  At least I can identify many of the parts of the machine though just in case he needs me to help pinpoint any problems.