For CNC machine operators you can probably find simple repetitive jobs you can train someone on in a day and then every week show them one more new trick until after several years they are useful for simple non-repetitive tasks and a few years later they are useful. I'm not sure what turner is, but if it is lathe operator you can train someone in a couple days to be minimally useful - on the types of things you should use CNC for, but it will be a year or two before they can do the complex things you wouldn't just drop to CNC. For engineers you really need a lot more training to be useful.