Unpopular opinion: the guy who trained me on the lathe taught me more in one shift than any class did
When I started running a Haas ST-20 about 4 years ago, I got paired with Ray, a guy who had been on machines for 26 years. First thing he did was shut my feed rate way down and tell me, 'You will hear the cut before you see a bad one.' We stood at that machine for a whole shift in Kentwood and he made me listen to every pass, good and bad. I could not tell the difference for the first two weeks, then one day a chip came off blue and squealing and I cut the feed before he even looked up. He just nodded and said, 'Now you know.' No video, no manual, no simulator ever did that for me. The sound of the tool is still how I catch most of my problems before the part is scrapped. So do you all train new guys by sound first, or do you start them on the numbers? I'm curious what works for other shops.
How many of you had a guy like that? A buddy of mine got hired at a shop down in Grand Rapids and his trainer was an old timer named Dennis who ran a big old manual lathe. Dennis made him cut scrap stock for a week straight, just listening, and would not let him touch a feed dial until he could call out a bad insert by ear from across the aisle. My buddy thought it was a waste of time until his first real job, where he heard a chatter start up and killed the feed before anything broke. Dennis just walked by and said "told you," and never brought it up again. To this day my buddy says he learns more from that week of scrap than any class he sat through.