Years ago while watching Mr Rogers with my kids, they took a tour of the William Kratt harmonica factory. I found it pretty interesting considering my mom worked for William Kratt when I was a kid. The old factory used to be in Union, NJ. I used to walk past it every day on my way to school and my mom started working there somewhere along the line, tuning reeds for pitch pipes and harmonicas. They made some pretty cool chromatics harmonicas. I have one that I've kept for old time sake.
In a later episode, they visited a manufacturer of saxaphones and showed the process of making these as well. You really don't see educational shows like this for kids these days.