When I was 19 I had a job at a wheel foundry. Was a union job and paid very well, but you had to do exactly as you were told by your supervisor. We would have 7 am to 7 pm shifts 5 days week during peak season, and occasionally called in for a Sat. We were not allow to sit down during floor time (I was an inspector) - you had to walk up & down rows of lathes machining wheels and take random measurements. You could only sit during breaks. if you got caught sitting it was a big deal, written up by supervisor etc. Plus we had to wear steel-toed boots in the foundry, so you can only guess how much your feet hurt when you got off shift! Absolutely brutal but I did make a lot of money that summer.