Do I detect a family resemblance? Could be father and son. The older man is dressed for forge work, so maybe the youngster produced the exceptional swarf.
There's something un-British about the cut of their clothes, especially the young man in his Tyrolean cap and short smock. My guess is they are Americans and being clean shaven suggests 1920's or 30's.
Why so unhappy? Maybe stopping for a photograph resulted in less pay because they were on piece-rates.
Dave