How it's made - Trombone

The famous series of Discovery Channel made a part about custom made S.A. Shires trombones. It's very educating and gives a brief introduction on how much craftsmanship it takes to make a good trombone. The skill that is needed to make trombones has not changed over the years, but I must always think on how they managed to do this in the past without the modern equipment of today like those acetylene burners. Coal-fired like a blacksmith makes his iron stuff?