Wooden barrels were still in frequent use in 1939 (my era) and barrel making is interesting. There are two general categories of barrels referred to as "slack" or "tight". Slack style barrels are used for dry materials whereas tight barrels are used primarily for liquid. The names are descriptive of how loosely of tight the barrel staves fit together. The other parts of the barrel are the headings and the hoops (either wood or metal).
Tight cooperage barrels are usually made from white oak or a similarly hard wood due to it's hardness, workability, and excellent seasoning qualities, is less likely to discolor or lend a disagreeable odor to the contents.
The staves are made from short logs about 3 feet long called bolts. The bolts are usually obtained green to avoid checking and splitting of bolts left out in the weather too long.
I am working on the floor and room design of the factory using rough sketches and room templates to ensure that it all fits and contains the necessary functions for making barrels.