Fitting of the top and bottom head pieces didn't happen during my visit: the hoops at either end of the barrel are removed to let the barrel expand slightly. The head pieces are slid inside, slotting into a groove cut around the inner circumferance of the barre. The steel hoops are tightened again to squeeze the barrel together and grip the head pieces. This short film by winepages.com was made in the cooperage of Louis Latour in Burgundy.