The sides and back are made from old-growth birch. It was harvested in the 19th century, but it sank in the Great Lakes before it could be processed. It was recovered, dried, and milled in the 21st century. It’s nice wood, with good grain, although it doesn’t really have much of the striking figuring that is often seen in fancy fiddles. The sides are shockingly thin, just 1.2 millimeters. The wood is cut into strips on a band saw:
The strips are then thinned to 1.3 mm on a thicknessing sander (the "Luthier's Friend"):
A block plane and scrapers are used to bring it down to 1.2 mm.