Atocha Iron Plain Bearing 1986.008.1922

3D Model

A circular, iron object comes from the wreck of the 1622 galleon Nuestra Señora de Atocha. It is thought that it is a plain bearing, used to reduce friction between a rotating shaft or spinning wheel and a support member. Similarly designed objects called “coaks” are found mounted in the wooden sheaves of blocks to prevent the wheel-like piece from wearing as it turned on the pin. Considering that this Atocha piece has an inside diameter of 14.2 centimeters, it was for something much larger than a pulley or sheave. Instead, it is thought that this object was a bearing fixed in a cannon carriage wheel to fit over the axle so as to prevent wear between the two pieces. The exterior of this iron piece tapers slightly: one end has an outside diameter of 16.9 centimeters; the other 16.5 centimeters. Three evenly spaced, angular “ears” project outward, and they would have prevented the bearing from spinning within the body that held it.