Norton Starr's model made of hydrostone in 1972.  Its outer diameter is 9 inches, and it consists of two toroidal halves glued together. 
Each half was cast in a wood mold prepared by the machine shop of the Amherst College Department of Physics.

Norton Starr's model made of hydrostone in 1972.  Its outer diameter is 9 inches, and it consists of two toroidal halves glued together.  Each half was cast in a wood mold prepared by the machine shop of the Amherst College Department of Physics.