George Gorton Machine models
Prior to the 1950's, the three common vertical mill models were the 8-D, the 8 1/2-D, and the 9-J. The 8-D was rather small, and quickly superceded by the 8 1/2-D, and the larger 9-J. Starting in the 1940s, some (somewhat custom??) horizontal mills were added, and …