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 The 8D was rather small, and quickly superceded by the 8 1/2D, and the larger 9J.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