This serial number data is from the Serial Number Reference Book for Metalworking Machinery (1959 edition).
                                                                                    Last Serial Number for each year.
Machine Tool Line | 1919 | 1927 | 1935 | 1947 |
3” Heavy Duty Horizontal Boring Machines | 571 | 642 |   |   |
3” Light & Heavy Duty Horizontal Boring Machines |   | T-3034 | T-3069 |   |
4” & 4½” Light & Heavy Duty Horizontal Boring Machines |   | T-2493 | T-24116 |   |
5” Light & Heavy Duty Horizontal Boring Machines | T-505 | T-503 | T-4021 |   |
Also see
The Bullard Co. Horizontal Boring Machine serial numbers.