Models 15 through 18 were all based on the same design with some minor differences, while serial number runs alternated with those of the Model 14. The factory appears to have had both the Models 14 and 15 in production at the same time, which is odd, since both are 6-size hunter lever-set movements. This second design, starting with the M15 and concluding with the M18, was divided into the Eagle and the Century Series, and roughly a half-million were produced in total. Complicating matters further was the 12 x 6 line, which used 12-size dials on 6-size watches.
The total production of the Model 15 was around 27,000 pieces in four runs from SN 128,001 up to 160,000. Jewel counts were 7, 11, and 15 in gilt, nickel and two-tone, and all were lever-set with flat hairsprings. Later 6-size models were all based on the Model 15 platform with changes to jewel sizes and the winding and setting mechanism. The Model 15 parts list shared some of those used on the 12 x 6 spread movements.
The Model 16 was made in two separate runs from SN 160,001 up to 200,000 and another one from SN 400,001 to 420,000 for a total of 59,000 movements. Other than some minor changes to the mainspring barrel and arbor they were identical to the Model 15 with the plate finishes and jewel counts of 7 to 15 remaining unchanged.
130,000 movements were produced in two runs from SN 420,001 up to 500,000 and from SN 900,001 up to 950,000. The Model 17 was nearly identical to the M16, but upgraded with Breguet hairsprings and now offered in jewel counts of 7, 11, 12, 15, and 17. The counts of 12 and 17 have been reported in only the Edgemere grade.
These watches first appeared around 1900 and were a Model 15 with a larger 12-size pillar plate, offered in the same three jewel counts in either lever-set hunting or open-face with no seconds bit on the dial. Later versions were based on the Model 18, with a longer setting arm appearing on the parts list. Some publications advertise these movements as pendant-set, despite the fact that neither the 1904 Model 15 or 18 parts lists include no provisions for a pendant-set mechanism. No model designates are known but they were included as part of the Eagle Series with six of their own grade numbers, continuing to the end in the 1913 Centennial Catalog.
The Model 18 was blocked from SN 950,001 up to 1,000,000 with no known interruptions. They had 7 jewels, flat hairsprings, solid center pinions and a separate parts catalog entirely its own. Production of 6-size watches continued well into the 3- and 4-million SN ranges bit it is not known which model was being used. The vast majority of the movements were named grades.
This assigned grade appears in several of the Ehrhardt volumes and is based on a 7-jewel Model 18 equipped with a Breguet hairspring, but any production totals or SN ranges are not known.
The Model 15 first appeared in the 1904 catalog, though it's likely that it debuted before that, given how its serial number runs dovetailed with the earlier Model 14. Later catalogs up to 1913 list a 6-size Eagle movement by differing grade numbers and jewel counts, so it's never clear exactly which model was being represented.
The earliest blocks of nickel Model 15s were stamped with the image of a rose and came equipped with either a colored fancy dial or one with a Rose-signature dial, and are very scarce.
Grade assignments for all the 6-size models are ambiguous at best because most reported examples are junk parts movements without a dial photo, so it's impossible to know if it's pendant or lever-set. For ease of research nearly all the 7-jewel movements are logged as lever-set Grade 35; though the pendant-set Grade 45 has been identified whenever possible. The Rose movements were designated as Grade 5 in at least one publication.
The 12x6 Spread Movements
All of the spread movements are standard 6-size models with a larger pillar plate to allow them to fit a 12-size case. They were advertised as both lever and pendant-set, but the various parts lists don't show any kind of pendant-set option. They did have six separate grade designations based on the two setting options and the three jewel counts, but again photos are sometimes so poor that it's impossible to identify the setting type or whether it has a larger-than-normal pillar plate. For ease of research all examples have been graded by jewel count, but if your watch is a spread movement use the chart to determine the correct grade.
* Grades 115 and 225 are both assigned and have been found exclusively on the Edgemere grade.
The Banner watches were 11-jewel Grade 105 Seth Thomas movements with specially marked dials, though the movements bore the standard markings and patterns. They have been reported in Models 16 and 17 Eagle Series serial number blocks, and were available as a movement or factory cased. It is not known for whom these pieces were made or if they were marketed alongside regular production grades.
The serial number runs for the various models alternated with each other up to SN 1,000,000. Factory records past this point have not been found, so it's not clear which model was being used or if it was more than one. For ease of research the Model 18 is listed on the chart for these runs, since it was the latest of the models.
There were plenty of named grades to accompany the factory-numbered ones.
Click here for the entire alphabetical list, along with models and jewel counts.