At run 16111201-16111200, a run of 845s, Waltham begins using the Ohlsen or 08 Regulator on Vanguards, Crescent Streets and 845s consistently until the end of Model 92 production. It will do the same on P.S.Bartletts and Appleton Tracys shortly thereafter although by this time relatively few ATCs were being produced. The 08 Regulator is found on some movements previous to the 16111201 run that were originally made for the Star Regulator. The inventive means by which Waltham does this is to plug the recess for the star and install the 08 Regulator over it. It is unclear as to whether there was a transitional phase to this variation or not. There are documented (and infrequent) examples of movements with plugged balance cocks and 08 Regulators as early as serial number 7011387, long before the 08 Regulator was devised so one would tend to think that these movements must be retrofits. However, as we approach the 16111201 run referenced above, the occurrence of the plugged balance cock increases. The table to the right lists serial number 16003138, a Vanguard as the starting point for what might be a transitional phase. The table consists only of serial numbers that are backed up by photographs and certainly many more movements were made during this period. As you can see, the Star Regulator is used much more frequently than the plugged bridge and 08 Regulator. For the most part the plugged bridge is found only on Vanguards, Crescent Streets and 845s. There are no examples of P.S. Bartletts and only one Appleton Tracy reported with the plugged balance cock. The author readily admits that there is no science to this table and offers it only as an attempt to give a sense of the frequency of the plugged bridge leading up to the 16111201 run. One could argue that it would have been cheaper for Waltham to plug the bridge than to use a gold star so the question remains open as to whether there is a transitional phase or just random use of the plugged bridge by Waltham to complete unfinished movements. Previous to movements in the 16 million range, there is only sporadic use of the plugged balance cock. One can easily recognize the plugged balance cock because the post that serves as the arbor for the star will still be present. The balance cock made specifically for the 08 Regulator can be seen in photo below on the right.
 | Table 5 showing style of balance cocks used on Vanguards, Crescent Streets
and 845s leading up to consistent use of the 08 Regulator Balance Cock
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