Initially, the regulator used on the Model 92 movement is a micrometric regulator common to many models and grades that Waltham made.  It is generally referred to as the “Star” Regulator.  The watch can be made to run faster or slower by pushing a point of the star to the left or right.  The “star” portion of the regulator occurs in Patterned Gold, Gilt Steel, and Polished Steel.  There is some relationship between the grade of the movement and the version of the star that is used but like many other things, it is not always consistent. The Vanguard, Crescent Street and 845 grades all use the Patterned Gold Star [ref photo #1].  The Gilt Steel Star [ref photo #2] is found on the P.S. Bartlett grade.  It is also found intermittently on Appleton Tracys from the 7026001-7027000 run up through the 8241501-8242000 run.  Beginning with the 8856601-8857000 run it is used consistently until the 08 Regulator is used.  The Polished Steel Star [ref photo #3] is found on Royals, Riversides and on early Appleton Tracys.  The current research would suggest that it is used exclusively on the first 2 runs of ATCs and then intermittently up through the above mentioned 8241501-8242000 run.  As this is more than a bit confusing, please see Table 4.
                                 Photo #1                                                                  Photo #2                                                             Photo #3


 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  The 08 Regulator is found on some movements previous to the 16111201 run that were originally made for the Star Regulator.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 on the Plugged Balance Cock  page 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 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 [ref  photo #4].  The balance cock made specifically for the 08 Regulator can be seen in photo #5
                      Photo #4                                                                       Photo #5


Another variation that occurs on the balance cock is one that occurs on the bottom side so it is not readily visible.    It has not been determined exactly when this change occurs.  Originally, Waltham uses 3 guide pins on the bottom of the balance cock and then reduces that number to 2.  3 pins have been reported on movements up through run 7025001-7025500.  Movements from run 7901500-7902000 have been reported with 2 pins so it would seem that this change occurs somewhere in between the two runs.  It is difficult to be precise in this area as all the movement photos in the world will not reveal the underside of the balance cock.  It is equally as difficult to know if a transitional phase exists.


A serious collector wants his or her watches to be original and a switched balance cock can be a problem.  Unfortunately, there is no hard and fast rule for determining by sight if a balance cock is correct or not.  A Vanguard, Crescent Street or 845 balance cock will have the Gold Patterned Star and the area surrounding the balance jewels will be recessed and polished.  This is helpful knowledge if you find such a bridge on an Appleton Tracy or P.S. Bartlett but it does not tell you for instance if a Vanguard bridge is on an 845.  Within some limited ranges we can determine if a balance cock is age appropriate. Beginning with run 10517801-10518500 the patented stud is used and the orientation of the balance cap jewel screws changes from north/south to east/west at run 11070301-11071100.  The current research would suggest the solid balance cock and 08 Regulator are not typically found previous to 16111201-16112000.  There is a lot of territory between these numbers and that leaves us with the reality that the only sure way to know if the balance cock is correct is to check to see if the serial number on it matches the others on the movement.

Subpages (1): Plugged Balance Cock