Just wondering how the rotation number was determined for cars on the assembly line. I have reviewed quite a few build sheets and it seems that it does not correspond to the Vin number. Was it random?
There are a fair number of threads discussing rotation numbers (mostly second ones) on the site. One such example is below and it may provide some additional reading material for you
https://www.concoursmustang.com/forum/index.php?topic=17074.msg107254#msg107254As mentioned in a few other threads.
Rotation numbers had no connection to the VIN other than that they a specific number assigned to that VIN or the body that would receive that VIN at some point in the car assembly line. Since the bodies/panel started out with no VIN and that cars were not built in sequential order the factory needed a different identifier for workers
Not certain if your asking about the first or second rotation number. One was assigned and used for the first "half" of the build then they were placed in a storage area and the "computer" rearranged the order so that two difficult cars didn't follow one another and slow down the process and given a new number that corresponded to the order they would enter the second "half" of the build.
As far as the second rotation since this is the most often asked about one job one for that production year got #1 and they went from there. When they got to the last number they started over with #1. Top number depended on when and where the car was built. At most plants and years the range was 001-999. Dearborn durign 69 production was one of the exception with numbers over 999 used for some reason. They didn't start over again at the morning shift with the first car added to the first car/body placed on the belt that morning according to the managers I've talked too. No reason to since there were partially completed with other numbers from the last shift still on the line and sub-assembly stations that had already been sent copies of buildsheets for the cars that would be in line that morning and parts already prepared and on the feeder lines to the car line.
As mentioned before a great example of documentation IMO was found years ago. It was a stack of maybe 20 buildsheets all in sequential order (by rotation numbers). Looked like some worker didn't throw them away but stacked them up and tossed them in the last, of the group, car. Car VIN's varied allot, scheduled build dates by four week and less and also provided support for things we had been told by workers.
One last note. Remember that all of the cars being assembled on that particular line in the plant were part of the process so in the example of 69. At plants where Cougars were being produced both Cougars and Mustangs were numbered in order so, for example, rotation number #600 would not be the 600th Mustang built in that order #600 could be a Cougar or in other years a Fairlane
