- Jul 12, 2015
Certainly plausible. Two data points that might slightly modify.I wasn't there, but have worked in a manufacturing environment, and currently still do, I do have a theory.
The steering necks are cut too to length, bored for the bearing pockets. If you pop them in a purpose built fixture, you can machine drill the 4 holes with precision. Then continue to have welded on the steering stops and steering lock tab. This piece goes to the frame assembly area to be incorporated in full frame manufacture.
Stove enamel in black.
Then when the frame gets to the bike assembly line, the frame is on its right side down . The little table or cart next to the assembly line with the number punches and box of cert plates and drive screws gets pounded in with a socket head punch. (matches the round head drive screws)
He then grabs the number punches and stamps the number in the cert plate which is in the up position. Writes it in the book? Frame goes "down the line".
Things would have changed if the production line changed or moved location. So this possible scenario could change over time.
Jan 1972 enter new cert plates after 2000+ combats already built.
Seems later production changed to the left side down for number stamping of the batch# as well as the VIN/SN
Just guessing what I would have seen if I was there-then.
1) I have a label that I believe to be original that has the serial number (203143) stamped readable in the same direction as the printed label and the stamp is deep enough that it is doubtful that it was done on the frame. The date is stamped upside down and not deep at all. Also, it is stamped "1972 Jan". I have been guessing that , at least at that time, that the label was stamped with the serial number and then it was installed on the frame. The date was later stamped.
2) If you zoom into the picture here: https://andover-norton.co.uk/en/service/ you'll see that the label is already on the frame and the steering bearings are installed. That's a weak data point, but something to consider nonetheless.
The label is 06.3247 (according to AN)