idrum4fun - The amount of variation you identify is consistent with what I have recorded. a five month difference in date stamp within a relatively small range of serial numbers is not out of line. Note that it could result from shells not being used in date order, badges not being used in serial number order or a combination of both.

wlfkurt - I cannot contribute much on the subject of when the date stamp was applied. We know it was applied after the shell interior was finished, otherwise we would not see it in the case of Resa-Cote and Lud-Cote interiors or be able to wash or wipe it away so easily. Perhaps if we could determine WHY the date stamps were applied, we might gain some insight into WHEN in the manufacturing/assembly process they were applied. Ludwig date stamps appear in some form at least as far back as the 1930s (in the related and predecessor companies). They stop in the 1971/1972 time frame. Where they used for internal tracking or inventory purposes? Was there ever an intention that the customer receive and use this information? Lots of unanswered questions on this.

I almost think the date stamps were intended for merchants so they knew how long a set had stayed on the floor. It appears that WFL did not start stamping drums until the mid 50's and the stamp was typically red ink inside the drum on the inside panel next to the vent hole. It seems by 1960 or so the date was moved across the shell so it could be seen when looking through the vent hole. I have to think that was deliberate on Ludwig's part so that either the customer or sales rep could see.

If I were to make a guess I would say they stopped as production slowed to a much more normal rate and Ludwig thought it better to leave the date out in case a set was sent out with a piece or two that was pretty far apart date wise. I just wonder if a customer noticed this and complained it would be more of a pain on Ludwig's part.

Of course by the late 80's-early 90's they started dating drums again. It's hard to know for sure on any of it and of course I am just making guesses at this point. Would be great if we could find someone that actually worked there in the late 60's though the early 70's.

This may just be a myth (which I'm happy to spread ;) ) but I recall reading somewhere that WFL II said that some dealers requested that the drums shipped to them NOT be date stamped. Presumably because they didn't want their customers to be able to see how long a set might have been languishing in stock.

If this were true it would A: explain why some sets are missing the date stamps and B: indicate that the date stamps were most likely applied as part of the final assembly process when it would be easiest to skip that step while getting a set ready to ship out.

Unfortunately I don't have a clue where this memory comes from. It would most likely have been something I read in MD as that would be the only place such info would be published back in the day...but I haven't been able to track it down so it may just be a phantom memory or something I simply heard somewhere (or read on the internet...wait then it would HAVE to be true).

Interesting to ponder what the date stamps were even for other than to track production. Ludwig did not keep any records of their serial numbers (this I do have in writing from Bill Ludwig II himself) so I doubt they would have kept any record of the dates...although it would make it possible to keep track of daily production levels...but so would a simple count taken each day. Hmmmm?

Just for fun I grabbed the drums that I have recorded which have date stamps from the second week of November 1970 like the ones idrum4fun cited in his initial post. They are listed below:

11/9/1970 821108

11/9/1970 823470

11/9/1970 823498

11/9/1970 823949

11/9/1970 824476

11/11/1970 812374

11/12/1970 812213

11/12/1970 812749

11/12/1970 812753

11/12/1970 821679

11/13/1970 812168

This gives you some idea of the range of serial numbers for drums with date stamps from one fairly randomly selected week. In this case, there are eleven drums with serial numbers from 812108-824476. This is likely a small percentage of the drums which were produced during this week, but it is the best I can do with the data I have collected to this point.

Remember that serial numbers were not necessarily applied in numerical order. Likewise, date stamped shells were not necessarily delivered to final assembly in any order that related to their date stamps. Given that two variables appear to have been changing, we should expect to see some variation between serial numbers on drums with similar date stamps. There are other variables involved here that are difficult to understand or track which also add variability.

I continue to work with the information I have collected as time permits. I will report other observations as they happen.