Some interesting conclusions can be drawn from what I have collected so far.
- Mirror serial numbers manufactured by Cave start with an “M”, mirrors refigured by Cave start with an “R”.
- At first it appears Cave probably just started at number 1 and went up, eventually getting into four digits. At some time prior to 6/18/1965 they started adding two digits for the year of mirror manufacture to the beginning of the four digit serial number making a six digit number. When this occurred it appears they may have started over at 1 again as the last recorded serial number without the year, 1898, is higher than the first with the year, 1485.
- The earlier mirrors with serial numbers not starting with the year were engraved in a different cursive script on the back, rather than the edge of the mirror.
- The four digit sequential part of the serial number did not start over at 0001 at the beginning of each year. It appears Cave went to 9999 and then rolled over to 0001 when they reached the 10,000th mirror (this occurred in late 1974).
- It does not appear that they rolled over from 9999 during the period when they were not adding the year to the serial number as it is unlikely they would have made 8000+ mirrors between April of 1961 and 6/18/1965. Further data is needed to estimate how many mirrors were produced during this early period with serial numbers that did not contain the year.
- Assuming Cave started over at serial number 0001 in the series where the year is part of the serial number one can assume Cave made about 14031+ mirrors by 9/25/1979 plus the ones made before the year was added to the serial number. There are statements on the Internet claiming Cave made 83,000 mirrors and 16,000 complete scopes. I don’t know what the source is for these statements. Given the above listing, and if one assumes these were originally all part of complete scopes, the 16,000 number seems reasonable. If Cave actually made 83,000 mirrors they must have made a lot with no serial numbers.
- There was not a specific date where the inscriptions changed from cursive to block lettering.
If the group here is interested in keeping this going and expanding it with new information I would volunteer to maintain this registry as I find this kind of information fascinating. If you own a Cave and are not in the above listing, or if you know of any errors in it, please PM me or post in this thread and I can update the list periodically. Actual pictures of your mirror inscriptions would be preferable so as to verify the information and the engraving style.
At first I thought about posting this to the Cave Yahoo group as there has been an attempt there to post pictures of Cave mirror inscriptions but it seems like more Cave owners find their way here to CN.
An example of the cursive style engraving on my 10” f/6 Custom Super Deluxe: