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Numbers inside a Borgel case back

Borgel Case Number Project

If you own a Borgel screw cased watch, and here I am talking about the early screw in cases made to Borgel's 1891 patent CH4001, then after finding out that it was made by François Borgel, and deciphering the sponsor's mark and the hallmarks, you may, like me, have wondered what the numbers stamped in the case back mean. I mean the numbers like the 3130633 and 40 that you can see in this Borgel case back.

I am collecting as many pictures as I can of case backs like this which can be accurately dated from their hallmarks. I hope that by building up a big collection of numbers and dates from the hallmarks, some sense may emerge from the numbers. It may be a long shot, but if the numbers can be put into sequence and matched up with the hallmark dates, we may be able to derive production quantities for separate years, or put dates to case that don't have hallmarks.

Most Borgel cases like this have a long serial number in the middle of the case back, which I have called the main serial number, and a shorter one or two digit number in the bottom of the case back which I have called the sub-serial number. Some also have a shorter number below the long serial number, which I have called the sub-main serial number, and a number, often a single digit punched on its side, below the sub-serial number, which I have called the sub-sub-serial number.

If you can contribute a picture of the inside case back of your Borgel watch, with hallmarks so that it can be accurately dated, to this project, or have any comments, requests or suggestions, then please feel free to email me at You shouldn't need to copy the email address, just click on it. I answer all emails I receive, so if you do write to me and don't get an answer in a few days, please check your junk and spam folders. Even better, when you write, add my email address to your contacts and my emails will not be filtered out. All contributions will be acknowledged - I look forward to hearing from you! Regards - David

I have put all the information I have gathered into a database and the results should be in a table below. If I have used your data and not put your name against it, plese let me know. You can click on a column heading to sort the table by that column, and then click again on the same heading to reverse the sort order. If you sort by one column, you can then hold down the shift key and do a sub-sort by a second column. The data is pulled off the database in year order. Remember that the hallmark years don't correspond to the calendar years - for offices with data in the table the hallmark years were:

• London: 30 May - 29 May
• Birmingham: July - July
• Glasgow: 1 July - 30 June