I have an IWC pocket watch with an "R" underneath the movement number and I was curious to find out what the "R" stands for.
Nobody on several watch forums had an answer.
I wrote to IWC in Australia and they forwarded my request to the IWC museum in Schaffhausen.
I was also curious to find out what/who the name engraved on the cuvette was.
The IWC Museum Curator, David Seyffer, who is an expert in historical IWC timepieces, has come back to me with the following.
To be honest, I never saw a engraved “R” like this on an IWC movement. So I ask our service watchmakers. They had no answer either.
So we have to guess: Looking at the engravings of the number of the movement and the “R” we are 99% sure that the engraving of the “R” was done when the watch was manufactured here in Schaffhausen.
There must be a reason for marking the plate with the “R”. Maybe it was some kind of special series and so the movement was marked. Around 1900 IWC did a lot of research and development on fine adjustment devices for the regulator.
Probably the “R” could mark a special version. If the watch someday may be serviced in Schaffhausen the service watchmakers could have a closer look on the movement and do an evaluation.
IWC started to give the movements names and beginning in 1893 the caliber numbers were introduced.
For example: the type of movement in your watch was first produced in 1888. IWC called it “Calibre IWC”; in 1893 it was called 52.
Looking at the Sales records unfortunately there is no hint for a modification or something else.
The watch was sold May 27 1904 to IWC retailer Dietrich in Basle. Due to our records it’s a Lépine Cal. 52 - 19’’’.
Nevertheless we wish you pleasant times with your beautiful antique IWC pocket watch. The engraved “R” makes it very special.
I suggested that the lettering could have been a quality mark as was used in the Jones caliber.
This was his reply.
You are absolutely right; F.A. Jones founder of IWC used letters to show the different qualities of his movements. So did his successor as CEO of IWC Fred Seeland.
When Schaffhausen manufacturer Johannes Rauschenbach bought IWC in 1880 the use of letters stopped.
The “R” engraved has nothing to do with the Jones system of letters that were in use from approx 1870 to 1880.
So, the letter "R" is still a mystery. The name on the cuvette has been solved.
If anyone has an IWC (JWC) with a letter "R" I would be interested to know.