An early 3646 Type A with case number 1009789 and an impressively aged plastic rivet dial was offered some time ago by a renowned Italian vintage shop.
The movement appeared to be a Rolex 618 Type 1b from a later 3646 Type D at first glance. This kind of mechanisms usually have ratchet and crown wheels with “swirl” finish. The movement in question has a ratchet (7) and crown wheel which seemed to be from a later Type 2 to 4 unit. Another detail which caught my eye was the regulator (3) on the balance cock. This kind of parts were used in regular Cortebert 616 movements in combination with flat hairsprings. Rolex 618 movement were equipped with Breguet overcoil hairsprings.
After looking at this movement for a while i noticed more irregularities. The Côtes de Genève (Geneva stripes) for instance, they are not original. It looks like this movement has been refurbished at some point. Unlike other Rolex 618 Type 1 units it also has a jeweled centre wheel (6) instead of a simple brass bushing. I kept looking at it and noticed the peculiar shape of the train bridge (2) and a not centered hole (5). Only now I realised it might be a converted Cortebert 616 with remanufactured 618 look-alike bridges. Note that also the escapement bridge has a strange shape (1) compared to proper movements.
A comparison of the ratchet wheel with typical Rolex 618 Type 2 – 4 parts showed differences. On the following picture the original ratchet wheel (right) appears to be more refined and subtle. The notch has a different position too.
The ratchet wheel on that movement is most certainly from a russian Molnija 3601! The 3601 is more or less a clone of the Cortebert 620. The screw head for the ratchet wheel has a smaller diameter on these kind of movements. As a result it looks like the larger screw sits on the ratchet wheel instead of being recessed as on original movements.
What about the rest of the watch?
Dial and hands could be original. I must admit i do not have enough experience with plastic rivet dials but i do know that this kind of dials have been successfully reproduced, even with the same kind of patina. A final test would be a geiger counter.
Other watches for sale
The same shop has several Vintage Panerai watches for sale. One of them is a 3646 with nicely faded and sought after “Tropical” dial bearing a radium burn ring and some stains, actually very similar to 6154 dials. The asking price is € 250.000!
This timepiece has been advertised as watch for presentation purposes, probably because it features a display case back with “Officine Panerai – Brevettato” engravings. My opinion about these case backs is that they were made in the 1960’s or later.
The movement of this watch looks like a genuine Rolex 618 Type 1a which leads to the assumption that this 3646 belongs to Type A, B or C.
I did some research about this watch too and i was quite surprised to come across a few pictures which show parts of this watch in a different case. The display case back was used as bezel and the movement was a Cortebert 616 with Rolex engravings.
This is the same watch with opened case. The movement in this picture is a late Cortebert 616 and is in my opinion spuriously signed as Rolex. The ratchet wheel still says “Cortebert”.
There is absolutely no doubt that dial, hands and display case back are the very same like on the watch that is currently for sale. It is obvious however that the case is different.
This dial is probably from a Ref. 6152/1 from 1955. Faded color in combination with stains, crackled indices and a pronounced ring are a very common aging signs for 1950s Radiomir dials. Note that the actual watch has a low bezel like the watches which were delivered with thin “California” or brass dials. A 2mm thick sandwich dial would not fit.
The display case back has a few individual characteristics and they absolutely match with the actual watch.
Closing the circle
What follows really amazed me. Case and the movement retaining ring of this last watch with Cortebert 616 movement are the very same as on the first watch with plastic rivet dial discussed further up.
The movement retaining ring has many individual markings, just like a fingerprint. Also the case bears a few marks which absolutely match the actual watch, although it might have been polished since then. Especially the soldering of the wire loops is identical.
A few matching scratches on the front leave no doubt. It is indeed the same case.
It is late and I honestly ran out of words… what the heck is going on in Rome?
Update February 8th, 2016
The shop in Rome is offering another 3646 with Radiomir Panerai sandwich dial. The case of this watch once housed the rivet dial of the first watch discussed in this article with case number 1009789 (right). The soldering of the wire loops is identical in my opinion.
The movement of this new watch has strong similarities with the movement mentioned above (1009789), which most certainly is a converted Cortebert 616. The ratchet wheel is probably a standard Cal. 616 wheel which has been polished in order to get rid of the “Cortebert” inscription. The movement ring has a completely different shape and is clearly not original.