Jaeger-LeCoultre Caliber 12A vs. 476 Bumper Movement

FanFrancisco · 2012-05-26T21:21:48Z

Unravel the mystery of Jaeger-LeCoultre's first automatic bumper movement. FanFrancisco's Caliber 12A sparks debate on JLC 476, history, and vintage watch collecting.

FanFrancisco

WPS member · Jaeger-LeCoultre forum

25 replies16926 views7 photos

FanFrancisco shares his accidental acquisition of a vintage Jaeger-LeCoultre watch, sparking a community discussion about the brand's first automatic bumper movement. His post, prompted by a discrepancy between his watch's Caliber 12A and official JLC history citing Caliber 476, invites experts to clarify this historical puzzle. This article synthesizes the community's insights into the early automatic movements of Jaeger-LeCoultre.

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... i have recently acquired a JLC vintage watch, beautiful patina dial plus heat blue hands, everything look pretty good to me. i got this watch to home purely by accident, not my intention at all. as my intention was to search one vintage pocket watch box for " my date-day pocket watch" . i found the box while i also saw in the seller's shop there was also selling one beautiful a JLC vintage watch housed with the so-called first JLC's automatic bumper movement as claimed by the seller. I clicked to buy without much hesitation.

in the recent " Friday's WristScan" , i posted the pic and stated it is the first automatic JLC, Caliber 12A. our Nico replied that the first JLC automatic movement is 476. after seeing his response and have further thought of that, and quickly done some research. very interestingly, according to JLC official website, it said as below:

"HISTORY

" First automatic Jaeger-LeCoultre watch"

At the end of the Second World War, the mood was geared towards reconstruction, efficiency and pragmatism. Jaeger-LeCoultre turned its inventive genius to the area of automatic round timepieces, forerunners of the Master Control line. The firstborn housed a Jaeger-LeCoultre 476 Calibre, driven by a ‘bumper’ type weight."

(following three pics extracted from JLC's official website)

i also found some sentences written by Zaf in his website as below:

"1946

First Jaeger-LeCoultre automatic watch At the end of World War II, the spirit of the era is geared towards reconstruction, efficiency and pragmatism. Jaeger-LeCoultre directs its inventive genius towards the field of automatic round timekeepers, forerunners of the Master Control line. The first is equipped with Jaeger-LeCoultre Calibre 476."

after reading these, it makes me puzzled whether my watch housed Caliber 12A was made before or after the Caliber 476?!

hope experts out there can help me to resolve this matter. thanks a lot in advance.

(following pics of my recently automatic bumper Caliber 12A watch)

(taken beside with my another manual winding JLC - Caliber P478, Ref E159)

(clearly see the 12A marked on the movement of my watch and it looks the same as the one shown in JLC's website, please note this pic was provided by the seller)

stefan

Key Points from the Discussion

A contributor found both '12A' and '476' stamped on their inherited JLC bumper movement, with '476' being tiny and partly obscured under the balance wheel, suggesting '12A' might refer to something else or be a different designation for the same movement.
The contributor's JLC bumper movement, identical to the author's, only runs for 15-17 hours on a full wind, leading to a question about whether this short power reserve is normal for the first JLC automatic movement or if the mainspring needs replacement.
It is speculated that a watch bought in Europe and later serviced in the US might have had its movement swapped by service centers, potentially explaining different caliber markings.
The author notes that his Caliber 12A watch has a production year around 1946, the same year as the Caliber 476, making it difficult to definitively say which came first.
A collector highlights the rarity of bumper movements, which went extinct in the 1960s, making the author's acquisition a good find.
The discussion raises two mysteries: why '12A' is written instead of '476', and why the movement is signed 'LeCoultre' while the dial is 'Jaeger-LeCoultre'.

The Discussion

amanico

May 26, 2012

It is the same movement. Which leads me to wonder ...

1/ Why it is written 12 A instead of 476. 2/ Why your movement is signed LeCoultre while your dial is signed Jaeger-Lecoultre. I have no answer to these 2 mysteries. Best, Nicolas

FanFrancisco

May 27, 2012

If you have no answer either, hope others can help!

Or perhaps we can ask MJLC? Thanks Nico, anyway. Stefan

amanico

May 27, 2012

We can try to ask, but it will take a long time before we get an answer...

FanFrancisco

Jun 12, 2012

yes understand that... hopefully someone could come in to answer this!

thanks, Nico. stefan

donperley

Dec 28, 2018

Name discrepancy

Just a guess.. the answer could be that the watch was bought in Europe, then serviced in the US. I've seen some reference that service centers would swap movements so the service could be done while you wait. -Don

Subexplorer

May 27, 2012

Hello Stefan! Sorry I can´t say anything of interest...

... about historical or technical aspects of your watch, but I can say it is really beautiful, so elegant and clean design of its dial. A real beauty! Watch collecting brings many satisfactions and enjoyment, as well as many misteries and incognitas! I wish youll enjoy so much your new watch, and will get answers to your questions. Very cordially, Abel.

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Jaeger-LeCoultre Caliber 12A vs. 476 Bumper Movement

Key Points from the Discussion

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