Bill Sohne offers a comprehensive collector's perspective on the Omega Seamaster Caliber 352, tracing the evolution of Omega's bumper chronometer movements. His article details the lineage from the 28.10 JUB to the 354, highlighting key technical distinctions and historical context. This deep dive provides invaluable information for enthusiasts interested in the early automatic chronometers that preceded the iconic Constellation.
Hello everyone....
We all collect differently. I was always drawn to Omega's Seamaster. The first generation bumper Seamasters were introduced in 1948 using a caliber 28.10 bumper movement family. In 1949 Omega moved over to the 3 digit caliber reference and the 330 and 340 ( sub seconds) and the 350 ( Sweep seconds ) calibers. As a collector I would love to collect an example of the entire Seamaster line. But reality rears it head and I have to "compromise" and create a sub set that I would find interesting.
I remember reading about "bumper" wound movements. I thought it sounded really cool. I then kept a sharp lookout for a "bumper" Seamaster. After about 6 months I found one, typical 34 mm in diameter with the beefy lugs and thick bezel. I loved the case style and the feeling of the gentle thump as I moved my arm around. The watch felt as if it was alive. I was more then happy with this simple Seamaster that was until I read somewhere that Omega made a few with a chronometre grade bumper movement.
Well, that did it for me.. I was on a NEW quest. To hunt for the elusive Seamaster bumper Chronometres and for the scope of this article I kept it to sweep second examples only. The Seamaster chronometre were the on the market before the Constellation was introduced, this point just pushed me harder to find them. The case reference for the Seamaster Sweep second bumper chronometre in 34 mm case was 2520, but most of the example I have came across were in 2577 cases that I confirmed were correct ( case ref numbers are cross referenced) . Omega also made the a "Jumbo" Seamaster bumper chronometre witha case ref of 2021 case diameter of 36 mm not counting lugs or crown and still took a 18 mm strap. The 2021 wears like a much large watch likes a flat lug Speedmaster.
But first lets look at the movements Omega used in the bumper chronometres. Omega wristwatch chronometre movements in my opinion started with the 30 mm manual wind family. The first bumper chronometre movements from Omega are the 30.10 JUB and the 28.10 JUB they were used in the Omega Centenary produced in 1948 for Omega 100th birthday.
In this diagram you can see the lineage of the bumper chronometre movements.
The 30T2Rg was used as the basis for the regulation system known as the " Omega System" for the deluxe finish execution chronometre. The first round of the bumper chronometres the 28.10 JUB and the 30.10 JUB has the fancy finished winding and setting wheels, the regulator was a simple stick regulation that was diamond cut. The next generation 343 (sub seconds) , 352 ( sweep seconds ) was based the the 28.10 JUB added the"Omega System" regulation to the rest of the deluxe execution finish. Then the 344 ( sub seconds ) and the 354 ( sweep seconds ) were produced cost cutting measures were taken, They are also chronometre grade but lost all fancy finished winding wheels and the "Omega System" regulation and these parts were replaced with standard finished wheels and a simple swan neck regulation system. The only descendent of the 30.10 JUB was the caliber 333 . The 333 also featured the deluxe execution chronometre finish and was only found in the large 36 mm sized sub seconds Seamaster chronometres and some large sized snapback bumpers from Omega.
Movement shot of a 30T2SCRg for your reference.
The following is an Omega sales tool a "paper" model of the deluxe execution bumper chronometre. a side note shows it as a 352, but the baseplate is marked 333.
Here are Scans of the parts list for the 352
Now that we have a little background... I started to hunt for some of the Seamaster bumper sweep second chronometres..
The bulk of the Seamaster Chronometre calbier 352 were made betweel 1952 and 1955 .
Here we have a early Steel 352 with the chronometre inscription below the center pinion. case ref 2577 / 2520 34mm case.
18k yellow gold Seamaster 352 case ref 2520 with a uncommon " OMEGA" applied plank dial.
18k yellow gold Seamaster 352 case ref 2520 with solid gold 18k yellow gold dial.
18k yellow gold Seamaster 352 case ref 2520 with typical silver dial and applied 18k gold sticks and numbers.
14k yellow gold JUMBO Seamaster 352 case ref 2521 with uncommon "OMEGA" applied plank dial. This watch wears big on the wrist !
14k yellow gold JUMBO Seamaster 352 case ref 2521 with aged cross hair dial. On a domestic 14k solid yellow gold period bracelet. This is one of my favorites !
movement finish shows some discoloration that matches that of the dial..
18k Seamaster deluxe OT 14324 " Ultima " 352 w/ 18k solid gold dial , 18k domestic mesh 18k yellow gold band ( band is not Omega) This watch was offered with a heavy mesh from the factory and when ordered together was known as the Ultima model !
Last but not lease my only other steel Seamaster chronometre with 18k pink gold applied markers. The dial is "peeling" but I love this one !! case rf 2577 with calbier 352.
Ok now time for a few group shots...
Here is the gang in a period correct vintage Omega Seamaster chronometre box...
On the deck of an 1910 pond sailer !!
Oh, almost forgot Omega did make bumper Seamaster chronometres using the caliber 354 as well. But I kept my focus on the 352 only.. why go for the standard finish when you can go for the deluxe finish !
i wanted to share with everyone on the forum a segment of my collection ... So stay tuned for the next installment Sub-second Seamater bumper chronometres. Just remember Omega never made a sub second bumper chronometre Connie !!
Good Hunting
Bill Sohne
This message has been edited by AnthonyTsai on 2009-04-30 22:04:09 This message has been edited by Bill Sohne on 2009-05-07 06:49:09 
