Hello Longines OFers,

Hoping you can help me with a bit of a puzzle. I recently acquired a very early 30L, that has the hallmarks (Breguet overcoil, truncated regulator arm) of the chronometer certified movements. This particular example, however, is not listed as a chronometer in the Longines archives. Doing a little more digging, Longines30L.com also has several examples of similar non-certified chronometer 30L's. (A wonderful resource for this movement, thank you Havi!) Almost all of these examples seem to be very early in the 30L's production, with serial numbers in the 9,600,000-9,700,000 range. This has led me to speculate that early 30L's were originally fitted with the Breguet overcoil and at some point (to cut costs, speed up production, etc.) Longines decided to shift to the more standard layout. (I've had no luck getting Longines to provide any greater detail on the matter.)

Unfortunately, I'm basing this off of a fairly limited sample size. This is where you come in! If you have a 30L with one of these early serial numbers, I'd be very greatful if you could post photos of the watch and the particulars of the movement here. This may provide a greater range of examples from which we can make assumptions/educated guesses.

The example I purchased has been posted on OF previously, but I've relisted the information below.



Serial number: 9693860
Reference: 6691
Invoiced to: Girod, Spain
Invoice Date: 23 March 1956

Thanks for your help!

 

http://longines30l.com/wordpress/?page_id=189

Some of the archive extracts here don't explicitly state their chronometer status either, however there are a few early examples which do indicate a chronometer. It appears to have been a sporadic practice.

 

If you look closely at the information on Longines30L.com, there are a few examples with 9.7 serial numbers that are certified chronometers. These, however, were invoiced much later than their serial numbers would suggest (late 1957 or later). I would consider them outliers based upon the invoice dates.

So I reached out to Havi (who runs Longines30L.com) regarding this. He has also been unable to get Longines to comment on these early models. Certainly by the introduction of the Flagship, they were certifying chronometers. But prior to that period, you have several watches (mine, multiple from Longines30L.com) particularly with 9.6-9.7 serial numbers that are 30L chronometers in everything but certification.

 

Calling @ulackfocus. Ever seen one of these 30L’s that wasn’t certified as a chronometer but has all of the hallmarks?

 

I'd need a better picture of the balance / hairspring area before commenting. @Tony C. should see this thread also - he'll be looking for the same things as I.

 

I’ll take it to my watchmaker tomorrow and have him pop the caseback.

You thinking it doesn’t have the overcoil? If not, it doesn’t make sense to me to use the truncated regulator arm...

 

That’s gets to the heart of the puzzle though doesn’t it? Why produce a watch with the same hardware as the chronometers and not certify them?

My suspicion is that very early 30Ls were all outfitted with what would later become the chronometer hardware. (Potentially, Longines discovered what we now consider the standard 30L was more than sufficient in the accuracy department, although that is mere supposition.)

Maybe a more accurate moniker would be pre-chronometer.

 

Rolex often used identical calibers - some rated as chronometers, some not. It was actually quite common back then because of tariffs on not only jewels, but how many positions a movement was adjusted to.

 

That would make sense if we saw this trend continue later in the production, but (from the admittedly small sample size) it seems to be confined to very early 30L examples. Then we see the line branching into certified chronometers, with the associated hardware, and standard 30Ls.

 

Well, that clearly isn’t the situation we have here. There are clear differences between 30L movements that are identified as chronometers that go beyond adjustments. Mainly a truncated regulator arm to allow for a Breguet overcoil.

If you see the two examples that are listed on Longines30L.com as non-verified chronometers (it’s where I got the term) both were shipped to Spain in late 1955. My was also shipped to Spain in early 1956. The earliest I’ve seen an officially certified 30L chronometer is 1957.

Frankly, I’m just hoping to learn more about what I find to be an intriguing pattern I noticed among early 30Ls. Not get into a fight over terminology.

 

I think it’s also worth noting that nowhere on chronometer certified Longines 30Ls is there any reference to adjustments like what you would see on an Omega from the time period.

 

Certainly these are interesting anomalies, but I doubt very much that all of the early ones had the chronometer parts.

 

Longines very rarely marked their chronometer movements in the same way Omega did. The only exception I can think of is the R.R. 280.

After looking at the evidence, in my opinion, all 30L calibres started with a Breguet overcoil, regardless of their certification (or lack thereof). After some time they replaced the overcoil with a flat hairspring for the majority (likely for cost-cutting reasons), reserving the overcoil hairsprings for chronometers.

To phrase it differently: a Breguet overcoil is only an indicator of a chronometer in later 30L calibres, it does not imply that all early 30L calibres were chronometers.

Of course, this theory could be proven wrong if we can find an early 30L with a flat hairspring.

 

Totally agree. @gatorcpa, I wasn’t claiming that is is a chronometer. Just that it has the same hallmarks that we identify with the (later) movements that are chronometers. Rereading my posts, I think my verbiage may have been confusing.

Could be that they were trying to perfect production before they submitted the 30L to the Neuchâtel Observatory trials in 1956 and then had a few extra examples laying around. Anybody know what the difference is in 20 Werken and 30 Werken?



Anyway, below are some better shots of the coil and regulator arm @ulackfocus.

 

How familiar are you with this movement?

If you look here, you can see a side by side between a standard 30L and a chronometer.

https://omegaforums.net/threads/longines-30l-chronometre.30166/