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Jaeger-LeCoultre Memovox cal 916 - any tips? "do not open" barrel.


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Hello everyone, 

I recently acquired a watch that I've long considered a "grail". A JLC Memovox. Specifically, the reference E875 ("Speed Beat") with a calibre 916. I got it for really good price and it is in full original condition. 

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It's still running quite well, but I do want to service it. 

I found the service manual online (attached) and it seems to be doable. JLC 916.pdf

But I'd still be grateful for any tips!! 

One specific question I have is related to the mainspring barrel. The manual says that the barrel "should never be opened. In case of defect, replace the whole barrel assembly". 

Now, I've opened "do not open"-barrels before and reused them with no problems. And there are other threads discussing this matter in a more general way. But I'd be very grateful if anyone had specific knowledge of this movement or other JLC movements from the 1970s. 

Obviously, it's impossible to source a NOS barrel complete for this movement (and even if, the breaking grease and arbor lubrication would not be in good condition anymore). 

So I'm left with only two options: open the barrel as usual or just leave it closed and reuse. (Well, or I pay 4-digit service costs at JLC/Richmond group.)

 

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I don't know for this specific calibre, but sometimes this kind of barrels can not be opened, as the lid is sealed by rolling  material of the barrel over it. So, if the barrel is openable, then open it and go ahead. If doesn't seems to be openable, then show pictures here to think on.

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Cousins show the complete barrel as discontinued, but they do show a mainspring. Doesn't say if it's the alarm spring, but I wouldn't expect the alarm spring would be an automatic?

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The JLC sealed barrels I've dealt with are sealed, with the lip burnished over like Nevenbekriev says. They can be opened, but you have to push the lip more open to get the lid to seat again correctly and it's still a bit hairy. They aren't as bad as Zodiac (those you can forget about opening much less closing without issue).

 

The chances of mucking it up are high enough that it's probably safest just to add a little lubricant at the arbor and call it good.

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Posted (edited)

Having sealed barrels like this must effect the value of some of these movements, if the mainspring cannot be changed.

If you search on ebay  @Knebo for "Jaeger LeCoultre cal 916 barrel", there are a couple of barrels for sale, but not cheap though. 

 

Edited by mikepilk
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33 minutes ago, mikepilk said:

If you search on ebay  @Knebo for "Jaeger LeCoultre cal 916 barrel", there are a couple of barrels for sale, but not cheap though. 

You are right. Very few though, and only one in Europe...for 180 EUR. 

But I'm not sure how useful it would be to get a 40-50 year old barrel complete. Even if NOS, wouldn't the contained (probably non-synthetic) lubricants be useless by now? 

1 hour ago, nickelsilver said:

but you have to push the lip more open to get the lid to seat again correctly and it's still a bit hairy.

Could you elaborate on this? I can't quite picture what you mean. 

 

1 hour ago, nickelsilver said:

probably safest just to add a little lubricant at the arbor and call it good

This raises an interesting question that I've sometimes wondered about in other situations. If I'm not sure which lubricant was used before, and I'm using what I think is right nowadays (e.g. HP 1300 in this case) - what are the implications/risks of effectively mixing different lubricants, especially if old/natural and new/synthetic?

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48 minutes ago, Knebo said:

You are right. Very few though, and only one in Europe...for 180 EUR. 

But I'm not sure how useful it would be to get a 40-50 year old barrel complete. Even if NOS, wouldn't the contained (probably non-synthetic) lubricants be useless by now? 

Could you elaborate on this? I can't quite picture what you mean. 

 

This raises an interesting question that I've sometimes wondered about in other situations. If I'm not sure which lubricant was used before, and I'm using what I think is right nowadays (e.g. HP 1300 in this case) - what are the implications/risks of effectively mixing different lubricants, especially if old/natural and new/synthetic?

I use a 3mm carbide rod with a crisp flat face (steel is fine too), and, holding the barrel vertically, under the microscope, teeth resting on a hockey puck, I carefully slide the rod along the part of the barrel that clips to the lid, pressing quite hard to deform the metal back out. If you don't do this, when you go to press the lid on it will catch, causing damage to the lid and barrel, often with no feasible repair. It's actually ok to tilt the rod a little after getting the lip straightened, to form a slight bevel around the perimeter to facilitate the lid going back in.

 

It's not a fun job to do.

 

As for mixing lubricants- that can be a real issue. One would imagine that given its age it was probably lubricated with non-synthetic, so probably best to use D5 or similar rather than an HP oil. I don't know specifically which lubricants aren't compatible or what the real results of mixing those are, but D5 is a pretty safe bet.

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41 minutes ago, nickelsilver said:

I use a 3mm carbide rod with a crisp flat face (steel is fine too), and, holding the barrel vertically, under the microscope, teeth resting on a hockey puck, I carefully slide the rod along the part of the barrel that clips to the lid, pressing quite hard to deform the metal back out. If you don't do this, when you go to press the lid on it will catch, causing damage to the lid and barrel, often with no feasible repair. It's actually ok to tilt the rod a little after getting the lip straightened, to form a slight bevel around the perimeter to facilitate the lid going back in.

Thanks for taking the time to describe this. 

I this what how I should imagine it? 

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Swing the rod 90 degrees, it's the side that does the work. If you have a lathe you can grab the barrel in a wheel chuck and hold the bar in the slide rest, turn the headstock by hand while applying pressure- much less awkward than holding the barrel by hand.

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OK, I see. I get the point.

Thank you!

Do you also try to "close the lip" again afterwards? Running the rod around the closed barrel from the other side? 

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Gone are the days where you could just replace the whole unit. If there is nothing wrong with the complete unit I would just clean it and a tiny drop of oil each side of the arbor. If you open it you could distort the cap and it will never fit proper again normally the cap is thin. My advice is do not open.   

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