

The Longines calibre 340 is designed around the autowinder device. The oscillating weight has teeth that engage with the reverser wheels allowing for very effective winding.

The setting lever spring is actually accessible from the top side of the movement.

Here you can see the gear train layout. The big toothed wheel is the intermediate autowinder wheel that engaged with the oscillating weight.

Getting a new oscillating weight ball bearing is out of the question. But it’s possible to tighten the bearing plates that hold the balls using the staking set. The bearing balls are made out of rubies on this one, but were not put up on the movement ruby count;)

I see that the balance moves freely after fitting the shock jewels. The Longines 340 has a nice micro regulator.
6 Responses to Service: Longines calibre 340
I love looking at these photos of these incredible, delicate machines, and seeing the journey you take with them — although the intricacies are lost on me! I wonder, how long does it take you, typically, to work through all these steps?
I’m glad your enjoying the page Terry, if nothing is wrong it can go fairly quickly, but I have spent up to a week on a certain projects 😉
Nice post .
I have a 340 cal. flagship myself and love it..took the decision to buy a N.O.S. barrel/mainspring when one popped upon ebay as I`ve read on the web that they were vitually impossible to open and close for service.how did you manage it?
great job on the enamel repair too ..did you do that yourself Mitka?
If so you might be seeing mine for a service at some point.
Great blog..I always enjoy it even though I can do little more than change a strap myself :o)
Martin Lee
Hi Martin,
A spare barrel is never a bad idea, but opening the 340 barrel i just like any other (except for the scary DO NOT OPEN tex;). Yes the Enamel is the cold enamel I wrote about here https://mitka.co.uk/2018/11/19/longines-case-back-enamel-repair/
Just fill in a booking form when your ready:)
Hi Mitka,
I saw your enamel article just after I`d posted my question :0)
I`ve since decided to sell my Flagship to part fund a trip to The Galapagos this year.
A lovely watch and an interesting movemenI enjoyed wearing it a lot.
Popped the spare barrel on eBay for what I paid for it if you know anyone who`s desperate for one.
Will be booking in a different watch with you shortly though.
Cheers for a great blog.
Martin Lee
Sounds like a good trade! Hope you have a great trip!