Faver-Leuba Cal 253

[Eeeb]

I harvested this out of the bay for about $50. It is a redial so that is not good but the price was right for a watch that I really wanted for the movement.



This is a Favre-Leuba 17 jeweled winder from what I assume to be the later 1960s. The interest is the Calibre 253 movement that Faver-Leuba made themselves. It is one of the few twin barrels (two mainsprings) movements. Longines made one. I assume others did too but have not yet encountered them.





The above picture shows the two barrels.

By having two mainsprings, a watch is more resistant to changes in time keeping due to changing spring tension due to state of wind... or so the literature reads. It may also allow a longer power reserve for the amount of space devoted to mainspringing ... but I know of no studies existent which would shed light on either conjecture. Maybe others do.





Not a bad buy for $50... but it is in bad need of a service so the cost will probably soon triple. (Watchmaker is backlogged and is only getting 'priority' watches nowadays.)

[Oldheritage]

Nice movement indeed

Slava also used two barrel movements

[Marrick]

Nice movement indeed

Slava also used two barrel movements

Indeed they did.

[JohnF]

Hi -

It's all about the power curve and making sure it is as flat as possible.

Every manufacture has their "thing" about how to make a better watch. For F-L it was largely the dual mainsprings, which run concurrently to transfer power to the movement. Hence you don't get longer torque, but you do get a significantly flatter torque curve over the life of any particular winding.

It comes with a price, though: significantly more complex movement with no complications, and you have to replace two mainsprings instead of one. The real-world advantages are fairly minimal, as other imperfections in the movement may well outweigh the advantages of that lovely, flat power curve.

Suffice to say that a watch with two mainsprings will, ceteris paribus, be more consistent over time than a watch with one mainspring. Does it translate into greater accuracy?

Somewhat, but it depends on the watch showing extremely good isochronism to begin with. The dual mainsprings improve on a good movement, properly tuned, maintained and regulated to perfection: it cannot make a poor movement better, or reduce the time between maintenance periods.

Looking at the success of such movements in the marketplace, I think that you can come to the conclusion that they really don't make much of a difference: if they really did, you'd see more movements with dual mainsprings...

JohnF

[Janne]

The only watch I have with a dual barrel is a JLC Reverso Day Moon. It ia a joy to use, as it only requires winding every 8 days. I wind it every Sunday morning.

[Roland Ranfft]

Hi there,

here some details about the movement:
http://www.ranfft.de/cgi-bin/bidfun-...avre-Leuba_253

With jewels on the winding side, a barrel bearing over the complete height
of the barrels, and optimum placement of the coupling wheels, reducing
bearing preasure to almost zero, this is probably the most durable wrist
watch calibre ever made.

Moreover it belongs to the easiest servicable movements of its kind:
Most screws have the same dimensions, and for assembling you'lll need
not more than putting all parts in a box, shake it - ready.

Regards, Roland Ranfft

[Eeeb]

Hi there,

here some details about the movement:
http://www.ranfft.de/cgi-bin/bidfun-...avre-Leuba_253

With jewels on the winding side, a barrel bearing over the complete height
of the barrels, and optimum placement of the coupling wheels, reducing
bearing preasure to almost zero, this is probably the most durable wrist
watch calibre ever made.

Moreover it belongs to the easiest servicable movements of its kind:
Most screws have the same dimensions, and for assembling you'lll need
not more than putting all parts in a box, shake it - ready.

Regards, Roland Ranfft

Way too cool! Thank you again for your contributions.

[Chascomm]

There is a company in America buying up the last of the Slava ebauches and modifying them. They claim an 80 hour reserve, so they've obviously installed longer springs. Hopefully the jewelled barrel bearings that are standard to the Slava movement will cope with the extra load.

If I was going to modify this movement for a longer reserve, I'd reduce the size of the ratchet wheel on the 2nd barrel and increase the size of the intermediate wheel between the barrels so that it would reach. that way the 1st spring would unwind slower and keep topping up the 2nd spring for longer. However the 1st spring would need to be stronger, not longer.

No doubt I've failed to consider something very important and Dr Ranfft will tell me what that is.

[Genway]

Beautiful watch. Other than service you will probably want to correct two things:

The dial been refinished but not by professional. The crown was bent (case tube), so that probably why the water went in, one of the case screw was rusted.

[Somewhere else]

There is a company in America buying up the last of the Slava ebauches and modifying them. They claim an 80 hour reserve, so they've obviously installed longer springs. Hopefully the jewelled barrel bearings that are standard to the Slava movement will cope with the extra load.

To the best of my knowledge, jeweled barrel bearings are not standard to the Slava at all, and would also be pointless, I think. These are not, as far as I know, motor barrels.

Russian watchmakers tell me that Slava is notorious for developing egg shaped barrel holes on the left hand barrel. They fix it by installing a plate that brings the barrel hole back to round, but having never seen one of these repairs, I'm not sure of the exact details.

As for the American company claiming 80 hour power reserve, I am more than just a little bit skeptical.Dual barrels are not for longer power reserve but for evening out power in the train. Maybe this is why the Slava movement, despite its' rough finish, is so amazingly accurate.

There is not enough room in the barrel to stuff in a spring long enough to give an 80 hour autonomy, in my opinion, unless they are making truly substantial modifications to the movement that I am unaware of.