1934 40mm Longines Cal 15 chronograph

DirtyDozen12

Firstly, thanks for the update on the Valjoux 22 jumper spring. Interesting that the locating pins are not identical but it was still able to fit. Superficially, this is a great result.

Secondly, two good questions re: the crystal, and dial cleaning. I am not certain about either. I am inclined to believe that the crystal could be original, as there appears to be relatively little visual distortion when viewing the dial head on. I would probably leave it on and polish it. As for cleaning an enamel dial, I recently asked the same question after attempting to do it myself with Windex and Q-tips (https://omegaforums.net/threads/cleaning-an-enamel-dial-cyma-with-windex.174953/). Given the rarity of your Longines, I would keep dial cleaning to a minimum in order to avoid any mishaps. I acknowledge that this might be an overly cautious stance given that it is an enamel dial.

DirtyDozen12

Firstly, thanks for the update on the Valjoux 22 jumper spring. Interesting that the locating pins are not identical but it was still able to fit. Superficially, this is a great result.

Secondly, two good questions re: the crystal, and dial cleaning. I am not certain about either. I am inclined to believe that the crystal could be original, as there appears to be relatively little visual distortion when viewing the dial head on. I would probably leave it on and polish it. As for cleaning an enamel dial, I recently asked the same question after attempting to do it myself with Windex and Q-tips (https://omegaforums.net/threads/cleaning-an-enamel-dial-cyma-with-windex.174953/). Given the rarity of your Longines, I would keep dial cleaning to a minimum in order to avoid any mishaps. I acknowledge that this might be an overly cautious stance given that it is an enamel dial.

Waltesefalcon

I've never had a problem cleaning an enamel dial with windex, or denatured alcohol, and a q tip. If anything was applied to the dial after it was fired (which should not be the case, but stranger things have happened) the windex will remove it.

AdamVT227

Thanks , Interesting thread on the enamel dial cleaning .

On the thread linked above , there is a Mido that had "india ink" which make me worried about cleaning my Longines .
Is there any way to spot if there’s any ink\paint added after the fire ? or it’s a risk it all situation .

DirtyDozen12

Thanks for the update! It is neat to see the dial side of the movement. I need to read up on the history of Valjoux again. The logo on your movement differs from the one found on later cal. 22 and cal. 23 movements. It seems as though the name change from Reymond Freres SA to Valjoux SA occurred not long before this movement would have been made. I also wonder about the five-digit number.