Service: Patek Philippe calibre 350i

IMG_7885Haydn sent in this Patek Philippe for a service. The power reserve is very low, and it doesn’t run reliably, and I can’t pick up a signal on the timegrapher.IMG_7887

The calibre 350i is a pretty special construction, and the winding/stetting wheel on the back of the watch gives us a hint to that.IMG_7891

The dial has screws as dial feet, which are held with nuts in the movement – very nifty.IMG_7893

Just what you expect from a PP – very nice finishes throughout.IMG_7894

The winding stem is at 4 o’clock of the large blued screw, and left of it the Geneva Seal. Note that the barrel arbor isn’t jewelled. Now you can see why the winding/stetting wheel is at the back. The rotor doesn’t move on top of the movement, but around it, so a traditional winding stem couldn’t be fitted. This construction makes the movement nice and thin, even though it’s automatic.IMG_8235

The auto winder gears. the brass coloured wheel at the bottom is the one that engages with the rotor. The rotor only winds in one direction, as you can see from the ratchet wheel and its click. Apparently, the original calibre 350 had bi-directional winding, which caused a fair amount of problems, so the 350i (improved) has only uni-directional winding.IMG_8237

The balance.IMG_8241

Here you can see the winding construction – the winding stem is held by a clamp with a blued screw. On the right side of the click wheel, the automatic winding mechanism sits. IMG_8248

Now the gear train is visible.IMG_8251

Now it’s time for the bottom plate.IMG_8252

The rotor, which is suspended from the inner rotor ring with ball bearing, which isn’t oiled.IMG_8257

All parts cleaned and ready for re-assembly.IMG_8260

Mainsprings aren’t available, but the old one is still in very good condition.IMG_8262

The escape wheel has cap jewels that can’t be removed, so they have to be oiled through the jewel hole.IMG_8264

The gear train is back in place.IMG_8267

The wheel bridge is mounted, and I can put the winding mechanism into place. IMG_8269

Now the auto winder gears go in.IMG_8270

And we have a beating movement.IMG_8273

Now I put together the bottom plate.IMG_8274

And the movement is ready for casing.IMG_8275

Back into service.IMG_8283And looking very good on the timegrapher, too!


28 thoughts on “Service: Patek Philippe calibre 350i

  1. this caliber was designed by JLC for Audemars,Vacheron and PP, The slimmest automatic watch in the world ‘almost’ ( Piaget designed one with a micro rotor .001 mm thinner) but it was too fragile to be of much practical use, the 60s model I own has ruby rollers that sermount a beryllium ring for the auto winding movement, Jaeger Le Coultre did not use this caliber on any of there watches,

  2. Can i ask how you dealt with the mainspring? Did you remove and lubricate the wall? I may have one coming in for repair and i’m curious if you have any other tips.

  3. hi,
    I need the gold screw that hold the gold winding crown for a patek 350.
    Please let me know if anyone has one available.
    thank you,

  4. i need the gold screw that holds the gold winding crown for a patek 350 back set.
    please let me know if anyone has one available.
    thank you,

  5. Hi,

    I am in the processing of buying a 3563… I-350 caliber. It seems to beat well, but I am buying unseen, so a bit nervous. As an specialist, do you think I am buying a heap of trouble? I really love this watch concept, but I am a bit afraid that it will turn out unreliable.



  6. Very nice movement!

    If the escape wheel endstone can’t be removed, how will it clean properly? Won’t it retain cleaning fluids or congealed oil? (I’ve never worked on a watch of this quality)

    • You just have to run it through the cleaning machine again if it isn’t completely clean… the rinse will dry off in the drying cycle, so it’s pretty much ok. You can find this construction in the Bulova Accutron watches as well.
      Not my favourite – I prefer being able to take the cap jewel out.

      • Maybe pressing the jewel brass ring with a seitz jewelling tool will help to extract the assembly and allow a proper cleaning?
        I find hard to believe that this part should be cleaned and oiled that in that so poor way.

  7. Thanks Christian for an excellent service. I have not received the watch yet whilst I am on holidays but your work is always excellent with great attention to detail. Is this the 3rd or 5th your have serviced for me! 😉

    I love the look of these watches without a crown. I have read so much opinionated rubbish on the web about this movement. Despite needing a service I found the watch to keep pretty good time after being worn for a while. But it does need to be worn and not left lying around. I also found it very comfortable and the back crown is not an issue at all. I don’t notice any disadvantages to be honest.

    • After the service, the watch now has a decent power reserve, so it’s not a problem if you leave it lying around for a day, and then pick it up again.

  8. That’s certainly a unique auto-winder! Kind of wondering how that crown feels against the wrist. Did you take it for a ‘test drive’ around the shop? Owner’s permission and all that, wink wink!

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.