Today, it’s a Seamaster Cosmic with the calibre 565 movement. Peter sent it in, as the female part of the winding stem is broken, and the crown fell off. The crystal is still half way decent, and he wants to keep it.
This is a monocoque type case, e.g. there is no removable case back, and entry is through the front. To remove the movement, you turn the movement until the 4 faces the winding stem, and you can take it out.
The jewels have caked-in oil and dirt in them, so I recommend a full service, and Peter goes along with that.
The balance jewels are dry as well – no oil left.
Balance and pallet fork removed, and the wheel and barrel bridges still in place.
The bottom plate.
Everything taken apart and ready for cleaning. Some of you might notice that I’ve bought a little basket for the very small parts, such as screws and jewels. Just to avoid anything slipping through the basket.
The new mainspring goes into the barrel.
I lift the wheel bridge into place.
The basic movement is back together and ticking.
Not fully wound, this is looking very good.
When assembling the bottom plate, I notice that the date doesn’t change. It wants to, put snaps back to the old date after having moved about half a day. This is the culprit. The date changer wheel has a little metal strip that engages with the date wheel. It has slipped back slightly, and I move it back into its original position and re-rivet it. If it slips back again, it will need replacing.
Casing the Cosmic movements is a bit tricky. You first have to make the final adjustment to the movement, then put the dial and hands on, put the second hand in place, which needs supporting the second hand arbor from the back, and then put the auto-winder on. Then the complete movement can be cased.
You can see that someone used polyWatch on the crystal. As Peter wants to keep it, that’s fine with me.