As usual, Cousins delivers the next day, and I’ve got the mainspring and gasket to put Stefan’s Constellation back together.

Having hardly seen any amplitude, I’m a bit worried about the state of the movement.

Al from Canada has given me a great hint on how to best clean the balance assembly. I used to take the balance off the balance cock, which is a bit risky…He told me to take the top and bottom jewels out, and to put the balance assembly back on the plate for cleaning. That means the balance is protected, and everything gets cleaned nicely. I’m always game for something that sounds better, and I’m going to try this for the first time.

You can see the balance shaft through the removed jewels.

I have also removed the jewels in the balance cock. Now the plate with the balance cock and balance in place goes back into the ultrasonic cleaner – together with the four jewels.

Time to put everything back together again. I start with the new mainspring.

The centre wheel and the barrel bridge go in first.

Then the wheel train and the pallet fork are mounted.

The balance jewels in the rinsing solution.

I oil the bottom jewel with some Moebius 9010.

Having oiled the bottom jewel, I put it into place.

Now I lightly oil the cap jewel and put it into place.

Now I put the balance assembly in. You can see here that the top jewels aren’t in the balance cock yet.

Now the oiled jewel is put into place.

Then I lightly oil the cap jewel, put it in and secure it.

Straight away, I have an amplitude of 282, and I only wound the mainspring a couple of turns. I don’t feel inclined to do anything about the 0.5ms beat error, as the risk of damaging the hairspring in the process is higher than what it’s worth.

The auto-winder gear is put back together and oiled.

I only put the rotor in once I have cased the movement.

The bottom plate is reassembled.

Now the date ring and cover plate go in.

The dial and hands are mounted. The dial has a bit of wear, but the watch is 60 years old. Considering that, it’s in very good condition.

Now I can case the movement and put the rotor in.

The new gasket.

Final adjustment on the timegrapher.

Lovely job – the Constellation restored to its former glory.

No, it’s not the 29th, but there is no fast date setting, so I will leave it to Stefan to adjust the date 😉

I fully wind the watch and put it on the timegrapher again – amplitude of 310!