The click is jumping out at me.
This is a cal 30 DP (double platine) which was used for accuracy competitions at the observatories.
A lot of differences to the regular cal 30, a Guillaume balance and an additional platine to enable a much higher/larger barrel are the most important among them.
Its a 30mm chronometre movement but looks plain, without further decoration or special finishing as known from the cal. 30 T2 Rg
What is weird on this movement: It says 17J but it has a simple bushing for the centre wheel instead of a ruby...
Obviously put together with parts from different movements, this was not uncommon with these "race horses" at that time. Not aesthetics counted but only accuracy, accuracy, accuracy...
According to what I have seen, Omega used to engrave the caliber serial number of its early chronometers under the balance wheel. It also seems that the first 30DP produced didn't have this, but Omega resumed this practice for later ones. As those also had the serial on the barrel wheel, they were double-engraved.
This is pure speculation based on what I have noticed, if I'm wrong, I will be pleased to be corrected. As Erich said, there were probably no strict rules for those specially prepared movements.
I have seen the serial number on an 30t2 balance arm that was not chronometer.
Interesting. Do you have a picture?
In my experience, 30mm had their serial engraved on the barrel bridge (balance side for the small second version, and opposite side for the SC). If it is not too annoying to you, I would be interested in a picture of a non DP with serial under the balance or on the balance cock.
No. But i will take one if it is something extraordinary. I thought it was very common.
Maybe there was some miscommunication...
To end the speculation and confusion about hand scratched numbers on the lower side of balance arms:
These numbers are 3-digit and are the last 3 digits of the movement serial number.
This was to match the right balance to the movement in which it was regulated. The particular balance might have performed worse on a different movement - hence they were numbered.
Maybe there was some miscommunication...
To end the speculation and confusion about hand scratched numbers on the lower side of balance arms:
These numbers are 3-digit and are the last 3 digits of the movement serial number.
This was to match the right balance to the movement in which it was regulated. The particular balance might have performed worse on a different movement - hence they were numbered.
I have never seen this before... is it possible to see without removing the balance, or do you mean the underside? Is it always present on 30mm movements? Very interesting indeed... 😀
Maybe there was some miscommunication...
To end the speculation and confusion about hand scratched numbers on the lower side of balance arms:
These numbers are 3-digit and are the last 3 digits of the movement serial number.
This was to match the right balance to the movement in which it was regulated. The particular balance might have performed worse on a different movement - hence they were numbered.
