With the base movement set up, the chronograph parts are added, starting with the cam and springs:
Then the start/stop lever and bridge.
All parts checked for wear and cleanliness as the build progresses. This is a chronograph runner.
Showing the chronograph runners in place.
And the hammers and bridge fitted.
Finally the remaining springs.
With the second and minute counting chronograph parts complete, the movement is turned over and fitted to a 7750 movement holder. This supports the movement correctly for hand fitting and also has pushers to mimic the final cased watch in order to test the chronograph functions.
At the lower, the hour counter runner, hammer and brake is fitted. At the upper, the calendar mechanism with one part requiring rotation as shown in green so that the date and day change at the same time.
Then the front plate and calendar mechanism. The movement is ready for the dial and hands and all functions are checked at this point. there’s a little more detail in these posts for an 1861 Omega.
Finally, the dial and hands are added and the movement is ready to be re-cased.
When cased, the final performance is checked and I use the specification from the ETA official website for this:
As usual with these, the performance across six positions is excellent and this shows the fastest and slowest, 30 minutes after full wind and the variation is 6.3 seconds.