The first part to be fitted is the blocking lever spring which keeps the blocking lever (brake) against the centre seconds chronograph runner when the chrono is off.  It fits close to the click spring in this aperture.

UK watchmaker showing service of Omega Speedmaster - brake spring aperture

And fitted.

UK watchmaker showing service of Omega Speedmaster - brake spring fitted

And then the hammer stem bolt and spring in this cut out.

UK watchmaker showing service of Omega Speedmaster - hammer stem bolt aperture

And both fitted.

UK watchmaker showing service of Omega Speedmaster - hammer stem bolt plus spring fitted

And then the actuator cams at the lower – this is a cam operated chronograph as opposed to the pillar (column) wheel chronograph system.

UK watchmaker showing service of Omega Speedmaster - operating cams fitted

The spring for the lower cam which controls the coupling clutch is fitted.

UK watchmaker showing service of Omega Speedmaster - cam spring fitted

Then the operating lever yoke and spring.

UK watchmaker showing service of Omega Speedmaster - operating lever fitted

And then the operating lever.

UK watchmaker showing service of Omega Speedmaster - operating lever fitted

The next stage is to fit the chronograph runners for the second and minute chrono hands and that continues here.