On first sight, you wonder what the strange central chronograph second hand is for … On the right of the needle, there is a scale with 9 graduations. After about 5 seconds of thinking, the light went on, and I realized that this was a vernier scale, just like on a caliper. This allows you to read 1/10s of time elapsed… well it would, if the movement beat at 36,000 b.p.h, but this one only does 6 beats a second, so there are in reality on 6 different positions on which the watch can stop to give different 1/10s readings.
Nevertheless a lovely feature, and a pretty rare one. The augmented mass of the central hand isn’t ideal, and it can come off quite easily when the chronograph is reset.
The Valjoux calibre 726, here branded as Longines 332.
The amplitude is so weak that the timegrapher can’t pick it up.
The centrail second hand is loose.
The bottom plate with the hour recorder.
I start off with the chronograph layer on the top plate.
A very traditional construction, and a very nice chronograph movement.
At the top, you can see the column wheel.
The gear train visible.
Now it’s time to take the bottom plate apart.
Only the setting mechanism left.
The parts are cleaned and ready for reassembly.
The plate is slightly bent where the barrel sits, and there are slight traces of friction. I bend the plate back using the staking set.
A new mainspring for the barrel.
The gear train is back on the plate.
The basic movement is back together and beating.
That looks very good indeed – typical Valjoux performance!
Now I can put the chronograph layer back on.
Last but not least, the hour recorder is assembled again.
The hands and dial go back on.
And I case the movement.Check out the second recorder in this photo – it’s 25 seconds and 5/10th, as the 5 on the nonius scale lines up with the 30 second mark on the outer ring. It’s the only marker that lines up directly with a marker on the outer ring. As the movement beats 6 times per second, it can show the 5/10s exactly, as it’s 3/6 beats.