Service: Longines Nonius Chronograph / calibre 332 / Valjoux 726

IMG_2014On 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.IMG_2016

The Valjoux calibre 726, here branded as Longines 332.IMG_2017

The amplitude is so weak that the timegrapher can’t pick it up.IMG_2019

The centrail second hand is loose.IMG_2021

The bottom plate with the hour recorder.IMG_2022

I start off with the chronograph layer on the top plate.IMG_2025

A very traditional construction, and a very nice chronograph movement.IMG_2031

At the top, you can see the column wheel.IMG_2038

The gear train visible.IMG_2040

Now it’s time to take the bottom plate apart.IMG_2047

Only the setting mechanism left.IMG_2052

The parts are cleaned and ready for reassembly.IMG_2053

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.IMG_2054

A new mainspring for the barrel.IMG_2056

The gear train is back on the plate.IMG_2060

The basic movement is back together and beating.IMG_2061

That looks very good indeed – typical Valjoux performance!IMG_2065

Now I can put the chronograph layer back on.IMG_2068

Last but not least, the hour recorder is assembled again.IMG_2069

The hands and dial go back on.IMG_2070

And I case the movement.IMG_2071Check 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.

 

6 thoughts on “Service: Longines Nonius Chronograph / calibre 332 / Valjoux 726

  1. Are the orange chronograph hand and the vernier scale on a transparant disk or something so that they turn together?

  2. It’s truly inspiring to watch Christian find the problem like the bent plate and fix the problem in the best possible way without damaging the watch! And yesterday I was stuck on how to reshape a hairspring for over 60min after 10min with Christian it was sorted out. Still the Padawan has much to learn from the master!:)

  3. I’d never seen this Longines model before. Then, earlier this week, a watch dealer/repairer that I know had one to show me. Very interesting watch. Although, his piece has a single sub-dial on it.

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