Teardown + Service: Shuangling Double Rhomb 40 Jewels / Beijing Shou Biao Chang

Firstly, thank you Torsten from Hong Kong for sending me this watch – it is indeed a very interesting Shuangling watch as it has 40 jewels. The high jewel count is due to their generous use in the autowinder mechanism.

And, congratulations, comrade, to your promotion to the higher echelons of the Chinese Communist Party! You were not the normal guy next door who had a hand-winding Shanghai – you were one class up! Like the guys on the poster, you had to be quite determined to get your mitts on one of these!

The movement itself is quite similar to that in the Shanghai 7120 watch as both movements are based on the Tongji Standard movement.

So, let’s take it apart and have a look!

The watch back - also with double rhomb

Nice details - I like the red drop on the second hand. Also, the loupe to enlarge the date bulges towards the inside of the watch - I think Rolex could learn from that. I never liked their bulging loupe. Unfortunately, there is quite a bit of a scratch on the dial left of the centre

First look inside - someone scribbled on the watch back - probably the last person to service the watch

The auto winder. The two wheels on the right have 7 jewels each - click on the photo to enlarge to get an eye full. Plus 2 x 3 jewels for the wheels makes a total of 20 jewels for the auto winding mechanism.

Time to let down the main spring

After having taken the movement out of the case, I always remove the hands and dial first as they are easily damaged

When the dial is removed, I wrap it in watch paper and put it to the side

The watch case has quite a bit of dirt on it, but that's easily cleaned

I start of with the bottom plate and the date wheel mechanism

These tiny little springs are notorious for flying long distances across the room - so I hold them down with a piece of pegwood whilst releasing and taking them out with tweezers

The date ring gets the same star treatment as the dial - as soon as I can remove it, it's wrapped in watch paper

This is where the Amoco Cadiz ran aground and spilled its 1.6 million barrels of oil

Bottom plate cleared

Movement turned around - top plate. First, I take out the balance cock with the balance

Balance assembly - all looks well

Now I unscrew the barrel and transmission wheel screws - always remember that the transmission wheel screw opens clockwise

Barrel and wheel bridges removed. No lack of dirt here

Main spring and barrel

All the parts that won't go into the cleaning fluid. As the crystal is acrylic, I will hand-clean the case

The most time-consuming part is done - after cleaning the parts in cleaning fluid, I hand-dry, inspect, and clean again if necessary. Here is the end result - everything ready for reassembly

The main spring cleaned, put back into the barrel (I do that by hand and not with a winder, it's faster), and oiled

All the nooks and crannies of the case are cleaned with a pegwood stick

Time to reassemble the watch - the barrel, centre wheel, escapement and centre wheel bridge go in

The rest of the wheels go in - the top wheel goes through the centre wheel and drives the second hand

The top plate assembly is finished, and the balance wheel is already swinging happily back and forth. The amplitude looks good - the timegrapher will tell us more at the end

The bottom plate assembly - the crown and castle wheels get some grease, the rest oil

The date wheel and cover plate are mounted - that's the bottom plate done

I clean the dial with a brush - not much more you can do. Note the brown blob of gunk that sticks to the right side of the 11 o'clock marker - I remove that with some pegwood

I put the dial on, then put the winding shaft in and forward the clock until the date changes - I can now put the hands on at 12 o'clock. I check that the three hands have the right clearance between them so that they won't get stuck on each other - you can now see the blob of gunk on the 11 o'clock marker gone. If you look at the crown, you can see that the crown sits slightly wonky on the winding shaft. I'm not tempted to rectify that as the winding shaft could break. If I had a spare one, I would replace it - but I don't 😉

I put the movement into the case, put the movement ring and the case screws in, and then put the auto winder on

Now the auto winder goes back on. One of the screws is a bit rusty, so I use a 9 micron sanding paper to polish the screw head again

Before I close the case, I regulate and adjust the watch. This is not easy, as the beat error adjustment does not move the rate adjustment with it. So modifying the beat error changes the beat rate - and changing the beat rate does change the beat error. Still, after 10 minutes, I'm done ...

The watch back didn't have an o-ring, but I've got one that fits. I very lightly grease it with silicon grease

I screw the watch back on - not too tight, you just tighten a bit after the o-ring gets contact

That looks a lot better than before, and everything is nice and clean

A nice watch – but it could do with some more work. If it were mine, I’d give it a new winding shaft, polish the case, polish and re-guild the hands, and give it a new glass. Not much you can do about the dial – somebody removed the hands without protecting it.

The list of Ali Baba and the 40 jewels:

2third wheel pivot

Quantity Location
2 balance cap
2 balance pivot
1 balance impulse pin
2 pallet fork pivot
2 pallets
2 escapement wheel
2 centre wheel pivot
2 fourth wheel (inside centre wheel)bottom pivot in centre wheel bridge, top pivot in wheel bridge
14 auto winder wheels (7 each)
6 pivots for the three winder wheels
2 barrel
1 bottom pivot intermediate wheel (to hour wheel)

4 thoughts on “Teardown + Service: Shuangling Double Rhomb 40 Jewels / Beijing Shou Biao Chang

  1. Another nice one, Christian. Saw this one by coincidence, but I always enjoy how you document your work. Chapeau!

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  3. The 14 jewels in the auto winder wheels seem only for decoration. I can see the 6 for the wind wheel pivots, and the barrel is always good: but, basically we are talking about a 26 jewel watch with 14 jewels added only to get get the number up to 40. In other words, it’s not the same as when patek says “32 jewel” automatic”, or Zenith prints 35 jewels for its tourbillon. So, mainly, my question is: Do the 14 jewels in the auto winder wheels have any function in the operation of the watch? I only ask because I just bought a 40 jewel watch with two balance cocks that I assume is of Chinese origin and after I added the 18 jewels for the two balance assemblies, I was curious where the other 22 came in. Your article was fascinating and very informative.
    Thanks for any response,
    Joe Conway (45 years a collector of watches)

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