First of all, I have to thank Joris from Amersfoort in the Netherlands for sending this one in. He took up my offer for a free service if I find the watch interesting enough. And I did 😉
This lovely Shanghai Shoubiao Chang 7120 (which stands for Shanhai Watch Factory) arrived in the mail yesterday, and I couldn’t resist taking it apart. The watch has the Tongji standard movement in the 19 jewel variant (with 2 jewels on the barrel) Â …
The back is screwed on and has a rubber o-ring seal
For a hand-wound watch, a tad on the thick side
First look inside - a 19 Jewel movement
First things first - let down the main spring. You do that with your other hand on the winding crown, but I need to hold the camera as well 😉
The release for the winding shaft
It is true that a small amount of grease helps to keep the watch water tight - a huge dollop of grease and hair probably doesn't help, though
The movement is held in place by a plastic ring
The first thing to do after removing the movement from the case - take the hands and dial off. They are really easy to damage
First look at the bottom plate. The dial was not only held in place by screws (of which one is missing), but also by strips of double-sided adhesive. At the bottom left, you can see the spring that keeps the date dial locked in place. This is one to watch as they really like to fly 4 metres across the room as soon as you look at them sideways!
As the date ring is also easily damaged, I start to take apart the bottom plate first
The wheels for adjusting the time when the crown is pulled out
Time to turn the movement around. I start by removing the balance wheel cock
The impulse pin on the balance wheel
The wheel bridge removed - nice bit of hair on the barrel wheel 🙂
The movement has a fair amount of dirt in it - you can see quite a few bits on this wheel
Escapement wheel bridge removed
And the pallet bridge taken out
Close-up of the escapement wheel with focus on the pinion
The pallet fork
Top plate cleared
These are the parts that won't go into the cleaning fluid
First part of the job done. Reassembly to follow in a couple of days!
To sum things up so far:
- the finish of the plates is a bit rough, but not in places where it mattes. It’s more a cosmetic thing
- where it matters, the movement is made well enough
- seen in context (cost of the movement, etc.) this should be a decent and reliable hand-wound watch. Nice piece to collect
The reassembly post is here.
I can’t get the back off of my Shanghai 8120. The back looks like a giant nut.
If you could give me a clue I’d really appreciate it. I tried a pipe wrench and just scratched it up.
Thanks so much!
Glue a large nut to the case back with superglue. Let it dry for half an hour, and use a spanner to turn the nut. Dissolve the superglue with acetone.
I own a similar watch (Shanghai Shoubiao Chang 7120-1028). Bought it on a market in a small village in China in 2007. Not really doing anything with it.
Is one of you interested to take it over?
Best put in on eBay, and somebody who wants one can pick it up.
Cheers,
Christian
I’m fortunate to be the new owner of this watch. Thanks to Joris’ generosity.
I must say, you did great work cleaning and servicing this watch!
Great story – I wonder where it will end up next…
I just serviced mine, and had to slightly enlarge the wheel bridge screw holes in order to float it on the pivots to re-install. Before enlarging the holes, the fit was so tight that it would require force to go down(I tried with the wheels removed), so much so that I couldn’t tell if it the pivots were aligned or not.
Did you encounter that problem? I can’t imagine how some guy in Shanghai installed that 30 years ago without crushing the pivots.
Did you oil your escapement wheel or pallets?
Great tutorial!!! Thank you! -Yue Fan
Was this 7120 a 70’s vintage? Looks quite new, despite the dirt.
Everything points to vintage – all parts are consistently old. But that is only me looking at the watch. Maybe someone else can shed light on this?
Thanks,
Christian
Found a link to a collector of Chinese watches http://ozputera.blogspot.co.uk/2010/06/shanghai-7120.html
It appears that the Shanghai 7120 series watches were very expensive (the equivalent of 4 months salary, plus a ‘watch coupon’, and an employer’s letter of recommendation). This led to a market of fakes…..can you imagine a fake Chinese watch of a Chinese watch!
There are links within the blogspot link above which provide information of the month and year of manufacture. The clue is in the letters under the balance wheel which is the date code.
I’m not enough of a watch technician to know whether this watch is well-crafted or not, but I’m enough of a technician in general to know that dirt is BAD, and too much grease is BAD, and that hairs don’t contribute to running smoothly…
I’m looking forward to seeing the reassembly 🙂
Thanks again for taking my watch in!
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