One of the many versions of this watch you can get on Ali. It's either NOS or reissue of the 70s watch with Tongji, Chinese standard movement. The strap is 19mm which is a pain, I'll have to figure out a strap that fits because my current 18mm wobbles.
Anyway, this is my second hand-winding watch and the knob is kinda hard to twist so I worry about snapping the spring/bar. Especially if it actually happens to be the 50y/o movement. I already did that with the first manual watch I had.. So I'd like to ask for advice. Really don't wanna break it because it looks very nice and is pleasant to wear with the low profile (much thinner than my automatics)
I got it on a lucky discount for 406czk (~$17USD) Cheers
edit: I found an interesting article in chinese that mentions this watch belonging to author's grandfather. Same design in their photos, and the back stamped with 7120937 just the same.
And the movement in this watch should be the Standard Chinese Movement - SS7 variant. Hope I can get a watchmaker to take a look at it, and see what marking is inside to date it.
19 jewels, ticking at 21600 and should take 20 turns to wind.
edit2: i managed to open the back carefully without scratching it, and there is no markings on the inside, as there should be with vintage movements. so this is a modern release. there is no grime or anything, so i assume the winding strength is some sort of o-ring that waterproofs the watch. iirc, the original spec of the tongji watch was to survive 1 minute under 1 meter of water.
and wile it was open, i tweaked the rate, and got it from 54s/d to 5s/d.
pic inside the case - imgur
In the absence of a user manual or trustable reference, you cannot know if the mechanism has over-winding protection.
Being hard to wind up probably means it's an older model or design. Start by giving it 15 strokes from completely stopped, and check out how long it runs; increase from there but stop as soon as you reach 30h, which should be the minimal power reserve of a mechanical watch.
The odd thing is that even turning the crown in the opposite direction is very stiff (rachetting backwards.) And same with setting the time. Feels like there's something that prevents it from moving freely.
Best bet, I'll try to find a watchmaker nearby to take a look at it.
Nice watch!
The oils could have started solidifying, or perhaps something worse.
A watchmaker's time will surely cost more than the watch, but worth a shot.
You're probably right about the oils solidifying because when the watch is stopped, and I set the time, it starts running. So I assume the "setting" position doesn't properly disengage the winding mechanism, and it winds itself up. I just set the time to 12 o'clock and it ran for 10 minutes.
That makes me think it may actually be a vintage movement, which is very cool!
If it's oils, then you have two options:
The latter you can learn to do yourself, but be prepared to break/lose some components on the first few tries.
Good luck!