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Discussion Starter · #1 · (Edited)
I am unsure of who makes this movement, but it is a copy of a Miyota 8215, with the addition of a hacking feature. It is marked with the crowned circle. Anyway...

Movement general view:

Dial side



Rotor removed, note how this one, unlike the ST16 does not have a separate auto-wind bridge, this saves about 0.75mm in height.



Here with the 3/4 bridge removed, showing the winding gears as they sit, this is a unidirectional winding movement, just like the Miyota



Here is the underside of the 3/4 bridge, note the location of the second hand pinion friction spring.



Here is a view of the one-way reversing wheel



Another



Here is a detail shot of the pallet, note that this movement uses banking pins, rather than the adjustable tabs on the pallet cock. Up at the very top, you can see the finger for the hack lever, just like the ST16 it arrests the third wheel



The dial side is the same as the ST16 so I'll save the bandwidth and not post images of its innards again



Parts, for comparison to the ST16





At the far right, the little "U" shaped spring is the hack lever (with integral spring) It is activated by the post on the yoke (below).



 

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Discussion Starter · #2 · (Edited)
The second movement we shall open up is what I consider the best of the lot. It has an offset center wheel, dual reverser (bi-directional) auto-wind system, and although this particular example does not hack, versions that do hack, operate against the balance directly. There are versions of this one made with an additional 24 hour GMT hand that is independently settable.

General shot of the movement: (this is a donor movement, so it is missing the floating gear, its screw, the stem and the winding pinion)



General shot, dial side



Rotor removed



The winding gears as they sit under the auto-bridge



An ingenious click, no spring. I am sure you think you recognize the base movement, but its not.



The wheel train



Here is the offset center (or second) wheel



And the dial-side cannon pinion (familiar, maybe?) It engages the third wheel of the train



Auto wind parts, the Chinese design is such that it uses two identical reverser wheels, unlike the Swiss, who omit the gear on the under side of one of them, it saves making two different parts.



Train parts



Barrel bridge parts



Calendar parts

 

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Dixmont Guangzhou DG28/38

Most excellent post with pictures and info!! (We definitely need a sticky now). Keep'em coming Mr. Lysanderxiii !!

:thanks :thanks :thanks

I believe Mr. Chascomm figured out just the other day that the crown logo under the balance wheel is a Dixmont-Guangzhou.

I found this picture on the Dixmont webpage. The circle crown is inverted and located at 12.



Now if we could just figure out if it is a DG2813 or DG38XX ???

DG2813


Well, we can officially rule out a Nanning 2813. I just found this on Cousins and it has a NN logo under the balance wheel.



Cheers,
gigfy
 

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I believe the second movement is the Shanghai B GMT. I think this is what I have in my Chronotac / Chronomat "Steve McQueen" watch. I haven't opened it to verify. Mine hacks & has the independently set 24hr hand like in the picture below.

Was this particular movement one of the 35 jewel versions?
https://www.watchuseek.com/showthread.php?t=180827&highlight=chronotac

pic of Dapper's watch



Cheers,
gigfy
 

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Discussion Starter · #5 · (Edited)
I think the 38 and the 28 are based on the same base, they seem to have the same basic architecture.

The second one is not a GMT, but its missing parts were used on a ChronoTac GMT, which was the same base movement.

As to the jewel count, let me see...I count 35 jewels, not bad for a movement originally marked 7 jewels on the rotor. (it was inked on long since rubbed off.)

Jeweled as follows:

4 Balance staff
1 Impulse
2 Pallet fork
2 Pallet staff
2 Escape
2 Fourth wheel (There is one inside the tube for the fourth wheel pinion, ETA doesn't even do that!)
2 Third wheel
2 Second wheel
8 Auto-winder gear pivots (two reverser, one reduction gear, one transfer gear)
10 inside the reversers (five each, acting as clutch elements)

Here's a picture of the 35th jewel: (Edit: sadly not the best picture, but there is one in there.)

 

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Is the Shanghai B (GMT and non-GMT variants) some sort of extensive modification of the Standard? I'm looking at the guts of my Alpha GMT (crown tube is messed up, so I took it apart to see if it will fit in my incoming Voow Sub) and it looks a lot like what you've got there, and a lot like the Standard in the envelope in my trashcan (utter watchsmithing failure).

And again, thanks for these posts. :-!
 

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This is great Lysander, thanks.

I think the second movement is the Cousins listed C13719....the dial side date retaining plate is a little different but the rest is spot on as far as I can tell...

 

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Discussion Starter · #8 ·
This movement is not based on the "standard" handwind, as far as I can tell.

If this is a picture of the "standard", then you will immediately note that this movement conventional cannon pinion, not the large gear type used earlier. Also you can tell this is a co-axial train movement, with the fourth wheel co-axial and on top of the second wheel.
 

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This movement is not based on the "standard" handwind, as far as I can tell.
So what is the base movement for the Shanghai B? (ha ha, ask question to oneself, look it up on wiki, get answer :) )

Development of the Shanghai B on the Wiki

"In 1982, the Shanghai Number 4 Watch Factory entered into a joint venture with the Shanghai Watch Factory to develop a new wristwatch movement to replace the ZuanShi SM1A and Shanghai ZSH (STANDARD MOV'T). As it happened, the ZSH was never replaced. The prototype series was designated SBS, and was characterized by a very thin design of simple construction and large balance wheel. An automatic version was also planned. Test batches of the SBS1B calendar hand-wind and SBS3 very thin watch were released to market in 1984, alongside the equivalent Shanghai SS8.

The full production ZuanShi SB1Z (date) and SB1ZB (day/date) versions were release in 1985. These early versions may be destinguished by a prominent, stylized B engraved on the movement. The day/date automatic SB1ZZ followed in later years. Curiously, although thinness was an important characteristic of the SBS design, the automatic module is reasonably bulky.

.....

Although Shanghai ZuanShi is now just a memory, the B calibre developed jointly with the Shanghai Watch Factory lives on in a proliferation of variants produced by Shanghai and used in both their own watches and sold to other watch companies. There are triple-calendars, dual-time, 24-hour, moon-phase. The most commonly seen in recent times is the GMT version, found in watches under the brands of Alpha, Aeromatic, Tauchmeister and many others."

Cheers,
gigfy
 

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Discussion Starter · #10 ·
I believe I have a SBS handwind, or something very similar. Maybe I 'll open it up today.

And, we may see the tear down of a skeleton standard , depends how bored I get.
 

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I believe I have a SBS handwind, or something very similar. Maybe I 'll open it up today.
Thanks, please do!

And, we may see the tear down of a skeleton standard , depends how bored I get.
I've got one I'll give you if you don't already have one.

I found this, yet another DG variant, the DG4813 but the seller says it has a beat rate of 28,800bph. Have you seen one of these?





pic from Ofrei


Seller's Description:
"This is a brand new Asian automatic movement with the higher beat rate of 28,800 bph, which is the same rate as an ETA movement or a Rolex movement. It can be used for date at 3 o'clock or 6 o'clock or no date at all. Please specify which datewheel you want.

This is a drop in replacement for the 2813 movement, same hand sizes and the dial feet holders are in the same position. It has a center sweep second hand and hack mechanism - stops movement when crown is pulled out to set time.

Movement size is 25.8 by 5 mm, which fits most mens watches. Hand sizes: 100/150/17 Dial feet at 5:30 and 11 o'clock.

I have tested the movements on my electronic timing machine and it is acurate with a beat rate of 28,800 beats per hour. The winding stem has its full length and it comes in the original plastic box."

Cheers,
gigfy

 

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Discussion Starter · #14 · (Edited)
ETA did the same thing with a few of their movements back before quartz ruled the low end market; stiffen up the balance spring, lower the mass of the balance slightly (doesn't look as if the reduced the diameter much, if any) so it oscillates at 4 Hz instead of 3 hz, increase the number the teeth on the escapement by 4/3x, and presto, a 21,600 bph movement is now a 28,800 bph movement.*

This new movement is no different internally the the old one (as far as disassembly goes), just a smoother sweep for the second hand.

That movement, the DG-48, is a drop-in replacement for the DG28.

_______________________________
* You can do it other ways such as keeping the same number of teeth on the escapement gear but increase the number on the escapement pinion, reduce the number on the fourth wheel, or a combination of the two.
 

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That movement, the DG-48, is a drop-in replacement for the DG28.
That depends if you get the taller hour wheel, cannon pinion and center seconds pinion version or the short version. The ones from Ofrei and cousins come with the shorter parts. Also the stem hole measurement is different and that may or may not cause problems.
 

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I believe the confusion may be the specific DG48 variant. The seller says his is a DG4813 which is a drop in replacement of the DG2813.

NEG, are you saying that the DG48 is not always a drop in replacement for the DG28? Or more specifically that the DG4813 may not always be a drop in replacement for the DG2813?

Cheers,
gigfy
 

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I believe the confusion may be the specific DG48 variant. The seller says his is a DG4813 which is a drop in replacement of the DG2813.
Could be....

NEG, are you saying that the DG48 is not always a drop in replacement for the DG28? Or more specifically that the DG4813 may not always be a drop in replacement for the DG2813?

Cheers,
gigfy
IME yes. You may have better fortune, I'll leave you to make your own mind up. There are at least two available hour wheel, cannon pinion, seconds pinion etc versions. The ones I've bought from Ofrei and Cousins all seem to be the shorter version (hour wheel 1.15mm), the 2813 may also come with the lower hour wheel etc but all the ones I've ever seen (including bare movements from cousins etc) have the tall hour wheel and pinion etc.

Dimensions for the 4813 here

However, I've found it's possible to swap the hour wheel, cannon pinion, center wheel and center seconds pinion from the 2813 and fit them to the 4813 but you may still be thwarted by the stem hole measurement of 1.6mm for the 4813 vs ~2.00mm for the 2813....

4813 on the left, 2813 on the right....

 

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I am unsure of who makes this movement, but it is a copy of a Miyota 8215, with the addition of a hacking feature. It is marked with the crowned circle. Anyway...

Movement general view:

Dial side

Rotor removed, note how this one, unlike the ST16 does not have a separate auto-wind bridge, this saves about 0.75mm in height.

Hey! I have this movement. Keeps very good time consisitently and yes, it hack, self-wind and can manual wind plus quick date set. Outshine the original miyota movement in my opinion.

Btw, is this movement 21 jewel?
 

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SomalCanada lists the DG2813 (central hr/min/sec; date at 3) as having 22 jewels.

Here is a reference pic from Cousins.



Cheers,
gigfy
 

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SomalCanada lists the DG2813 (central hr/min/sec; date at 3) as having 22 jewels.

Here is a reference pic from Cousins.



Cheers,
gigfy
Gigfy, di u know know how to remove the crown? Thanks for any reply..
 
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