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ST7 Photos for youMay 4 2011 at 5:39 PM
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Response to There are two versions of the vintage auto Sea-Gulls... Both rare...
I have been working on the ST7 for you. You wanted it regulated, and also noted that the manual winding was a bit stiff and jerky.
The case back was screwed on very tightly - had to use a lot of force on the opener to get it open:
Here is a shot of the movement:
Not anything too fancy in terms of decoration, but not completely ugly either. In the photo above there is one jewel that has no function, but it's unclear if this is included in the total jewel count or not.
Here I have removed the oscillating weight, so you can see some of the winding/reversing wheels:
And with the loose wheels removed, I can tip it up and get a good close shot:
The arrow indicated the jewel that has no purpose:
The manual winding was very smooth with the automatic parts removed, so the stiffness is certainly in those parts. The only way to know if it's unusual or a function of the design is to clean and lube it all again, so here it is ready for the cleaning machine:
Once I had it back together and lubricated, it was slightly better. My feeling is this is like trying to get the grinding noise out of an ETA 2824-2. You can improve on a little with a service, but for the most part is the characteristic of the movement.
I fully wound the watch and timed it in 6 positions:
The results were fast overall, but quite good actually. The Delta is a little over 9 seconds in total, but if you take off the last position, which is crown right, the result is very good at something like 3.1 seconds over the first 5 positions:
When watches are adjusted in 5 positions, the crown right position is typically the one not adjusted, and tends to be a flyer. Likely a poising issue.
The watch was slowed slightly to bring the overall rate down.
Note that the balance amplitude in the first two positions (dial down and dial up respectively) is a bit low, but I find this is typical of Asian watches for some reason, so I'm not alarmed by it.
I like the fact that there is no reversing wheel assembly (ratchet and pawl type like in an ETA 2824-2) like in many modern watches, and they use a simple reverser set-up with two wheels on a pivoting base to change directions. Complex reversing wheels in older watches can be quite a pain.
Overall a pretty nice movement.
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