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I've seen a lot of 7j and 15j watches listed from early 1900s (not RR movements) that people list as running perfect but upon inquiry are off by about 2 min a day. My questions are:

1) is this within spec for the watch or a product of its age?
2) are these likely to improve with a servicing?
3) should I be worried just like the watches from india that are "serviced" yet unregulatable at +2-3 min because they are cobbled together by amateurs from a bucket of broken watches?

I don't mind it being so off if that is normal, I just didn't want to spend money on something that should send up red flags.
 

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Even for a non RR timekeeping piece, that accuracy is horrible.
 

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Even for a non RR timekeeping piece, that accuracy is horrible.
That was my initial reaction but I did not know if I was expecting too much. I understand that with the price of them they are def not serviced.
 

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You'll certainly have better luck with 15j ones.

The problem with 7j is twofold: First, since they were cheaper, they don't tend to be treated that well. Second, since they don't have jeweled pivots, the the pivot holes are usually elongated due to wear and that severely affects rate. And also they aren't usually adjusted, so they suffer from positional errors. I wouldn't expect much from them.

The 15j ones are better, but it all depends on the state of the movement and how much time/money you're willing to put on it. Yes, servicing may help, but in the end it all comes back to the money question. For a 15j, I would be happy if it would keep +/- 30sec/day without too much tinkering.

For comparison, my Hamilton 992 (21 jewels, railroad grade) is accurate to less than +/- 30 sec/week (yes, week not day).
 

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You'll certainly have better luck with 15j ones.

The problem with 7j is twofold: First, since they were cheaper, they don't tend to be treated that well. Second, since they don't have jeweled pivots, the the pivot holes are usually elongated due to wear and that severely affects rate. And also they aren't usually adjusted, so they suffer from positional errors. I wouldn't expect much from them.

The 15j ones are better, but it all depends on the state of the movement and how much time/money you're willing to put on it. Yes, servicing may help, but in the end it all comes back to the money question. For a 15j, I would be happy if it would keep +/- 30sec/day without too much tinkering.

For comparison, my Hamilton 992 (21 jewels, railroad grade) is accurate to less than +/- 30 sec/week (yes, week not day).
I'm a bit more optimistic about the performance that's possible, but, yeah, if the pivot holes in a 7j watch are ovalized, it's best not to bother. I would note, though, that I have several 7j watches from about 1870, some with solid balance, and they all run within a minute a day - IN USE. That is, wound up and carried all day, then left on the nightstand overnight, they all keep time within a minute per day. On the bench, though, the solid balance ones gain a bit more time because they're not temperature compensated.

I have an 18s 15j Elgin that runs within 15 seconds per week, and that's in use or on the bench.

My 7 21-23j railroad watches mostly keep railroad time, with one staying within low single-digit seconds/week.

And these were all serviced by me, an all-thumbs amateur. So, if the watch itself is in good condition, and it's been serviced properly, and the mainspring is not 'set', running within a minute a week should not be a problem.
 
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