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Seiko skx007 regulating question

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My Seiko skx007J was running a bit slow when new (around -10 seconds per day), so I regulated it, got it to +1 second per day.

 

Several weeks later it started running slower to -10 seconds per day. I rarely use this watch. I wind it every night (gently shaking it 300 times) and place it face up on a flat surface.

 

So, I regulated it again (using my timegraph) to +3 seconds per day. Ran well for about a week, but then started running slow again. It now runs -20 seconds per day; not magnetized,  no impact (same as always, I don't use it, I wind it every night and set it face up on a dresser).

 

Any suggestions (other than scrapping the movement and replacing it with another)?

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While I appreciate this is a new(ish) movement, and a Seiko to boot, it does look a whole lot better than a lot of movements that I have worked on of various types, that actually performed within spec. I understand and agree that the amplitude should be as close to 270 as possible, with a full wind, but if the performance over 24hrs is consistent and within spec, then that is pretty much all you can ask for.

I'm wearing an ancient Timex at the moment (1967, so not as ancient as me perhaps, but not far off). It runs fine, but the amplitude is a little on the low side at around 240 fully wound. It is currently sitting within 8 seconds of my Swatch on the other wrist after 2 days of wear.

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2 hours ago, AndyHull said:

 I understand and agree that the amplitude should be as close to 270 as possible, with a full wind, but if the performance over 24hrs is consistent and within spec, then that is pretty much all you can ask for.

In service sheets we rarely, if ever, find a definite minimum amplitude, and Seiko is no exception. Various performance parameters are specified, but amplitude never is. 

So it's common knowledge that Japanese mov.ts have a smaller one compared to the Swiss, and I suppose (without scientific proof) that is because the hairspring is thinner, the balance lighter, in search of better efficiency. 

Still we don't know much the real bare minimum is, I recall a thread where JohnR mentioned 200 deg based on solid formulas as well practical experience. 

The entire subject of the escapement is so incredibly complex and fascinating, I intend to do some serious studying about that myself. 

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I thought you might find this interesting normally Seiko doesn't have much for technical specifications for the watches but if you look in the 4006 a service information step number 12 image attached. I was having a discussion with another watchmaker regarding Seiko's amplitude and he told me about this. He was like the rest of you concerned over amplitude but decided that Seiko designed them to have low amplitude.  There's nothing wrong with low amplitude as long as at the end of 24 hours the watch is still running and keeping time.

 

Seiko 4006a.JPG

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Seiko movements definitely have the capability to perform in access of 300 degrees. I've gotten plenty to go above 300 by lubricating them like I would any Swiss movement, with the exception of using  9010 on the third wheel cap jewel.

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I would just like to share my situation regarding 7s26 movement.

For more than 10 years I've got a SKX007J, with eng/arabic day wheel and a 7s26B movement. Perfect watch, but with one big disadvantage : the movement accuracy.

Yes, more or less it was still running within specifications (-20 to +40s/day) but I would expect at least better consistency. I expect that during normal wear in the office (with no stress) the watch would every day advance/loose for more or less same ammount.

But my watch at first run one or two days 30s fast, then the next day was all of a sudden 20s slow , etc. Upon regulation it was ok for a limited time but then it started to gain / loose again.

Last year I disassembled, cleaned and oiled the movement. I tried to tune also the etachron regulator pins, but no luck - here I must admit I don't have much experience with Etachron tuning, so I already asked Mark for a video tutorial how to do it...

Two days ago I mounted a new 7s26A balance complete into my movement - I needed also 7s26A balance bridge, which I took from a scrape movement. It's been only two days, but now the watch seems to be working perfect, with minimum differences. Will see in the next days, how it performs...

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11 hours ago, dreja said:

Yes, more or less it was still running within specifications (-20 to +40s/day) but I would expect at least better consistency. I expect that during normal wear in the office (with no stress) the watch would every day advance/loose for more or less same ammount.

Normally a 7S26 does much better than that. When checking on the timegrapher, (before of after servicing) it's immediately evident it there are accuracy issue based on the three parameters below, in my experience if 2 of more of these are a fail the watch will perform poorly on the wrist too.

  • amplitude, looking for a min of 210°
  • pattern regularity
  • less than 20 secs rate change between dial up, 3 down, 12 down.
Edited by jdm

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