Seiko 6106-7729 Service

[Saldog]

I'm not highly experienced and I didn't photograph this service enough to give a walkthrough and it was a straightforward thing, going smoothly for the most part. I just wanted to share the only glitch that I got on this one.

I used a K&D mainspring winder and I made the mistake of rotating it the wrong way for just a couple of rotations. I then rotated the right way and went all the way through the process and loaded it into a barrel. Once I pulled it away, I saw that the loop end of the MS was completely kinked, folded over on itself. I imagine that rotating the wrong way caused the loop end to fold in under itself and then winding it up in the winder smashed it home. Of course, trying to bend it back caused it to break. I am guessing this could happen with any winder and nothing against the K&D.

This picture is before that happened, after cleaning everything:

In this photo is the MS that I broke. I had another laying around and used it instead. I couldn't remember where it came from, but I think it was an older one that I had re-loaded into a washer. I just grabbed it and threw it in, but in hindsight, I should have unloaded it and checked it for shape and hygiene before reloading it.

You can see from the time graph that the amplitude is on the low side.

It drops down to 175º in some positions. But otherwise, it is running well. I think it would be best to replace the mainspring. It will be interesting to see the difference in this amplitude with only that difference. If I do and see a noticeable difference, I'll come back here and update the post.

Here's the completed watch, which also needed considerable case work, done a few days ago. What looks like an anomaly on the pic is actually refraction caused by the faceted crystal.

From 1975, the Seiko 6106-7729:

 

[Kalanag]

Well done! Thanks for sharing mistakes also. That‘s how we all learn.

I read recently that Seikos are low on amplitude. Please let us know whether a new mainspring makes a difference. I‘m not so sure…

[Saldog]

1 hour ago, Kalanag said:

Well done! Thanks for sharing mistakes also. That‘s how we all learn.

I read recently that Seikos are low on amplitude. Please let us know whether a new mainspring makes a difference. I‘m not so sure…

If I shared all of my mistakes I’d be the most frequent poster on this board! Yes, Seikos are low but they should be 220-250. I serviced another a week ago and got 260 with a brand new mainspring. For sure I will come back here when I get around to replacing this one in a couple weeks or so. 

[Kalanag]

I serviced two identical Citizen ladies watches (caliber 6900) which were in very good condition. But I couldn‘t get them above 240° (lift angle is 46°). Seems to be normal…

[jdm]

Just now, Kalanag said:

But I couldn‘t get them above 240° (lift angle is 46°). Seems to be normal…

Surely normal. But even a larger Seiko with "just" 210 deg amplitude can have a perfect pattern, sufficient positonal deviation, and more importantly, excellent timekeeping. In the end, that's all what matters.

[Saldog]

I have ended up becoming close to a watchmaker near me as he has serviced 5 of my watches now and we have had a few conversations. He is a formally-trained watchmaker from Paris and has been in the business his whole life (he is about my age, near 60). He is not a fan of Seiko and admittedly a bit of a Swiss watch snob but he said that anything over 180º is nothing to worry about and there is such a thing as too high an amplitude. 

17 minutes ago, jdm said:

Surely normal. But even a larger Seiko with "just" 210 deg amplitude can have a perfect pattern, sufficient positonal deviation, and more importantly, excellent timekeeping. In the end, that's all what matters.

I agree with this. If the watch is running fine, that's what matters. But I think each watch design has a range that is optimal for it and when we service a watch, we want it to fall into the expected range. As a newb, I don't know what to expect really, but I have serviced a half dozen movements based on the 6106 caliber or similar to it over the last couple of months. I have seen anywhere from 180 to 260 degrees of amplitude so it is hard to say where it should be. I've seen this with existing and new mainsprings also. I suspect there are many factors that determine the amplitude and one of them is the mainspring condition and perhaps that is not the key factor either. I'm sure the balance has more to do with it. Even two watches of the same caliber will behave differently because they have seen different circumstances. All we know is what a timegrapher tells us, and we all probably put too much stock in what the timegrapher tells us. Our wrist, over time, tells us much more.

I have ordered a new mainspring so it will be interesting to see what happens when that will be the only change I make to this watch. Stay tuned.

Edited June 21, 2022 by Saldog
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