Why is my Unitas 6325 intermittently losing time?

[VWatchie]

A few weeks ago, I serviced this, in my opinion, very cleanly looking and easy to read watch housing a Unitas 6325. Amplitude is not perfect, about 260 degrees dial up and dial down and about 230 degrees in all other positions. As I like it a lot, I’ve been wearing it every day since the service and I always wind it fully just before I go to bed and let it rest on its back overnight.

It has been performing persistently losing about 3 to 4 seconds per day. However, a couple of days ago I noticed that suddenly and without any obvious explanation it had lost about 4 minutes (yes, minutes) within a time span of about 2 to 3 hours. I concluded that it must have happened sometime between 11 am and 2 pm. So, at that point I reset the time, and it started to perform persistently again losing about 3 to 4 seconds per day. However, after a few days the exact thing repeated itself. That is, the watch lost about 4 minutes sometime between 11 am and 2 pm. Having reset the time again it now runs persistently again.

I am clueless about what might be causing this, and it puzzles me that it is intermittent and doesn’t happen every day. So, any suggestions of what I could try to look into?

[jdm]

1 hour ago, VWatchie said:

Amplitude is not perfect, about 260 degrees dial up and dial down and about 230 degrees in all other positions.

These are small values for a quality Swiss, and the discrepancy between DU and all the rest (especially DD) is too large to be acceptable by good standards. Of course the watch will be practically usable,  but at the same time I don't think the above will be enough for great timekeeping.

[Doninvt]

I had a 6r15 that was intermittently losing time.  It turned out it was actually stopping for a few minutes at a time. In my case it was kicked into restarting by some movement of the wrist, so I don't know if that could be the case sitting on a table.

[Nucejoe]

Considering it occurs in same time span and in static position, I looks for the fault in the minute train including canon pinion, hands, hands tubes rubbing.

Elimination would,nt do much good here, since you would eliminate the min hand which is what you need to observe the reocurance with..Unless you set the hand 12 hr ahead, then the fault is to be ran through in day time, when you have a your eyes open and better chance  to catch the guy red handed, if you did, your tg can help confirm.

I make an observation with the dial removed, hands installed too. 

 

 

 

[vinn3]

58 minutes ago, Doninvt said:

I had a 6r15 that was intermittently losing time.  It turned out it was actually stopping for a few minutes at a time. In my case it was kicked into restarting by some movement of the wrist, so I don't know if that could be the case sitting on a table.

      I have seen this in used watches.  return to seller or keep for parts,     vin

[nickelsilver]

I'm with joe here, the amplitude could be better but it's not severely bad (though, are you checking at the correct lift angle? Should be 49).

If the canon pinion is on the light side of friction, any little nick or abnormality in the minute wheel, hour wheel, intermediate setting pinion etc. can cause it to slip. Those faults should be corrected anyway, but are likely your problem.

[aac58]

That's happening between 11 am and 2 pm, so it's not in a static position but when in your wrist, isn't it?

I had a similar problem a month ago and the reason was a faulty cannon pinion, letting the hands to move if I moved the watch a bit heavily than usual. Maybe you did something rough in that time interval both days?

If this could be your problem then you'll feel too few or none resistance in the crown when setting the hands.

Edited February 22, 2020 by aac58

[Doninvt]

9 hours ago, vinn3 said:

      I have seen this in used watches.  return to seller or keep for parts,     vin

Seiko service in New Jersey was able to sort it out under warranty.  I don't know whether I got the same movement back or not.

[Nucejoe]

11 hours ago, aac58 said:

That's happening between 11 am and 2 pm, so it's not in a static position but when in your wrist, isn't it?

I had a similar problem a month ago and the reason was a faulty cannon pinion, letting the hands to move if I moved the watch a bit heavily than usual. Maybe you did something rough in that time interval both days?

If this could be your problem then you'll feel too few or none resistance in the crown when setting the hands.

Oops that is daytime, I think this goof up of mine can qualify for a genuine brain fart.lol.

[VWatchie]

15 hours ago, nickelsilver said:

I'm with joe here, the amplitude could be better but it's not severely bad (though, are you checking at the correct lift angle? Should be 49).

If the canon pinion is on the light side of friction, any little nick or abnormality in the minute wheel, hour wheel, intermediate setting pinion etc. can cause it to slip. Those faults should be corrected anyway, but are likely your problem.

 

11 hours ago, aac58 said:

That's happening between 11 am and 2 pm, so it's not in a static position but when in your wrist, isn't it?

I had a similar problem a month ago and the reason was a faulty cannon pinion, letting the hands to move if I moved the watch a bit heavily than usual. Maybe you did something rough in that time interval both days?

If this could be your problem then you'll feel too few or none resistance in the crown when setting the hands.

@nickelsilver Yes, checking at 49 degrees. Perhaps the cannon pinion is a tad on the "light side of friction". The fourth wheel keeps ticking freely when I set the time, but I still need to apply some slight pressure to the crown with my index finger (only) when I set the time. Tightening the cannon pinion would be a very delicate job as it seems near perfect. I do have the "bits(?)" designed for tightening the cannon pinion using my Seitz jewelling tool as well as Bergeon's cannon pinion pliers tool. Never used the jewelling tool for this. What would you recommend, the jewelling tool or the pliers?

@aac58 You are quite right! It is happening when I'm wearing it on my wrist. I never saw this problem during the night when it's resting on its back, and it always happened while I was working moving around my hands trying to make my students understand a certain concept (I work as a teacher).  Yes, so I guess I "did something rough"!

You both seem to be pointing to the cannon pinion so I guess that's what I should try. They are so easy to mangle so I usually try to avoid tightening unless absolutely necessary. Anyway, perhaps that's what I need to do...

Thanks all!

 

[VWatchie]

Just to clarify; What I meant was that "the fourth wheel keeps ticking freely when I set the time" counterclockwise.

To those of you new to watches; When the cannon pinion is too tight it will not release properly from the centre wheel arbor when setting the time, dragging the train of wheels along with it, which is no good. When this is the case and the time is set in a counterclockwise direction it will stop the seconds hand (sitting on the fourth wheel, sometimes called the second wheel (a bit confusing yes)) and this could even make the seconds hand spin counterclockwise and this could potentially damage the movement.

Edited February 23, 2020 by VWatchie

[VWatchie]

So, I decided to tighten the cannon pinion using my Seitz jewelling tool (which I had never done before) and it was a pretty smooth operation. I tightened it about 0.015mm and it felt pretty perfect after this.

However, I ran into more serious problems as I noticed that the amplitude was seriously off. So, I've decided to start a new thread to address my amplitude problem and if you are interested and/or perhaps can provide me with some advice, please go to this thread: Need help with Unitas 6325 amplitude problem.