Thank you for the explanation.

Jan 12, 2020,22:00 PM
 

I also have several watches, including a 240 PP movement exhibiting the same.
In addition to the friction in the minute tube, can it also be attributed to the placement of the dial.
Ideally, the dial centre is also the exact centre of the hour/minute hands rotating axis.
If the dial is placed so slightly out of centre, would the above observation be seen as well? /W72

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240 Q movement question

 
 By: Chromatic Fugue : January 12th, 2020-12:07
I bought a 3940 (2006 vintage) in November, and I'm having an accuracy issue that is more interesting than it is troubling. The watch is accurate over the long term (say, after a month) and never more than a minute off. But if I check it in any given mome... 

Yes.

 
 By: baufoam : January 12th, 2020-13:16
I wore a 3940 nearly every day for about 10 years. It behaves in exactly the way that you are describing. It speeds up and slows down but ends up back on time or very close to it. My 3940 is probably accurate to within about 3 minutes per month. I have ha... 

thanks --

 
 By: Chromatic Fugue : January 12th, 2020-17:33
happy to hear mine is not the only one. The variation here is not a problem for me as long as it stays within its current bounds.

3min per month is

 
 By: Rapwatch : January 22nd, 2020-12:40
Pretty average to poor. Especially if you are cogniscent enough of your positional performance to rest overnight in suitable position to gain or lose against real time. You should achieve close to 0 PPs are supposed to run -3 2 s/d according to their own ... 

Thanks, but

 
 By: Chromatic Fugue : January 22nd, 2020-13:34
I now realize, for the reasons discussed here, that problem isn’t with the movement. The problem is with the play in the joints between the movement and the minute hand. Because of the nature of the issue, the minute hand can “gain” or “lose” a minute a d... 

A quite common problem is to little friction in the minute tube.

 
 By: kjell_watchmaker : January 12th, 2020-13:27
Can be fixed, but it requires some skills and experience (and a dismantling of the movement). So your theory is most likely correct.

thanks for the insight!

 
 By: Chromatic Fugue : January 12th, 2020-17:34
I'm OK with the status quo and in no hurry to have anyone open the case, so I think I'll do nothing until the next service interval.

Such a high fluctuation is very poor. You may have a bent pivot

 
 By: Rapwatch : January 22nd, 2020-12:33
I suggest you attend to it soon.

Thank you for the explanation.

 
 By: W72 : January 12th, 2020-22:00
I also have several watches, including a 240 PP movement exhibiting the same. In addition to the friction in the minute tube, can it also be attributed to the placement of the dial. Ideally, the dial centre is also the exact centre of the hour/minute hand...