It's Me Again...

[fjseal]

So, I've got a wheel train that moves at the slightest blow, a hairspring that is as close as I can get to what it should look like, I'm sure it it reasonably in beat. However, the watch runs nicely for a few hours then stops for no apparent reason, particularly as the date change approaches. It is a STD 96-4 movement. Could this be a weak mainspring?

 

Frank.

[Ishima]

Hard to say, could be a fault with the mainspring, it's well known that a watch needs more torque (power/force) to complete a date change than when it's running at other times.

But I'd be more tempted to look into the calender/motion work behind the dial, to find faults or parts that need cleaning/lubricating, or even a damaged wheel tooth or something of that nature. 

Edited May 24, 2015 by Ishima

[fjseal]

Thanks Ishima. That makes sense because the problem seems to have occurred since I fitted the calendar and dial. Something to do tomorrow!