I just discovered a neat little thing on my cal 613 Geneve. The crown rotates on its own throughout the day, this 1/2 turn is 1 1/2 hours apart after full wound this morning. I guess it's normal?
It's certainly not normal. I'd bet there's a click that's bent or out of place, so it isn't preventing the crown from spinning backwards because the mainspring is unwinding.
I wonder if this is something of concern, this watch is stable, quite accurate +4s consistent and power reserve of 49+ hours. In observation, the crown rotates a couple of revolutions in the first few hours after full wound, it has since turned a quarter for the rest of the day.
It sound like something is worn to the extent that under full wind (when the mainspring has most power) the click is unable to hold properly so it is allowing the spring to unwind. Just my thoughts so maybe @Archer or @ChrisN can comment
I have thought of this, but power reserve is not affected perhaps even longer. The crown's rotation is very slow it does not appear moving, a turn and a half in the first 5 hours after full wound, and near still (1/4 turn) for the rest of the day. This turning seems to be related to the tension of the main spring.
it is conceivable that the crown might turn counter clockwise during wear, after winding is complete. This likely would happen only by the crown being very loose on the case tube, allowing it to turn from rubbing on shirt cuffs, etc. Normal running of the watch can not cause the crown to turn.
If the crown isn't loose, is it possible that the setting lever spring is broken allowing the yoke and the clutch wheel to flop around and engage with the setting wheel, therefore "powering" the crown as the hands turn. Whatever, this is a job for the watchmaker.
I think I've found the problem, the crown does not rotate on its own but its light to touch anti clockwise, I must have inadvertently move it during wear.