Winding the JLC Master Ultra Thin Moon

ottobonn · Jul 29, 2015

Hi all,

This is my first post around here. I recently acquired a Jaeger-LeCoultre Master Ultra Thin Moon, which is an automatic. I know most automatics have overwinding clutches to protect them, but I wanted to confirm that this watch does indeed have a mechanism to prevent overwinding. The manual simply says "the crown will not lock when the watch is fully wound." I'm just being extra cautious!

Also, does anyone know how many turns of the crown fully wind the watch?

Thanks!
ottobonn

pr1uk · Jul 29, 2015

ottobonn said:
Hi all,

This is my first post around here. I recently acquired a Jaeger-LeCoultre Master Ultra Thin Moon, which is an automatic. I know most automatics have overwinding clutches to protect them, but I wanted to confirm that this watch does indeed have a mechanism to prevent overwinding. The manual simply says "the crown will not lock when the watch is fully wound." I'm just being extra cautious!

Also, does anyone know how many turns of the crown fully wind the watch?

Thanks!
ottobonn

Welcome,
It's an automatic so you do not wind fully like a manual one so as it says in the manual
"a few clockwise turns of the crown will suffice to start the watch. it will then automatically wind up when you wear it"

CometHunter · Jul 29, 2015

ottobonn said:
... I know most automatics have overwinding clutches to protect them...

Actually, ALL automatics have this feature. And, yes, that includes yours!

I'm just being extra cautious!

There's nothing wrong with being cautious!
In this, the manual is correct. And thank you for caring enough to ask. You have a wonderful watch. And if you'd like to get out your camera and show it off we'd be tickled pink to see it.

Also, does anyone know how many turns of the crown fully wind the watch?

This is actually quite hard to answer the way you want.

According to the database supplied by the watch winder company ORBITA, the Jaeger LeCoultre caliber 925 movement requires approximately six hundred counter-clockwise revolutions of the rotor to become fully wound. The problem is knowing X=Y, where X is the # of crown turns and Y is the # of rotor revolutions.
Not all auto movements are geared exactly the same, and we don't keep track of that kind of info. Also, the math is too technical for the average watch owner. So instead, we simply keep track of the number of rotor rotations. Some buy an electric watch winder and let the machine do all the work. (Be forewarned: good watch winders tend to be rather expen$$ive, and the cheaper ones are just that...cheap. As in poorly made)
Most of us just give the crown 50 or 60 turns. That's generally enough to give the watch a good start and your arm motion does the rest (assuming your lifestyle isn't too sedentary). Personally, when I wear autos, I give the crown 50 turns to begin with, and then 30 or 40 turns every other day. Then again, I'm not as active as men half my age, so my watches need that extra little boost.
And as you already know: the clutch mechanism prevents overwinding, so no harm is being done by winding the crown a few extra times.

ottobonn · Jul 29, 2015

Thanks pr1uk and Bill. I didn't realize it could take so many turns! I had the number 20 somewhere in my mind, so I was surprised when I reached about 20 turns and didn't really feel increased resistance on the crown.

I know the manual says to give it a few turns and then the auto will do the rest, but I'm not able to wear the watch every day (work is pretty rough-and-tumble), and I like to keep it running for the days when I can. I'm also curious about the power reserve

I'll shoot some photos when I get home tonight