What's the best way to let down a main spring?

[cp5184]

What's the best way to let down a main spring on a wristwatch?

Thanks

[AbslomRob]

Dunno about the "best" way; I put a screwdriver in the screwhead of the first wheel, "wind" it enough to move the click, then use a piece of pegwood to hold the click out the way. Then I let the mainspring unwind by letting the screwdriver "turn" between my fingers, until it's down.

The risk with this method is that if the screwdriver slips, you'll probably scratch the first wheel and the plates. I know a lot of people do this by using the crown, but I find that awkward, and too often the crown slips through my fingers. The crown method works better with larger watches, because the crown is larger.

[GeneJockey]

I suspect AbslomRob's got better screwdrivers than I have!

Generally I take the movement out of the case, return the stem and crown to the movement, then do what AbslomRob does, but using the crown instead of the screwdriver. Yes, they slip a bit, but when I've done this with a screwdriver, IT slipped and made a nasty track across the ratchet wheel.

There are watches where this can be a problem. The Elgin 760 automatic uses a rocekr plate instead of a clutch, and if the winding wheel isn't engaging the ratchet wheel idler when you release the click, it will unwind through the autowind works REALLY FAST, with potentially disastrous effect on the fragile 2nd automatic winding wheel.

[AbslomRob]

I actually have a set of cheaper dollar store drivers that I use for this; I find that the wider drivers in my "good" set are too thick to engage the screw head properly, so I took a cheap set of "precision" screwdrivers, and shaped the heads to fit this screw properly.

[Mirius]

I think safe depends on the skill of the watchmaker. De Carle suggests that experienced watchmakers brake the centre wheel with their finger after they have removed the pallet fork. I suspect that this probably works better on larger calibres.

[watchma]

Can't you just leave the watch alone for a couple of days ? - job done

[AbslomRob]

Only if it actually works; you find that watches that don't run properly often come to you fully wound (because the first thing people do when they get a watch that doesn't run is try to wind it; the main reason people often describe non-working watches as "overwound").

[emso]

on fine pieces of watches i dont remove the crown or movement from case
i put away the click and let the movement unwind through the crown. the gasket on the crown makes enough friction so its not fast unwinding.

br

[watchma]

Only if it actually works

Ah yes , that might help

[James Haury]

Gently?