FOIS is a chronometer?

[Aspirin]

The FOIS was fit with calibre 1861, so is this 1861 a COSC chronometer? Can anyone help? Thanks!

[sensui]

It is not.

[Aspirin]

Originally Posted by sensui

It is not.

Thanks, sensui

[Aspirin]

Originally Posted by sensui

It is not.

By the way, do you know the reasonable span of accuracy per 24 hours? Thanks!

[sensui]

Originally Posted by Aspirin

By the way, do you know the reasonable span of accuracy per 24 hours? Thanks!

I don't think there is any set standard the manual wind speedies (321, 861, 1861)....I think people usually expect them from -5 to +10 seconds a day. They can certainly be regulated/serviced to run within this range. It also highly depends on the watch's positional behavior (what kind of wrist time it gets and in what position it sits in throughout the day).....I think even more so with the Speedy than other COSC pieces (since they can clearly drift way out of spec in one position vs another to make up a wider spread error average).

[Bushido]

Omega has a listed precision tolerance for their non chronometer watches (of which the 1861 belongs). Daily tolerance is listed at -1 to +11s/day.

[sensui]

Originally Posted by Bushido

Omega has a listed precision tolerance for their non chronometer watches (of which the 1861 belongs). Daily tolerance is listed at -1 to +11s/day.

That's good to know actually.....though I've had many Speedies that run out of this range heh....I am in favor of consistency to determine watch health anyway....if my Speedmaster runs at ~+12 seconds per day for example every day with similar wear patterns...I consider that healthy. Thanks Bushido for the info.

[Aspirin]

Originally Posted by sensui

I don't think there is any set standard the manual wind speedies (321, 861, 1861)....I think people usually expect them from -5 to +10 seconds a day. They can certainly be regulated/serviced to run within this range. It also highly depends on the watch's positional behavior (what kind of wrist time it gets and in what position it sits in throughout the day).....I think even more so with the Speedy than other COSC pieces (since they can clearly drift way out of spec in one position vs another to make up a wider spread error average).

Originally Posted by Bushido

Omega has a listed precision tolerance for their non chronometer watches (of which the 1861 belongs). Daily tolerance is listed at -1 to +11s/day.

Got it, thanks Sensui and Bushido.

[bp1000]

Mine ran at +8 when I very first got it

Now consistently +3