after getting my watch back from a complete overhaul, i noticed it was within 1 sec for the first few days while on my wrist. after putting it crown down over night,it was at -3 secs and today at -4 secs after leaving it dial up.
i'm guessing its in the "break in period"? How long after should i check for accuracy?
Watch is Omega PO 2500C

 

After 2,208 hours or 3 months, whichever comes first.

 

What is your concern and what are you trying to determine with those observations? Are you trying to determine positional variation or consistency? As you know, watches almost always keep somewhat different time in different positions, so your observations seem in-line with expectations, and a loss of 4s over three days seems excellent to me. Who told you that watches need a break-in period?

 

Al (Archer watches) has written about this "break in" period before:

From 2018:
"I see a lot of people write about this "break in" period on watch forums, but when measured under controlled conditions I've never had a new watch show any significant change in the first few weeks or months. Ask yourself what use chronometer testing would be if the watch was going to drift significantly in the first months of use...this idea makes little sense to me."

 

I was within 1 sec after 3 days and all of a sudden jumped to 4 secs that's why I ask.

 

As for "break in period", Archer's post made it clear, thank you.

 

So you put the watch into a different position and it ran at a slightly different rate, exactly as expected.

 

Ok. Thanks

 

I get quite a range of variation with watch positioning, try :
dial out, dial down, crown up, crown down, crown left, crown right.
perfect normal for a mechanical watch

 

There will be variation depending on watch position, how much the mainspring is wound etc... I go by performance over a week. Wear it around, live your life and check how it is doing at the end of the week...

 

It doesn’t take much positional change to get a different value for rate. No surface is perfectly flat nor level, so you might not be as consistent as you thought.

 

I guess I was expecting more accurate deviations coming from a coaxial.
All good.

 

These watches are anti magnetic as we all know. The master chronometers are rated to resist up to 15000 Gauss. Is it known as to how much can the non master chronometers can resist?

 

Probably a tenth of that? I checked the 1120 technical guide, didn't see a spec.

Note that even a 15000 gauss (1.5T) watch can be magnetized; it's just that it will still run.