So I set my watch yesterday at 9 am (SMP 2500d movement....watch was stopped from not wearing it). I fully wound it. I just noticed that it’s 11 seconds fast in the past 30 hrs or so. Now when I first got it, (about a 2 months ago) I tested its accuracy and it was +3. Now all of a sudden it gained 11 seconds in a day. So is this cause for concern, should I wait longer and see what happens? Could it be from letting it stop for a week? Is this supposed to average out, everything I read says it’s an average but I really don’t know how it averages...

 

Try it over a longer time and also when wearing it.

 

I would not worry about 11 seconds. A cheap casio will be more accurate. There are too many variables with positions and state of wind. If you are concerned, you could take it into your watchmaker to check it.

 

I’m just curious bc is supposed to be COSC certified. So +11 seconds seems wildly out of spec. However it could loose time over the next 2 days I don’t know. I’m kind of new to this

 

11 seconds would concern me. But then I still listen to vinyl records.

have fun
kfw

 

COSC is -4 to +6 so +11 in two days is barely within.

But what matters is the accuracy on the wrist, unless you will never wear your wristwatch?

 

Leave with the crown facing up at night and it will slow it down a couple of seconds a day. My Omega watch technician told me that how you place your watch at night could cause to slow down or gain seconds, face up will slow it down, laying the watch with the case back on the table will just leave it as is. This was Omega, don’t know if it would apply to your watch

 

All watches react differently. The op will have to try different positions and note the results accordingly. A 2500d is not a new movement. Has it ever been serviced? When was it last serviced? Do you have paperwork confirming service? Maybe a service is in order. Perhaps a quartz watch would suit you purpose better? Have fun, check resting positions and power reserve again.

have fun
kfw

 

Positional variation will differ from watch to watch. It is not possible to apply position/rate of one watch, and apply the variations in rate of that watch, to all watches. The quality of a watch, state of wind, and its condition might even make it difficult to determine a predictable rate on a given watch, with repeated tests.

 

Here is a good article written by Ashton Tracy, an excellent watchmaker up in Canada that explains the ratings and how they are measured.

https://www.ablogtowatch.com/accuracy-understanding-what-to-expect-from-modern-mechanical-watches/

 

I did not buy it new, the receipt I have from the guy says it was purchased in Feb 2017 from sterling jewlers. Not serviced yet although it shouldn’t have to be. I do have quartz watches My work watch is a luminox, and I have several autos. Just my first Omega. Never really cared about accuracy when it came to things like my SKX or Oris aquis. But they never claimed that they were COSC.

Maybe I did not pose my question correctly. I tested the accuracy and the power reserve on the watch two weeks ago it was running a little bit over +3 seconds. I tested it over about a week. The power reserve lasted approximately 54 hours.
A few days ago I set it again as it was stopped for several days and in one single day it gained 11 seconds. It was running fine a week ago at +3 now I reset it and it’s +11.. right now it’s about two days and it’s at +15.

My question was what would cause the watch to go from running from +3 and then a week later running to +11 when it wasn’t used. Or am I being ridiculous by testing it every day as opposed to testing it over a months time doing the math and seeing if it actually is in COSC standards.

 

54 hrs power reserve indicates the winding system is working efficiently. If it was +11 after 30 hours, as you stated and w/o resetting, it was then +15 a day later, I would let it go longer and see how it does.

 

You set that watch at a slight slant and not with the dial exaaaactly level and it could run quite differently.

The COSC specs are for a movement in usual testing positions outside of the case.

The number YOU need to care about is how it runs on the wrist. A consistent +3 is pretty good!

 

Wear the watch for a long period of time on a daily basis maybe for a few months, give the watch a chance to settle and be used on a regular basis, monitor the gain/loss at the end of each week but don't reset, at the end of the test period 10-12 weeks you will have good idea of what is going on. It is not unheard of a watch getting a bit out of sync and needing an early adjustment, just as there will be people quoting owning a watch for 20 years never been serviced and is out by 1 second a day.

 

Well the guy did say he only wore it 2x since he bought it. He said he never put it in it into his rotation. It was literally pristine. Didn’t even get a scratch on the bracelet. Then bc of Covid he needed to trim his collection. So In reality it’s been sitting in the box for 3 years. Never even broken in. So I don’t know if things change over time with these or what.
Or if sitting for 3 year not running can damage it. I’ve heard two schools of thought, one it should always be on a winder if it’s not being worn to keep everything moving , and two you should let them rest. That being said I don’t know if resting for three years can mess things up.

 

Give it a chance to run a couple weeks then and see what you see.

 

What skunk said. I've found that watches I haven't worn for awhile take a bit to settle back in. Plus , I've found that climate matters.... Some watches run differently in summer vs winter, certainly been my experience here in Florida...outdoors in heat more now.

COSC is only valid the day the test was done, and under those test conditions. Alot of factors play into how long that lasts in the real world.

 

If this sort of deviation from a time standard really bothers you and you feel like turning owning a watch or watches into a bit of a hobby, you can invest in a timegrapher for under $200 or possible try a smartphone application first.

I like this video as an introduction:

 

What makes you think it doesn't need to be serviced?

have fun
kfw

 

This is probably going to sound a little ignorant to most people here. However, it may NEED to be serviced, But I Don’t think it SHOULD need to be serviced. It’s only halfway through it’s service interval.
Now saying that, I’m not stupid, things happen, I don’t know exactly how the watch was treated by the previous owner. He may have left it in his freezer for 3 yrs. Letting it sit and never worn may have gunked some stuff up in there. I don’t know.

but this is part of my learning experience here. What would make it go from +3 to +11. Could it be from me letting it stop? Is this normal to have a variation like this? Should I bring it in.
now since most people are telling me to stop being so anxious and just give it time and see what happens, that’s probably what I’m going to do.