COSC Chronometer accuracy.. do you care? I do.

[Burlington]

Reasonable accuracy is important as it needs to get me places on time most days.

[chronoman]

You bet. I track prescision, repeatability, and accuracy. It let's me know if there are problems with my watch. I had an Omega moon watch get magnetized. From then on, i paid closer attn.

[pickettt]

I appreciate it when I get what I pay for.

[Sub Capt.]

Originally Posted by padi56

Today for any purely mechanical watch to run within a few seconds a day truly is a mechanical marvel myself would not sweat about a few seconds either way in a day.So guys next time your watch is perhaps a few seconds fast or slow just outside COSC spec, just think about John Harrison's watches made almost 320 years ago.No computer aided graphic designs no machine robots to cut the precision parts. Only his bare hands and by today's standards very primitive tools.And a watch that was tested in one of the hardest environments around today on the open sea.John Harrison's son William set sail for the West Indies, with the Harrison newly made H4 marine chronometer, aboard the ship Deptford on 18 November 1761. They arrived in Jamaica on 19 January 1762, where his watch was found to be only 5 seconds slow! in almost 2 months this accuracy three times better, than that required to win the £20,000 Longitude prize,in them bygone days £20000 must have been quite a massive sum of money.

Great story! Quite the accomplishment.

[Centron]

It absolutely matters to me. I enjoy the accuracy of my SD43 as well.

[kieselguhr]

It’s nice. I check the accuracy when I buy a new watch. Then maybe one a year if I remember. Just compare it to time.gov after a week of wearing. Nothing fancy

[Meyrin]

Originally Posted by jrs146

As long as I can tell the time without being late or early I’m fine. I could care less if it’s within seconds.

I couldn't have put it better, that's exactly how I see it

[123Blueface]

Couldn’t care less.

[Blansky]

Nope.

And besides I rotate watches every 4-5 days anyway.

I realize when you buy expensive watches they should be fairly accurate but for me not an issues really.

[JoseR]

Originally Posted by Rebel

I just like mine to be within specs.

+1. I love when the time on my phone and watch are right on to the second... amazing that a mechanical watch could be so accurate. It's important to me because I paid for quality and accuracy..

[214270Explorer]

The Rolex "Superlative" spec is more than good enough for me for almost all of my applications.

What really needs to be "accurate" is my Sky-Dweller. As it is designed to be set 'only once per year,' it would be nice for this watch to have great accuracy.

At 2 seconds deviation per day, a watch would drift by about 12 minutes per year.

Some recent tests of my Sky-Dweller show that in the worst case scenario (various night positions tested), it could be off in one year by as much as (theoretically) 5-1/2 minutes. Even closer depending on alternating two storage positions. Its average deviation so far is way under 2 sec/day.

The next calculation will be done in March (don't have a TimGrapher; I'd rather do it the old fashioned way.)

For me, 5-1/2 minutes per year worst case would be great for the Sky-Dweller and that means it would truly and only need to be reset every March 1st when the date needs to be manually adjusted as the watch cannot deal with the 28/29 February days.

So yes - accuracy is something I desire -- but as you see, the amount of accuracy for me is more dependent upon a long term application.

In the past when I rotated watches on a monthly schedule, the deviation was absolutely meaningless for me.

[crewsin]

Since I only own/wear one watch, yes it matters. That being said, I’m a “set it and forget it” kind of person and don’t obsessively check to see how much it deviates from day to day...but, if I don’t compare it to my iPhone clock for a month or two I also don’t want it to be off by 10 minutes.
When I first got it, I timed it because it’s a good thing to know and my Explorer gains about 1/2 second per day (depending on how active I am and placing it crown up when I sleep). I think that’s an amazing feat to pull off for a mechanical device - but if I’m paying 5k and up for a machine that tells time and is advertised as being “superlative” (I mean it’s printed on the freaking dial) it damn well better be incredibly accurate...and it is.

[djgallo]

COSC doesn’t matter to me...I expect to lose or gain a few minutes over time. If I want better ....I just use my cell phone

[Sharkhandler]

My 2018 SD43 was also running slow at about 10s loss per day. I took it back to RSC got a repair under warranty, it took 4 weeks to come back and it’s now utterly bang on with about 0.5s deviation per day.

To me, buying a Rolex is as much about function as it is form. Not only is it exquisitely built, but it’s also a world class example of precision engineering, and I expect it to behave so.

If I spent £150k on a Bentley, I wouldn’t expect a misfire or a drop in power from the W12 engine. If I wanted that I would have spent £10k on a flat four Dacia.

Spending £10k on a Rolex, I expect precision from a watch, that most WIS refer to as a ‘timepiece’. If I wanted approximate accuracy I would have bought a pulsar.

Just my 2p’s worth, and I couldn’t be happier






Sent from my iPhone using Tapatalk

[Swilder916]

Well said

Originally Posted by Sharkhandler

My 2018 SD43 was also running slow at about 10s loss per day. I took it back to RSC got a repair under warranty, it took 4 weeks to come back and it’s now utterly bang on with about 0.5s deviation per day.

To me, buying a Rolex is as much about function as it is form. Not only is it exquisitely built, but it’s also a world class example of precision engineering, and I expect it to behave so.

If I spent £150k on a Bentley, I wouldn’t expect a misfire or a drop in power from the W12 engine. If I wanted that I would have spent £10k on a flat four Dacia.

Spending £10k on a Rolex, I expect precision from a watch, that most WIS refer to as a ‘timepiece’. If I wanted approximate accuracy I would have bought a pulsar.

Just my 2p’s worth, and I couldn’t be happier






Sent from my iPhone using Tapatalk

[watchaser]

Accuracy not as important. Owning a piece if more fun than telling time on it.

[The Libertine]

Originally Posted by Danny83

Does not matter to me. I dont understand the big deal about cosc

Agree. A handful of seconds won’t make a difference to me one way or the other.

[DJTOSUB]

Originally Posted by Swilder916

On the flip... my 5007 IWC Portuguese and my Tudor Black Bay 41 always leave me just slightly..... sad that they are always about 20-30
Seconds fast....

I would not be satisfied with any watch being off 20-30 seconds per day. I would have them regulated assp.

[No SUBctitute]

"Today for any purely mechanical watch to run within a few seconds a day truly is a mechanical marvel"

"think about John Harrison's watches made almost 320 years ago.No computer aided graphic designs no machine robots to cut the precision parts. Only his bare hands and by today's standards very primitive tools. And a watch that was tested in one of the hardest environments around today on the open sea.John Harrison's son William set sail for the West Indies, with the Harrison newly made H4 marine chronometer, aboard the ship Deptford on 18 November 1761. They arrived in Jamaica on 19 January 1762, where his watch was found to be only 5 seconds slow! in almost 2 months this accuracy three times better, than that required to win the £20,000 Longitude prize,in them bygone days £20000 must have been quite a massive sum of money."

-----------

The second quote is very interesting. Thanks for sharing.

I agree with your first quote. I am impressed that my Sub can run for seven years at +1.6 s/day. I am less impressed with watches that merely make COSC standards, as its been shown that many watches at a far lower price range than a $10,000 Rolex can operate within COSC. If I spend $10,000 on a Rolex and its operating at +6 s/day, I wouldn't be very impressed.

My understanding is that any modern Rolex should be able to be regulated to within about +/- 2 seconds per day, regardless of the wearer's movement, surrounding humidity, temperature, gravity exposure, etc. But I'm not a watch tech so that's just my guess.

[No SUBctitute]

This.

Originally Posted by Sharkhandler

To me, buying a Rolex is as much about function as it is form. Not only is it exquisitely built, but it’s also a world class example of precision engineering, and I expect it to behave so.

Spending £10k on a Rolex, I expect precision from a watch, that most WIS refer to as a ‘timepiece’. If I wanted approximate accuracy I would have bought a pulsar.