Accuracy of an automatic?

Accuracy of an automatic?

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Discussion

tertius

6,838 posts

229 months

Saturday 12th January 2008
quotequote all
Freddie von Rost said:
Wadeski said:
A chronograph means it has little sub-dials on the face, and is not a certificate accuracy like a chronometersmile

Edited by Wadeski on Friday 11th January 09:23
Not quite. I think you will find that the term Chronometer is applied by COSC [Contrôle Officiel Suisse des Chronomètres], the Official Swiss Chronometer Testing Institute, who certify the accuracy and precision of wristwatches. Only watches certified by the COSC may use the word Chronometer.
I think that's what wadeski was saying, the term "chronometer" refers to the accuracy of a watch of any type; the term "chronograph" refers to the functionality of the watch (ie it is also a stopwatch) and does not refer to accuracy at all.

So when you said:

Freddie von Rost said:
it is only rated as a chronograph rather than a chronometer.
Doesn't really make sense: watches aren't rated as chronographs - they either have chronograph functionality or they don't.

Of course a chronograph may also be a chronometer if it meets the COSC specs.

Freddie von Rost

1,978 posts

211 months

Saturday 12th January 2008
quotequote all
I bow to your words of wisdom and my late night alco confusion:

Freddie von Rost said:
it is only a plain, cooking, humble Omega chronograph, rather than a chronometer.
EFA.

[Still think 60 seconds a month is pretty good]


smile

Stevorocket

408 posts

218 months

Saturday 12th January 2008
quotequote all
I have a Divers Seiko automatic - gains a couple of minutes a week - I also have a Fortis Flieger automatic which is totally accurate over a week.

Seiko 250 quid

Fortis retail now 1200 quid.

Nuff said.

cerbfan

1,159 posts

226 months

Sunday 13th January 2008
quotequote all
I was told that IWC watches are not COSC rated as they believe they build there watches to a higner accuracy standard than that and therefore do not bother with the certification. Is this true?

tertius

6,838 posts

229 months

Sunday 13th January 2008
quotequote all
cerbfan said:
I was told that IWC watches are not COSC rated as they believe they build there watches to a higner accuracy standard than that and therefore do not bother with the certification. Is this true?
It may well be - quite a few higher end makers do not bother with COSC certification, e.g. JLC who feel their "1000 hours" testing is more rigorous than the COSC tests.

Also COSC certification applies to movements not watches. That is to say the movement is tested and [bi]only then[/i] put in a watch case. JLC's testing and certification is of the complete watch.

andy97

4,691 posts

221 months

Monday 20th February 2017
quotequote all
Apologies for bringing this thread back to life but I have an issue with the accuracy of my recently acquired Christopher Ward C60 Trident 600. Yes, I know some consider CW to be the DFS of the watch world but at the price point it suited me as my first automatic watch.

I have had it about 3 weeks now and I reckon it's gaining 2 mins (ish) in 3 days. That to me is unacceptable. Any thoughts from those more experienced / knowledgeable than me. I'm used to the accuracy of my Quartz Breitling or another CW, and this is a bit of a shock, even though I do like the style of the watch.

Is it within acceptable limits or should I send it back to be adjusted?

Thanks.

randlemarcus

13,507 posts

230 months

Monday 20th February 2017
quotequote all
If you've read the rest of the thread, you'll know that some inaccuracies are OK in a non-COSC automatic. And the price difference between a CW COSC and the non-COSC is quite high.

Best bet is to give them a ring, see what they say, and if you aren't happy, use the 60 day return policy.

AlexC1981

4,904 posts

216 months

Monday 20th February 2017
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That's 40 seconds a day. I would have thought half that was bad!

CardShark

4,190 posts

178 months

Monday 20th February 2017
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I don't know if CW state accuracy expectations/limits for their non-COSC watches however approx 40sec per day is poor, and I'd be surprised if CW don't agree.

Give them a polite nudge and see what they come back with, as has been said you have their 60 day returns policy to fall back on if it turns sour.

andy97

4,691 posts

221 months

Monday 20th February 2017
quotequote all
I have read the rest of the thread. Thanks, all. I will see what CW say. I certainly think that 40 secs a day is unacceptable but I had nothing to compare it with. I was keen to have an automatic but I Can't remember the last time I adjusted the time due to inaccuracy in my Breitling, other CW, Seiko, or even my Casio. All Quartz.

We shall see.

andy tims

5,571 posts

245 months

Monday 20th February 2017
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AlexC1981 said:
That's 40 seconds a day. I would have thought half that was bad!
Not great for a new watch, but just for perspective that's 99.95% accurate.

hilly10

7,076 posts

227 months

Monday 20th February 2017
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My Oris GMT is a fantastic time keeper knocking my more expensive pieces out the water.

andy tims

5,571 posts

245 months

Monday 20th February 2017
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hilly10 said:
My Oris GMT is a fantastic time keeper knocking my more expensive pieces out the water.
I've had several Damasko's and most of them were +/- 2 seconds a day.

thebraketester

14,192 posts

137 months

Monday 20th February 2017
quotequote all
andy97 said:
I have read the rest of the thread. Thanks, all. I will see what CW say. I certainly think that 40 secs a day is unacceptable but I had nothing to compare it with. I was keen to have an automatic but I Can't remember the last time I adjusted the time due to inaccuracy in my Breitling, other CW, Seiko, or even my Casio. All Quartz.

We shall see.
I thought COSC(?) was +-6 seconds per day


Edited by thebraketester on Monday 20th February 21:29

FarmyardPants

4,099 posts

217 months

Monday 20th February 2017
quotequote all
If it's a cheapy auto and runs consistently fast, it is worth unscrewing the back and having a go at adjusting it yourself. You should see the adjuster with + and - situated over the oscillating hairspring. The trick is to make the tiniest adjustment you can, using a small screwdriver or similar. Be very careful not to touch the balance wheel.

Then screw the the back on finger tight and wear the watch to see how it performs over the course of a few days. Also, leave the watch unworn for a while to see whether it gains or loses time. Repeat the adjustment as necessary.

It took me about 20 sessions of messing with my Seiko - sad, I know - but it is now spot on (gains or loses a second or two a day depending on whether it's worn or not). Good luck!

Edited by FarmyardPants on Monday 20th February 21:31

UnclePat

508 posts

86 months

Monday 20th February 2017
quotequote all
andy97 said:
Apologies for bringing this thread back to life but I have an issue with the accuracy of my recently acquired Christopher Ward C60 Trident 600. Yes, I know some consider CW to be the DFS of the watch world but at the price point it suited me as my first automatic watch.

I have had it about 3 weeks now and I reckon it's gaining 2 mins (ish) in 3 days. That to me is unacceptable.

Is it within acceptable limits or should I send it back to be adjusted?
Nothing wrong with the Trident - solid, good-looking & pretty much exactly the same build materials, quality & movement as a Tag Heuer Aquaracer, but at a third of the price.

Uses an ETA 2824-2 or Sellita SW200 movement (both virtually identical) which are excellent, robust, proven & capable of great accuracy when regulated correctly. The mid-tier Elabore version which CW uses is meant to perform at an average of +/- 20 secs daily 'off the shelf', but at that price level, CW don't hand regulate them, they just drop the movement in the case (fair enough, to regulate each & every one would add cost). There's a lot that can happen during casing of the movement & shipment to the buyer.

+40 secs a day is too poor, though. CW will regulate it at no charge to a better standard under their excellent 60:60 warranty, but you will be without it for a month or so. If you've still got the stickers, tags etc. attached (doubtful) and it's in unworn condition, you can return for a no-quibble refund within 60 days. E-mail them and see what their current backlog is.

Any competent watch-maker can do the same for you, over a day or two, but anyone other than CW opening the case back will void the warranty. If you don't know what you're doing, I wouldn't try it yourself - without correct tools you'll butcher the case-back removal. The regulating lever only needs moved the most minute amount - if you can see visible movement, that's too much. If you slip & touch the hairspring, you're f@cked. Also, CW doing it will ensure your water-resistance is warrantied - last thing you want is to shear or crimp the gasket.

There are some (limited) things you can try to better the daily rate a little - keeping a full wind (turn the crown an initial 30-40 times to full wind and make sure you're wearing it enough thereafter to keep a full reserve), and then check after a few days, as a watch with poor isochronism will be all over the place. Or try experimenting with overnight positioning (crown-up, dial-down etc.) to manipulate timing.

To be honest though, none of that will buy you more than a few secs daily though, so I'd send it back. A total pain, but they'll look after you.

CardShark

4,190 posts

178 months

Monday 20th February 2017
quotequote all
thebraketester said:
I thought COSC(?) was +-6 seconds per day


Edited by thebraketester on Monday 20th February 21:29
The watch that andy97 is referring to isn't sold as a chronometer therefore it can't be expected to run within COSC tolerances, though some non-chronometer watches do run very well. From memory in order to gain COSC certification a movement, prior to being cased, must run between -4 to +6 per day over a 15 day period in a number of position and temperature combinations smile

thebraketester

14,192 posts

137 months

Monday 20th February 2017
quotequote all
Ahh. Sorry I didn't realise that.

Wills2

22,669 posts

174 months

Monday 20th February 2017
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There is also a master chronometer rating of 0 - +5 secs a day in all tested conditions including up to 15000 gauss magnetic resistance.


Edited by Wills2 on Tuesday 21st February 00:01

HaiKarate

279 posts

133 months

Tuesday 21st February 2017
quotequote all
Indeed. COSC is -4 to + 6 over 24 hours.

Rolex now, although still COSC certified, guarantees -2 to +2 out of the box. Plus 5 year warranty.