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Of course I am more than happy if a watch runs +1 sec/day on my wrist but I would not call it to run within COSC specs.
Most people would.

I think you're taking things too literally. I don't think it's unusual to talk about the primary timing variation (+6/-4) as "COSC specs". It's a commonly referred to short hand, and should not serve as a stand-in for "meets every letter and test of the entire COSC standard". If you look at the context in which Archer was using it, I think that's pretty clear. All he was saying is that he can get many movements to run with that daily rate variation.

So YES, when a watch runs within the daily rate many, many people refer to that as running within COSC specs. Would it pass the actually COSC testing? Maybe, maybe not, but that's not what is being referred to. I'm not sure why it would
 

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Most people would.

I think you're taking things too literally. I don't think it's unusual to talk about the primary timing variation (+6/-4) as "COSC specs". It's a commonly referred to short hand, and should not serve as a stand-in for "meets every letter and test of the entire COSC standard". If you look at the context in which Archer was using it, I think that's pretty clear. All he was saying is that he can get many movements to run with that daily rate variation.

So YES, when a watch runs within the daily rate many, many people refer to that as running within COSC specs. Would it pass the actually COSC testing? Maybe, maybe not, but that's not what is being referred to. I'm not sure why it would
He says as much himself:

I'm not sure if I can make any clearer - I never said I was testing to COSC specs - please go back and read what I have written again. I said that I have made watches run tighter than the tolerances the manufacturer's use for their COSC rated watches. The manufacturers do not use temperature variations in their post service testing.

I am not trying to convince you of anything. If you have any detailed knowledge of watch timing specs, what I have posted is self evident. You can keep saying I haven't proven a claim that I did not make if you want...

Cheers, Al
I'm actually not sure what's happening here.
 

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I am not a watchmaker. I would put the cart before the horse after dissasembling and assembling a movement.

But the following that you wrote triggered my initial response:

==
I have serviced hundreds of watches that were not COSC and they ran well within COSC specs when I was done, so that is not a particularly unusual achievement (watches of many brands, and many with ETA movements of course as they are very common).
==

All I wanna say: how do you know if a watch runs within COSC specs? I mean the daily rate is just a small subsection of the entire COSC watch testing protocol.

Of course I am more than happy if a watch runs +1 sec/day on my wrist but I would not call it to run within COSC specs.

I was really surprised to hear this from a watchmaker who I guess knows his trade better than me.

I have clarified now three times what I meant by that statement:

I have serviced them and tweaked them to run to much tighter tolerances than brands have for their COSC watches.

what I am saying is that I can get these movements to be in the manufacturer's service tolerances for their COSC watches.

I said that I have made watches run tighter than the tolerances the manufacturer's use for their COSC rated watches.
I'm not sure what it is that you are not understanding mate...but I'm done trying to explain anything to you I think.

Cheers, Al
 

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I have clarified now three times what I meant by that statement:

I'm not sure what it is that you are not understanding mate...but I'm done trying to explain anything to you I think.

Cheers, Al
I think we are going on and off. But your statement would imply your serviced movements would pass a COSC test. Call me dumb but this is how I first interpreted your text. Now I have no idea if it will, and I would probably lose money on it, but I think it will not. I agree you never claimed you said it will pass a COSC test or you are COSC testing.

And I think you are on thin ice with "I have made watches run tighter than the tolerances the manufacturer's use for their COSC rated watches" without showing how the movement would do under different temperatures. It seems to me a glucydur balance wheel is very important in any ETA/Sellita top-grade and COSC movement to offset strong temperature variations.
 

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I know where you are coming from and I get your point. As I said my expectation is completely unrational.
On the other hand it would be interesting to know if it is possible to distinguish the ETA movement made by the ETA from the ETA movement made by the Sellita. Just out of the curiosity. Do they have some different markings, serial numbers or perhaps some different parts that can tell the two movements apart?
 

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On the other hand it would be interesting to know if it is possible to distinguish the ETA movement made by the ETA from the ETA movement made by the Sellita. Just out of the curiosity. Do they have some different markings, serial numbers or perhaps some different parts that can tell the two movements apart?

Interesting question indeed. Would like to know myself.
 

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And I think you are on thin ice with "I have made watches run tighter than the tolerances the manufacturer's use for their COSC rated watches"
what?

i) Al is certified and trained to service movements as per manufacturers requirements.
ii) he performs those services to standards higher than expected by those manufacturers.

I struggle to see how you fail to understand what is being said there.
 

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what?

i) Al is certified and trained to service movements as per manufacturers requirements.
ii) he performs those services to standards higher than expected by those manufacturers.

I struggle to see how you fail to understand what is being said there.
I have never questioned his experience in servicing watch movements or commented on his conducted service work; that is not the point.

All I am saying: if you don't have a COSC certified movement you don't have one. And it is simply wrong to talk about COSC specs for movements which would never pass a COSC test (I posted a link to the official COSC site although I agree it may be highly biased towards COSC its own opinion on the matter).
 

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I think we are going on and off. But your statement would imply your serviced movements would pass a COSC test. Call me dumb but this is how I first interpreted your text. Now I have no idea if it will, and I would probably lose money on it, but I think it will not. I agree you never claimed you said it will pass a COSC test or you are COSC testing.

And I think you are on thin ice with "I have made watches run tighter than the tolerances the manufacturer's use for their COSC rated watches" without showing how the movement would do under different temperatures. It seems to me a glucydur balance wheel is very important in any ETA/Sellita top-grade and COSC movement to offset strong temperature variations.

Wow, you just aren't getting it!!!
 

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Wow, you just aren't getting it!!!
No. He is. Just no one else is.

'COSC' specs is thrown around too lightly around here.

Archer doesn't time based on temp. His movements don't meet 'COSC' standards.

His watches are within the timing range provided by the manufacturers. This range doesn't have the same temperature element as COSC.

Manufacturers tolerances for the watch is not the same as COSC.

Archer's very well regulated watches are not 'COSC' spec.


But hey someone got a fluke standard movement that by chance ran +1 sec over a day wearing it is totally the same thing though...
 

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I think most of us understood what was meant, and the context in which it was said.

THANK YOU!!!!!


THIS!!!!!!!

Of course I did not conduct full COSC testing - not even the brands do this when they service a movement, so to expect that is a bit much. I very much doubt the article where they tested the 2 movements did full on COSC testing either. Please read what I wrote again, as I did not claim that I had tested them to COSC standards. I time watches to the standards set out by the brands, using a timing machine as they would do when they service a watch.
The brands set out tolerances for timekeeping, and those tolerances vary based on the movement being a COSC movement or not - what I am saying is that I can get these movements to be in the manufacturer's service tolerances for their COSC watches.

For example, non-COSC movements are typically checked in just 3 positions, where COSC movements are checked in 5 positions. I actually check all movements I service in 6 positions, because I want the fullest picture I can get of how the watch is running, regardless if it is COSC or not. I also perform extensive testing after the watch is fully assembled (that as you likely know, COSC does not do).

So for the Seliits SW200 I reference having just serviced in the Oris, this is not a COSC grade movement of course. If I look at the standards for an Omega COSC watch for example, which is a brand I service often (all of their COSC watches have the same tolerances) they allow positional variation at full wind to be as much as 12 seconds, measured over 5 positions. I measured this SW200 over 6 positions, and had it down to 5.9 seconds of positional variation, so 1/2 of what Omega would allow on a COSC watch. I then fully assembled this watch, and checked it for 24 hours in each of the 6 positions, and also 24 hours on the final test winder - this is my normal testing procedure. It averaged +3.3 seconds per day over the those 7 days of testing, with the slowest position being +2.5 seconds, and the fastest being +5.5. COSC specs that everyone on watch forums quote for average daily rates are from -4 to +6, and this watch is obviously well within that.

Another example is a just serviced an ETA 7750 (non-COSC again in a Wenger chronograph, so not particularly high end) that was 4.1 seconds over 6 positions, so about 1/3 of what Omega would allow for a chronometer grade watch, and over one more position than COSC checks to. I am starting all the 24 hour long positional checks today. Here is a shot of the timing results for the Wenger 7750 - note the Delta at the red arrow is 4.1 seconds, and average rate is 0:



So yes you are absolutely right that I have not performed the COSC tests to the letter (no service facility does and I didn't claim that I did), but I have certainly exceeded the requirements of the brands for their COSC watches, and believe I can say what I said without any concerns.

Cheers, Al
 

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No. He is. Just no one else is.

'COSC' specs is thrown around too lightly around here.
I believe that most people on here understand the context and what is meant by saying a watch is "running within COSC specs" when talking about timing variation, even with non-COSC movements. If you would like to only use it to refer to actual COSC movements and full certification, then I believe you're in the minority.

This to me sounds like people talking about the proper use of certain words, even when their common use has superseded the "proper" definition. For instance, "begs the question" is used much more frequently just to mean "obviously asks the question" than its original meaning. So you can just take it in the context it was used and understand what was meant, or you can try to get everyone to go back to the original meaning. I'm guessing getting the original meaning re-instated won't ever happen.
 

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I believe that most people on here understand the context and what is meant by saying a watch is "running within COSC specs" when talking about timing variation, even with non-COSC movements. If you would like to only use it to refer to actual COSC movements and full certification, then I believe you're in the minority.

This to me sounds like people talking about the proper use of certain words, even when their common use has superseded the "proper" definition. For instance, "begs the question" is used much more frequently just to mean "obviously asks the question" than its original meaning. So you can just take it in the context it was used and understand what was meant, or you can try to get everyone to go back to the original meaning. I'm guessing getting the original meaning re-instated won't ever happen.
I think most people only know about the -4/+6 spd specification, and not about the positional variance and isochronism standards. Given that the -4/+6 spd requirement is the least stringent of the many aspects of COSC certification, and speaks to regulation as opposed to adjustment of the movement, it is essentially a meaningless standard. Archer does mention the positional delta, which is a measure of positional variance, and a small delta does indicate that a movement is well adjusted, but even that goes beyond what people colloquially refer to as COSC specs.

Having said that, it is correct that the COSC testing does include temperature variance, but on most chronometer grade movements, this is achieved by the use of a Glucydur balance, so a separate adjustment for temperature is unnecessary to achieve the required standard. On a lower grade movement without a Glycydur balance, having the movement properly adjusted at a specific temperature may not necessarily imply that it will achieve the required rates at a different temperature.

In any case, while the COSC testing requirements are well documented, Archer was referring to the internal service standards for brands on their chronometer movements, and I assume that these are less standardized, so it is useful to be more explicit about what is meant by this.
 

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Archer does mention the positional delta, which is a measure of positional variance, and a small delta does indicate that a movement is well adjusted, but even that goes beyond what people colloquially refer to as COSC specs.
Yes it does. And when most people talk about the -4 to +6 as the COSC specs, they are measuring performance on their wrist, which is not how COSC or the brands check these watches. Of course testing has to be done in a far more controlled manner than someone wearing a watch in random positions for a day, and it being a variable states of wind, etc.

On a lower grade movement without a Glycydur balance, having the movement properly adjusted at a specific temperature may not necessarily imply that it will achieve the required rates at a different temperature.
Very true, however given that I service watches people send me from literally all over the world (from colder places the Yukon and Alaska, to hotter like Hawaii, Australia, and even very hot places like Qatar) there are no issues with timing performance, even on watches that do not have glucydur balances. I think the idea that temperature plays a really big part in timing results might be true if you have a watch made before temperature compensating balances were invented, but even a typical nickel gilt balance wheel is not going to give you massive variations from temperature changes. Other factors like positional variation, poise, iscohronism, etc. are much more impactful than temperature.

In any case, while the COSC testing requirements are well documented, Archer was referring to the internal service standards for brands on their chronometer movements, and I assume that these are less standardized, so it is useful to be more explicit about what is meant by this.
I'll expand - for a typical Omega COSC watch, as I have said at full wind the delta has to be 12 second or less measured over 5 positions. At full wind -24 hours, it can be large so as much as 15 seconds. In addition there are minimum balance amplitude requirements that vary by movement, and these are also measured at full wind -24 hours.

Finally there is regulation, so as you mention what most people think about when they think of COSC specs. For Omega it's not the -4 to +6 that COSC requires for average daily rate, but -1 to +6 for Omega COSC watches, so tighter than COSC is. Omega also calls for a target rate of +3 seconds for the average rate. Other brands handle this differently, but keep in mind these are the standards the movement is tweaked to before being sent for the COSC testing.

Hope this helps people understand these tests better at least.

Cheers, Al
 

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Having read this entire thread I have the following comments:

1. Archer is a legend around here and his knowledge and advice is always solid. He has always been very accurate in what he says and it's backed by a ton of training and knowledge and real experience. Trying to pick apart his statements and argue with him about something that he knows about so well, seems silly to me. Unless the point is just to troll the thread.

2. If you have a mechanical watch that keeps time within COSC daily rate on the wrist, does anything else really matter? My speedy pro is not a chronometer but Archer got it running to +3 per day, on the wrist. Do I care if it would pass several other COSC tests? Am I traveling to Antarctica or the Sahara? No. I think sometimes people get hung up on the status of having a chronometer and get upset if someone has a watch that is not a chronometer that runs within COSC timing on the wrist...so it becomes really important to say their chronometer is still "better". BTW my speedy is not a chronometer but it runs +3 per day and could take a trip to the moon and back. So there. ;-)
 
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