explain chonometer grade please

[Winstriumphs]

I have been wondering about the chonometer grades of the 2824 and 2892 movements. I understand there are different grades depending on the parts used and the plus or minus tolerances of time accuracy in seconds per day. My question is if one had a sw200 or eta 2824 or 2892 and they were standard grade can a watchmaker upgrade those movements with parts to chonometer? Does anyone offer that service? I am very interested. Thank you

[jdm]

19 minutes ago, Winstriumphs said:

My question is if one had a sw200 or eta 2824 or 2892 and they were standard grade can a watchmaker upgrade those movements with parts to chonometer?

No. It is already difficult or almost impossible to obtain regular ETA parts, let alone special ones.
But with accurate service, lubrication and adjustment the watch cam be made perform equally well.

[CaptCalvin]

Technically no. "Chronometer" refers to the certification. The most you're able to upgrade to with parts swaps would be top grade. In order for it to be "chronometer" you'd have to submit it for certification. That is not to say a movement of any grade can't be made as accurate as a "chronometer"-rated movement, it just has to be tested and serialized by COSC for it to become "chronometer."

[vinn3]

   what is COSC ?   I have an old swiss watch  - stem wound and no buttons,   but the word "chronometer"  on the mvt..  vin

[Nucejoe]

Mechanical movements (tested by COSC ) with 3 to 6 seconds accuracy within 24 hours are regarded as Chrono. German Guilochet and Japan have similar standards.

Here is how bad my french smells COSC stands for Chronomitter Officiale Swiss    I guess Commissioner.

[AndyHull]

COSC

 

https://en.wikipedia.org/wiki/COSC

Edited February 27, 2020 by AndyHull

[nickelsilver]

ETA's higher end versions of their movements do (did?) have some improvements, nicer pallet jewels*, better hairspring shock system etc. I forget the specifics, and it may be in recent years they just settled on one grade (maybe two?) and those that time like beasts are chronometer and the rest not.

* if you look at a lot of ETA pallets they are often opaque, the "good" ones are transparent.

End of the day a run of the mill 2824 or 2892 tends to run pretty darn close within COSC standards. 7750 too.

[jdm]

9 minutes ago, nickelsilver said:

I forget the specifics, and it may be in recent years they just settled on one grade (maybe two?) and those that time like beasts are chronometer and the rest not..

Still four grades for ETA, as well Sellita and Soprod. But the full details of what exactly changes are confidential, as well the price difference. 

[jdm]

Going over a 2824 service document2824-2.pdf like the attached we an impressive number of parts with "var" as number. But most are about finishing / looks, hands height above dial, etc.
I can notice the pallet fork having a fixed number, perhaps that has to do with the stones being standardized to a syntetic material?
And the one I'm repairing now the regulator has no micro adjustment at all, in fact is almost impossible to push counter-clockwise the regulator without removing they auto work. 
 

[CaptCalvin]

From my experiences with 7750 the Top grades do come with certain jewels being bigger and clearer like the escape and forth wheel jewels, as well as obvious differences in the appearance of the balance. In my research into the topic the top and chronometer grades have upgraded materials in jewels, balance hairspring and escape wheel. In theory these can make the movement ever so slightly more temperature and magnet resistant, but I think in practice these differences are pretty inconsequential. Like mentioned before most modern lower grade ETA movements can simply be regulated to or near chronometer standards of accuracy anyway. 

[Winstriumphs]

7 hours ago, Nucejoe said:

Mechanical movements (tested by COSC ) with 3 to 6 seconds accuracy within 24 hours are regarded as Chrono. German Guilochet and Japan have similar standards.

Here is how bad my french smells COSC stands for Chronomitter Officiale Swiss    I guess Commissioner.

Can one send a movement to COSC to be granted Chonometer status? Why or why not? Thank you

[Winstriumphs]

3 hours ago, jdm said:

Going over a 2824 service document2824-2.pdf like the attached we an impressive number of parts with "var" as number. But most are about finishing / looks, hands height above dial, etc.
I can notice the pallet fork having a fixed number, perhaps that has to do with the stones being standardized to a syntetic material?
And the one I'm repairing now the regulator has no micro adjustment at all, in fact is almost impossible to push counter-clockwise the regulator without removing they auto work. 
 

Question. I own a Sellita sw200 movement. I see gold rotors online for 2824 aftermarket. Can one place the 2824 rotor into the Sw200? My watch currently is an Invicta 9937ob with display caseback

 

[Nucejoe]

5 hours ago, Winstriumphs said:

Can one send a movement to COSC to be granted Chonometer status? Why or why not? Thank you

  the cost I imagine is prohibitive enough. I buy me a round trip ticket to the orbit instead.

[Klassiker]

I visited the Wempe observatory in Glashuette last year and if memory serves they will do chronometer testing for private persons. It's the DIN test, not COSC, so the complete watch, not just the movement.

[Winstriumphs]

https://www.govbergwatches.com/blog/chronometry-explained-cosc-certificate/?amp

 

I found that site and it has a great amount of good information on the topic. I am wondering whom among the watch makers, repair peofessional or builders is able to upgrade the 2824 or 2892 or sw200 with all of the finest parts to reach the desired -2 to 2 seconds per day that would qualify as Superlative Chonometer quality. Thank you

Edited February 28, 2020 by Winstriumphs

[jdm]

9 hours ago, Winstriumphs said:

 I own a Sellita sw200 movement. I see gold rotors online for 2824 aftermarket.

Already discussed, and answered:

 

1 hour ago, Winstriumphs said:

I am wondering whom among the watch makers, repair peofessional or builders is able to upgrade the 2824 or 2892 or sw200 with all of the finest parts to reach the desired -2 to 2 seconds per day that would qualify as Superlative Chonometer quality.

This has been also already answered above, including by a Master watchmaker.

[AndyHull]

"...C.O.S.C. specified a daily rate of −4/+6 sec."

The ancient Sekonda I am wearing at the moment is capable of that level of performance, however it isn't C.O.O.S.C, for a number of reasons, principally the fact that it is an ancient piece of USSR era Russian technology, and has been no where near Switzerland (to the best of my knowledge) but also because it hasn't been tested by an approved source, in a lab, over 15 days.

It has however been tested by traveling half way round the world, being bounced about in uncomfortable transport on the roads of India, and subjected to extremes of environment, and managed to keep pretty much within +/- 3 sec per day the whole trip (yes I am daft enough to have checked).

Now this doesn't mean the watch is in any way exceptional. Good, yes, but not exceptional. Most well maintained calibers should be capable of getting near the basic COSC standard, assuming they don't have too much wear and tear. The trouble is that it takes quite a bit of effort to maintain them to this standard. Which brings me to my point. C.O.S.C. testing only proves that when tested, the watch reached a particular COSC standard.

After you have worn it for a while, it will most likely drift, particularly in the longer term, and if you don't get it serviced regularly.

In other words a "fine chronometer" only remains "fine" if well looked after, and its adherence to COSC standard is only true, if you have had it tested recently.

This is one of the selling points of the likes of Rolex. When you send in your Rolex to a Rolex approved service center to get serviced, they will service, maintain and test it (replacing any worn or damaged parts) to ensure it is still performing at the level it should. They obviously charge quite a lot of money for this.

It could be argued of course that since your smart phone is accurate to a fraction of a second a month, then none of this is relevant, but that kind of misses the point of having a fine mechanical time piece in the first place.