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I believe that the current COSC standards for quartz watches are relatively recent. Prior to this, it's my belief that quartz specific standards or guidelines still existed, and were more stringent than those for mechanicals. True? Also, does anyone know what these older standards are or have a link to them?
 

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I believe that the current COSC standards for quartz watches are relatively recent. Prior to this, it's my belief that quartz specific standards or guidelines still existed, and were more stringent than those for mechanicals. True? Also, does anyone know what these older standards are or have a link to them?
You are right, Bruce! The current COSC standards for quartz watches were introduced in the year 2001. Prior to this the COSC standards for quartz were still more stringent than those for mechanicals but were far from the strict current standards for quartz. Accuracy had to be within the +/-0.2 second per day mark. Now compare that to the current +/-0.07 second per day! It's +/-73 seconds per year vs +/-25 seconds per year... That must have been the main reason why Rolex finished with the OysterQuartz. Rolex could not market it as COSC certified anymore.
In our lost old forum we had a "sticky" where we compared the old and new COSC standards for quartz. I don't know any link right now but my numbers (regarding to the accuracy standards) are correct.
 

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Discussion Starter #3 (Edited)
In our lost old forum we had a "sticky" where we compared the old and new COSC standards for quartz. I don't know any link right now but my numbers (regarding to the accuracy standards) are correct.
Thanks, George! I remembered that, but for the life of me could not remember where I'd seen it. Right here, as it turns out. :)

We lost a lot when we lost the old forum. :-( I've added this info to the sticky post covering COSC.
 

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Had the same question today on pre-2001 COSC Quartz standards vs post-2001 so that post answers it nicely and deserves to be BPTT ;-)

Why was I wondering about that? Well because I saw a nice 1422 based Omega Constellation Chronometer in a shop today. Apparently the 1422 (like the Omega 1420 ?) is the ETA ETA 955.411 (Flatline II range) and while I didn't find any accuracy numbers for it, the fact that it met the pre-2001 COSC criteria means it did better than the current +/- 15spm standard (at least 6spm using 73spy).

Question is how were they achieving this with an "ordinary" quartz? Actually even the old 1301 (beta-21) movement was rated at 5spm so why the theoretical loss in accuracy for current quartz and the lack of intermediate movements between the HEQs rated between 5/20spy and the rest of the quartz rated at 180spy ? Is it just the watchmakers being conservative ?

I wonder if there aren't any "in-between" movements. Heck, my TAG Heuer F1 Calibre S has been achieving 25spy over the past 4 months at room temp (just started it on warm temp testing) and it's not rated specifically by TAG.
 

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I'm far from an expert, but I believe Omega was giving 5spm specification based on some conditions. Like wearing the watch 12 hours a day and not exposing it to extreme temperatures. And COSC compliance was tested under limited temperatures. But those old movements are as precise as the current standard 15spm ones.
 

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I'm far from an expert, but I believe Omega was giving 5spm specification based on some conditions. Like wearing the watch 12 hours a day and not exposing it to extreme temperatures. And COSC compliance was tested under limited temperatures. But those old movements are as precise as the current standard 15spm ones.
No one has ever posted Omega documentation giving 5 spy. 5 spm is relatively easy to attain.

The 'new' COSC quartz standard is quite a bit tighter and does require temperature compensation to pass.... hummm... maybe I should dig out the two kinds of certs and post both. I keep the certs with the boxes... and I have several boxes of boxes... hummm... nah, it's a nice day and I'm going outside to enjoy it! :-d
 

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That would be great!

5spm may be easy to attain but I'm not aware of many watch manufacturers currently giving a rating different than 15spm, other than the rare COSC Quartz watches on the market?

The question is why were Omega able to rate the 8Khz 1300 (beta21) at 5spm in 1970 and current makers can't do better than 15spm with a 32Khz quartz. You mention certain conditions, probably, like Citizen or Seiko for their HEQs, let's check in the manuals that survived, not sure that's the only explanation though.
 

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...The question is why were Omega able to rate the 8Khz 1300 (beta21) at 5spm in 1970 and current makers can't do better than 15spm with a 32Khz quartz. You mention certain conditions, probably, like Citizen or Seiko for their HEQs, let's check in the manuals that survived, not sure that's the only explanation though.
Many makers do better than 15 spm... they just don't bother to claim it. Indeed, the only actual 15 spm quartz I have seen lately are "Japan Mvmt" watches with a Miyota ten cent movement.
 

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Actually I see that 15spm spec pretty often, Seiko Kinetic recently, a higher end quartz, it's a spec different from 15spm I'd like to see!
 

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Actually I see that 15spm spec pretty often, Seiko Kinetic recently, a higher end quartz, it's a spec different from 15spm I'd like to see!
I think Eeeb meant to say 'watches that do in real life as bad as the spec' - I only have two Casio 5600 radio models which do that bad when radio is not available (and the spec is 20s/m on those) ... but I believe that soon the video method and a very ordinary fridge might tell us more why the spec has to be much wider than the actual performance between room and wrist temperatures ...
 

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Just came across this on the Omega site :
What are the precision tolerances for OMEGA quartz watches ?
All OMEGA quartz movements are produced in accordance with OMEGA’s highly renowned procedures and quality standards. Ambient temperature may affect the precision of quartz movements, which can lead to variations of between -0.5 and +0.7 seconds per day.
Quite conservative at -15/+21spm
 
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