# jewels in quartz watches?



## Kyle L (Dec 2, 2008)

I have a Seiko that my grandfather passed down to me, and yet it says 5 jewels. I thought they were only in wind and automatic watches?


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## South Pender (Jul 2, 2008)

Kyle L said:


> I have a Seiko that my grandfather passed down to me, and yet it says 5 jewels. I thought they were only in wind and automatic watches?


Some quartz watches (actually probably most) have jewels--although usually far fewer than found in manual watches. Although you don't say this, I'm assuming that the watch you inherited is quartz. Not all Seikos, however, are quartz. The company has a long and distinguished history of over a century of making manual (hand-wind and automatic) watches, and today some of the nicest automatic watches available come from Seiko.

BTW, a better home for this thread would be the Seiko, Citizen & Orient forum or the Public Forum.


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## Kyle L (Dec 2, 2008)

Yes, it is a quartz. Whats the purpose of the jewles in the quartz watches?


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## Eeeb (Jul 12, 2007)

Kyle L said:


> Yes, it is a quartz. Whats the purpose of the jewles in the quartz watches?


Jewels in quartz watches do the same thing they do in mechanical watches, they reduce friction. In mechanical watches this is more critical than in quartz watches. Today, a high jewel count in a quartz watch represents an attempt to get marginal efficiencies. In a mechanical watch it is a necessity.

You can build accurate quartz watches with no jewels... and they will stay accurate until the wear is so high the gears don't mesh properly or won't spin - which will happen... eventually. But it will take a long while. A zero jeweled mechanical watch will do the same thing... but it will happen in a couple of years.

Almost all HEQ have some jewels but not usually as many as a mechanical watch.


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## Kyle L (Dec 2, 2008)

Thanks for the info Eeeb, quite helpful


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## dwjquest (Jul 22, 2006)

Kyle L said:


> I have a Seiko that my grandfather passed down to me, and yet it says 5 jewels. I thought they were only in wind and automatic watches?


The IWC Mecaquartz and JLC Mechaquartz movements have 25 or 27 jewels. This is because they are basically mechanical chronographs driven by a quartz timing mechanism.

The early Seiko 7A28, 7A38 and 7A48 quartz chronograph movements had 15 jewels and all metal construction.

As mentioned in this thread by Eeeb, jewels are not necessarily needed for proper and long lived operation of a quartz watch. It is just nice to see a movement with jewels in critical places. The optimum number of jewels depends on the type of movement and number of pivot points that can wear. Modern quartz movements using stepper motors instead of gears might only require 1 jewel.


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## Eeeb (Jul 12, 2007)

Heuer has a quartz chronograph that has 20 jewels.... it has a Dubois Depraz chronograph module wedded to a modified Eta quartz. The mechanical version of this has 31 or 39 jewels.


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## rex (Feb 12, 2006)

*17 jewels is what the A660H has.>>*

Who knows why they use so many jewels.
Maybe why it's so silent...I can hardly hear mine tick.


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## robert11 (Jun 15, 2008)

*Re: 17 jewels is what the A660H has.>>*



rex said:


> Who knows why they use so many jewels.
> Maybe why it's so silent...I can hardly hear mine tick.


Except an Exceed is almost silent too, and has no jewels at all.


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## rex (Feb 12, 2006)

*Re: 17 jewels is what the A660H has.>>*

That's wierd! I wonder what they use to reduce friction within the drive train...Bushings maybe?


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## lysanderxiii (Oct 4, 2006)

Jewels, being very hard, perform two functions, one, reduce friction as noted above, and two, reduce wear.


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## Bruce Reding (May 5, 2005)

*Re: 17 jewels is what the A660H has.>>*



rex said:


> That's wierd! I wonder what they use to reduce friction within the drive train...Bushings maybe?


There is no drive train in this watch. Each hand has its own motor. That's how they accomplish the fly-by-wire approach.


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## South Pender (Jul 2, 2008)

*Re: 17 jewels is what the A660H has.>>*



Bruce Reding said:


> There is no drive train in this watch. Each hand has its own motor. That's how they accomplish the fly-by-wire approach.


Bruce, I've wondered for some time just what the "fly-by-wire" approach entails. Can you explain how it differs from other quartz movements like, for example, the Citizen A660? Does the term describe a _class_ of movements that all share features not found in more common quartz movements?


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## jenswatches (Apr 28, 2008)

*Re: 17 jewels is what the A660H has.>>*

Hello

My watches have an ETA movement with 22 jewels as well. It is a chronograph and although I'm not entirely sure, i assume the jewel count is high because of the additional function of the stop watch feature.

Jens


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## Fatpants (Sep 6, 2007)

*Re: 17 jewels is what the A660H has.>>*



South Pender said:


> Bruce, I've wondered for some time just what the "fly-by-wire" approach entails. Can you explain how it differs from other quartz movements like, for example, the Citizen A660? Does the term describe a _class_ of movements that all share features not found in more common quartz movements?


The A660 uses a gear train to drive the hands, hence the 17 jewels in its construction. The Exceed has stepper motors that drive each hand. I think that a series of magnets is used to set the time, date etc, as there is no physical connection between the crown and the hands.

I think..;-)


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## artec (Oct 31, 2006)

*Re: 17 jewels is what the A660H has.>>*



rex said:


> Who knows why they use so many jewels.
> Maybe why it's so silent...I can hardly hear mine tick.


If jewels reduce friction and wear, and I agree that those are the likely purposes, they probably also reduce power consumption a it, too, so do you think they may play a part in the long battery life?

Although it may be my ears more than my watch, I can't hear my Chronomaster at all. Looking at the excellent photo of your movement, it looks as if there ought to be a way of adjusting it, though I gather Mr Citizen is not letting on what it is. I sent mine back for adjustment quite soon after I got it because it was obviously nowhere near the spec and since then it's been nearly perfect. Absolutely on the money since May this year.

Do you know what you are supposed to PUSH or what happens if you do? I would suspect it's something to do with taking the crown and stem out? I can't see quite enough of the movement to know if that radial component at the top right is in the stem. Just curious!


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## South Pender (Jul 2, 2008)

*Re: 17 jewels is what the A660H has.>>*



artec said:


> If jewels reduce friction and wear, and I agree that those are the likely purposes, they probably also reduce power consumption a it, too, so do you think they may play a part in the long battery life?
> 
> Although it may be my ears more than my watch, I can't hear my Chronomaster at all. Looking at the excellent photo of your movement, it looks as if there ought to be a way of adjusting it, though I gather Mr Citizen is not letting on what it is. I sent mine back for adjustment quite soon after I got it because it was obviously nowhere near the spec and since then it's been nearly perfect. Absolutely on the money since May this year.
> 
> Do you know what you are supposed to PUSH or what happens if you do? I would suspect it's something to do with taking the crown and stem out? I can't see quite enough of the movement to know if that radial component at the top right is in the stem. Just curious!


That's interesting, Artec. I've wondered just what Citizen does when a Chronomaster is sent back because it's out of spec's. Do you think they adjusted the movement in your watch? Perhaps they just replaced it with a movement they knew was right on the money. I gather from previous threads that they can determine in a very short time how close to spec's a movement is performing. For us, we'd probably have to wait for several months, I imagine, before feeling we had a strong enough case for returning the watch for being out of spec's. Otherwise, wouldn't they just say that we hadn't given the watch sufficient time to demonstrate its performance level?


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## Eeeb (Jul 12, 2007)

*Re: 17 jewels is what the A660H has.>>*



artec said:


> ...
> 
> Do you know what you are supposed to PUSH or what happens if you do? I would suspect it's something to do with taking the crown and stem out? I can't see quite enough of the movement to know if that radial component at the top right is in the stem. Just curious!


By convention watches have "push" or an arrow or both to indicate how to engage the release mechanism for the crown and stem.

Push it and the stem will pull out.

Push it and insert the stem and wiggle it and swear a lot and it will go back in... or, at least, that's my experience :-d


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## Bruce Reding (May 5, 2005)

*Re: 17 jewels is what the A660H has.>>*



Fatpants said:


> The A660 uses a gear train to drive the hands, hence the 17 jewels in its construction. The Exceed has stepper motors that drive each hand. I think that a series of magnets is used to set the time, date etc, as there is no physical connection between the crown and the hands.


I don't know about the magnets. In general, the E510 (the Exceed) has a means of sensing the crown position and rotation. That's used to then perform the various crown functions in the absence of a mechanical train.

The lack of a mechanical connection between the hands gives the designers lots of freedom. They can put in "sleep" modes in which the two hands stop after the watch senses its been in the dark after a some period of time, and then the hands can rapidly and independently move to the right position when it senses light. Also, time zone changing is very easy.


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