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Discussion Starter · #1 ·
In almost each comparison of ETA and Sellita movements I can see that Selita SW200 is pretty much clone of ETA 2824-2 and Sellita SW300 is a clone of ETA 2892.
Since they are "clones", can someone please explain me the different number of jewels in these movements:

ETA 2824 - 25 jewels
SW200 - 26 jewels

ETA 2892 - 21 jewels
SW300 - 25 jewels

I don't understand what is the reason behind the extra jewels in Sellita movements... mostly for SW300. A movement with 4 extra jewels doesn't sound like a "clone" to me.
Any insights are appreciated.
 

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Simply muddying the waters and brand differentiation. "We can't possibly be the same; you see we have more jewels!"
 

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Many years ago...They told people the more jewels the better. They would take a mvt. that only needed 17 jewels and put 32 jewels in it.
Then say, "our mvt. is so much better, we use 32 jewels versus Brand X 17." The extra did nothing.
 
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Discussion Starter · #5 ·
Okay, so I understand that the extra jewels are just to look differently on the paper... but it sounds very strange to me that a mass produced SW300 has 4 jewels with absolutely no real functional reason behind them. That sounds little costly just for looking different. Any ideas where are these extra jewels located?
 

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It is important to know where the extra jewels are and what they do, before you say "more jewels are better."

Sometimes more jewels IS better, sometimes there is no difference.

SW200 v 2824

The extra jewel is on the bridge side of the barrel arbor.

ETA:


SW200:

(actually, this is a Hangzhou 6300, but the jewel is in the same place)

The 17th jewel on a 2824 is on the other side of this pivot, the dial side of the barrel. Having only one side of any axle jeweled makes little sense, so, Sellita adding the additional jewel re-injects and little common sense to the design, that said, the 17th and 26th jewels do little to improve the efficiency of the movement, but ETA likes to keep their jewel counts at 17, 21, or 25 and without the semi-useless 17th jewel the 2824 would be a 16 or 24 jewel movement.

It also should be noted that if jeweled in a logical manner, the ETA 2824 would have 28 jewels, the first 26, in a manner of an SW200 and the extra 2 in the other reverser wheel. If you look at the image below, the ETA autowinding module has reverser wheels, one jewelled, one un-jewelled. The two Chinese clones jeweled both reversers. Not that these jewels are all that important.




As to the ETA 2982 v the SW300, I have never taken apart an SW300, so I am not 100% sure where the additional 4 jewels go, but the 21 jewel ETA 2892A2 does not have the jewelled barrel like the 2824, so two could go there, or all four could go into the autowinding system.
 

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Discussion Starter · #7 ·
lysanderxiii: Wow, thank you very much for this detailed explaination! It makes much more sense to me now.
 

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@lysanderxiii: Wow. It's posts like this that makes this a great place to come for extra knowledge. Thanks for the thorough response!
 

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And also I suppose that sometimes less is better (2892 vs 2824), right? :)
Well, less is never "better", but sometimes it is not any worse.

15 jewels (in a center wheel design) is really all that are required for accurate running, 17 is better, and 21 (with none in the autowinder) is much better, ie capped jewels for the important pivots, 25 (with none in the autowinder) would cap jewel everything and have the lowest friction....

However, the 2824 and 2892 are not center wheel designs and 16 jewels adequate for their design, if they really wanted to improve things, the 17th jewel would have been put in the center pipe, so the 4th wheel could ride on two bearings. All of the jewels over the first 17 are in the autowinder.

Putting jewels in the autowinder pumps up the jewel count fast, but doesn't improve the accuracy. Sometimes jeweling the autowinder helps efficiency of the winding, but the gain depends on the design. The 2892 autowinder design, while basically the same idea as the 2824, is arranged quite differently, so adding eight jewels is a bit harder, while keeping all the jewels "functional".
 
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Discussion Starter · #13 ·
Well, less is never "better", but sometimes it is not any worse.

15 jewels (in a center wheel design) is really all that are required for accurate running, 17 is better, and 21 (with none in the autowinder) is much better, ie capped jewels for the important pivots, 25 (with none in the autowinder) would cap jewel everything and have the lowest friction....

However, the 2824 and 2892 are not center wheel designs and 16 jewels adequate for their design, if they really wanted to improve things, the 17th jewel would have been put in the center pipe, so the 4th wheel could ride on two bearings. All of the jewels over the first 17 are in the autowinder.

Putting jewels in the autowinder pumps up the jewel count fast, but doesn't improve the accuracy. Sometimes jeweling the autowinder helps efficiency of the winding, but the gain depends on the design. The 2892 autowinder design, while basically the same idea as the 2824, is arranged quite differently, so adding eight jewels is a bit harder, while keeping all the jewels "functional".
Thank you once again for your excellent answer.

While this may lead to a slightly a different topic that has been discussed many times, I cannot resist raising the following point:
My understanding is that 2892 should be little more "advanced" and elegant movement from to horological perspective compared to 2824 (even despite the lower jewel count).
Many say that from the functional perspective there is almost no difference, but since 2892 has a thinner design, a little longer power reserve with the same (or possibly better?) reliability as 2824, I believe that this case a movement with less jewels (2892) can be relatively "better" than a different movement with more jewels (2824). Or am I missing something?

And in general, I would just like to confirm that when comparing two similar movements with the different jewel count, in some cases the less jeweled can be better in many aspects compared to the more jeweled.
 

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I find it hard to believe that an unjeweled bearing is better than a jeweled one. Even if it would make any sort of difference in a very long run, it's still a better option.
 

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Discussion Starter · #15 ·
I find it hard to believe that an unjeweled bearing is better than a jeweled one. Even if it would make any sort of difference in a very long run, it's still a better option.
I am not saying that unjeweled bearing is better than jeweled one. I just wanted to make sure that some movements with less jewels may be better compared to more-jeweled movements - not because of the number of jewels but because of better design while the number of jewels doesn't have to make that much difference (as long as the important parts are jeweled of course).
 

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Thank you once again for your excellent answer.

While this may lead to a slightly a different topic that has been discussed many times, I cannot resist raising the following point:
My understanding is that 2892 should be little more "advanced" and elegant movement from to horological perspective compared to 2824 (even despite the lower jewel count).
Many say that from the functional perspective there is almost no difference, but since 2892 has a thinner design, a little longer power reserve with the same (or possibly better?) reliability as 2824, I believe that this case a movement with less jewels (2892) can be relatively "better" than a different movement with more jewels (2824). Or am I missing something?

And in general, I would just like to confirm that when comparing two similar movements with the different jewel count, in some cases the less jeweled can be better in many aspects compared to the more jeweled.
The 2892's autowinder does not have as many axle pivots as the 2824, most are post-and-disc type arrangements, so jeweling adds only one jewel per pivot whereas the 2824 can add two per pivot. Also, a jewel post is not as durable as a steel post, and a jewelled disc (a wheel with a jewel in the center) is more expensive than a plain wheel.

The 2892 has fewer jewels because it has fewer places to put these extra jewel cheaply. Actually, the 2982 has four more pivot points than the 2824.

Less is never "better"...

As to comparing similar movements....

Unless the two movements are the exact same design (e.g. comparing the SW200, Hangzhou 6300, TY2130 and ETA 2824-2) you cannot compare by jewel count, there are just to many variables.

Then even when comparing two identical movement designs, a jewel count comparison is pointless, unless you know where the extra jewels are put. Are two jewels put in an accuracy improving useful place, like cap jewels on the escape, or places where it does not really do anything, like in the reverser (given the looseness of the fit, and the purpose of the pivot that is actually being jeweled, and the loads on that pivot, jeweling make no difference).

Stay tuned.....
 

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Did ja ever notice guys like lysanderxiii are the "smartest guys in the room?
Wish I had his watch moxie. My local 3rd generation watchmaker seems to have lost interest in his profession. Has turned his shop over
to his daughter and she doesnt know beans about mechanicals. Good to know there are still guys like lysanderxiii arround.

X traindriver Art
 

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I saw this article, have not seen it posted before.

For many years, Sellita operated as one of ETA’s major out-sourced assembly operations for their 2824 movements.
They would receive 2824 movement kits from ETA and assortments from Nivarox directly (now part of the Swatch Group) and simply add wheels and screws and sell the movements to many famous Swiss watch brands as ETA 2824-2 movements, which in effect they were.
When it was announced that ETA would no longer be providing unfinished movement kits, this threatened Sellita’s survival as a business. Their solution was to buy the parts from suppliers outside the Swatch Group with the exception of Nivarox who, as a result of the long-standing relationship over 50 years, they continued to use. At first, they weren’t sure if they would have IP issues if they copied the movement exactly so they re-engineered the movement, changing some minor details These changes, although minor, added up to reduced reliability in the pre-series movements and so, Sellita decided (having now learned that there were no remaining patents for the 2824) to return almost entirely to the ETA movement design.
We started to use Sellita’s SW200 ( the name for Sellita’s 2824-2) at this point and, having checked the performance of each subsequent delivery of both movements, we are able to confirm the movement performance exactly matches the ETA.
Aesthetically, the movements are identical and difficult to separate and the only significant difference is in the number of jewels. Sellita added a 26th jewel on the upper side of the barrel axis which sits just below the ratchet wheel. This jewel slightly reduces the friction associated with automatic winding. However, as the ETA movement has never had a problem of reliability in this regard, it is my view that this is most likely a marketing device used by Sellita to create some separation from the ETA movement although one could make a case for the small benefit in reliability the adjusted jewel height gives.
Overall, however, the two movements are so identical in every aspect, it is difficult to have a meaningful discussions about the differences.

Johannes Jahnke

The ETA v Sellita Story
 

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I saw this article, have not seen it posted before.

For many years, Sellita operated as one of ETA’s major out-sourced assembly operations for their 2824 movements.
They would receive 2824 movement kits from ETA and assortments from Nivarox directly (now part of the Swatch Group) and simply add wheels and screws and sell the movements to many famous Swiss watch brands as ETA 2824-2 movements, which in effect they were.
When it was announced that ETA would no longer be providing unfinished movement kits, this threatened Sellita’s survival as a business. Their solution was to buy the parts from suppliers outside the Swatch Group with the exception of Nivarox who, as a result of the long-standing relationship over 50 years, they continued to use. At first, they weren’t sure if they would have IP issues if they copied the movement exactly so they re-engineered the movement, changing some minor details These changes, although minor, added up to reduced reliability in the pre-series movements and so, Sellita decided (having now learned that there were no remaining patents for the 2824) to return almost entirely to the ETA movement design.
We started to use Sellita’s SW200 ( the name for Sellita’s 2824-2) at this point and, having checked the performance of each subsequent delivery of both movements, we are able to confirm the movement performance exactly matches the ETA.
Aesthetically, the movements are identical and difficult to separate and the only significant difference is in the number of jewels. Sellita added a 26th jewel on the upper side of the barrel axis which sits just below the ratchet wheel. This jewel slightly reduces the friction associated with automatic winding. However, as the ETA movement has never had a problem of reliability in this regard, it is my view that this is most likely a marketing device used by Sellita to create some separation from the ETA movement although one could make a case for the small benefit in reliability the adjusted jewel height gives.
Overall, however, the two movements are so identical in every aspect, it is difficult to have a meaningful discussions about the differences.

Johannes Jahnke

The ETA v Sellita Story
(Bold) Sellita would have been very sure of were they stood in regards to IP rights long before they started to even think about making 2824 clones. I dare say it would be the first thing I would get straight before I invested a dime in clone movement production.

All of the differences I have noted between the ETA and Sellita movements were production streamlining changes, i.e., thing that allowed Sellita to make the movement cheaper, such as pin and hole bridge alignment versus trepanned studs and hole alignment. The only major "reliability" issue I have heard of with the SW200 was shearing of the ratchet wheel teeth by the crown wheel. Contrary to the above quote from Chr. Ward, the original ratchet wheel used the same tooth profile as the ETA 2824-2*, to improve the reliability they changed to a new and different tooth profile. The current SW200-1 is actually moving further away from being an exact copy of the 2824-2, as now at least three gears use a different tooth profile.....

______________________
* Why did the original ETA-style Sellita ratchet wheel fail when the ETA 2824 ratchet wheel never had a history of this type failure? Good question, but it should remind everyone that "reverse-engineering" still requires "engineering". There could be a number of reasons, different materials, different manufacturing methods, hardening, finishing, etc.
 
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It is important to know where the extra jewels are and what they do, before you say "more jewels are better."

Sometimes more jewels IS better, sometimes there is no difference.

[pics deleted]

The 17th jewel on a 2824 is on the other side of this pivot, the dial side of the barrel. Having only one side of any axle jeweled makes little sense, so, Sellita adding the additional jewel re-injects and little common sense to the design, that said, the 17th and 26th jewels do little to improve the efficiency of the movement, but ETA likes to keep their jewel counts at 17, 21, or 25 and without the semi-useless 17th jewel the 2824 would be a 16 or 24 jewel movement.

...
Unless you can demonstrate your benefits, all you are left to compete with is price.
― Jeffrey Fry

One of the themes in your comments -- certain design/build choice provide marginal if any tangible benefit to the real world operation of the movement -- applies t more than just the jewels. For example, several movement finishing techniques, I've read, supposedly increase the corrosion resistance of the movement. Among those techniques are beveling and poli noir. Purportedly they reduce the likelihood of a movement corroding by reducing the quantity of surfaces to which corrosive substances can adhere. Rhodium plating also reduces the risk of corrosion damage in that the element itself is chemically inert. I don't know it for a fact, but it seems plausible to me that jewel bearings might be less susceptible to corrosion as well.

Perhaps before airtight watch cases were the norm, those sorts of actions actually had an impact that users could realize within their lifetime. Now that even the cheapest watches are WR on the Earth's surface, those techniques provide negligible benefit, if any beyond aesthetics, to the user. At best, corrosion resistance provided by finishing techniques might be useful if one mistakenly leaves the crown extended for long enough periods of time an air/moisture containing corrosive elements enters case. It's plausible that in such cases, the beveling, plating and polishing may buy one some extra time before the corrosive elements can begin to have an impact on the movement.


Many years ago...They told people the more jewels the better. They would take a mvt. that only needed 17 jewels and put 32 jewels in it.
Then say, "our mvt. is so much better, we use 32 jewels versus Brand X 17." The extra did nothing.
Many years ago, more jewels probably was better insofar as it referred to the number of jewel bearings in the watch. Jewel bearings offer the benefits of low friction, long life, and dimensional accuracy, traits that are critical in mechanical watches. However to lysanderxiii's point, then as now, more jewels were pointless if they weren't deployed so as to make a difference.

Moreover, insofar as consumers' sophistic reasoning that equates price to quality is not unique to the 21st century, more jewels forced the cost of the watch to increase. (Synthetic jewels came about in 1900 or so.) As a result, a pocket watch that had more diamonds, rubies, sapphires, etc. inside did cost more as was thus "better." Since it's not unreasonable to transfer certain basic "truths" from a pocket watch to a wrist watch, more jewels in a wrist watch was also "better."

We see exactly the same specious reasoning today when we read that certain elaborately finished watches are "better" and cite those finishing attributes as ones that made the watches having them better.

All the best.

A gift consists not in what is done or given, but in the intention of the giver or doer.
― Seneca, Moral Essays, Volume III: de Beneficiis
 
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