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calibre 8R28 musings and questions for the experts

March 21 2009 at 3:53 AM
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  (Login sashko_1)
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Hi All,

Having seen and become convinced to buy a new Brightz chrono;

[linked image]

when they come out, I'd like to share some theories about this little known new calibre and ask the experts like Randall and John Davis what they think.

[linked image]

Firstly it's obvious the new movement is based on the 6R series, Kohei-san on TZ confirmed this, the 6R is in turn based on the 7S series with additional features and made only in Japan, the 7S as far as i know and can see seems to be a 'detuned' economised version of the old 7000 series including the venerable 7016 chronograph movement.

Taking this into account could it be that this new calibre designed and made by Seiko Instruments is actually an evolution of the 7016?

My initial thought when seeing pictures of the 8R28 was that it could be a 6R with a piggy-back module, such as the ETA 2894 or more elaborate GP or AP calibres with piggy back column wheel designs. However having seen detailed pictures of the 7016 it seems this new calibre could well be a design derived from the 7016 which has the chronograph mechanism hidden beneath the winding bridge?

Of course there are differences between the 8R28 and 7016, the new calibre has a traditional tri-compax sub-dial layout and AFAIK features not only a vertical clutch but also a tilting pinion such as the 6S series. It also runs at 28,800 bph as opposed to 21,600 in the 7016 and also 6R it's derived from, it also hand winds, and I'm assuming hacks.

All in all though this is a very interesting new calibre, even if it is derived from the 7016 as I suspect- what's most heartening though is that this puts Seiko in a very elite position, they now have two different automatic chronograph movements, both featuring column wheel actuation with vertical clutch engagement and tilting pinions- in fact I can't think of another company that has one, let alone two chronograph movements with such sophisticated chronograph designs- perhaps only Rolex produces such a technically advanced design in the 4130- i own one but I must say for $2000 there is no doubt these new chronographs have little competition, as most in their price range and above feature the much less advanced and cam-actuated eta 7750 or 2894 with DD piggy-back module.

Would love to hear what you all think about this.



This message has been edited by sashko_1 from IP address on Mar 21, 2009 5:58 AM
This message has been edited by sashko_1 from IP address on Mar 21, 2009 4:10 AM
This message has been edited by sashko_1 from IP address on Mar 21, 2009 4:07 AM

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(Login neil101)
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I'm very much a newbie and no expert, but...

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March 21 2009, 4:31 AM 

I am interested in the sometimes prolonged history of the seiko caliber streams, and one thing I have noticed is that while some base calibers are only ever used in high end watches and others only in low end, there are others which seem to be able to work both as cheap, mass produced movements and (in other incarnations), as obviously very high end, very finely adjusted movements. The classic example has to be the 61xx series; used extensively in all sorts of mass produced Seiko 5s etc in the late 60s, but also in the Grand Seiko as the 614x & 615x, and even in the legendary Grand Seiko "V.F.A." as the 618x. It seems that the 70xx series has this same flexibility of potential, although it has taken a lot longer to realise it; but I guess that the base caliber itself is not /necessarily/ any indication of the quality of the movement, and that the 6R and 8R must be in a completely different league from the old mass produced 70xx movements, despite sharing the same underlying design.

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(Login rileynp)
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I'm interested to hear more about this caliber too...

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March 21 2009, 8:47 AM 

I'm not sure the descriptions so far are accurate. I can't see how a chronograph can have both a "vertical clutch engagement" (ala Seiko 613x) as well as a" tilting pinion" (ala 7750). Both terms describe methods of engaging/disengaging the chronograph mechanism from the rest of the movement. You can't have both in the same movement. There must be some translations that are less than accurate floating around right now.
I hadn't thought about the 7016 connection before, that is interesting to ponder. However, if you look at where the continuously running seconds hand is located on the movement (towards the winding/setting mechanism area located towards 3 0'clock), it seems difficult to imagine sticking an additional 4th wheel all the way through a 7S26/6R15 movement- there are too many other parts in the way. The 7016 has no such continuously running seconds hand. It seems more likely that this is indeed a modular chronograph, which is interesting in its own right as I do not know of a previous modular chronograph from Seiko. Let us know if you find any better pictures of the movement or descriptions in English. --Noah

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