Vintage Gruen: The caliber database

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The Cal 870/871 [message #8775]

Sun, 11 February 2018 18:32

JackW
Messages: 1869
Registered: May 2013
Location: Denver

Gruen Authority
Head Janitor
Site Admin

The caliber 871 and the 870 are the numbers for the open face/lupine (stem at 12-o'clock) or hunter/savonnette (stem at 3-o'clock) configurations.

Which one is which I'm not sure. They also came in a non-subseconds version too. There is also a variation in the setting works. Gruen and Rolex are not the only ones to use the movement either. Rumor has it that there is an outfit that will buy non-Rolex versions of this watch, mark the wheels with "Rolex" and then case and sell them as such.

index.php?t=getfile&id=3639&private=0

Borel has the mainsprings listed with 1.60 x .14 x 340 11 and CousinsUK has them in 1.60 x .15 x 320 12. Both are white alloy.
Gruen (1947 Horological Manual) has them as 1.65 x .15 x 320.

Attachment: Rebberg_870_bridges.jpg
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Attachment: Rebberg_870_marking.jpg
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Attachment: Rebberg_870_top.jpg
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All I know is based on hard work & writing by others. I can only aspire to augment this body of knowledge. If I am wrong it is because of my own failings. -me

"If I have seen farther it is by standing on the shoulders of giants." - Newton

[Updated on: Sun, 11 February 2018 19:38]

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Re: The Cal 870/871 [message #11484 is a reply to message #8775]

Tue, 22 October 2019 01:56

Case
Messages: 1178
Registered: May 2019
Location: Cincinnati

Gruen Authority

To the question of which was hunter vs. open face, here's another hunter example with WSC marks from a 1918 trench watch I'm restoring. Dial back and inside caseback both stamped "871", so the 870 will be the open face.

/vgforum/index.php?t=getfile&id=5396&private=0

/vgforum/index.php?t=getfile&id=5396&private=0

/vgforum/index.php?t=getfile&id=5395&private=0

/vgforum/index.php?t=getfile&id=5394&private=0

/vgforum/index.php?t=getfile&id=5393&private=0

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My two caveats:
1) I'm wrong many times a day --just ask my wife!
2) Always seeking to learn more

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Re: The Cal 870/871 [message #11630 is a reply to message #11484]

Wed, 13 November 2019 19:58

mikey
Messages: 709
Registered: May 2013
Location: Paris, Ontario

Gruen Master

I have a DG&S 870 also in my collection that i believe was previously identified as a 'Rebberg' movement?. I'll have to disassemble it to take a photo of the top plate;

/vgforum/index.php?t=getfile&id=5492&private=0

/vgforum/index.php?t=getfile&id=5492&private=0

/vgforum/index.php?t=getfile&id=5493&private=0

/vgforum/index.php?t=getfile&id=5494&private=0

/vgforum/index.php?t=getfile&id=5495&private=0

Attachment: DG&S 870 Rebberg pocketwatch dial.JPG
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Attachment: DG&S 870 Rebberg pocketwatch inside caseback.JPG
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Attachment: DG&S 870 Rebberg pocketwatch movement 1.JPG
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Attachment: DG&S 870 Rebberg pocketwatch movement.JPG
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Still here....

[Updated on: Wed, 13 November 2019 19:59]

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Re: The Cal 870/871 [message #11631 is a reply to message #11630]

Wed, 13 November 2019 20:37

Case
Messages: 1178
Registered: May 2019
Location: Cincinnati

Gruen Authority

Nice one, mikey! Is that an opera watch?

My two caveats:
1) I'm wrong many times a day --just ask my wife!
2) Always seeking to learn more

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Re: The Cal 870/871 [message #11632 is a reply to message #11631]

Wed, 13 November 2019 22:02

Gary
Messages: 2108
Registered: May 2013
Location: Left Coast

Gruen Authority
Cheerleader

Could be, no second hand, no need to keep precision time. ;-)

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Re: The Cal 870/871 [message #11635 is a reply to message #11632]

Thu, 14 November 2019 18:14

mikey
Messages: 709
Registered: May 2013
Location: Paris, Ontario

Gruen Master

Not sure if it would be an 'opera' watch but it was the first Gruen pocket watch that I collected a few years ago. I do remember posting it on the old vintage Gruen site.

Still here....

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Re: The Cal 870/871 [message #11636 is a reply to message #11635]

Fri, 15 November 2019 00:53

thesnark17
Messages: 649
Registered: January 2017

Gruen Master

Generally these are called opera watches. The only watches that were ever sold as "opera watches" were Walthams - 6/0 movements in 10 or 12s cases. In other words exactly the same design as this one.

The advantage is that the watch is incredibly thin for its diameter - but this is somewhat deceptive, as you see.

[Updated on: Fri, 15 November 2019 00:57]

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Re: The Cal 870/871 [message #15351 is a reply to message #11636]

Wed, 18 August 2021 20:43

Gary
Messages: 2108
Registered: May 2013
Location: Left Coast

Gruen Authority
Cheerleader

Bringing this thread back to life.

There is a Rolex trench out there that resembles the Gruen 22B. It's been referenced before that the 870 design by Rebberg was used by both Gruen and Rolex.

/vgforum/index.php?t=getfile&id=8432&private=0