Vintage Gruen: The caliber database » Semithin 754/756/758

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Semithin 754/756/758 [message #15573]

Fri, 24 September 2021 15:54

Jenneke
Messages: 2009
Registered: May 2013
Location: Netherlands

Gruen Authority

Type : Pocket watch
Period/date : 1920-1930
Gender : Men's

Caliber : 756 (17 jewels), others are 754 (15 jewels) and 758 (16 jewels)
Gruen Guild - Adjusted temperatures
Size: 17ligne
Movement Maker : Lavina
Movement Serial:

Dial release: side screws

Other: The detent and detent spring make it hard to pull out the crown to set the watch. Dial made by Flueckiger et Fils/ Zelim Jacot dial factory: https://www.diju.ch/f/notices/detail/6494

/vgforum/index.php?t=getfile&id=8565&private=0

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/vgforum/index.php?t=getfile&id=8574&private=0

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Edit: corrected 758 jewels

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You can only waste time if you forget to enjoy it - Loesje

[Updated on: Sat, 25 September 2021 06:55]

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Re: Semithin 754/756/758 [message #15577 is a reply to message #15573]

Fri, 24 September 2021 20:05

Jenneke
Messages: 2009
Registered: May 2013
Location: Netherlands

Gruen Authority

In the 1926 Gruen standardized parts the 754 is not shown. And strange enough, they mention a 16 jewel version.

/vgforum/index.php?t=getfile&id=8575&private=0

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You can only waste time if you forget to enjoy it - Loesje

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Re: Semithin 754/756/758 [message #15579 is a reply to message #15577]

Sat, 25 September 2021 03:29

Case
Messages: 1178
Registered: May 2019
Location: Cincinnati

Gruen Authority

That’ll be the 758 for 16J.

Curious that 754 isn’t listed...never noticed that! It was already in play by 1920 in cases stamped “750,” and ran for years after 1926.

Also curious enough, there are two bridge designs stamped 754: spade tips (identical to the 756 except the center bridge) and later round tips—like a fatter version of the 850.

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Re: Semithin 754/756/758 [message #15976 is a reply to message #15579]

Sun, 02 January 2022 19:10

Jenneke
Messages: 2009
Registered: May 2013
Location: Netherlands

Gruen Authority

Something fishy is going on.

Caliber 758 exists with 15 and 16 jewels.

In the 1939 material catalogue the 754, 756 and 758 have the same setting mechanism:
/vgforum/index.php?t=getfile&id=8887&private=0

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The spare 754 movement I bought for my 756 turns out to have a different setting mechanism.
In fact, that looks the same as the caliber 740 in the 1926 parts catalogue. Almost as if the 740 is the 17 jewel and the 754 the 15 jewel version.

Somewhere over the years the 754 setting bits where changed. From a two part stem to a single, from two sides setting bits to one side with different shapes.

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You can only waste time if you forget to enjoy it - Loesje

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Re: Semithin 754/756/758 [message #15989 is a reply to message #15976]

Mon, 03 January 2022 00:22

Case
Messages: 1178
Registered: May 2019
Location: Cincinnati

Gruen Authority

Aha, that’s certainly the old style setting, like the 740 & 750. Transitional? Perhaps the later book is showing the last versions of them, for which parts were on hand? Just trying to make the puzzle fit.

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Re: Semithin 754/756/758 [message #15992 is a reply to message #15989]

Mon, 03 January 2022 17:56

Jenneke
Messages: 2009
Registered: May 2013
Location: Netherlands

Gruen Authority

Yeah, maybe when the 740 ended they switched to the new setting. Or the old style 754 was phased out by 1926 and resurrected in a different form after 1926.

Still odd there are two 15 jewels versions in 1939. What would be the difference.

You can only waste time if you forget to enjoy it - Loesje

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