All about Gruen

[Mr. Bieser]

Question/discussion. I'll lay it out so it's easy. This is the 833. Serial number 1384072
http://www.ranfft.de/cgi-bin/bidfun-db. ... &Gruen_833


It carries Swiss patent 97101:

Here are the parts list for 833 from 1926:

First thing to focus on this image from the ranfft link of sn 1384072:

Gruen_833-1.jpg (18.78 KiB) Viewed 117 times

Now, this is a completely different 833, sn 1514235.

What is this part exactly? Never seen that before!
What does it do? Why isn't the part on 1384072 example or in the 1926 parts book?
Is this some sort of 833 variant I've not noticed before? Can anyone who has studied the 833 explain this to me? Let's discuss:

Thanks!

[Dietrich]

Indeed an interesting detail which I have not observed yet as well. But to be honest I rarely removed the dials of my Cartouches...
The 15xxxxx serial should be from 1927, so I would not wonder if there was a change in the 833 after the photo for the 1926 book was taken. To me it looks like a provision for a center second variant. May be this was experimental in Aegler before it was decided not to launch an 833SS in favor of the 835SS as center second movement? Also the setting lever spring is differing from the older movement.

In theory something like this center spring holder from the same maker?

Center Holder.jpg (36.22 KiB) Viewed 114 times

[Mr. Bieser]

I understand, I have a few 833's that are running as complete watches that I also will not take the dials off at this time, like a lot of Gruen research, this is all online based observation so far.

Yes something like the spring holder theory also crossed my mind.

Perhaps something in the development of the 835, but total guess.

http://www.ranfft.de/cgi-bin/bidfun-db. ... &Gruen_835

Imo, this looks factory, especially with that attachment on part 1131,but the question should probably be asked, is it possible this is an addition from a tinkerer/watchmaker? Of course the question is still, for what purpose?

[Fred]

First, I’ve looked under dozens of 833 dials—never seen something like this!

I think it relates to the slot I’ve circled.

E1798136-F88C-4A45-9751-CD4903434429.jpeg (32.77 KiB) Viewed 103 times

So… why?? Best I can figure, the slot may allow more flexibility (more spring travel or fit new style spring to old lever). But more helpful (perhaps) I also think it spreads/shifts the moment force further down towards the center of the setting spring. I have seen several springs with the tip (that touches the lever) broken off.

Either way, I think the metal piece braces the spring below the cut so it doesn’t crack off. Maybe?

And it makes me want to go digging through the orphans to see if I’ve one nearby sn to check under the dial!

[Mr. Bieser]

A really good eye for detail, as always.
There is a slot. There's not one on ranfft example. Or one in 1926 parts pic. In fact part 1131 looks completely different on this example in question.
Different shot of slot, possibly clearer:

Or look yourself for further data if you haven't seen:

https://www.ebay.com/itm/115731215747

But compare, 1926 parts:

Ranfft

In question

[Mr. Bieser]

I believe this issue is explained simply by it being an O.M. intermediate bridge, and a N.M. intermediate bridge. The part 1131 on ranfft example matches the 833 setting works in 1926 parts book.
But the example in question matches the intermediate bridge to 833 in the 1939 parts book.
Still not sure of the part name I first pointed out, as parts are not all listed in 39.