Bulova set o matic

[Orologi67]

anybody have any experience with a bulova set o matic setting mechanism? I bought one and the movement is in excellent shape, however, the final pullout of the staff isnt there and i cannot adjust the hands.  Replaced staff? Synched incorrectly?  I found a diagram of assembly online but wanted input from here.

Thanks.  Cheers

Steve

[WatchMaker]

Is this an AS-2066 you're dealing with.

If the stem (I know you use the term 'staff') isn't moving as it should and allowing you to move to a position to change the hands then clearly there must be a problem with the keyless works in some way. 

A good bet would then to look at, say, https://www.youtube.com/watch?v=WM5gD6PQm5Y around the 13:30 mark and compare where your keyless works are compromised.

[Nucejoe]

Based on WatchMaker comment, I guess you are working on AS2066.

Will you always disclose the caliber and as said the first place to check is the keyless.

Regards 

[Orologi67]

Yes gentlemen i know its the keyless work that is causing the issue.  Its a 1974 11BSACB. 

There seems to be a replaced part from another movement.  Its the setting lever or the set bridge.  Im unsure.

I ordered the same calibre junker to see if i can find out whats the difference between the two might be.  

I investigated mine for quite a while today.

Set bridge has another bridge attached on the bottom with a series of gears.  This should contact a wheel (2nd wheel) that has a slip fit pinion on it.  This pinion moves the hands.  Its a rather ingenious design but the STEM doesnt want to pull out to a third notch.

As far as i can tell its got an incorrect part.  Like i said above.

Edited July 24, 2020 by Orologi67
misspelling

[Orologi67]

if you will see from the picture the set bridge has a hole at the 6.30 position.  Thats the cam that should fall diagonally left to interact with the slip fit pinion under that pivot hole you can see just slightly below the hole in the bridge.

The series of cams under the bridge is called the rocking bar.  There is a prong coming off this that interacts with the setting lever.

If i place that prong under the bottom pin on the lever the STEM will not move from winding mode (fully imbedded) which as i see it thats the way its supposed to be positioned.

If i place that prong above the pin the STEM will pull out one time.  This sets day and date.

So im back to square one until the junker arrives such that i can analyze and hopefully steal a part.

Thanks for your help.  In the future i will refer to it as a STEM and always give the calibre

Edited July 24, 2020 by Orologi67
misspelling

[Orologi67]

[Orologi67]

 

Edited July 25, 2020 by Orologi67
Double picture

[Orologi67]

Ok.  The long story.  The setting bridge tension arm/spring with two notches that interacts with the setting lever.  The setting lever's pin is supposed to pass the bottom hump for the 2nd pull out of the stem which sets the time (see above pics).  Even after cleaning and oil the setting lever pin just would not pass that second larger hump which is so much larger than the first that it in fact looks like a stop. 

i ordered, as i said, a 20 buck junker, thinking i had a wrong part on mine.  On the junker the the setting bridge's setting lever spring was snapped off.  My suspiscions were founded.

So i took off the bridge on this bulova and got a fine grade vallorbe file and slightly rounded off the bottom hump.  Then i polished that curve with sandpaper.  Then i washed it.  Reinstalled it. Lubed it.  Put the stem back in and Voilá! It finally pulled out twice and now the hands can be set.

Im a clockrepairman learning to repair watches.  Rule #1 in clock repair is never take away metal from a piece.  But this really is an issue of that hump being designed ever so slightly too large.

Im sure customers were snapping stems and breaking setting springs trying to set the hands on this bulova series.

And i do apologize if my terminology is not to watchmaker specs.

Cheers