AS 1906 Losing Lots of Time

[HorologicalHobby]

So I have an AS 1906 movement that keeps perfect time, if the calendar parts are not assembled, but once those are in, it looses time like it has a loose cannon pinion. I tightened the cannon pinion slightly, and there was no improvement. It's losing hours a day. Kinda baffled, to anyone with experience on this stuff, I greatly appreciate the help.

Edited May 14, 2016 by HorologicalHobby

[noirrac1j]

I am guessing the sweep second continues to tick away then? How soon after you set it does it begin to show loss? There's a lot going on near the minute wheel, and it looks like the date wheel is powered there? 

JC

[HorologicalHobby]

Yeah it ticks away, and the timeographer says it's within a few seconds a day. I'm going to check the gear that transmits power from the mainspring to the dial side, and is also coupled to the setting system, it's a bit too loose to properly transmit power, in my opinion.

 

The date wheel is powered off the hour wheel, by the way.

[Cad101]

Does this movement also have the split cogs on the driving wheel for changing the date but also powrs the hands I had this problem on a AS1904 i had to change the cog ib the end it was just age related and wear. Is it out of a Elgin from the seventies.

Mick

[noirrac1j]

8 hours ago, HorologicalHobby said:

Yeah it ticks away, and the timeographer says it's within a few seconds a day. I'm going to check the gear that transmits power from the mainspring to the dial side, and is also coupled to the setting system, it's a bit too loose to properly transmit power, in my opinion.

 

The date wheel is powered off the hour wheel, by the way.

Its probably that gear then. I've not worked on an AS 1904, but have worked onRoskopf type watches that have the main drive wheel riveted onto the mainspring barrel itself. This rivet point can sometimes become too loose to drive the hour hands, but it will tick away because of the indirect second...it will also look OK on a time grapher because there's nothing to indicate a beat error problem or amplitude. I don't know if AS 1904 is set up like a Roskopf-style movement, but I'd check that gear you mentioned. Pictures?

JC

[HorologicalHobby]

That's exactly what happened! I cleaned the gear last night in the ultrasonic tank, then took off what was basically a canon pinion gear, tightened it over a reamer, and reattached it. Works like a charm now, and the setting system isn't super light anymore.

 

 

[noirrac1j]

It's a fantastic feeling to be able to troubleshoot and then repair the issue. This is just how I really started learning about mechanical watches--figuring out stuff like this. Great job!

JC

[HorologicalHobby]

Thanks! I've never seen a canon pinion like that before, glad I could get it to work!