Moon dial

rondele

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Mar 9, 2013
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Hi Folks-

Well, finally got moon dial working again but now another problem (it never ends!).

It is advancing a full day every 12 hours. I think the problem is insufficient tension on the spring device that holds dial in place. It allows the dial to advance beyond one tooth. Can anyone advise me how to increase tension and exactly what part of the spring device goes between the teeth?

xyzzytom_190835
 
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shutterbug

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Post a pic of it. I'm sure we can help :)
 

Tinker Dwight

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Are you sure you have the right moon dial.
One has 59 teeth. It is intended to be advanced
only once a day with a reduction wheel.
The ones with 118 teeth are intended to be advanced
once every 12 hours.
Tinker Dwight
 

rondele

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Mar 9, 2013
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Prior to removing dial to do some repair work, the moon dial would advance twice a day, however it would only advance one tooth such that the pointer would be halfway to the next date. At the next 12 hours it would move another tooth forward so that the pointer would be exactly at the new date.

Now however, it is still advancing twice a day but it's advancing a full day rather than half, so that essentially it will take 15 days rather than 30 to complete a full cycle.

Only thing that might be responsible is that the index spring does not have the same tension as before, thus allowing the dial to advance two teeth forward each 12 hours rather than one.

Hope the pics help.
front.png back.png
 

shutterbug

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The images are too small to really see, but it appears that there is no spring to control the rotation. If there is one, we need a close up pic of that.
 

Tinker Dwight

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It is a 118 tooth at least.
We'd also need to see more of the linkage
or wheels to help. The retaining spring as
Sbug says as well.
Tinker Dwight
 

rondele

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Yes there's an index spring mounted to face plate, tried to take pic of it in first post above. Will do so again, but first I'll try increasing tension to see if that retards dial from advancing two teeth instead of one. index.spring.png
 

shutterbug

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Yeah, that should work.
 

rondele

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Mar 9, 2013
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So after much tinkering with the index spring to put more tension on it, no luck. The moon dial is still advancing a full day every 12 hours whereas before it would advance only half day (or one tooth). I tried to manually retard dial from moving into the 2nd tooth as I was advancing the minute hand and it did stop it, but with that amount of tension it would not have even advanced into the first tooth.

I'm totally baffled. Had clock since the 70s and it would always advance just halfway to next day starting around 3pm or so, so that the next morning when it had advanced around 3am it would be pointing to the correct day. Not anymore.

I don't like to give up on these kinds of things because sooner or later I can generally figure out the problem and fix it. Not this time.

Any ideas would be welcome. Nothing was done to the pin that engages the dial so that can be ruled out. And the more I think about the index spring, if it had enough tension to retard dial from moving a full day every 12 hours, it would also retard it from moving a half day as it used to.

R
 

Earl Stedman

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Rotate the hands until the pin reaches a tooth on the dial and see if it is engaging correctly (if not this may your problem) keep rotating the hands and watch to see if the dial advances one tooth. If it advances more than one tooth check the shape of the tention spring it could be shaped as to jump a tooth. Hope this helps
 

Tinker Dwight

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We've not seen a clear picture of what advances the
moon dial.
I'm assuming, it is a wheel with a pin on it.
If that is so, it is the distance between that
wheels arbor and the moon dials arbor that
may need to be adjusted.
As the moon dial ages, it drops because of wear.
The engages the pin into the ratchet teeth deeper.
At some point it will advance the moon dial more than
one tooth. Look at how the moon dial is mounted to
see if you can raise it a small amount. It is possible
that it is mounted on an eccentric shaft for such
adjustment.
You want the pin to just engage the moon dials
teeth but not too deeply.
Tinker Dwight
 

rondele

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Mar 9, 2013
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moon.6.png The pin projecting from upper wheel (about 9 o'clock) engages the teeth on moon dial. And yes, the pin projects quite a bit beyond the teeth when engaged. This may be the answer! I'll once again remove dial (been dealing with multiple problems since last March and when finally finished this new problem occurred!) and see if I can fix it. Thanks to all!
 

Earl Stedman

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I beleive Tinker and I know I'm refering to the depth of engagement of the pin (distance from pin to arbor) the dial will need to be on and then watch when the pin advances the dial (does it move one tooth or more) check to see if moon dial is worn.
 

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