Different sized center wheel pivots for same grade movement question

[Max50916]

Hello! I've been having trouble with an Elgin 554 movement but am eager to wear the watch so I attempted to swap the movement with another strong running 554. However the trouble 554 and the strong running 554 are for different dial types (trouble 554 is for a flat dial, running 554 is for a curved dial). I assumed that I would be able to just swap the cannon pinions and hour gears, however I found that the center wheel pivot was a slightly different diameter. The curved dial cannon pinion was much too lose on the other center wheel pivot and the flat dial cannon pinion was much too tight on the curved dial center wheel pivot. I was surprised that the pivots would be slightly different diameters for the same (554) movement, BUT I'm also very new to this and wanted to ask two questions: 1) will also swapping the center wheel between movements fix this problem? And 2) is this a common issue I'll find when trying to source parts from other movements of the same caliber? 

(Apologies if any of my terminology is wrong)

Thank you for any help!

[Nucejoe]

Do both your movements have same jewel counts? 

You might have two different variant, are bridge layouts same on both?

[Poljot]

1 hour ago, Max50916 said:

Hello! I've been having trouble with an Elgin 554 movement but am eager to wear the watch so I attempted to swap the movement with another strong running 554. However the trouble 554 and the strong running 554 are for different dial types (trouble 554 is for a flat dial, running 554 is for a curved dial). I assumed that I would be able to just swap the cannon pinions and hour gears, however I found that the center wheel pivot was a slightly different diameter. The curved dial cannon pinion was much too lose on the other center wheel pivot and the flat dial cannon pinion was much too tight on the curved dial center wheel pivot. I was surprised that the pivots would be slightly different diameters for the same (554) movement, BUT I'm also very new to this and wanted to ask two questions: 1) will also swapping the center wheel between movements fix this problem? And 2) is this a common issue I'll find when trying to source parts from other movements of the same caliber? 

(Apologies if any of my terminology is wrong)

Thank you for any help!

If you have not seen this already (see attached): Elgin 554-556 parts list.

p07-556 - Copy.pdf

[Max50916]

48 minutes ago, Nucejoe said:

Do both your movements have same jewel counts? 

You might have two different variant, are bridge layouts same on both?

Seem to be!

[Poljot]

The cannon pinion and hour wheel are different for flat and curved dial. See the parts list above.

[Poljot]

By looking at the parts list - you should be able to swap both, the cannon pinion and hour wheel. Hope the Hands dia remains the same.

[JohnR725]

Usually when dealing with American watches especially the older pocket watches swapping components Is undesirable. Even though you can have a wonderful parts listed indicates that all the parts will interchange because are mass-produced. But then in the older watches they typically hand  fit the component so they may have been modified slightly. Then there were made in batches and there's going to be variations between the batches depending upon when they were made it but it watch being new war shouldn't perhaps have those issues.

 

 

[Poljot]

The question was very specific - so was the answer.

[Max50916]

2 hours ago, Poljot said:

By looking at the parts list - you should be able to swap both, the cannon pinion and hour wheel. Hope the Hands dia remains the same.

Thanks guys! Yes it's strange that according to the parts guide you should be able to use the same center wheel but they're not actually quite the same, if I were able to change the movement entirely (put a slightly newer 554 instead of the original (I think) movement would there be any decrease in the value? The one I'm having trouble with is military issue

[Poljot]

1 hour ago, Max50916 said:

Thanks guys! Yes it's strange that according to the parts guide you should be able to use the same center wheel but they're not actually quite the same, if I were able to change the movement entirely (put a slightly newer 554 instead of the original (I think) movement would there be any decrease in the value? The one I'm having trouble with is military issue

I don't believe that value would decrease at all. Not according to pocketwatchdatabasedotcom

[saswatch88]

On 12/12/2020 at 12:47 PM, JohnR725 said:

Usually when dealing with American watches especially the older pocket watches swapping components Is undesirable. Even though you can have a wonderful parts listed indicates that all the parts will interchange because are mass-produced. But then in the older watches they typically hand  fit the component so they may have been modified slightly. Then there were made in batches and there's going to be variations between the batches depending upon when they were made it but it watch being new war shouldn't perhaps have those issues.

 

 

I have to agree with this whole heartedly because coming from a guy who has always worked on older waltham/eglin movements this is almost always the case even when using the same grade and calibre. However I have swapped parts between 554 movements and they are supposed to be interchangeable but as John stated they rarely are. My rule of thumb is always keep the wheels and top plates together as much as possible. Its not always how they were made but how they had worn down in the last 80 years. Some pivots could have worn down much more or even differently than others. But not sure why you have to swap these because I have used civilian curved 554s and 555s with a flat military dial and hands. I suggest you keep the nickel black movement, service it, then just swap the balance only. I would test the balance first to make sure there is no variances in the jewel heights, because that is also an issue. But its an issue that can be rectified with shimming or jewel pushing. The Mil-spec nickel black movement should be preserved esp if the watch is military. the hands should also be interchangeable.