Hamilton cal.629 (Buren 1281)- Need to replace spring washer on indirect drive center second

[Latetothegame]

I think I have a simple question and I also think that I know the answer but I just want to confirm.  Please see the pictures below.  The first picture is on a Hamilton cal.629 movement with the watchmaker side up and dial side down (obviously).  I am getting a lot of “center second jitters” on the indirect drive second hand and I’m working on trying cut that down a little.  The jewel in the center second bridge is pretty worn and the spring washer is mashed flat.  The last two pictures are of the new parts that are on the way.  The first red arrow points to the second pinion pivot jewel in the bridge.  The second red arrow points to the gold spring washer between the second pinion gear and the second pinion pivot jewel. This is the part that my question is about.  I am trying to understand the correct orientation of that spring washer in relation to the other two parts.  The grey sketch shows the three parts in question.  The very primitive sketch is my attempt to depict how I believe the parts are supposed to be assembled.  The picture is an attempt to depict the following:  the pinion goes through the base plate with the second hand point going through the center tube and coming out the center of the cannon pinion.  The dial side is down so the gear on the end of the pinion is now facing up.  Here’s my real question.  I believe that the spring washer is installed with the large open end facing down and going around the gear wheel on the end on the pinion, with the pinion pivot extending through the hole on the small end of the spring washer (top of the cone so to speak) and then going into the jewel on the underside of the second pinion bridge.  Correct??  Hopefully, someone will say “Yes Paul, you have that exactly right.  Carry on.”  I would love to hear the correct answer if I have it wrong though.  As I said, the current spring washer is mashed completely flat so I’m not sure which way the cone is supposed to point, up or down.  Small end toward the jewel seems to make the most sense to me.  Thank you in advance for your help!

[Simeon]

I don't know the answer to this but it looks to me that if you install it the opposite way to what you are describing (the smaller hole down to the pinion, bigger to the jewel) it will actually push the pinion down and away from the jewelled bridge which is what you want. 

You look like you have a few spares so, why not try it both ways and see which gives the best result? It might possibly not make a difference. 

 

[rjenkinsgb]

I'd put the convex side against the smaller part, whichever that is, or which ever way keeps the washer evenly compressed?

It would not make any difference if both parts were larger in all directions than the spring washer, but if it could overlap one with the concave side towards that, it could wrap over the edge and snag rather than turning smoothly, as well as reducing the applied force.

[Latetothegame]

1 hour ago, Simeon said:

You look like you have a few spares so, why not try it both ways and see which gives the best result? 

I have 5 so ai will definitely try both options if the first one doesn’t fix it.  I was just hoping someone had already been down this road.  
Thanks.

Edited September 23, 2024 by Latetothegame
Typo

[nevenbekriev]

@Latetothegame, what You have drawn is wrong as the spring washer will prevent the pinion leaves from normal mesh with the 3th wheel table. There are two possible positions of the spring. One is above the pinion, and the other is under it. In both cases, the top of the spring must point to the pinion leaves. You must chose the position where the pinion leaves are on the proper height to meet the 3th wheel table. The strenght of the spring is critical.

I will be curious to see worn jewel on this particular place. This will be miracle. Broken - yes, but worn...

[Latetothegame]

nevenbekriev, based on all the input I have received and my own ongoing consideration of this question, I have also now come to the conclusion that my recommendation in my initial drawing was incorrect (see my updated skilled artwork).  The red is the jewel and the gold is the spring washer.  This position makes the most sense.  The spring washer will push the pinion gear down toward the baseplate  to ensure better engagement with the gear  and allow the wider part of the cone of the washer to rest on the underside of the center second bridge with no chance of interfering with the mesh of the gears.  
Broken would have been a better choice of words when describing the jewel.  When observed through a loupe, the opening has a somewhat irregular shape from either a crack or chip.   
Thanks for your input.  New spring washers arriving on Friday.  

[HectorLooi]

32 minutes ago, Latetothegame said:

see my updated skilled artwork

Wow! That's really good. I could see that hanging on the walls of a modern art gallery.

[Neverenoughwatches]

5 hours ago, Latetothegame said:

nevenbekriev, based on all the input I have received and my own ongoing consideration of this question, I have also now come to the conclusion that my recommendation in my initial drawing was incorrect (see my updated skilled artwork).  The red is the jewel and the gold is the spring washer.  This position makes the most sense.  The spring washer will push the pinion gear down toward the baseplate  to ensure better engagement with the gear  and allow the wider part of the cone of the washer to rest on the underside of the center second bridge with no chance of interfering with the mesh of the gears.  
Broken would have been a better choice of words when describing the jewel.  When observed through a loupe, the opening has a somewhat irregular shape from either a crack or chip.   
Thanks for your input.  New spring washers arriving on Friday.  

 

5 hours ago, Latetothegame said:

nevenbekriev, based on all the input I have received and my own ongoing consideration of this question, I have also now come to the conclusion that my recommendation in my initial drawing was incorrect (see my updated skilled artwork).  The red is the jewel and the gold is the spring washer.  This position makes the most sense.  The spring washer will push the pinion gear down toward the baseplate  to ensure better engagement with the gear  and allow the wider part of the cone of the washer to rest on the underside of the center second bridge with no chance of interfering with the mesh of the gears.  
Broken would have been a better choice of words when describing the jewel.  When observed through a loupe, the opening has a somewhat irregular shape from either a crack or chip.   
Thanks for your input.  New spring washers arriving on Friday.  

Yes Paul you will have that exactly right when the springs arrive, carry on.  Anyone have an idea how to make these spring washers, the usual flat fork springs look simple to make. Paper thin brass sheet and a paper punch ?

Found 0.3mm sheet brass, large dial washers ?

Thick tin foil ?

[CYCLOPS]

sorry late, it says place under the pinion, I would place cupped down position for more tension....

 

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://mccawcompany.com/guide/hamilton-626-627-628-629/&ved=2ahUKEwjRu9T3jIyJAxXorokEHbq5BCsQFnoECB0QAQ&usg=AOvVaw1vapdX3DnUGJ6ZtduDhEcn

[Latetothegame]

Thanks, I reviewed the note in the service bulletin.  That’s how I placed it.  Very helpful document.