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Help with chiming mechanism on Seth Thomas quarter hour!!!

LittleWatchShop

By LittleWatchShop
in All Things Clocks

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LittleWatchShop Distinguished Member

LittleWatchShop

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I am flummoxed!

This is the second one of these clocks I have serviced and the first was very straightforward to get the chimes calibrated.  I must have gotten lucky.

Here is the first problem.

In the first picture I show the cam and lever that drops in.  In principle, I think when the lever drops into the cam the "stop" at "A" should hit the pin ("D") on the wheel...shown in the fourth image.  This can ONLY happen if the cam "C" allows the "stop" at "A" to drop.  Thus the phase relationship between the cam  "C" and the wheel with pin "D" is critical.  Yet, I see no way to adjust this relationship!

Is it possible that cam at "C" is friction fit and adjustable???

st1.png

2022-03-15 17_50_57-IMG_8271.JPG ‎- Photos.png

ST2.png

ST3.png

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oldhippy Distinguished Member

oldhippy

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I need to see all of that cam can you photo the other side of it and does it screw onto the wheel or is it just friction tight. Do not move try to move E as that is in line with the pin.  Do you know if this movement puts it self right with the chimes if they are out of line with the hands?

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LittleWatchShop Distinguished Member

LittleWatchShop

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1 hour ago, watchweasol said:

I think the problem is with the Autocorrection set up, when hands are moved out of sync the chime is locked,  out by the mechanism only to be released on the 3/4.  Explained in many books.

Ah, the 3/4 cam position seemed to have no purpose...I need to investigate this. Can you recommend a book.

i will post more pictures today.

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watchweasol Distinguished Member

watchweasol

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Thats the chime warning wheel, when the strike is initiated the warning lever releases the wheel 1/4 to 1/2 a turn wherei it is arrested by the locking lever and released at the chime point. the cam turns during the strike depending on the profile and is locked again when the lever drops in to the slot,  at this position the warning wheel is arrested again to await its next release.

Books  Laurie Penman       The clock repairers Hand book

            Mike Watters           The Clock repairers Manual

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LittleWatchShop Distinguished Member

LittleWatchShop

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Thank you for your patience @watchweasol!!  I see how the strike initiation works...and it seems to be working properly.

My fundamental problem is the relationship between the pin on the warning wheel and the cam on the "other" wheel with the smallest cam (shown in this video I made).

Notice where the pin is when the striking stops.  I think this is wrong.

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LittleWatchShop Distinguished Member

LittleWatchShop

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2 minutes ago, watchweasol said:

The warning wheel is being arrested by the auto correct cam not the locking lever. The warning wheel should be arrested by the lever when the lever drops into the slot. when locked the pin should be resting on the face of the lever in the approx 12 Oc position

That is my observation as well.  So!!  This requires the relative precise positioning of the warning wheel DURING assembly, correct?  There does not appear to be any way to adjust this once assembled.  IF I could turn the auto correct cam, then I could make this adjustment in situ.  But, the cam does not appear to be movable--I have not tried.

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LittleWatchShop Distinguished Member

LittleWatchShop

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1 minute ago, LittleWatchShop said:

Notice the first comment below the video.

Here is the question he posted:

Paul Dyck

1 year ago

Great video! My experience in reassembling time and strike movements with a count wheel is that when you are putting the plates back together you have to be very careful on the strike side that the pin on the warning wheel is close to the lock point and that the maintenance lever bottoms out in one of the gullies of the maintenance cam. With this clock it looks to me from your video that you don't have those issues with the ST 124 at the stage where you are putting the plates together - you just have to get all the pivots in the right holes, and all of the adjustments come later after the plates are back together. Is that right?

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LittleWatchShop Distinguished Member

LittleWatchShop

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OK, I think I have to tear this thing down, adjust, and reassemble.  One unrelated question.  I have not been removing the gathering pallet but allowing that associated wheel to remain on the upper plate for cleaning.  What is the best tool for removing it?  I am a little paranoid about bending the pivot.

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watchweasol Distinguished Member

watchweasol

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  It is possible to spread the plates to re adjust the wheel position but it is ill advised as pivots can get broken.  Set the warning to the 12 position so as when teleased you get 1/4 to 1/2 a turn be fore being stopped by the lever.      To remove the gathering pallet I usually use levers and lift it parallel.  Do not remove the STAR cam fron the center shaft pe positioning is a PIA. Only remove it if the bearing hole is worn and its slopping about.  I have some notes somewhere about the autocorrect I will see if I can find them. 

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LittleWatchShop Distinguished Member

LittleWatchShop

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BAM!!  Thanks @watchweasol!  I fully understand this now.  I have moved the warning wheel to the correct position (full disassembled and set in the proper position--no plate bending!!).  I adjusted the auto-correct lever so that it locks and unlocks properly. 

This is a clever system.  However, I am surprised that the warning wheel phase with respect to the small cam does not have some adjustment.  This requires setting the wheel in the right position during assembly.  OK...not that hard once you know what is going on.

The other piece I was missing is that the minute-wheel cam has one cam longer than the other so that the auto-correct can work.  Very clever.

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LittleWatchShop Distinguished Member

LittleWatchShop

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It is mostly assembled.  Had to pull the gathering pallet because it too needs to be in a calibrated position.  I searched the web for the right tool to do this.  When I saw it, I knew I had seen it before.  Back to drawer #2 in my Dad's watch bench.  Yup!  That was it.

I calibrated the quarter hour chimes also.

It is mostly back together but I am double checking everything before attaching the motor and putting it in the case.

Thanks for all the help!!!

BTW, this is my clock.  I bought it yesterday for $6 at a thrift store.  I could see that it had never been serviced.

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LittleWatchShop Distinguished Member

LittleWatchShop

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I noted that I had repaired one of these a couple of months ago.  Did not have this problem.  I must have gotten luck when I placed the warning wheel.

However!  I had discovered that the clock got out of sync with the chimes.  It seemed odd to me that there was not a trigger to advance the chimes in this situation.  Today, I opened it up and realized that I had not properly set the auto-correct lever.

I have learned SO MUCH today!!

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watchweasol Distinguished Member

watchweasol

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Not bad that a Seth Thomas for $6  the last one I looked at over here was £70 needless to say I refused, but they are good clocks.  What tool did your Dad use, I just use levers.  There is a site Dave West clocks that has a lot of useful info on the chine note sequence for the wittington and other chimes as well.      dont for get a picture of the finished article up and running         cheers

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