Seth Thomas Sonora Repair Advice

[Richard Hatch]

Gentlemen:
I could use a little (well maybe a lot) of advice on a ST 5 Bell Sonora clock. A couple days ago the mainspring broke on the time train. I had the time to pull it out of the case last night and I saw something that I’d not seen before. There are small brass wires (springs) wrapped around the Hour Hammer Arbor and several others. They look to be return springs for the arbors. My question is how do you go about taking them off? They are wrapped around the arbor and through holes in the plate and look like they have never been removed. The rest of the repair is rather straight forward, maybe a bent pivot, damaged wheel or pinion. Also on the same topic…what is the length and strength of the spring required on the time side? Is there any sort of repair manual on this movement? Now just one more question (I seem to be full of them) how do you go about removing the Chime Mainspring? Since I’m into this clock I might as well do it right. It looks as if the potential for property damage and personal injury is high for this operation!!! I was thinking of using a lathe and building a barrel clamp to hold it down to the cross slide. Any thoughts! Maybe someone has a picture or drawing for a spring winding fixture?

 

[Richard Hatch]

Gentlemen:
I could use a little (well maybe a lot) of advice on a ST 5 Bell Sonora clock. A couple days ago the mainspring broke on the time train. I had the time to pull it out of the case last night and I saw something that I’d not seen before. There are small brass wires (springs) wrapped around the Hour Hammer Arbor and several others. They look to be return springs for the arbors. My question is how do you go about taking them off? They are wrapped around the arbor and through holes in the plate and look like they have never been removed. The rest of the repair is rather straight forward, maybe a bent pivot, damaged wheel or pinion. Also on the same topic…what is the length and strength of the spring required on the time side? Is there any sort of repair manual on this movement? Now just one more question (I seem to be full of them) how do you go about removing the Chime Mainspring? Since I’m into this clock I might as well do it right. It looks as if the potential for property damage and personal injury is high for this operation!!! I was thinking of using a lathe and building a barrel clamp to hold it down to the cross slide. Any thoughts! Maybe someone has a picture or drawing for a spring winding fixture?

 

[Robert M.]

Rich,if you remove the end of the helper spring from the plate you should be able to remove the spring intact with the arbor without any problem.If they still look functional I would leave them alone.If they do need to be replaced check out the post on "Helper Springs",That will give you a few ideas on how to fabricate new helper springs.As far as the chime side mainspring on a Sonora,its the 800 lb. gorilla of mainsprings.It would be the equivalent of a 25' Anaconda if it gets away from you and decides to attack.Unless you have a real good mainspring winder capable of handling those heavy duty mainsprings I would suggest for the time being you just put some Keysone Mainspring Oil or whatever in the barrel and live with it.I know this advice may seem like a blasphemy to some of our posters but if I have to weigh personal injury against accepted practices I would suggest you take the path of least resistance.There's no sense hurting yourself.I'm sure one of our other knowledgable posters will chime in on the mainspring dilemma but thats my own personal advice based on removing chime side mainsprings from S.T. #113s and Sonoras.
As far as a good repair text goes you may want to get hold of a copy of Chime Clock Repair by Steven Conover.It contains an excellent chapter on repairing Sonora Chime Clocks plus approx. fifteen other common chimers.Well worth the money.
Well best of luck with your repair job.I own a 5 bell Sonora Chime also,they are beautiful clocks.
Respectfully,Bob Fullerton

 

[Richard Hatch]

Robert:
Thanks! I kind of hate to leave the chime spring in the barrel, that's not the way I was taught, however.....better safe then sorry. I do remember wrestling a time recorder spring once, Ouch! This looks more like working on a Victrola!!! As to the helper springs, if this clock has been apart whoever put it back together did a great job, as these springs look untouched by human hands! I only hope I can do as well, Richard

 

[Robert M.]

Rich,they can say all they want about the quality of European movements.In my own humble opinion the early Seth Thomas movements didn't take a back seat to anyone in the quality dept.Personally and others may disagree I think the #113 Westminister is one of the best chime movements ever manufactured.That baby was built to last.I have one in a maybe 80 year year old Tambour that I rebuilt and it still chimes beautifully.You've got yourself a great clock there.Sonoras are about as good as it gets.
Respectfully,Bob Fullerton

 

[Richard Hatch]

I thought I'd try out the Flickr.com picture posting. Here (I hope) are two pictures of my Sonora movement. Can anyone tell me the movement number and the correct timeside mainspring? Also the helper springs on this movement are in pristine condition, I don't think this movement has been apart. Or someone is very good at replacing them!


[ATTACH]369381[/ATTACH]

 

[David Robertson]

Richard,

It may be that the springs are factory installed... I don't know.

Installation of the these springs is a manual task and anyone is capable of doing this quality of work if they will learn how and take the time. It requires winding the springs on some sort of arbor and then istalling them during reassembly rather than as afterthought when the movement is put back together.

Admittedly, you don't often see helper springs done this neatly. I see very few. The more common situation is a bird's nest of brass wire..

It is a great goal for us all to aspire to.

Thanks for sharing it.

David

 

[Richard Hatch]

It may well show that a "botch" has not been here!

 

[DenisG]

Hi Richard,

Just to cover your question on the correct time side mainspring. I'm pretty sure that my Sonora uses a standard American movement mainspring, available from Timesavers, LaRose, Merritts etc...

Denis

 

[Robert M.]

Actually Rich helper springs of that quality are quite easy to make.When I first started tinkering with clocks I use to wrap mine around the arbor by hand and as the other gentleman stated they looked like a birds nest,down right awful.What I wound up doing was to take a pc. of Brass rod about 5/32" in diam. and about 2"long.Then I cut a slot on one end about a 1/4" deep.I would then chuck it up in my lathe with about an 1-1/4" protruding out.Take one end of your Brass wire and insert it in the slot with approx. 1-1/2" protruding pass the edge of the slot.Leave the wire on the spool and run your lathe fairly slow and allow the wire to coil around the mandrel.Stop when you are satisfied with the width of the fabricated coil and cut off approx 2" from the spooled side of the wire.This excess will give you plenty of wire to play with for binding purposes.After you complete your helper spring you can just thread it on the arbor like a threaded nut.I've made more than my share of helper springs using this method and I can assure you if you take your time they will look every bit as professional as the example in your picture.Rest assured the first couple times you try this they may be a little rough but have patience this trick works well.
As for the movement nos. for the S.T.Sonora.
1. Hour Strike or time movement= #89
2. Chime movement= #119
I hope this is of some help to you.Best of luck with your repairs.
Respectfully,Bob Fullerton
P.S.,Great Pictures.....

 

[Richard Hatch]

Robert:
Thanks for the advice and assurances! Assuming that I do make good looking springs, a couple of questions remain:
<LI>What type of Brass wire would you recommend (full hard)?
<LI>And how much “set up” on the arbor is needed? Thanks, Richard

 

[Robert M.]

Rich,I buy my wire straight from Merritts right off the shelf.I really don't worry about the metallurgical angle.The sizes I buy;22,24,26 Gauge.Based on what the existing size is I try to use the same diam.from the spools.I've never had a problem with their wire but I will tell you that when you bind it to the movement its not very forgiving.In other words once you bind it to the movement you can't keep removing it to re-adjust it or it will break but I think that would be true of any wire of that diam. unless it was dead soft and of course the wire would have no practical value then.
As far as set up goes either a Jacobs Chuck or the proper size collet will do just fine.We're not striving for machining accuracy,just something to grip the mandrel while it rotates.
I hope this answered your questions.If I can help with anything else just ask.
Respectfully,Bob Fullerton

 

[Richard Hatch]

Robert:
Thanks! When you install the spring is it "set up", i.e. twisted a few turns, to establish the return force? Richard

 

[Robert M.]

When you thread it on your arbor Rich make sure you have the proper tension rotation on your coils.This will be determined by the original spring and the way you fabricate it on your lathe.It could be clockwise or it could be counter clockwise.You will have to rotate your lathe accordingly to fabricate the proper spring.Fabricated properly the spring will have plenty of compression in the as installed condition.Its a helper spring,not a valve spring that has to have an extrodinary amount of strength to function properly. Personally I don't remove the old spring until I make the new one and have the opportunity to compare them.Don't worry if you coil it the wrong way in your lathe on the first few tries.Just make another one,there's a helluva lot of wire on one of those spools and what the hell it'll be good practice for you.
Best of luck with your helper springs.
Respectfully,Bob Fullerton