Mainspring issue for Sessions Time and Strike

Rockin Ronnie

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Got a Sessions tambour style clock pretty cheap as part of my learning. It came to me non-working and I immediately observed that a click was worn and bent on one side and the spring was fully extended. I filed down the click, tapped the rivet to tighten it and got that part to work but now find that I can't hook the spring to the main wheel despite my best efforts and even following advise from other threads.

I have a feeling that the fact that I can't hook it and the fact that the click was bent might be related so I am left with the purchase of a new spring. I have a chronometer and can measure the width and the thickness but I can't uncoil it enough to determine the length but it must be a standard length for Sessions tambour clocks. Am I correct? If I replace one side should I also replace the other?

Ron
 

scottmiami

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Most of these are 3/4 x .018 x 96".

For the mainsprings, no, as long as the other side seems in good shape, I'd only replace the one.

For the clicks, these are notorious for letting loose, make sure both are replaced or in very good shape.

try to avoid the asian made springs, here's one that should work:

http://timesavers.com/i-22342597-3-4-x-0177-x-96-loop-end-german-mainspring.html

But I don't understand. You want to replace it because the arbor won't catch or because the spring is damaged? If because it won't catch, you could easily have the same problem with a new one, might be better to keep trying the old one. Bend the inner loop tight enough to be a little difficult to squeeze the arbor in.
 

Dick Feldman

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Ron,

Your problem catching the inside loop of the spring may not be with the spring. If the arbor hook that catches the inside of the spring is bad, you will have little success with any spring you try. That arbor hook must be able to catch the inside hole in the spring.

As to the clicks and return springs. Both trains in that clock have been wound nearly the same amount of times. If one click is loose, do you think the other may be loose or about to fail? Check also to see if the click return springs are made from brass. If they are, you might want to think about replacing those with spring steel return springs. Brass is a rather poor choice of material for click return springs. After flexing with winding, those springs become weak, brittle and are prone to breakage. Many times the click shows wear, etc. because it has not been returning properly. Thus—the click return spring is sometimes the culprit and the click is the victim. If you repair only the click, you may have a reoccurrence of problems. If you want to be sure the click/spring assembly does not fail, install a second set of clicks and springs on each wheel.

Good for now may not be good enough.

Best,

Dick Feldman
 

harold bain

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It is easier to form the spring end without the arbor in the way. This is a common problem after a click failure as the force of the spring takes it past fully unwound enough to bend the end of the spring. Nothing in normal use wears the hook on the arbor, but many were not very large as made.
 

scottmiami

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And not to be a master of the obvious, but you're putting it in the correct direction? FWIW, all of the sessions T&S clocks I have worked on wind CCW.
 

Willie X

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Ron,
Yes, a click failure causes a severe kickback that violently unkooks the spring. Sometimes, the inner coil is opened maybe 1/8" larger than the arbor.
When the inner coil is properly formed, it will be round and smaller than the arbor. You will have to force it in place and it will actually snap in place.
Willie X
 

Rockin Ronnie

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Ron,
Yes, a click failure causes a severe kickback that violently unkooks the spring. Sometimes, the inner coil is opened maybe 1/8" larger than the arbor.
When the inner coil is properly formed, it will be round and smaller than the arbor. You will have to force it in place and it will actually snap in place.
Willie X
Sounds like what might have happened. Am also aware of the correct orientation of the arbor to the spring but don't mind being reminded of the obvious.

Ron
 

Willie X

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Hard to tell for sure but the base of your arbor hook seems to have a little hump where it joins the base. The hook could probably be improved with some judicious strokes with good 3 corner file. The hook should have about 20 degrees draw to pull that spring in.
Willie X
 

Rockin Ronnie

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Hard to tell for sure but the base of your arbor hook seems to have a little hump where it joins the base. The hook could probably be improved with some judicious strokes with good 3 corner file. The hook should have about 20 degrees draw to pull that spring in.
Willie X
It is a storm day here in Nova Scotia (lots of snow) so a great day to work on this.

Ron
 

R. Croswell

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It is a storm day here in Nova Scotia (lots of snow) so a great day to work on this.

Ron
Be careful not to reduce the diameter of that pin any more than it is. 0.018" thick spring is loading it pretty heavy and the last thing you need is to have it snap off. Also make sure the second coil is not flat afainst the first coil. You need a little room for the pin to extend through the hole. The Sessions arbor is very small in diameter and this one can be challenging.

RC
 

scottmiami

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Ron, also, just a word of encouragement.

I only started working on my clocks within the last year or 2, and this was the most frustrating thing to me on my first ones. Don't give up! After you do a few it does get easier.
 

Rockin Ronnie

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Ron, also, just a word of encouragement.

I only started working on my clocks within the last year or 2, and this was the most frustrating thing to me on my first ones. Don't give up! After you do a few it does get easier.
Thanks. With a little encouragement I took another stab at it and it finally caught. Great practice with my new Ollie Baker and some lessons learned in the process.

Ron
 

Tracy L Willits

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I had the same issue last week. I took a small punch and drove out the spring catch about 1/32nd of an inch. It doesn't seem like much but it worked great-and is still working. You just want to make sure that you have enough left inside the mainspring arbor to "keep" the catch.
 

Rockin Ronnie

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I had the same issue last week. I took a small punch and drove out the spring catch about 1/32nd of an inch. It doesn't seem like much but it worked great-and is still working. You just want to make sure that you have enough left inside the mainspring arbor to "keep" the catch.
Yes, I had to create a "space" so that the arbor would hook. Frustrating but time and patience paid off.
 

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