Sessions tambour cathedral gong clock questions

Schatz70

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I bought this clock from a Craigslist seller for $15 a couple days ago. It is very similar to the Sessions bim bam clock I worked on recently - both of them have count wheel strike sides, both have a passing strike for the half hour (there are two cams on the center wheel, one of which activates the strike side on the hour and the other lifts a hammer and lets it drop on the half hour). The main difference is that the bim bam clock has two hammers for two strike rods, and this one has one hammer for a gong. The time side seems to run OK but the strike side isn't assembled correctly which is what I want to ask about.

As it is now, the strike side doesn't lock properly. When the count finger is in one of the deep grooves on the count wheel, the maintenance lever is bottomed out in one of the gullies of the maintenance cam as it should be, but the warning pin is not at the top and therefore the stop lever can't grab it to stop the strike. If that were the only problem, maybe I could just put clamps on the springs and loosen the plates a little and pop out the warning wheel to adjust it. But there is another problem - both of the brass wire springs on the strike side lever arbors are missing (you might sorta kinda be able to see that in the fourth picture). My experience with the bim bam clock tells me those brass springs are very important to the operation of the strike side, as in you can't depend on just gravity to bring those strike side levers down, you need the extra little oomph from the brass wire springs. At the moment, the only thing causing the strike side to lock at all is that the tail of the hammer arbor seems to be bent wrong so that after a while it jams on one of the tabs on the maintenance wheel which locks up the strike side.

So here is what I'm thinking - it might be possible to install new brass wire springs on the two strike side lever arbors with the movement fully assembled, but it would be a lot easier if I took the whole thing apart. Also I need to straighten out the tail on the hammer arbor so it doesn't jam up the strike side. And if I'm going to go that much trouble, I might as well take the main springs off for cleaning and run everything through an ultrasonic cleaner. From what I can see, it doesn't need any bushing work. That's what I'm thinking, but what do I know? I'm new at this. What do you think?

Sessions tambour cathedral gong clock 7 16 2020 002.JPG Sessions tambour cathedral gong clock 7 16 2020 003.JPG Sessions tambour cathedral gong clock 7 16 2020 004.JPG Sessions tambour cathedral gong clock 7 16 2020 005.JPG Sessions tambour cathedral gong clock 7 16 2020 006.JPG Sessions tambour cathedral gong clock 7 16 2020 007.JPG
 

lpbp

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You might be able to install the helper spring while it's assembled, but I always advise to tear them down, clean, oil and fix what's wrong and put back together.
 

Schatz70

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You might be able to install the helper spring while it's assembled, but I always advise to tear them down, clean, oil and fix what's wrong and put back together.
Thanks! I think that's what I'm going to do.
 

John P

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Yes, indeed. do a complete restoration on the movement. Clean oil and rebush as needed.
I find it easier to leave out the stop wheel and fan until the plates are together. Making sure
maintenance cam and count wheel lever is correct. Then gently spread the plates and install the
stop wheel correctly, then fan.
my 2 cents
 
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shutterbug

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The brass spring wire is easy to find at most suppliers. You need the thin kind. Just hook it on and wind it around the arbor a few turns. Be sure to get the direction right :)
 
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Schatz70

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The brass spring wire is easy to find at most suppliers. You need the thin kind. Just hook it on and wind it around the arbor a few turns. Be sure to get the direction right :)
Thanks. I have a couple spools of the brass wire. I had to replace both helper springs on the Sessions bim bam clock I worked on recently - now as you say I just have to remember which way to wind the wire. My experience with the bim bam clock is that the right time to tie off the loose ends of the helper springs to the pillar is after the plates are back together; otherwise the tension they exert interferes with reassembly.
 
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R. Croswell

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I bought this clock from a Craigslist seller for $15 a couple days ago. It is very similar to the Sessions bim bam clock I worked on recently - both of them have count wheel strike sides, both have a passing strike for the half hour (there are two cams on the center wheel, one of which activates the strike side on the hour and the other lifts a hammer and lets it drop on the half hour). The main difference is that the bim bam clock has two hammers for two strike rods, and this one has one hammer for a gong. The time side seems to run OK but the strike side isn't assembled correctly which is what I want to ask about.

As it is now, the strike side doesn't lock properly. When the count finger is in one of the deep grooves on the count wheel, the maintenance lever is bottomed out in one of the gullies of the maintenance cam as it should be, but the warning pin is not at the top and therefore the stop lever can't grab it to stop the strike. If that were the only problem, maybe I could just put clamps on the springs and loosen the plates a little and pop out the warning wheel to adjust it. But there is another problem - both of the brass wire springs on the strike side lever arbors are missing (you might sorta kinda be able to see that in the fourth picture). My experience with the bim bam clock tells me those brass springs are very important to the operation of the strike side, as in you can't depend on just gravity to bring those strike side levers down, you need the extra little oomph from the brass wire springs. At the moment, the only thing causing the strike side to lock at all is that the tail of the hammer arbor seems to be bent wrong so that after a while it jams on one of the tabs on the maintenance wheel which locks up the strike side.

So here is what I'm thinking - it might be possible to install new brass wire springs on the two strike side lever arbors with the movement fully assembled, but it would be a lot easier if I took the whole thing apart. Also I need to straighten out the tail on the hammer arbor so it doesn't jam up the strike side. And if I'm going to go that much trouble, I might as well take the main springs off for cleaning and run everything through an ultrasonic cleaner. From what I can see, it doesn't need any bushing work. That's what I'm thinking, but what do I know? I'm new at this. What do you think?

View attachment 600649 View attachment 600650 View attachment 600651 View attachment 600652 View attachment 600653 View attachment 600654
I believe you know what should be done and good advice has already been given. I'll just add be sure to check the clicks and click rivets. Almost every Sessions movement that I service has loose click rivets and worn clicks that are in danger of failing. The best time to assess whether bushings are needed is after the clock is apart and clean. I expect you will find significant wear in some pivot holes.

RC
 
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Schatz70

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I believe you know what should be done and good advice has already been given. I'll just add be sure to check the clicks and click rivets. Almost every Sessions movement that I service has loose click rivets and worn clicks that are in danger of failing. The best time to assess whether bushings are needed is after the clock is apart and clean. I expect you will find significant wear in some pivot holes.

RC
Thanks, RC! On the Sessions bim bam clock, I ended up replacing the time side brass smooth sided click rivet with a steel shouldered rivet I made on the lathe after you explained that to me. I was a little bit tempted to do the other one but it's a lot of work so I just left it. Do you ever just go ahead and replace both click rivets to save future trouble, or do you sometimes leave them alone?
 

R. Croswell

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Thanks, RC! On the Sessions bim bam clock, I ended up replacing the time side brass smooth sided click rivet with a steel shouldered rivet I made on the lathe after you explained that to me. I was a little bit tempted to do the other one but it's a lot of work so I just left it. Do you ever just go ahead and replace both click rivets to save future trouble, or do you sometimes leave them alone?
That's a judgement call. If I do one I usually do both and I replace quite a few click rivets and not just in Sessions movements. One might say "if it ain't broke don't fix it" but if it is at all loose It will soon be a "broke" problem.

RC
 

Schatz70

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That's a judgement call. If I do one I usually do both and I replace quite a few click rivets and not just in Sessions movements. One might say "if it ain't broke don't fix it" but if it is at all loose It will soon be a "broke" problem.

RC
I took it apart, and both click rivets are too loose and will need to have rivets replaced. One was so bad that it was slipping on the spring winder. Thanks for the warning. As I remember, you replace the click springs as well using steel. Is there anything important regarding what kind of steel wire to use for the click springs?
 

R. Croswell

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I took it apart, and both click rivets are too loose and will need to have rivets replaced. One was so bad that it was slipping on the spring winder. Thanks for the warning. As I remember, you replace the click springs as well using steel. Is there anything important regarding what kind of steel wire to use for the click springs?
If you replace the brass spring wire with steel you will probably go with a slightly smaller diameter. Use spring steel such as pivot wire, music wire, or perhaps a guitar string. You want about the same tension. I don't recall ever having a brass click spring fail, but I feel safer with steel if I replace the spring.

RC
 

Schatz70

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If you replace the brass spring wire with steel you will probably go with a slightly smaller diameter. Use spring steel such as pivot wire, music wire, or perhaps a guitar string. You want about the same tension. I don't recall ever having a brass click spring fail, but I feel safer with steel if I replace the spring.

RC
Thanks, RC. You are consistently very helpful. Thank you for generously sharing your knowledge.
 

shutterbug

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When winding the brass wire for the helper spring, just remember that you wind it in the direction you want the arbor to move :)
 
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