Seth Thomas electric

Discussion in 'Electric Horology' started by sshroyer, Apr 7, 2008.

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  1. sshroyer

    sshroyer Registered User

    Feb 12, 2004
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    Greetings,
    I have a Seth Thomas electric mantle clock in the shop with the self winding strike mainspring. The mainspring appears to need service, but I have not taken one apart yet. Please advise how to disassemble the mainspring barrel.
    Thanks so much,
    Steve
     

    Attached Files:

  2. LaBounty

    LaBounty Registered User
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    Aug 29, 2002
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    Hey Steve-

    Clamp the barrel in a vise and use a flat-faced punch to tap the cap off. Once the cap is removed you can see how things come apart. You can use smooth-jawed pliers to press the cap back on once the mainspring is serviced.

    Good luck with it!
     
  3. sshroyer

    sshroyer Registered User

    Feb 12, 2004
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    Thanks David!
    As you can see below, I was able to take apart the barrel with your help. Looks like the spring has been repaired? The spring is 3/16" by .006". Timesavers offers one 3/16" spring that is .009" Is the stronger spring okay to use here?
    How does the mainspring stay wound with nothing to grab onto in the barrel?
    Thanks,
    Steve
     

    Attached Files:

  4. LaBounty

    LaBounty Registered User
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    Aug 29, 2002
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    Hey Steve-

    Good job so far! Your mainspring has a broken bridle.

    These mainsprings don't actually hook into the barrel but are allowed to slip inside since they are under a constant wind from the motor. It is the pressure of the bridle against the side of the barrel which gives the mainspring enough tension to run the train.

    You should be able to identify which of the two pieces is an extension of the mainspring and which was attached with the rivet. I believe you can move the rivet back a bit and reattach the bridle without significant change in the performance of the strike or chime. You may need to make a new rivet and anneal the mainspring in the area where a hole will need to be drilled.

    Good luck with it!
     
  5. johnboy

    johnboy Registered User

    Apr 15, 2007
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    I repaired a similiar electric clock last year and had trouble with the springs not slipping in the spring barrels. It caused the clock to loose time. I will try to attach the answer below that explains this spring action and why they slip.

    - Re: Seth Thomas Electric clock runs slow (17:28:29 19 Apr 2007)


    johnboy

    post # 6 of 36

    Quote: 12:08:37 17 Apr 2007 by Eckmill
    Although "The movement has been completely been gone through and repaired for worn bushings." I wonder if Johnboy examined the condition of the two mainsprings?

    The spring barrels have no hook so that the outer coil of the spiral spring simply slips in the barrel when fully wound. It is possible that there's not enough "slip." Consequently the spring or springs may be presenting an extra heavy load on the motor causing it to slow except during the quarterly chime and strike phases.

    Do this: force the chime and strike trains unlocked so that they run continuously and observe if the clock looses its rate.




    Eckmill - At first I didn't understand your suggestion but after looking at the movement again you may be on to something. No, I did not disassemble the 2 mainsprings because they seem to be free and not sticky. Also because the spring housing did not come appart easily. I thought the slip clutch on the spring drive gear would slip when completely wound up but I think I see that is not the case. I tried winding the springs from the back with the small key with the clock. The spring in the strike side seems to slip as you cannot get it to wind tight. The spring in the chime side locks up when I wind it tight. Is this what you were referring to? If so I need to disassemble the chime side spring housing and/or both sides.

    NAWCC Member: Yes | Location: MI | Registered: 16:34:38 15 Apr 2007

    Steve - LaBounty has you on the right track - as usual.
    Good luck on completing your repair.

    Johnboy
     
  6. Dave T

    Dave T Registered User
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    Dec 8, 2011
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    I know this is an old post, but I have most likely the same problem with my Seth Thomas Brookfield Electric Banjo fitted with the A-300 Series chime.
    I'll admit my ignorance here by telling you what I've done so far.
    When the clock was first purchased the time function is okay and keeps good time, but the chime did not work at all.
    I cleaned the entire movement, (except the motor of course) in my ultrasonic cleaner. And after re installing in the clock the chime worked fine for about a week, and then began to slow down until it now doesn't work at all.
    I'm thinking the strike spring must have some damage internally from the cleaning?
    I have yet to attempt disassembling this movement, but think from this post that's most likely what needs to happen, and take a hard look at the inside of the spring barrel.
    Any advice would be greatly appreciated before I proceed. I'm not sure quite how to proceed with tearing this movement down, especially in the area of the chime components.
     
  7. Dave T

    Dave T Registered User
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    Dec 8, 2011
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    As a follow up to my last post. I have got the chime spring assy out of the clock, but I need some guidance as to how to remove the two gears on both sides of the barrel, (the drive gear and the winding gear).
     
  8. Dave T

    Dave T Registered User
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    Dec 8, 2011
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    Never did get any resolution to this problem. The clock runs but no chime!
    Anyone ever take one of these apart? EDIT: I just re-read the entire post. Think I'll take a crack at it!
    Seth Thomas Brookfield Electric chime spring.jpg
     
  9. Dave T

    Dave T Registered User
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    Dec 8, 2011
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    Well, I've got this spring out again, but now I'm wondering how to get at the barrel with gears on both ends?
     
  10. Dave T

    Dave T Registered User
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    No answers on how to get that thing apart. So, I cleaned it up the movement, put it back together and it runs like a champ!
    Easiest clock I ever worked on!
     

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