Understanding Seth Thomas 89 Movement Variations

Discussion in 'Clock Repair' started by Dave T, Oct 12, 2019.

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  1. Dave T

    Dave T Registered User
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    #1 Dave T, Oct 12, 2019
    Last edited: Oct 12, 2019
    I just recently cleaned and serviced a 89 C and was very well pleased with how it runs and the amplitude of the pendulum. Indicating to me that it is a strong and healthy movement.

    So, I have an old ST with an 89 AD movement, that has never been very reliable. I tore it down and serviced it too. It does have a little more play in the bushings and could use about 3 new ones. But, I assembled the time side (which has always been the problem - strike side works great). And the train runs free with no spring. So, I put the spring in, wound it up and it still doesn't have much amplitude, and not near as much as the C movement (above).

    So, here's one question and would appreciate any input from others who might help me analyze this.
    What's the difference between the two movements, and how do you interpret the ST descriptions.

    Seth Thomas 89 comparison A to C.jpg
     
  2. bruce linde

    bruce linde Technical Admin
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    a tired mainspring? Escapement? Mostly sounds like a tired mainspring… Why don’t you swap out the wheels and see what happens?
     
  3. Willie X

    Willie X Registered User

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    They are all basicly the same. There are many variations though within the group.

    A slight pendulum swing on an 89 is usually caused by wear in the upper pivot holes with the associated rough pivots. If the train is in good condition look for a badly worn escapement. The pallet tips will wear to a point where there is no clear delineation between the dead faces of the pallets and the impulse face. This alone can make for an unhappy pendulum swing.

    I am working on a S-T 89 now. It has severe wear in the upper train but a good escapement. It's doing a solid 1 1/4" on the pendulum swing.

    WIllie X
     
  4. R. Croswell

    R. Croswell Registered User

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    ST made quite a few variations of the No. 89 - some had solid back plates, some cut out, some had a passing bell on half-hour, there were some quarter strikers, I believe thee was even a bim-bam striker, plus a couple models that were paired with a separate Sonora chime unit. I wish someone would produce a table listing all the variations. That said, I agree with Willie, the difference in performance between the No. 89-C and 89-AD is more likely some issues with the 89-AD than any design differences. The adjustment of that strip deadbeat escapement, and pivot/pivot hole wear being probable causes assuming that everything has been cleaned (taken apart and disassembled) and oiled.

    RC
     
  5. Dave T

    Dave T Registered User
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    Appreciate the inputs.
    Think I can eliminate the springs. I cleaned and oiled all four of them in both clocks, and can't tell any difference in any of them.

    The first 89 has at least 1 1/2" swing and has a healthy beat.

    The second one is about 1/2" swing and sounds anemic.
    The escapement looks good on it, (to me). I do think the pivots on the verge could use a polish, but didn't think it would have much bearing?? Would it?

    At this point all I know to do is replace some bushings and polish pivots.
     
  6. Dave T

    Dave T Registered User
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    You and I posting at the same time. I do have the Seth T variations complete list. I'll post it here.
    Can you elaborate on the adjustments of the strip deadbeat for me. I was studying that, and it appears that the pivots are stationary. There is hardly any lock.
    Seth Thomas 89 movements.jpg
     
  7. Dave T

    Dave T Registered User
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    Pretty good video of deadbeat here.
     
  8. Uhralt

    Uhralt Registered User
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    Can you post a picture of your escapement? There should be a way to adjust the verge for more lock. If the teeth fall on the impulse face, that would rob a lot of power.

    Uhralt
     
  9. Willie X

    Willie X Registered User

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    Look up 'adjisting dead beat escapement'.

    Basicly, every e-wheel tooth must always fall onto a 'dead' pallet face, then the pallet moves about 1/2 mm across the dead face and crosses a sharp transition ledge onto the 'impulse' face. Here the tooth slips quickly across the impulse face before sliding off the tip. Then the exact same process repeats on the opposite pallet.

    WIllie X
     
  10. Dave T

    Dave T Registered User
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    Willie/Uhralt,
    I've made a video and still trying to get it posted here.

    But I think I see the pallet landing on the impulse surface as you and others have suggested. So if that's true, how do physically adjust it?
     
  11. Willie X

    Willie X Registered User

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    #11 Willie X, Oct 12, 2019
    Last edited: Oct 12, 2019
    First, take the pallet assembly out and inspect it for wear. No need to waist your time adjusting the pallets if they are in a worn down condition.

    There are two little brass dogbone shaped arms riveted inside the plates. The arms can be carefully moved up or down to adjust the pallet's height. The pallet arbor should remain close to level after adjusting.

    WIllie X
     
  12. bruce linde

    bruce linde Technical Admin
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    upload the video to youtube and then copy and paste the youtube url into a post here....
     
  13. Dave T

    Dave T Registered User
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    Bruce, I normally do that via Youtube, but the video for some reason (in mp4 format) is not usable.??
    Possibly codec error? Beyond me.

    All I'm trying to do is adjust my escapement. I do think the verge is adjustable, but it's riveted on both sides of the frame and real tight. Evidently I managed to move it some, as the clock quit running altogether. So I moved it back and it's where I started.

    This isn't at all like any adjustable verge I ever worked with. I don't know how to adjust it, and not sure that's what is needed.
     
  14. Tom Kloss

    Tom Kloss Registered User
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    Hi

    Tran's Seth Thomas book list 14 variations of the 89 movement.

    Tom
     
  15. Dave T

    Dave T Registered User
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    Just saw this Willie, Thanks!!!! I thought that's what I needed to do. Now you've confirmed that for me.
    So at least, I know I'm not headed down the wrong trail. I'll take it out, and take some pictures for you all. I did adjust it evidently in the movement, as the clock stopped running! So I moved it back and it's where I started.

    I'll keep you posted.

    Dave
     
  16. bruce linde

    bruce linde Technical Admin
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    worked for me... probably a network or browser-needs-be-restarted thing...

     
  17. Dave T

    Dave T Registered User
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    Amazing, not sure how you got that. I kept getting errors and unable to play it. Sorry the video isn't very clear. But I still think I need more lock. Now that Willie explained I'm on the right trail, how do you move those dogleg adjustments? They are tight!
     
  18. Uhralt

    Uhralt Registered User
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    The lower pallet is hard to see in the video but the upper pallet clearly needs to be moved closer to the escape wheel. The teeth are landing on the impulse face. These dog bones are sometimes hard to move or move abruptly too much when using pliers to move them. I have made a tool with a slot in brass pipe and a cross bar to turn the rod. The slot is such that the dog bone fits in. I use it to move the dog bones by turning the tool with the cross bar. You can also use a flat stake and a small brass hammer to move the dog bones cautiously towards the wheel. Just a little at a time, testing in between.

    Uhralt
     
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  19. Bruce Alexander

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    Dave,
    In the past I've found it all too easy to move one of the verge pivot holes more than the other one. If that happens, even a little, you can get binding. Assuming that your verge surfaces aren't worn, when you make your small incremental depth adjustments on both plates, make sure you still have end-shake.
    Good luck with it.
    Bruce
     
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  20. Dave T

    Dave T Registered User
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    Good to know Bruce, I think so far I've been able to move only one side. It has made a very slight difference in amplitude, but I'm not there yet.
     
  21. Dave T

    Dave T Registered User
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    Trying to picture what this tool looks like and how to make one. I think If I could control the movement and then watch the changes it would be much easier to get maximum amplitude. Right now it's (hit and miss).
     
  22. Uhralt

    Uhralt Registered User
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    Her are
    Here are two pictures. One shows the tool in total and the other the slot where the dog bone needs to fit in. I made this (in a hurry) to set the depth of verges that are outside the plates. I could have made it better with straight edges rather than the half round of the cut out, but it works well. For your dog bones, because they are inside the plates, you need to have cut outs on both sides of the pipe and probably need to use a pipe or rod with a smaller diameter. But I think you'll get the principle.

    Uhralt
    tools1.JPG tool2.JPG
     
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  23. Dave T

    Dave T Registered User
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    Thank you! That's what I somewhat had envisioned. I'll see if I can make something.
     
  24. R. Croswell

    R. Croswell Registered User

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    Dave, others have covered this pretty well except perhaps one small but important point. When setting the "lock" it is not a case of more is better. No power is transferred while the escape wheel tooth is on the locking face. All that's required is a good positive lock on the dead face just a little past the impulse/dead face transition line. Excessive lock is counter productive. Don't confuse "lock" with "over swing". (See the video in post #7), lock is the point where the tooth touches down on the dead face. Over swing is the distance the tooth continues to travel after it makes contact. If the clock is healthy it will have significant over swing as seen in that video. The duration of the impulse is fixed by the physical size of the impulse face and is not affected by the amount of lock so long as the lock is on the dead face.

    RC
     
  25. Willie X

    Willie X Registered User

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    #25 Willie X, Oct 14, 2019
    Last edited: Oct 14, 2019
    On this clock it's difficult to actually see the pallet contact points but it's easy to check the adjustment by simply watching the movement of the e-wheel (using good magnification). When the crutch is slowly moved by hand, the
    e-wheel should stop 'dead' (no recoil) after the tick. When the crutch is slowly moved back toward center, just a small amount, you should see the impulse kick in with a quick foward movement of the e-wheel followed by the next tick and another 'dead' stop with no recoil, etc. etc. etc.

    For practice you can watch the second hand on any modern GF clock. The e-wheel motion, on a deadbeat escapement, is always a simple start - stop with never ever any backwards motion.

    WIllie X
     
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  26. Dave T

    Dave T Registered User
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    I have considered the overswing, but guess I was getting confused in trying to get this movement to perform the same as the other 89 I just finished.
    This movement has more bushing wear than the other. And there are no doubt other differences between the two, that makes one 'healthier' than the other.

    I do have good positive lock on the dead face and more swing than when I started. In video #7 - that video was before I adjusted the pallets. It had very little swing and I think the pallets were landing on the impulse face.

    Now that I've adjusted it, it has about 1 1/4 - 1/2 swing and is locking on the dead face. Sounds like I may have it as good as it will get without rebushing, new springs, etc. Think I'll leave well enough alone!

    Adjusting pallets on this movement was new territory for me. All the others (that I've ever worked on) have screws that you can loosen to move the anchor. Which is a whole lot easier task. Guess I just needed to get through the learning curve.

    Thanks!
     
  27. Dave T

    Dave T Registered User
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    Well, now it's time to move over to the strike train. As best as I can remember it was striking okay before I tore it down. Now, it stalls occasionally during the cycle.
    I haven't been able to identify any particular reason. But I do see the governor slowing down also during the cycle. And then, occasionally it stops altogether during the cycle.

    Not sure how to go about resolving this one. Except to tear it down again and closely look at the meshing of each pair of gears one by one. And/or to replace bushings.

    Need some suggestions on how to approach it. Hate to tear it down again as these are difficult to re-assemble with the full front plate!
     
  28. shutterbug

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    Yes, something is robbing power. The only other possibility is that there's not enough power being supplied. But be careful there.
     
  29. Willie X

    Willie X Registered User

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    "Tearing it down" should not happen until AFTER the 'aha there's my problem' moment ...

    WIllie X
     
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  30. Dave T

    Dave T Registered User
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    Yes I do like that idea, but so far I haven't had that "aha". o_O
     
  31. Willie X

    Willie X Registered User

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    Just keep studying it. It's time well spent. :) Willie X
     
  32. Dave T

    Dave T Registered User
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    Well, I've spent three days studying it, and still haven't had that 'aha' moment.
    A couple of things I have considered. The train is a little noisy when it runs through the cycle. But, I've seen a lot of clocks that are.
    The other thing I've considered is that the hour tube is a little loose in the frame. If I move the hands I can see the play in it. Considering bushing the front side of the hour tube?? Any thoughts on that?

    Also, when the time strikes the hammer bounces.

    So, I've got it torn down again!!! I'm going to replace 4 bushings in the time side on the 3rd and 4th wheels. Still not completely satisfied with it. Seems as though it has to be exactly in beat to continue running without stopping.

    Look at all the pivots closely and polish, re-assemble and see what happens.
     
  33. R. Croswell

    R. Croswell Registered User

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    I guess I missed something, I thought you had the time side working OK with 1 1/2" swing which isn't bad for a short pendulum strip deadbeat. I thought the current problem was that the strike train stalls during the cycle.

    As for the hour pipe and lost motion in the hands, this type of clock where the center arbor is not part of the power train will always have a little backlash in the gears. If it didn't it would have excessive friction and stop. As for the hour pipe wobbling or being loose in the hole in the front plate, that's mostly just an annoyance. Very little power is used to move the hour hand and this is not usually a problem with the running of the clock. You can bush the large hole in the front plate and the inside of the base of the hour pipe if it really bothers you but I think most people just live with it.

    Bushing the 3rd and 4th time train arbor pivot holes may improve the performance of the time train if these holes are worn but are not likely to solve the strike train issue.

    If I understand correctly, the strike sequence begins but the wheels turn sluggishly and sometimes it stalls out. Is that correct? The strike train failing to start is an entirely different problem.

    Before tearing it down, let down both main springs into clamps or wire binding, release the clock springs, make sure you can jiggle the main wheels back and forth with absolutely no power from the spring. Place the movement on its back. use a probe to "lift" each wheel up to the front plate and release it. It must drop back down quickly on its own. Now place the movement face down and do the same thing. We are looking for a tight pivot and the most probable cause being a pivot that got bent during assembly, or a bushing that was installed crooked or broached at an angle that seemed OK alone but not being perpendicular to the plate (parallel to the pivot) now causes it to bind. Sounds like a power problem, I doubt that it is a spring issue unless someone installed the wrong spring.

    RC
     
  34. Dave T

    Dave T Registered User
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    Great info here RC. Thanks so much! A lot to digest, but believe me I will study this. I've inserted some answers above. (underlined and Italics) Unfortunately, I've already got it torn down again.
     
  35. Dave T

    Dave T Registered User
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    I've put this movement back together for the 2nd time, but can't say I've gained much yet on the strike side. I'm comfortable with the time now, as it has decent lock but not excessive.

    As I move the hands through the time occasionally it tends to lock up when the cam on the minute arbor approaches the lift arm for the strike. And when this happens the warning wheel seem to be locked tight against with the pin against the stop arm. (Hope that makes sense). Can't move the warning wheel backward with my hand, as I usually can when it's not locked, to check to see if it's turning free.

    And when this isn't occurring the strike cycle almost always complete as it should. I've found it slowing down a little but not as much as before. I polished all the pivots on the second teardown, and I don't see much bushing wear at all.
    With the springs letdown, all the wheels have good up and down motion from both sides of the frame. The only one that might be suspect to me is the strike cam wheel. Doesn't seem like it has as much free up and down motion as the rest of the strike train wheels.
     
  36. shutterbug

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    When the cam starts the lift, the stop pin should unlock and at the same time another lever raises to stop the pin. That's the warning run.
    It sounds like the stop wheel is not unlocking as it should. You'll have to watch the levers that are rising to see what's happening. The stop lever should rise enough to unlock. If it's not raising enough you may need to adjust the lower lift lever a little (not the J hook, the next one). It should contact the next lever shortly after the J hook starts rising.
    Also be sure the stop lever is not under the pin. The pin should bump against the end of it.
     
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  37. R. Croswell

    R. Croswell Registered User

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    It doesn't matter how much end shake you have as long as you have some. You might try the lift and drop test again, but this time press the wheel "up" with enough force to ensure that the end of the arbor is actually in contact with the plate and let it drop on its own. We are looking for a tapered pivot that might be tight as it enters the pivot hole..

    As for the stop wheel locking up, that's a puzzler. Check that the governor fan isn't hitting anything. One edge of the fan should have a notch cutout so it clears the pinion on the stop wheel. If the fan is put on upside down the blade may be in contact with the pinion of the stop wheel. While it is locked up it shouldn't be too hard to see what's preventing it from turning.

    RC
     
  38. Dave T

    Dave T Registered User
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    Thanks Shutt. All of that part is working as it should, ( as near as I can tell ).

    BUT, I think I've found it! The pinion on the governor is not meshing deep enough on the gear teeth of the warning wheel. Occasionally, it hangs up with one pinion on top of a tooth. And there is some bushing wear on both of those wheels. I didn't think there was enough wear on those bushings to cause that.

    That might (most likely) be why the train slows down during the cycle?

    Teardown #3 ahead! Another day, not today!!!
     
  39. Bruce Alexander

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    That's a lot of wear that you're describing Dave. Either that or perhaps someone before you has bushed the pivots way off center. Have these pivot holes been worked on before?

    Also, just curious as to the state of your Verge. Was there any noticeable wear to it? Willie has brought up the issue a couple of times. Are there any ruts in your Verge's impulse/lock faces? If you responded and I missed it, my apologies. Just want to make sure that wear to the verge has been ruled out.

    Regards,

    Bruce
     
  40. Dave T

    Dave T Registered User
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    I was thinking the same thing Bruce. A lot of wear for no more play than there is in the bushings. But, yes, the clock does show signs of previous repair and I was wondering myself if the bushings were installed off center.
    However, I don't know how to determine if they were or not. Or how to be sure I've gained the proper spacing between wheels when I replace them now. (ie: to regain the proper centers)
    I just took some pictures and looks to me like they are original but have been punched but not replaced! Can't be certain.
    After studying these pictures, it looks like the warning wheel bushings are low on both sides of the frame. What do you all think?

    Seth Thomas 89 strike train bushings 3.jpg Seth Thomas 89 strike train bushings 2.jpg Seth Thomas 89 strike train bushings 1.jpg Seth Thomas 89 verge.jpg
     
  41. Willie X

    Willie X Registered User

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    #41 Willie X, Oct 24, 2019
    Last edited: Oct 24, 2019
    I'm not seeing any bushing work?

    Pallet wear seems to be slight but the photo isn't good enough to tell for sure.

    WIllie X
     
  42. Dave T

    Dave T Registered User
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    Good, after studying the pictures I think I would agree. So, that means centers should be good?
    I've tried to see if I have a deep set mesh between the warning wheel and the 2nd wheel, but it's hard to see.

    And one thing I think I've discovered is that it only locks up (between the governor and the warning wheel) is when I move the hands manually or lift the locking cam to allow strike. The clock ran all night long and didn't lock up!

    Looks like the two worst bushings are on both sides of the warning wheel. Governor bushings don't look bad.
     
  43. R. Croswell

    R. Croswell Registered User

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    #43 R. Croswell, Oct 24, 2019
    Last edited: Oct 24, 2019
    Dave, you can't tell much about the wheel to pinion spacing just by looking at worn pivot holes that have been punched. You need to look at the point where the pinion trundles actually contact the driving wheel teeth. Technically it should be at the pitch diameter of the wheel, but for a fly pinion like this you can get it close enough by eyeball. This picture is not a Seth Thomas but is a working movement with unbushed and unmolested original pivot holes. Notice where the wheel teeth contact the pinion.

    RC

    wheel-pinion-setup.jpg

    Are you rally sure that the governor pinion and warning wheel is the contact point that's locked? Next time it locks up, use magnification and observe the governor pinion and very gently rock the fan back and forth and see if there is any free play between the pinion and the wheel. If there is then something else is locking up the train.
     
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  44. shutterbug

    shutterbug Moderator
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    How does the pinion look? It's a lantern pinion, yes? Does it look like the trundles were replaced? They might have used the wrong size wire.
     
  45. Dave T

    Dave T Registered User
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    Pinions look fine. They're bright where contact is, but very little wear, and don't look like they've ever been replaced.
    Yep, I'm sure about that. When it locks up the warning wheel is stopped tight. And the only way to release it is to back the governor off a tad and it immediately frees up. (by popping the pinion off the top of the tooth) And I could see the pinion sitting on top of the tooth of the warning wheel.
     
  46. Bruce Alexander

    Bruce Alexander Registered User
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    Dave,

    If you have an unworn "side" to the original pivot hole, using it as your reference point you should be able to see if the pivot is off center. That situation will only occur if there has been wear on the bearing side of the pivot hole. Punched pivot holes only really bother me when the punch marks are all around the pivot hole as opposed to being just on the worn bearing side.

    As a matter of course, I normally bush a punched hole but it was a common practice and if done properly (punched and broached) it might be okay to leave alone. At that point it's really a matter of preference. The condition of the pivot might inform your decision.

    There are a number of ways to re-establish center. I have an inexpensive Depthing Tool in my shop. It works with larger pivoted wheels but it's accuracy wanes a little with smaller pivots. A precision tool can be a little pricey. See this link: Mile Hi Clock Supplies - Keystone Tools One can find used ones on the market of course. One way to test an example's precision is to see if both sides can scribe an identical arc. If not, the runners are not parallel and the Tool can potentially introduce an unacceptable amount of error when you want to transfer the wheel depth to the movement's plate(s).

    Jerry Kieffer has described several additional methods to re-establish center using a Mill, Lathe and a low-cost drilled steel "guide" plate which has been clamped over the re-established center to guide placement of the new bushing. You can perform a Search on "Depthing Bushings" or similar phrases to find Threads in the Archives which can help you to better understand the goal and methods used to achieve good results.

    All methods require the operator to temporarily adjust the meshing of two adjacent wheels until they reach the low-friction pitch diameter that RC has demonstrated for you. You'll be able to tell by feel when the wheels are at the optimum mesh as they'll "glide" to a smooth stop when you manually spin them.

    If something is causing periodic binding, you should strive to find and correct it while the movement is on the test stand. If it happens once, chances are really good that they'll happen again after you've put everything back together. I hate when that happens!

    Regards,

    Bruce
     
    Dave T likes this.
  47. Dave T

    Dave T Registered User
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    Thanks Bruce, Good information. But as a hobbyist, I think I'll take a chance on replacing the two warning wheel bushings and try to get the centers as close as possible. And I think I'll assume the bushings are original.
    I can see the pivots have dropped a little on both sides of the warning wheel due to wear.
    Here's a picture of the warning wheel pinion. (when not locked).
    Seth Thomas 89 warning wheel pinion.jpg
     
  48. Bruce Alexander

    Bruce Alexander Registered User
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    The mesh looks a little deep to me. In my experience Depthing problems between these two wheels is common and problematic. Some higher grade movements have off-set bushings to adjust the depth of the Fans but those usually have very fine driving teeth and equally fine leaf pinions to fine tune.

    Use your sense of feel. If you manually drive the mesh and it doesn't feel smooth and if the gears don't glide to a smooth stop, there's a problem with the depth. They won't glide for long because the Governor is doing its job.

    See what others think.
     
  49. R. Croswell

    R. Croswell Registered User

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    #49 R. Croswell, Oct 24, 2019
    Last edited: Oct 24, 2019
    Very likely one of three possible problems:
    1. One of the trundles in the lantern pinion is bent slightly. The trundles usually can rotate in the shroud so a bent trundle so it is easy to miss and would not happen all the time.
    2. One of the teeth on the warning wheel is bent or otherwise buggered up.
    3. The alignment of the wheel to pinion is not as shown in post # 46. Check for every tooth in the warning wheel.

    Next time it locks up use a felt tip marker to mark both the pinion and the warning wheel where they are in contact. If the pinion is always in the same position when it locks up then there is something wrong with the pinion at that point. If the warning wheel is always in the same place every time, there is likely something wrong with a tooth at that position.

    Can we see pictures of the governor pinion? If the clock has been messed with there is always the possibility that someone may have replaced the governor fan, arbor, and pinion with one that isn't the correct size.

    RC

    OK I see you posted a picture. The depth looks OK but some of the teeth on the warning wheel look a little chewed up on the tip. With a small lantern there isn't much room for error. As suggested, it might help to turn by hand and "feel" for the problem. Best done with just the warning wheel and governor in place between the two plates.

    Hay, wait a minute! That picture isn't the governor pinion and warning wheel. Lets take a look at the pinion that's actually locking up.
     
  50. shutterbug

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    Good pic. Yeah, you have a bind there. The part of the tooth where the straight part ends and the taper begins should hit at about mid-point of the trundle. It could be a depthing problem, it could be oversized pinion wires, or it could be a replacement lantern pinion from another clock. It might be any of the things already mentioned. You may have to build yourself a makeshift depthing tool to check things out.
     

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