Alignment of Anchor Pin in Gustav Becker

Discussion in '400-Day & Atmos' started by KurtinSA, Aug 16, 2018.

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  1. KurtinSA

    KurtinSA Registered User
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    I'm working a 1913 GB clock...it's the one in this post:

    My Collection has Grown!

    It has not run since I got it, and early on noticed something unusual about the anchor and escapement. I'm finally getting around to it. I was thinking that I might discover some reasons when I cleaned and reassembled.

    What I'm noticing is that anchor pin never comes past the vertical position as I manually operate the anchor with my finger. The pin stays completely to the right of center as you look at the back of the clock. I guess that's going to be a problem, right?

    The anchor pin points straight up when the anchor sits on the bench. As near as I can measure, the pallets are exposed the same amount which results in the pin pointing straight up. Nothing is bent. I'm getting good movement of the train...the EW takes off with just a few clicks of the main spring. I thought that maybe the anchor bushing and the EW bushing weren't on a vertical line, but that doesn't seem to be the case. The locks and drops appear to be reasonable, but I haven't really looked that deeply yet.

    What controls the position of the anchor pin? AFAIK it should move about 4 degrees each side of center for proper operation. I'm not anywhere close to that. What should I be looking for? Here's a picture of the eccentric slot...pretty well abused. I don't know if this is where I need to be looking.

    Thanks...Kurt

    GB1913Eccentric.jpg
     
  2. MartinM

    MartinM Registered User

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    If the locks and drops look right by measurement, how does the pin look during the impulse phases (manually manipulating the anchor pin to see where on the pallet the impulse begins and ends and checking the range of motion and relation to the clock centerline for the pin in both directions.
     
  3. KurtinSA

    KurtinSA Registered User
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    #3 KurtinSA, Aug 16, 2018
    Last edited: Aug 16, 2018
    Martin -

    The pin never comes to center. I get all my locking/unlocking with the pin to the right of centerline.

    This clock has the pin inserted into a brass collar which is then pushed/staked onto the arbor. Not sure how many makers do that, but typically, the pin is inserted directly into the arbor...maybe that's done on the much younger clocks and requires fewer machined parts. But as I said, with the pallets sitting on the bench, the pin was pointing straight vertical. I'm just having trouble understanding how this can be. The EW pivots are centered in the plate, the pallets are evenly exposed, but yet the pin is off to one side. :???:

    Kurt
     
  4. Harry Hopkins

    Harry Hopkins Registered User
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    Kurt, Is the collar that is fit on the arbor similar to this one? I had to make this collar and pin assembly for a customers clock recently. I had not seen the arrangement before but the one I worked on was a Junghans and the collar had to be a tight but adjustable fit as it was the adjustment for beat. Is that how the beat is set on your clock? If so if the suspension spring has a small bend between the fork and the top block it would cause you to have to have the anchor pin off center a bit to get it in beat.
    image000000 (37).jpg
     
  5. KurtinSA

    KurtinSA Registered User
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    Harry -

    Attached is a similar picture of the anchor for this clock. The saddle is essentially #7 in the repair guide. The upper block is captured by the bigger block and the beat is set by turning CW or CCW. The suspension spring is unmolested. I don't even have that hooked at this point as you can see. I'm just advancing the escapement with my finger.

    Note the appearance of a small hole or gap next to the base of the pin. The pin is solid in the collar, so it's not rocking back and forth.

    I just can't figure out how this can be happening.

    Kurt

    GB1913Anchor.jpg
     
  6. Harry Hopkins

    Harry Hopkins Registered User
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    If the pin was moved in the direction of the gap would that make it more centered? I wonder if someone has re drilled the hole for the pin for some reason. The only other thing that comes to my mind is if the pallets are mis adjusted it would cause the pin to be off center.
     
  7. KurtinSA

    KurtinSA Registered User
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    No, I believe if the pin were moved towards the hole, it would only make things worse. The view of the picture is from the front towards the back plate. The pin spends all of it's time to the right of center....or to the left of center per the picture. Moving the pin towards the hole just makes it more left of center.

    The pallets are sticking out the same amount. So I'm still scratching my head why the anchor pin moves completely to one side.

    Kurt
     
  8. Harry Hopkins

    Harry Hopkins Registered User
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    If the escapement geometry looks good and the collar that the pin is mounted in is a friction fit on the arbor it may be you just need to move the collar radially a bit to get it centered so you have your 4 degrees each direction.
     
  9. KurtinSA

    KurtinSA Registered User
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    Harry -

    I thought about that and actually tried to move it a bit...but wasn't sure what it might take and backed off. But the point I keep coming back to is that if I move the collar and reorient the anchor pin, it will be pointing off the one side when the anchor sits on the bench. The pallets are equally exposed. It was my understanding that the "perfect" anchor would have equal pallets with the anchor pin straight vertical.

    Kurt
     
  10. KurtinSA

    KurtinSA Registered User
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    I will say that it seems clear that the anchor pin is not original to the clock. The top point shows signs of being cut by a pair of wire cutters. When I get the chance, I'll remove the anchor and take some better pictures on the bench.

    Kurt
     
  11. Burkhard Rasch

    Burkhard Rasch Registered User
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    there are clocks with"oblique" anchors ,that is the axis of the anchor is not parallel with the upper edge of the plate . If that was the case rotating the anchor pin with its collar would be the option of getting the anchor pin upright.
    (allthough I´ve never heard of a GB with that feature)
    Burkhard
     
  12. KurtinSA

    KurtinSA Registered User
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    A few more pictures of the anchor...kinda poor lighting. The pin isn't as vertical as I thought, but that's not really enough to contribute to my problem. I mentioned that the pin is not original to the clock. It now appears that the collet/collar is also not original. The brass is much shinier than the anchor itself.

    In my case, the pin comes near vertical during part of the escapement, but then goes back to the right. So, it would appear that the "center" of the movement is around 4-5 degrees too far to the right in these pictures. If I were to rotate the collet to the left that 4-5 degrees, it will be pretty clear that the pin would be angled to the left. I can see that's "better" for the escapement, but why is it necessary for such a big offset?

    Kurt

    GB1913Pin1.jpg GB1913Pin2.jpg
     
  13. KurtinSA

    KurtinSA Registered User
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    So, I decided to do the deed. Made some marks on the pin's collar for a starting point and put the arbor in a hand vise. Gave it a tweak and moved it a bit. Put the anchor back in the clock and found that I might have gone a skosh too far...but as they say, better is the enemy of good. I assembled the clock (no motion works) and started it up. It picked up power from barely tick-over after setting the beat. Cautiously optimistic with nearly 180 deg total swing and some healthy over swing. I forgot to check the fork-tine clearance but can do that later. I can also think about raising the fork. I'll just let it go for now.

    Kurt
     
  14. Harry Hopkins

    Harry Hopkins Registered User
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    Glad to hear it's running. Sometimes you just have to try something that may not seem to make sense. Is the anchor pin centered now to your eye?
     
  15. KurtinSA

    KurtinSA Registered User
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    Harry -

    Given the age of the clock, I thought I had one shot at getting it right...figured I'd better get some ideas. On the bench, the anchor pin is now to the left of center. In the clock, the pin travels slightly more to the left side than to the right of center. As I said, I overshot a bit...but as long as it runs and has good power (aka over swing) I'll leave it as is. Still haven't progressed to putting on the motion works...maybe tomorrow if it behaves itself!

    Kurt
     
  16. Burkhard Rasch

    Burkhard Rasch Registered User
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    never change a winning adjustment!Congrats! I wonder what John´s got to say about an oblique anchor in a GB,neverheard of that.
    Burkhard
     

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