Mauthe Movement - Pin or Cam Stop

Discussion in 'Clock Repair' started by MuensterMann, Aug 25, 2019.

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  1. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
    1,121
    11
    38
    I just reassembled a 1930s Mauthe movement. I noticed that the strike stops not on the pin, but rather on the edge of the gathering pallet. The pin is used on the warning, but not to stop the train - at least as far as I can figure out. All is fine, except that the time train has to lift the lever at warning to a height above the valley on the gathering pallet - and there is too much friction between the pallet valley wall and the lifting lever. I polished a little, but it often stops the time train at warning.

    Is it a normal design for the edge of the gathering pallet to stop the train as opposed to the pin? What would be best to resolve this problem?

    The image is before cleaning and it does not show the gathering pallet in the stop position.
    P8160008.JPG
     
  2. shutterbug

    shutterbug Moderator
    NAWCC Member

    Oct 19, 2005
    39,678
    533
    113
    Male
    Self employed interpreter/clock repairer
    Iowa
    Country Flag:
    Region Flag:
    You can adjust that with the gathering pallet. You want the train to stop as the hammer falls.
     
  3. peanuts

    peanuts Registered User

    Mar 21, 2017
    315
    21
    18
    Male
    Retired
    Shaftesbury, UK
    Country Flag:
    Region Flag:
    I have been working on an English 3-train movement that stops the strike train in the same way. It too would often stall when trying to go into warning. I did everything I could to reduce friction and to increase the energy in the time train. In the end it seems the back of the collet in the minute hand was touching the front of the hour pipe and that was robbing it of just enough energy to stall when going into warning.
    So check for lost energy in the time train somewhere.
    Simon
     
  4. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
    1,121
    11
    38
    When I lift by my finger the lever to trip the strike, I feel considerable resistance to lift the lever off of the pallet. The friction is there at the pallet and I can feel it. Help!
     
  5. Willie X

    Willie X Registered User

    Feb 9, 2008
    11,292
    507
    113
    The cam and/or the lever tip may have been over modified to increase the 'draw'.

    A common problem with this type stop is bounce. After some years of running the leaver can become worn and bounce up instead of cleanly capturing the cam. This can add one (or many) extra counts of the strike. Some repairers will fix this problem by fileing the lever tip and/or the cam notch to draw in at locking. This will cure the strike bounce problem but add a lot of unnecessary resistant to raising/unlocking of the cam.

    Watch the cam closely as you slowly raise the lever. The cam should not move the cam backwards more than a couple of thou during the unlocking and the motion should be smooth. Correct as necessary to give minimal but notacable draw. Polishing is not necessary but the active surfaces should be smoothed with a fine jewelers buff, popsicle stick with #800 paper).

    When correct the hook will cleanly stop the cam every time, even with a little extra pressure on the 2nd wheel at full wind. And, you should feel very little resistance when lifting the locking lever with a toothpick.

    If this action is good, the problem will probably be low power in the time train.

    Hope this helps, Willie X
     
  6. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
    1,121
    11
    38
    Okay, so using the cam as a stop is a normal design AND others have had this problem where the force is too much for the lift. This is good to know. Lifting with a toothpick is really difficult. The power on the train is very good.
     
  7. Willie X

    Willie X Registered User

    Feb 9, 2008
    11,292
    507
    113
    The lever should lift easily, assuming the toothpick is being placed close to the locking point.

    Some have near neutral draw. These will have a small coil spring to prevent the bounce. Most HM movements of late use a spring.

    This system goes way back. Some old American clocks used it and it is still used on many German clocks today. I think most, if not all Kieningers have this system. But, on a three train clock the lever lifting is done indirectly by the chime sequence cam.

    Willie X
     
  8. R. Croswell

    R. Croswell Registered User

    Apr 4, 2006
    8,893
    414
    83
    Male
    Trappe, Md.
    Country Flag:
    Region Flag:
    The answer to your question is sometimes yes, and sometimes no. I have a clock in right now that is supposed to stop on the pin but initially after I put it together is was actually stopping on the gathering pallet cam. It was working but for my clock is is not supposed to do that. The problem was that the gathering pallet cam was dropping before the stop pin was in position to be captured. A slight repositioning of the can solved the problem.

    So how do you tell if it should stop on the pin or the cam? Look at the wheel with the stop pin and look for any lever tabs that can move into the path of the stop pin. If there are two tabs that can contact the stop pin, then one is the warning stop and the other is the stop after striking and that clock should stop on the pin and not the cam. If there is only one stop tab then that tab is the warning stop and the stop after striking is at the cam. These details are not visible in your picture and I'm not familiar with that particular movement. You must have a warning stop and a final locking stop. A few clocks have the warning stop on one wheel and the final stop on another. On close inspection it should become obvious whether there is a stop tab that isn't stopping anything or not.

    I'm guessing that your cam is too advanced and that it is dropping the lever before the stop pin is in position to be arrested, but I could be wrong. Just can't tell from the pictures.

    RC
     
  9. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
    1,121
    11
    38
    Looking closely at the levers. The only part that interacts with the stop pin is the lifting lever - and that is to stop it in warning. The lever that falls into the cam does not have any part that goes to the inside of the plate.

    The force is strong against the cam stop. Gee, I have some polishing to do and perhaps some filing!
     
  10. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
    1,121
    11
    38
    Well, after some reshaping and polishing of the cam, the friction was less. At first, the lever would bounce once after hitting the cam wall, but it did stop. However, that didn't last long and the level would not stay in the cam valley. But, after a little more shaping the opposite way I found the happy shape! The clock is now functional - as the friction no longer stops the time train. And, the strike does stop when it is supposed to. Yeah!
     
  11. peanuts

    peanuts Registered User

    Mar 21, 2017
    315
    21
    18
    Male
    Retired
    Shaftesbury, UK
    Country Flag:
    Region Flag:
    Well done - what was the trick? Can you post a close-up photo showing the new shape? I ask because I have the same issue.
     
  12. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
    1,121
    11
    38
    The objective was to reduce the lifting resistance of the lever against the cam wall. Assumption was that the rotational force of the cam was fine and we do not want to change that. So, the focus was on the lever (portion that falls into the cam slot and stops against the wall) and the cam wall. Reduction of surface area between lever and wall was number one. Instead of a 90 degree wall, I angled the wall slightly. I also polished the lever and wall interface. This combination was what did it for me.
     
  13. peanuts

    peanuts Registered User

    Mar 21, 2017
    315
    21
    18
    Male
    Retired
    Shaftesbury, UK
    Country Flag:
    Region Flag:
    Thanks for the clarification - I know what to try now if I my issue resurfaces. At the moment, my movement is behaving itself since I improved the energy in the time train.
     

Share This Page