Expert: Martin Meyer - 3/5/2008

Question
the pendulum dropped off when my wife pulled up the chains to rewind the clock.  I hung the unit back on the space for it, but it would not stay running.  I removed the back and found if I moved the arched metal piece above the moving gear, it would run.  sliding it back, caused it to stop running and I assume moved the arched metal piece.  I am considering replacing the timing unit, because it does not look hard to do, considering the cost of having it fixed, and if I can get a replacement unit.  good idea?

Answer
Hi Leon,
    If you mean you are considering replacing the entire movement, that  is not a very difficult repair if you are mechanically inclined. Most movements cost under $200. The repair involves transferring the hands and dial, transferring the moon gear (if it has one) from the handshaft of the old movement to the new one, adjusting or transferring the chime-silent lever so that it protrudes through its slot in the dial, mounting the new movement on the seatboard, adjusting the chime and strike hammers to line up with your chime rods, and adjusting the bushing on the minute hand so that it is synchronized with the chime. If your movement is more than 20 years old, it is probably worn and should be replaced.
    As far as your immediate problem, please see the photo in my previous answer: Marianne-"Hermle Clock Pendulum Leader" for reference. I think you are referring to the triangular-shaped part at the top of the back plate of the movement, which holds the long post which the pendulum assembly attaches to. This part is held to the back plate by two screws, and the holes in it are oblong, so that the height of the part can be adjusted. This height adjustment is very critical, and the screws should generally not be loosened. This part raises or lowers the "anchor" so that it engages the escape wheel (gear with saw-tooth-like teeth) more or less deeply. The correct adjustment is to set the anchor so that it is as low as possible that will still allow the escape wheel teeth to release ("tick") from both points of the anchor as the escape wheel turns. You can set the anchor so that the escape wheel is locked, then raise it in tiny amounts until the escape wheel releases on every tooth. This will be the correct setting, and you should then tighten the two screws.