Expert: Martin Meyer - 4/18/2009

Question
I have a Franz Hermie model 340-020 that is several years old.  It ran about five minutes slow a week.  It suddenly quit one day so I oiled it, and it ran for a few days and then stopped.  I started it again and it got to where it would run all week, but it was about five minutes slow a day, I cranked up the timing and now it runs slow about a minute a day.  I hate to keep cranking up the timing when it probably is something else.  It is at least 20 years old.

Thanks.

Answer
Hi Don,

There are several possible causes of your problems with this clock, and I could only guess at exactly which one, or combination, is the answer.

First, 20 years is well beyond the expected lifespan of this movement. It is entirely possible that the movement has severe bearing wear. The oiling might have been simply "the last straw" and not the true cause of the clock's stopping.

That being said, the oiling, if not done properly, could be the origin of the problems. Possible causes of problems due to oiling are: 1)use of anything but Clock Oil, especially spray solvents like WD-40; 2)improper application of the oil, which must be applied in very small amounts, only to each point where a pivot (gear shaft end) enters a hole in the front or back plate, and no oil must get on the gear teeth or other parts; 3)any oil getting on the floating balance assembly, especially on the helical spring, on the balance staff (shaft) pins, or on the fork; 4)any disturbance of the set adjustments of the floating balance assembly, especially the helical spring.

A loss of 5 minutes a day is within the range of adjustment on this clock, and an adjustment of the regulating mechanism may be correct. The key thing to look at is the range of motion of the floating balance. Ideally, the floating balance should rotate at least 3/4 of a full turn, that is 270 degrees. If its motion is significantly less than that, the movement has problems probably due to one of the above causes.  http://www.clockmasteronline.com