Expert: Martin Meyer - 1/18/2009

Question
I recently replaced the pendulum wire on my 400 day clock. when I start it in  motion, it flutters and eventually stops.

Answer
Hi Clyde,

The adjustment of 400-Day clocks is extremely complicated, and there are multiple possible causes of this problem. First, it is essential that you use the Horolovar 400-Day Repair Guide in setting up the suspension wire and positioning the top and bottom blocks and the fork.

"Fluttering" is several teeth of the escape wheel slipping past the verge pallets at a time, rather than the teeth being released one at a time by the back-and-forth motion of the verge. This action is normal when turning the minute hand to set the time, but should not happen while the clock is running on its own.

The most common cause of fluttering is that the fork is set slightly too low on the suspension wire. You should check the precise position of the fork by placing the suspension unit on the correct template for your movement in the Horolovar Guide. You can also try very slightly raising the fork on the suspension wire.

The other likely cause of fluttering is that the depth of locking of the pallets on the escape wheel teeth is insufficient. The remedy for this is to lower one pallet very slightly. But be warned that all these adjustments on 400-Day clocks are very critical, and it is extremely easy to compound a problem by making excessive or unnecessary adjustments, thus resulting in multiple problems which become nearly impossible to correct.

Note also that the most common cause of stopping in a 400-Day clock is not fluttering, but that it is out of beat. The beat adjustment will be changed by almost any other work on the suspension unit, and so the beat will probably  have to be reset after you correct the fluttering. http://www.clockmasteronline.com