The Upper Suspension Block Must Fit the Saddle Correctly
June 21, 2008 . by BillA recent repair job on a Kundo oval base 400 day clock reminded me that the upper suspension block must fit properly in the saddle.
I cleaned the movement and replaced the suspension spring. It did not need any pivot polishing. After assembly, the clock ran, but the pendulum made a small rotation even when fully wound (about 3/4 of a turn with small overswing or supplementary arc).
The upper suspension block had some play in the direction of rotation of the pendulum, causing energy loss. I closed the slot in the saddle slightly, just enough to remove the play, but still allowing the block to pivot freely about the suspension holding screw. The swing of the pendulum increased to about one full turn. Now I am satisfied that this clock will run well.