There are two methods of adjusting the time regulation on your pendulum clock

1. Adjustment screw on the pendulum, If your clock has a small screw, in the middle, or at the bottom of the pendulum, then use this method:

To adjust the time, the pendulum rating screw must be turned, and the amount depends on how much time the clock is in error. If your clock is off less than five minutes a week, you may only need to turn the screw a revolution or less. If the clock is off more, you may need to turn it more. To accurately adjust the clock, make the adjustments once a week when the clock is wound. If you do this and keep a record of how much it is turned each week, you should be able to adjust the clock’s accuracy to within a minute or two a week. Use the following rules to adjust the Pendulum Screw;

If the clock is running slow, turn the pendulum screw clockwise to increase the time.
If the clock is running fast, turn the pendulum screw counterclockwise to decrease the time.


2. Adjustment screw on the dial, If your clock has a small arbor protruding the dial, then use this method:

Some clocks will have a “S or F” by this arbor. With a ‘S-F’ marking, turning the arbor clockwise to make the clock run faster and counter-clockwise to slow it. With a ‘F-S’ marking, adjust the arbor opposite as stated above. If there are no ‘S or F’ markings near the arbor, then use the trial and error method to determine the correction direction to make the time adjustment. Some times this adjustment can be turned too far, so do not force the adjustment if it tightens.