There are two methods of adjusting the time regulation on your pendulum clock
- Adjustment nut on the pendulum, if your clock has a small nut on the bottom or another place on of the pendulum, then use this method. To adjust the regulation, the pendulum rating nut 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 nut 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 NUT; If the clock is running slow, turn the pendulum nut clockwise to increase the rate. If the clock is running fast, turn the pendulum nut counterclockwise to decrease the rate.
- Adjustment on the dial, if your clock has a small arbor protruding the dial near the “12” or the “6” or perhaps in the center of the dial, then use this method. You will need smaller key to turn the rating arbor. Some clocks will have a “S or F” by this arbor. For a ‘S-F’ mark, turn the arbor clockwise for faster and counter-clockwise for a slower rate. 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.
Credited to: https://clocksofyore.com/
