How to Adjust a Grandfather Clock

Grandfather clocks are classic, functional art forms that have been around for centuries. They're also notoriously difficult to keep set at the correct speed. Unlike modern electric clocks, the rate of a grandfather clock is regulated by the swinging of the pendulum below it, which can be adjusted to make it longer or shorter, affecting the rate of the hands. Getting it calibrated just takes a little patience.

Adjust a Grandfather Clock
  1. Assess how fast or slow your clock is running. Do this by winding the clock, setting the time and starting the pendulum with a gentle swing.

  2. Wait a full day, then see how far off it is, and in which direction. If it's more than a minute off, the pendulum should be adjusted.

  3. Find the adjustment nut at the bottom of the pendulum. This raises and lowers the pendulum, which in turn speeds or slows the rate of the clock. The shorter the pendulum, the faster the clock will run.

  4. If your clock is running too slow, turn the nut clockwise by one full turn, to raise the pendulum. If it's running too fast, turn it counter-clockwise. Wind and reset the clock as before, then wait one full day.

  5. Check the clock's time again. If it's still off, adjust the nut farther. Repeat over days until the clock is keeping the correct time.