How to Adjust your Grandfather Clock to Keep Good Time

The pendulum length dictates how fast or how slow your grandfather clock will keep proper time. If you take time to adjust it properly, your grandfather clock can keep exceptionally good time.

§  The longer you make the pendulum, the slower your clock will run.

§  The shorter you make the pendulum, the faster your clock will run.

Adjusting the speed of the clock is accomplished by moving the pendulum disk (bob) up to speed it up or down to slow it down.  The pendulum disk is moved up or down by turning the adjustment nut.

 Process:

1) Start by seeing exactly how far off the time is over a 24 hour period. Set the grandfather clock correctly by using your cell phone. Watch your cell phone time as soon as it advances to the next minute on whatever hour it is on, set the minute hand on the grandfather clock to that location.

The grandfather clock pendulum adjustment is done by turning the nut at the bottom up to speed up the grandfather clock or down to slow the grandfather clock.  Hold the pendulum secure while you are adjusting the nut as shown.  By placing your figure between the top of the pendulum ball and the static part of the pendulum (Not shown) it is easy to tell if you’re moving the ball up or down.

2) Day 2: Look at the clock again exactly 24 hours later and see if it is fast or slow. Move the nut up or down depending if it is slow or fast about a full turn for a minute a day.

3)  Day 3: Look at the grandfather clock again another 24 hours later and see if it is fast or slow. Reset the minute hand to the correct time as above.

4) Day 4 to Completion: Repeat the above steps until the clock is accurate.

It is very important to reset the clock hands after the pendulum adjustment is made.  Chasing the error will not enable you to regulate the clock properly.