Adjustments for most pendulum clocks.
NOTE: If you are not a clock professional, or familiar with the intricacies of your clock’s mechanism, we recommend calling Clock Repair Studio for professional service.
To adjust the time for fast and slow:
Your clock’s rate of speed is determined by the location of the disk (the bob) on the pendulum. The bob’s position is adjustable using the rating nut. On most pendulums, it is situated precisely beneath the bob, but on some, it is situated above the bob.
Move the bob up by twisting the nut to the right to quicken the clock (Your thumb to the right).
Move the bob downward by moving the nut to the left to slow the clock (Your thumb to the left).
Be aware that the clock’s speed won’t change unless the bob moves.
Wood stick pendulums
To adjust the bob, turn the bottom nut down a few turns, push the bob up with the top nut or let it slide down on the stick, hold the top nut, and turn the bottom nut back up until it is snugly attached to the top nut.
When you move the nut up, the nut will push the bob up on the stick; however, when you move the nut down, you must also check that the bob has moved. If you see a space between the bottom of the bob and the nut, gently pull the bob downward until its bottom once more rests on the nut while holding the stick in place.
For the majority of wood stick pendulums, a 360-degree rotation of the nut equals a difference of half a minute during a 24-hour period. The difference for one turn, though, can be up to three minutes every day.
Metal lyre pendulums
For the majority of pendulums, turning the nut below the bob 360 degrees will modify the clock’s pace by 30 seconds over the course of a day. Most contemporary metal/lyre pendulums are true to this. For many old pendulums, a turn corresponds to one minute each day. Before the rating nut on certain pendulums begins to move the bob, it may take a few spins. Remember that the bob must move if there is play between the nut and the bob in order to modify the clock’s pace.
Understanding how your Rating Nut changes after one turn
- Set a dependable watch or clock to the current time.
- Permit a whole day. The amount of time the clock is off should be noted or written down.
- Complete one full spin (360 degrees) of the nut in the correct direction. Turning the nut to right is quicker; left is slower. (Ensure that Bob moves)
- Let 24 hours pass. Take note of how much closer the time is than the actual time.
Now understand what changing the pendulum nut on your clock will do.
You should be able to adjust this setting during the course of the upcoming week.
Your clock should maintain nearly perfect time once the pendulum has been adjusted to the correct length.
Remember to always reset the time whenever you move the pendulum up or down for the fast and slow adjustment. After a day, check the time once more. Continue until the time on the clock is accurate.