Ever since the advent of time, all clocks have had to be adjusted or regulated in order to keep accurate time. The rate of accuracy can be influenced by many factors, mainly environmental factors such as heating, air conditioning, humidity, dust, and floor vibrations due to foot traffic. Therefore, placement of your clock within your home should be given careful consideration. The concept about to be covered is governed by the laws of physics. The general rule of thumb is: 1) to speed up the time, raise the pendulum bob or disc; and 2) to slow down the time, lower the bob or disc.
Regulating the Time
First, select an accurate timepiece to use as a monitor. Generally, quartz analog watches or clocks with hands are the most accurate. Avoid calling a “time” recording and using digital clocks found on microwaves, VCRs, or those that display the hour and minutes only. These will have an error rate of about 59 seconds.
Second, set the hands of your clock according to the time on your monitor. Do not attempt to synchronize the seconds if your clock features a sweep second hand because this component is extremely sensitive. Besides, some movements do not have a “true second hand”. The minute hand can be safely moved forward or backward on most modern day clocks. If your clock features an Auto Night Silencer, be sure that you have distinguished AM from PM. To determine AM from PM, with the Auto Night Silencer engaged, advance the minute hand forward to the 11:00 o’clock position. If the clock chimes, it is in the AM position. If it is silent, it is in the PM position.
If your clock loses time (for example is 5 minutes slower today than yesterday), then follow the same steps above, however, turn the rating nut to the right or tighten it about 5 revolutions. This will raise the bob up the shaft. Again, make sure the bob is resting on top of the rating nut. Sometimes the nut may slip behind the bob instead of raising it. There may be some resistance while turning (tightening) the nut. If the resistance feels too extreme, then slightly loosen the 2–4 mounting screws on the harp above the bob. Remember that you are actually sliding the bob/harp assembly up or down the pendulum shaft when regulating the time. In general, 1 full turn or revolution of the rating nut will change the time by 1 minute per 24 hours, but this may vary from model to model. Once you regulate the time within 1 minute per 24 hours you may want to decrease the turns by ¼ to ½ or “toy” with the rating nut. BE PATIENT!
- Set hands to correct time.
- Recheck in 24 hours and note number of minutes gained or lost.
- Stop pendulum and turn rating nut to right (tighten) to speed it up or to left (loosen) to slow it down (1 turn for each minute).
- Swing pendulum and reset hands to the correct time.
- Re–check in 24 hours.
- Continue procedure for 7–10 days or until clock is accurate within 1–3 minutes per week.