There are several problems which can occur with a grandfather clock’s chimes, including not striking at the correct time or the tone being incorrect. If you have purchased a modern grandfather clock the first step will always be to consult your manufacturer’s manual or request the maker or supplier for information and advice. An antique clock may be more fragile and not come with any instructions. It may even require the attention of a professional horologist. The following instructions presume your clock is already set up and working. They may not apply to your particular grandfather clock so if in doubt, consult a professional.
Check whether your clock has an automatic correcting device fitted. Most clocks that are less than 50 years old will have one of these. If not, proceed with the following manual correction.
Open the cover to the clock face and turn the minute hand backward and forward 15 minutes to the quarter hour positions. Repeat until the chimes and the quarter hour pointed to by the minute hand are synchronized.
Close the cover.
Monitor the chimes to ensure they are correct. If the problem persists use a pair of pliers to carefully remove the nut that holds the minute hand in place and gently lift the minute hand straight off.
Replace the minute hand at the time indicated by the chimes. Replace the nut and turn until finger tight.
Adjust the hands to the correct time.
Follow the same procedure with the hour hand if the grandfather clock is not striking the correct hour. Move the hour hand backward and forward between the hour positions until the clock chimes the correct hour, then adjust to the correct time.
Open the side or back panel to the grandfather clock to reveal the chime mechanism and check the hammer adjustment only if you are sure the chime tone sounds incorrect. Sometimes the hammers hit the chime rods off-center or interfere with each other as they strike.
Bend the hammer arms slightly in the middle to align them 1/8 inch above the chime rod. The hammer arms are usually made from brass and can be bent safely, but if you find this is not the case, do not attempt to use excessive force. Never try to adjust the chime rods themselves.