With most grandmother/grandfather clocks, if the chimes are off, you need to unscrew the nut on the front of the clock that holds the hands in place after you hear the chimes. Once the nut is unscrewed, you simply manually move the hands to the corresponding time and reattach the nut. Your clock should chime at the proper hour from that point forward.
Key to remember when setting the clock is to allow the chimes to complete at each hour before moving the hands again. Don't speed through setting the time, as this is often what causes the problem.
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