The ticking sound of a properly balanced clock will be as even and consistent as a metronome as the pendulum moves from side to side. When a pendulum clock stops running, it’s usually because it’s “out of beat.” This happens if the clock is not perfectly level, and can be easily corrected.
Pull the pendulum to one side and release it. As it starts to swing, you should hear a ticking sound at each end of its arc. If the tick is irregular, with a galloping or uneven sound, the clock is not in beat. To correct this problem, begin by making sure that all points are wound and the pendulum is hanging correctly with nothing obstructing its path. Anything that interferes with the pendulum’s arc will usually stop the clock.
An out-of-beat clock is corrected by levelling the clock case. Tilt the clock slightly to the left or right as you listen carefully to the ticking sound. You will notice that the ticking becomes more consistent as the case is levelled. On mantel clocks, place appropriate shims under the base to hold the case in a level position. If your clock stops after a while, just start the pendulum again and repeat the levelling procedure until the beat is as even as possible. Once you master this technique, you’ll have no trouble setting up any pendulum clock in the future.