The center of motion of the crutch must be in the center of the clock. Sometimes the crutch gets bent or rotated on its shaft causing the clock not to run. To determine which way to adjust the crutch, get the beat even by picking up one side, or the other, of the case. Repeat until it runs when level. The rotation of the pendulum causes a small, two prong fork to move back and forth.
Many clocks have time adjust shafts which lower and raise the bob from the front.
With time adjust shafts, turn in the direction indicated about one turn each try. Do not force. All of these clocks can be adjusted to keep accurate time. Set hands to correct time. The minute hand is fixed firmly on a rectangular shaft and geared to turn the hour hand which is a friction fit.