Countwheel A countwheel is a slotted wheel that controls the strike mechanism. For the hour train the wheel has 78 divisions of 4.62 degrees with 12 slots positioned with increasing divisions around the wheel. The strike train starts when a hook-shaped locking detent (catch) is lifted out of one slot, thus allowing the train to run and the wheel to rotate; the train stops when the detent falls into the next slot in the wheel. By spacing the slots unevenly around the wheel, the strike train will strike more times at 12 o’clock than at one o’clock. This can also be called the locking plate.
