In the days before electricity and batteries, clocks were wound with a key. This tightened the main spring in the clock, allowing it to run for a week at a time. Regulator clocks had a pendulum that swung back and forth beneath the clock face, and many had a chime that rang every half-hour or hour. A separate spring that powered the chime had to be wound in addition to the mainspring. These clocks, expensive in their time, were found primarily in train stations, banks and city buildings. To set such a clock is not difficult, but requires that the clock be hung properly first, then set and wound, which requires patience. Follow these steps.
Install a 3-inch long screw into a wall stud from which to hang the clock. Use a mollie bolt, if you must hang it from the drywall. Ensure that the hanger on the back of the clock is solid before you hang and level the clock.
Hang the pendulum and move the bottom of the clock so that the pendulum is centered and does not rub the back of the case. If you need to, pull the top of the clock slightly forward on the screw so that the lower end of the case falls back against the wall to allow the pendulum to hang further away from the back of the case.
Gently move the minute hand (the longer one) slowly in a clockwise direction, stopping at the quarter hour, half hour, or hour mark and allowing the clock to complete the chime for that time before moving the hand any further.
Place the key in the keyhole and wind the mainspring clockwise, being careful not to over-tighten it. If there is a chime, place the key in the other hole and wind the spring that drives the chime.
Touch the pendulum to start it swinging back and forth, and listen for an even "tick-tock" sound. If the sound is not even, the pendulum may not be plumb or the wall may not be straight, and you may have to make some adjustments, including placing small, "no-slip" plastic "feet" (used on the backs of some picture frames) on the back of the clock case to help bring it out from the wall a bit.