How to Make a Pendulum for a Clock
Clock pendulums help to regulate the momentum to regulate the escapement in a clock. This means that the weight and movement of the pendulum swinging side to side wiggle the part in the clock that controls the speed of the clock's tick-tock mechanism. The momentum of this pendulum can be altered by changing the position of the weight, called a pendulum bob.
Empty a can of whipped cream. As soon as you have emptied the can and no more pressure is coming out, suck on the end with the valve opening. When the can "sucks back" from the partial vacuum you create from your suction, use a smooth-edge can opener to remove the cap on the bottom of the can. Rise the cream off the cap, and peel off any glue that is around the edges of the cap. Repeat this process to get two of these caps.
Trace a hole for the bar stock 1 cm from the edge of one of the caps. This hole is needed so that the wide, flat side of the bar is parallel to the edge of the cap. Turn the cap around 180 degrees, and then repeat the process. Carefully, so as not to leave a mark, clamp this cap into a vice between cardboard. Use the cutting disk on your Dremel to make the holes you just traced. Remove the cutting disk from your Dremel after it has cooled.
Drill a hole for the machine screw in the cap that already has the two holes drilled into it. Make the hole for the machine screw the same diameter as the machine screw shaft (not the threads on the screw). Drill the hole in the center of the cap between the two holes that you made previously. Test the hole by inserting the machine screw into the hole and testing it to see if it will screw and unscrew from the hole.
Slip the bar into the two rectangular holes on the back of the end cap that you cut, and tighten the screw in the back once it is to the desired height. Apply hot glue with a hot glue gun to the cap on the bar, careful not to get the glue on the bar. Place the second cap onto the hot glue of the first so that it makes a "disk" shape that the glue will hold together.
Glue the top of the pendulum to the clock escapement, and loosen the screw to adjust the height of the pendulum before tightening the screw again. This will adjust the speed of the pendulum. Do not make the pendulum too slow or the escapement will not function properly.
Things You Will Need
- Two cans of whipped cream
- Smooth-edge can opener
- Aluminum bar stock that is 1/8 inch thick and 1 inch wide (typically come in 3-foot lengths)
- Measuring tape
- 1 machine screw 1/2 inch long (shaft same diameter as drill bit for Dremel)
- Dremel (with cutting disk and drill bit same size as screw shaft, not threads)
- Phillips-head screwdriver
- Hot glue
- The pendulum can be painted, covered in gold foil, polished, or decorated in a number of other ways. If your clock is meant to be more than just a simple hobby, you may want to solder or weld instead of using the hot glue gun.
- Always wear goggles and work in a well-ventilated location. You will need a mask to avoid inhaling particles. A Dremel grinding through metal can get hot and release hot sparks, so be aware of the area where you are working. Do not cut metal near flammable vapors or other potential fuel source. Beware of the cardboard used to cushion the part in the vice, and pay special attention so that it does not catch fire. Cut metal can be hot and sharp.