The Bullzeye Clock is a penny weight driven mechanical gear clock. It is so named because the face looks like a target and the pendulum is reminiscent of an arrow. It should run for about 8-12 hours depending on your string length.
Penny_weights.stl is from the MakerBot Clock http://www.thingiverse.com/thing:18214
Aside from the 3D printed parts you will need:
4 feet of nylon string
$2.50 in pennies
1/16 stainless steel rods (~1.6mm)
3.5 feet 3/16 wooden dowel (~5mm)
The pinions are superglued to their corresponding gear numbers but the spacers are not glued. gear1top is glued to gear1bottom and the nylon string is wrapped 1.5 times around the drum with the counterweight on the left and four penny weights on the right. Make sure gear1 is tight with the rod and rotates it while the other large gears are loose and rotate around their rods freely. For the hand gears only gear10 is tight and turns with the shaft while the other gears are loose. You may want to use some powdered graphite on the rods to keep things turning smoothly.
Please study the photos and TinkerCAD screenshots for assembly.
UPDATE: I have made an alternative way to wind the clock using a ratchet mechanism. ratchet-top, ratchet-gear, and ratchet-gear. This allows for a way to using something like fishing line tied at the halfway mark though ratchet teeth. The weights can be started out where small weight is unwound and the drive weight is wound. Make sure you just glue the rod to the ratchet gear -otherwise as you wind the clock the time hands will reverse!
I have designed this to be printed on at least a 100x100mm print bed.
Usually the first layer extrudes more than the others, so you must make sure the gears do not have extra material in them. Also, make sure the clock is level and firmly against the wall when mounting.
To adjust the beat of the the clock just move the pendulum bob higher on the rod to speed it up and lower to slow it down.
TinkerCAD is great