Nearly two months ago I had never seen a 3Dprinter.
Fascinated, I borrowed an old printer and built the easy clock, #16, because it seemed like a good (easy) place to start.
Once finished, it ran on the first try.
Then I took it for a car ride and I was unable to get the clock to run again when I returned home..
For the next three weeks I built and rebuilt it, printed some new parts, verified the spacers -- printed new spacers -- which are a big deal becasue they easy to switch around.
After dozens of experiments I decided the stack of gears on the top arbor was 2mm longer that the available space. (Yes, I had pushed and positioned and adjusted a dozen times.) I was unable to reduce the height of the stack of gears by the necessary 2mm.
Interim Fix: I added a spacer on the top…
Great looking clock. It even matches the tablecloth.
Testing the clock without the pendulum is a good first check. It helps break in the components and gives you an indication of overall dynamic friction. Clocks are sensitive to static friction as well. This gets tested by the start/stop action of the escapement.
Add the pendulum and slowly move it from side to side. The escapement should start spinning instantly when the pallet tips clear the escapement. If the escapement is sluggish, then there could be high static friction somewhere. You could try lubricating the pinion teeth with a thin layer of grease to see if it improves.
Also the escapement should have equal action in both directions. Make sure the table is level. Add playing card shims under corners until a ball can rest in the lower tray without rolling. You may need to remove the tablecloth until you get the clock working. The side screws on the pendulum arm can be used to adjust the beat if needed. As Andrew mentions, they should start in the middle of the adjustment range on both sides.
Both of these issues are related to the escapement characteristics. A 10 second video showing a closeup of the escapement can often help pinpoint where to focus the next debug effort.