Clean up all the printed parts. Closely inspect all the gears and trim or shave away any excess PLA (hobby knife). Pay particular attention to the teeth. If there any significant defects on a part reprint it.

Drill out the shaft/axle holes and set screw holes on the gears and gear box by hand with a pin vise and 1.0 mm drill. Check that the gears spin freely on 1mm stainless shaft.

Drill through the shaft/axle holes on the gear box with the 1mm drill with the pin vise.

Clean up the hole for the quartz clock movement so it fits with a round file, knife or drill (I used a 5/16 drill by hand).

Drill with pin vise the set screw holes further with a 1.2/1.3 mm drill (test which works better) and fit a suitable length M1.4 screw. This is slightly longer than the required depth to tighten on axle. I just let them self tap. Note: any suitable miniature screws could be used as long as the length will not interfere with other surfaces in the final assembly. Also photo shows M1 screws in the 14 tooth gear which I later changed to M1.4.

Test fit the inner hemisphere, the axle cylinder, spacer ring, and final gear. On the top and bottom surfaces of the hollow cylinder on the inner hemisphere, carefully remove any bumps/roughness with a flat file and/or fine sandpaper on a flat surface. Gently sand the bottom surface on a flat with concentric motion. Repeat the same with the upper sliding surface of the 35 tooth final gear. I had to reprint the axle cylinder with scaling at 98.5% in X/Y for the correct fit. With a file and/or sandpaper remove any seam bumps on the axle cylinder and sand lightly, if needed, to fit. The axle cylinder should fit snug in the inner hemisphere but should be able to be turned with some resistance, as this is the method to set the current moon phase when setting the clock. The final gear should slide on easily but with essentially no side to side play.

Trim the metal screw on the shaft of the quartz clock module. I did this with a rotary tool (Dremel) with an abrasive saw blade; Wear safety glasses and avoid being in the same plane of the blade (especially your face) in case the blade fails. You can use a sharpie marker or tape to mark the line. Very carefully grind through the metal, trying not to contact the underlying plastic hour shaft. I cut this on twice; I left it too long first cut. Leave at least 5 mm of the thread, but it only needs trimmed enough to fit the gear far enough on. In retrospect, I cut away too much on the second cut and should have left about 10 mm, but it was still OK.

Size the 17 tooth gear to fit the clock hour shaft for a press fit (quite snug) with fine sand paper on a round mandrel, if needed. Do not actually press it on fully yet, although it shouldn’t be so tight it can’t be pulled back off. If it is too large the part will need scaled slightly or modified with smaller shaft hole and reprinted. In principle, scaling shouldn’t be done as it changes the module of the gear but the change should be insignificant assuming the clock hour shaft is ~5.7 mm. Note the hour shaft is stepped with the diameter for the hour hand slightly smaller.

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