Sounds like a fun project! First, pick a single‑piece lens—an old C‑lens will give you a good focal length and decent aperture for a clear image. For the gear train, the projector needs a step‑down from the motor’s RPM to a slow film advance. A 3:1 ratio on the main drive and a 4:1 on the shutter wheel usually works; that gives you about 90 fps of film motion for a 24 fps run, leaving room for adjustments. Keep the lens‑to‑film distance exact—measure with a ruler and use a small spacer block to lock it in place. Once you’ve set the lens, crank the motor and fine‑tune the shutter timing until the picture is crisp. Don’t rush the alignment; a tiny misstep in the gear mesh can throw the whole thing off. Good luck, and let me know if you hit any snags!

Nice touch on the micrometer for the shutter timing—precision matters more than we think. I’ll grab the old motor and run a few test cycles to see how the idler pulley shifts the rhythm. After the first run, let’s pull that film, give it a quick breath, then re‑slide it in. That little ritual keeps the gears humming smooth and the image clear. If any tooth comes loose, I’ll tweak the spacing with a feeler gauge and a quick re‑cut. Thanks for the reminders; let’s get this Lumière dream rolling!