Turn the outer ring or the lever arm and every geared blade swings at the same time, opening and closing the central aperture smoothly. That is what this first test version of a geared mechanical iris does once it is put together, and the maker says it worked pretty well. The parts are cut from 3 mm plywood, and the maker finds mechanical irises beautiful and wanted one, which I completely understand.
The assembly sequence looks satisfying. Bamboo skewers were cut into dowel pins and tapped into holes in a circular base frame with a metal hammer. Each blade went on one at a time, with the tips overlapping in a spiral pattern, before an outer ring gear was set around them to engage the geared edges. A matching top frame was lined up with the pins and pressed down by hand to enclose everything.
Several details stand out to me. The outer ring carries internal gear teeth, with spur gears arranged around the central opening, all inside a clean circular outline. The top spoked frame has cross-braces and pin holes to hold the internal parts in place, plus a lever arm with a hole that protrudes past the outer edge, which seems like a handy grab point. The layered wooden parts with their dark cut edges give the whole disc a crisp look.
One thing is left open: the blade count is inconsistent, with some views showing four blades and four spur gears while the mechanism running shows five mounting holes, five dowel pins and five blades. I would like to know which arrangement is the final one. As a first prototype it already moves nicely, and a refined version would be worth seeing.
Project by Maker Design Lab. Watch it on their YouTube channel: