This is a mechanical iris lock box that I made on my Shapeoko for my fiancee's ring (Yes, turns out you can use your cnc to get engaged). It consists of two gears, key and lock, LEDs with hidden switch and batteries to illuminate ring when opened, solid walnut box, 22 walnut inlays and of course the iris mechanism. Each joint uses 3mm ID micro bearings so the operation is very smooth.
Walnut - home depot
Aluminum (6061) - amazon/ebay
3mm micro bearings
Electrical switch and battery pack
1/4" 2 flute
1/8" TiAlN 2 flute square (primary aluminum cutter 2.5 on Dewalt, .25 mm DOC, .75 mm stepover, 1000 mm/min)
1/8" TiAlN 2 flute ball
1/16" 1 flute (just for marking holes to drill)
30 degree engraver
[The EV-Guide vacuum nozzle did a great job of keeping the aluminum chips out of the tight corners when machining the gears (see below).]
CAD and CAM:
Fusion 360 - Gears generated using Fusions built in application, set backlash to 0.2 mm. I found the best finish on the teeth was achieved by leaving .05 to .1 mm radial stock for a full depth finish pass. The mechanism was also animated in Fusion.