Everything is 3D printed.
The axle shaft expands and contracts ~15mm in diameter; I haven't found a spool of 1kg filament that the mechanism cannot accommodate. Can add larger leaves if needed for some large ID spools.
You need a rubber band to go around all the leaves (any size, just double it up)
The axle is inserted through the leaf fixture, and held in place with a printed crosspin that is push-to-latch. Best of luck!
The author hasn't provided the model origin yet.