The design is also available here: printables.com

Design Intent

I was looking for a spool hub that could fit different size spools while, other than e.g. stepped hubs, maintaining the same width of the spool when mounted. I also wanted it to lock reliably into the spool, print quickly and with little material.
As this thing was constructed in openSCAD you can adapt it to your requirements in Customizer, click "Open in Customizer" above for that.

The clamp in the picture is this one: https://www.thingiverse.com/thing:2356396.

Customizing

If you adapt the hub to your spool sizes make the diameter bigger than the maximum hole size you want it to fit. As a rule of thumb about 5-10% plus. This guarantees that the springs have enough tension to lock it in.

Learnings

• The design shows that even PLA can be used to create quite robust springs as long as they are long, relatively thin and printed with perimeters only.
• It was quite a trigonometry challenge to calculate the position of the root fillet in the back of the vane :-).

FAQ - What does "customizable" mean?

Customizable means that you can modify the model by changing the parameters that define it. In case of this thing you can modify for example its main diameter the diameter of its center bore and much more just by changing the respective numbers in the Customizer App.
The beautiful thing with parametric models is that you can adapt something to your needs without understanding the underlying design principles. Give it a try by clicking "Open in Customizer".

Revisions

rev2: fixed missing path in vane profile
rev3: exported root fillet parameter
rev4: added optional bearing seat
rev5: fixed warning "variable not specified"