Spool Holder (many spool sizes, easy spool exchange)

This spool holder can accommodate many different sizes of spools. A pair of cones holds the spool in place and centered. Bearings are used to minimize friction during rotation. Spool exchange is simple: lift the spool/rod from the frame, untighten the wing nut at the two-part cone, take apart the cone, take the rod out of the spool, then do the reverse for the new spool. But don't forget about the wide washer which likes to fall into the spool.
With the default parameters:
- Spool hole diame