Sliding Adjustable Spool Holder

**Note:** I highly recommend [Version 2 of this spool holder](https://www.thingiverse.com/thing:3152545) which corrects issues in the original design with very full spools.

A spool holder, sufficient for placing on a shelf. Many of these have been made before, but this one is mine.

The Fusion 360 archive `.f3d` is included, if you need to make any changes. **Two sizes are included** because it's common for 4" rods to be sold as supposed 100mm ones, but that's not the same size. Measure the