Updated design: https://www.prusaprinters.org/prints/114513-din-spool-holder-v3

This is a (fairly) simple spool holder I designed that uses 607 bearings to support a variety of spools. Unlike other adjustable spool holders I've seen, this one mounts on DIN rail using an adapted version of the clip from my RPiDIN project. I made two variants: one is held together using M3 screws with press-fit hex bolt holes (same as the printer kits), and the other with holes for M3 brass heat set inserts.

Although I used 607 bearings since they were available at my local hardware store, it would be relatively easy to adapt the design to support 608 bearings.