Designed a Spool Holder for the 3D Printing Nerd Design Contest. I based the design off the Spool Holder used on the Prusa i3 MK3 machines, because the attachment mechanism is very much the same (clipping onto a rectangular cross section of material.

Since it was for the 3D Printing Nerd, I added the 3DPN logo to the shaft for extra swag!

I would recommend printing in either PETG, ABS, or Nylon so that there is a little flex as you snap it onto the 1x2, and I don't know if PLA has enough flex for that.