A Very Simple Spool Holder/Axle is for the 51mm diameter spool center. The holes are for a 3/4 inch dowel rod. It has 6 circumference rods, 1 center rod (slightly longer), and 4 leg rods. Make the axle as wide as you like and legs as long as you want!
This was printed with a Printrbot+ using Pronterface with Slic3r. Layer height 0.3mm, 3 solid layers, 3 perimeter layers, 20% fill, and rectilinear support get the support material out easily.
Print off 2 sides, pull out support material, cut dowel as wanted, and you might want some sand paper on hand if the dowel is just a smidge too tight a fit.