I wanted a spool holder that could be adjusted to size for different spool and didn't use any expensive parts. So I came up with this simple one that uses cheap 3/4" PVC braces and drops in from the top.

Print to size using 3 or more perimeters and top/bottom layers. I found about 35% infill provided decent rigidity. This is a large print, so you need something like a RMAX, gMax or CR-10 to pull it off. I found cutting the PVC to equal lengths of 4.25inches (108mm) was about perfect for all the spools I had on hand, but you can adjust accordingly to your needs. If you find the nubs that push into the PVC pipe are a bit loose, you can just add a dab of hot glue and it will hold fast, but allow it to be pulled apart later to break it down or change pipe lengths.

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Spool, Holder, PVC, Adjustable