Ender 3 Small Diameter Spool Adapter

The holes in the center of filament spools aren't perfectly standardized, and I've noticed that occasionally the stock spool holder for the Ender 3 doesn't always fit.

So I designed this smaller-diameter spool holder, which presses into the stock one and extends out the back side. I've included a thumbscrew to lock your spools in place during printing.

This is a structural part that takes some weight, so infill settings are important!

I recommend >30% density with at least 4 external perimeters, to ensure that it won't break when you load it down with a heavier spool. Ideally, you should print it 100% dense, although that probably isn't necessary if your printer has good layer adhesion.