Cardboard Spool Insert

This is a simple spool adapter for use within the cores of cardboard spools. 

Cardboard spools appear to have increased friction compared to traditional plastic spools, making it more difficult for them to feed into the 3D printer. (However, cardboard is recyclable, which is absolutely wonderful - I'm happy to see more companies doing this!)

I primarily use Matterhackers filament, who estimate the Inner Hole Diameter of their cardboard spools to be approximately 50mm. However, I've experienced this estimate to be slightly off, since I've only received rolls with inner diameters of 55mm.

As such, I designed a 53mm wide adapter for usage with Matterhackers Cardboard Spools.

This print also works with Overture cardboard spools, of which I also purchase and use frequently.

You will need to print two (2) of these, one for each side of the spool. This isn't a snap-fit. Rather, its to easily insert / remove and assist with reducing friction, which it does successfully with my Prusa Mini. (This also assumes that the listed diameter estimate on their webpage remains inaccurate, at time of this upload)

For context, I use a slightly scaled down version (85% size) of this spool holder, and as pictured, the 1 kg cardboard spools with these inserts fit perfectly.