When I switched to direct drive I had trouble finding a spool holder solution with just the right level of resistance.

My previous bearing based system was just too freewheeling and created tangles and worse.

The perfect solution wound up being PTFE wrapping on the stock Ender 3 V2 spool holder.

Then came cardboard spools that just tore up my wrapping.

I designed a simple cover to use for cardboard spools. I wrapped quite a bit of cheap PTFE tape around my holder so the radius of the cover is designed to handle that.

It should work with most Ender 3 variants. 

I made the tolerance pretty close to the end of the spool to avoid the cardboard edge slipping into a crack. If its a little too long for your holder its real easy to take a few layers off the end with a box cutter. If you print vertically that is.

Printing Notes:

0.4mm Nozzle, 0.2mm layers

Orient vertically, support required.