My remix of dontbesalty's excellent https://www.thingiverse.com/thing:3573692

I was constantly dropping the bearings because there was nothing holding them down. My simple solution was to add 4 tie-wrap slots to hold the bearing pins in place.

As shown, it requires buildplate-only support. (If you do support everywhere you'll never get the supports out of the tie-wrap slots!)

If you want a stronger version, turn it on end and slice with supports everywhere.

Update: I've made the pins a bit longer to make sure there's enough for the tie wraps to grab onto.

Update 2: Unless you're getting consistently great layer adhesion, I now strongly recommend turning this on end for slicing, and enable supports everywhere. Otherwise, the legs will probably not tolerate enough flex to snap over the spool holder without at least one of them breaking.

Monoprice

Mini Delta

No

Yes

0.21mm

15%