Summary

This is my modular filament hybrid roller. It has the smooth rolling benefits of a outer-rim spool roller, but the ability to hold multiple sizes of spools, including spools too skinny to stand on a spool roller. This was designed in mind to fit every roll I own, including several 1kg and a few 500g and a 250g roll. The first version of this, I used for a year, and I made the second version of this to address some issues I had with the first. I am sharing it.

MATERIALS/PRINT INSTRUCTIONS:
All models are already oriented for printing

1 x Endplate - Use supports, 3-5 walls/floors/ceilings, ~25% infill
1 x Baseplate - No supports, 3-5 walls/floors/ceilings, ~25% infill
1 x Lever - No supports, 8+ walls/floors/ceilings, 50%+ infill
1 x Bridge - No supports, 8+ walls/floors/ceilings, 50%+ infill
(Pick 1 out of the 3 sizes. I recommend 95mm, it fits all of my rolls up to 1kg)
4 x BearingDouble OR BearingSingle, 8+ walls/floors/ceilings, 50%+ infill
(BearingDouble holds 2 608 bearings. BearingSingle holds 1 608 bearing)
4 x BearingWasher, 8+ walls/floors/ceilings, 50%+ infill (OPTIONAL)
(If you want extra space between the sides of the bearings and the baseplates)

You will also need the following

3 x M4 20mm socket-head screws.
7 x M4 nuts
4 x 608 Bearings + 4x 20mm M4 screws (if using BearingSingle), or 8 x 608 Bearings + 4 x 28mm M4 screws (if using BearingDouble)
1 x Bracket/Adapter/Mount with 34mm x 34mm square array of M4 holes, to attach the roller to. I will supply two designs (one for an i3 clone, one for a Sculpto) as remixes as examples.

Examples of brackets:

i3 clone/Anet A8/alunar m508: https://www.thingiverse.com/thing:4604373
Sculpto Pro 2: https://www.thingiverse.com/thing:4604372

To assemble:

1) Test fit the Bridge into the EndPlate. If it is too tight, you may need to sand it down a bit. You want this to be snug but still movable.
2) Press nuts into the 2 hex holes in BasePlate, 3 hex holes in EndPlate, and 2 hex slots in Bridge
3) Insert the non-rounded end of the Bridge into it's corresponding slot on the BasePlate. Insert 2 screws on the other side of the BasePlate to secure the bridge. (You can actually use longer than 20mm screws for this if you want to)
4) Insert the Lever into the EndPlate. Notice that the hole is off-center. You want the edge of the Lever that has more space between the hole and the edge to be on INSIDE of the EndPlate when the Lever is folded up. Line up the holes and install the M4 screw
5) Insert a BearingDouble/BearingSingle on the M4 nut, with the large-circle end against the screw head. Put 1 or 2 bearings (depending on which you printed) on. Optionally, put a washer on the other side. Screw two into the EndPlate.
6) Mount the BasePlate + Bridge onto your printer (using the appropriate adapter, NOT included in this upload)
7) Screw the other two Bearing assemblies into the BasePlate