Twin Roller Bearing Spool Holder (No supports!)

A spool holder designed for Ender 3 Pro and possibly other printers that use the same steel mounting bracket.

Features:

• Usable with spools of internal diameter ≥55mm
• Twin roller design. No more spool rocking, especially with large ID spools. No need to fiddle with any settings when changing spools with different ID sizes.
• Rollers surfaces are gently tapered 1 degree towards the middle to encourage self-centering of the spool.
• No supports needed to print any of the components--maximum overhang 30 degrees from vertical.
• The spool holder can be oriented in multiple of different positions (360 degrees in 45 degree increments). Side mounting users rejoice!

Cons:

• Requires 4x 608 bearings. I will recommend to buy a set. If you are willing to print some, here's one design but I have not tested with printed bearings.
• Requires Ender 3/Pro steel mounting bracket.

Print:

• 4x roller_half, 1x body_half_A, 1x body_half_B, 2x nut.
• Print in original orientation without supports. Body and roller parts have 0.2mm chamfer on the base edges to fight elephant's foot and other first layer inaccuracies.
• 0.20mm layer height for all parts. You may want to use 0.10mm for the rollers to make them as smooth as possible. I did variable LH 0.10-0.20mm for the rollers.
• Body & nuts: 2mm walls (4-5 perimeters), min 20% infill. Load bearing parts, especially the threads. Don't skimp.
• Rollers: 1.6mm walls (3-4 perimeters), min 10% infill.

Assembly:

• The body and rollers are designed to be printed in halves. The roller halves are assembled by press-fitting 608 bearings on the opposite ends. The body halves are assembled by fastening the nuts on both ends. The assembled rollers will snap fit into their positions on the assembled body. See pictures.