Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4790426.
A simple wide roller that aligns the filament with the extruder hole.
Uses a 8x22x7mm bearing (standard 608ZZ bearing) and one M5 screw and nut. the nut should embed flush with the plastic.
The model also includes a filler to go around the screw and mitigate the space between the screw and the inner shaft of the bearing, but I'd recommend you design your own filler to make sure it will fit your screw and bearing.
It might be compatible with the Ender 3 "Original" edition as well as the Ender-3v2, but I cannot test it since I only own the Ender 3 Pro.
I printed it in PETG, but I have no doubt that any filament material would do for this roller.
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TLDR, You'll need : - M5 screw - M5 nut - 608ZZ bearing (8mm x 22mm x 7mm)