90 degree filament roller guide for Prusa MK4

I made this to pull filament from a dryer I keep next to my MK4. The clip is rotated 180 degrees to help clear the extruder when it gets to the top. The extruder cable will hit the bottom of the clip at the very top, but clears at 2mm from the top.

Required parts:

• 608 bearing
• M3x16 bolt (included with the MK4 kit)
• M3n nut (included with the MK4 kit)

To build:

1. Print one of the frames depending on the side of the printer from which the filament will be pulled, one pulley, and two spacers
2. Press the bearing into the pulley
3. Insert 1 spacer into each side of the bearing
4. Press the nut into the hex hole in the frame
5. Insert the pulley assembly into the frame
6. Insert the bolt and tighten*

* Should be able to to tighten without impeding rotation of the pulley, but in case pulley rotation does stiffen up, just back off the bolt until the pulley can rotate freely.

Slicing notes:

• Used perimeters to achieve 100% infill for all parts
• Spacer thickness is 0.5mm, so I sliced at 0.15mm with a 0.2mm first layer to achieve this thickness with 3 layers
• Pully sliced at 0.1mm
• Frame sliced at 0.2mm

The pulley and filament path are based on the design of the Ender 3 Filament Roller Guide, but tolerances have been tightened, chamfers added to help guide the filament, holes sized for an M3 bolt, and pockets added for the head of one of the M3x16 bolts and one of the M3n nuts included with the MK4 kit.

The clip was cut out from the Spool Holder for Original Prusa MK4.