Filament Bearing Guide MK4

This is a filament guide for a Prusa MK4 that uses bearings to guide filament from above the printer into a more accessible location. 

Part List:

• (4) 3mmx8mmx4mm bearings
• (4) M3x20mm bolts
• (2) M3x12mm bolts
• (6) M3 hex-nuts
• (8) M3 washers
• Additional (1) M3 nut and (1) M3x8mm bolt if using the taller hook option and would like to fix it in place on the printer.

Materials:

• Enclosed Printer: I would recommend printing this out of PETG for the higher temperature resistance if it will be placed in an enclosure.
• Non-Enclosed Printer: I would still recommend PETG, but you could also get away with using PLA if the printer is not enclosed.

Print Settings:

• I would recommend using a .15-.20mm layer height to make ensure accuracy of the holes and spacing.
• I would recommend using a 30-50% infill to ensure no sagging on the internals of the bearing block. Any infill should work for the hook.
• I would recommend the walls are at least 1.2mm thick to ensure strength on the hook.

Step 1: Install the bearings into the bearing block with M3x20 screws, and install a washer on both sides of each bearing. 

IMPORTANT: Make sure the bolts are snug but not too tight! Ensure bearings still roll freely.

Step 2: Attach the bearing block assembly onto your choice of either hook. The taller hook allows more clearance while the regular hook provides better performance. Use the 2 M3x12mm bolts to attach the 2 pieces together.

Step 3: Place the top of the hook onto the top cross member of the MK4 and snap it into place. It is a tight fit, so you might have to press hard!