Prusa MK3/4 frame mounted filament roller.

This filament roller mounts on the frame of the Prusa MK3 and likely MK4.  It can be a replacement for the spool holder supplied with the original printer.  Four 608 bearings are required.  The front filament guide is designed to align the filament with the extruder gears and prevent rubbing of the filament on the spindle.

Maximum Z print height must be reduced to 165 from 210mm.

This filament roller will accommodate spools up to 80mm wide.  If required, 2 spool holders can be used at the same time. 

Parts are intentionally set for interference fit and should not require glue.

Assembly:

1. Install the 608 bearings into the ends of the Spindles so that they are flush with the end surface of the spindle.
2. Insert the Front Filament Guide and the Rear Spacer into the corresponding cutouts of one of the Side Walls.  
3. Place the 2 spindles onto the pegs of the Side Wall.
4. Place and align the other side wall on top and press everything together.

Printed without supports.