This is a remix of Holspeed's filament guide, which is pretty darn close to perfect, and my changes are pretty minor:
- I lowered the guide wheel a smidge, with the goal of aligning the bottom of the guide wheel tangentially with the extruder inlet.
- I opened up a little more space around the guide wheel to prevent rubbing.
- I added a couple fillets to the wheel's OD (also to prevent rubbing) and a chamfer on the ID to make inserting the bearing a little easier. It should be a really tight fit onto a 608 bearing.
- I expanded the spacer's OD into a press fit into the bearing, and the ID into a close fit for an M4-threaded bolt. I also added chamfers to make it easier to insert a M4-threaded bolt.
- I added a counterbore for an M4 SHCS and a pocket for an M4 nut on the other side. An M4x15 SHCS is just the right length.
- I filleted off a lot of the sharp corners, for purely aesthetic reasons.
The bracket is still a press-fit onto the z-carriage, and should slide on with moderate effort until its seated. No hardware required!
The bracket can be printed with 3 outlines, I designed it for 0.5mm extrusion width.
The wheel should be printed with better resolution (I used 0.15mm layers) and 100% infill (or more outlines).
I found the spacers were strongest when printed on 0.15mm layers, 10ºC hotter than usual, 40mm/s print speed and fans on full blast after 3 layers.
I printed all the parts with PLA on blue tape.