Stacker F-Box Bearing upgrade

This in a replacement part for the Stacker F-box spool holder. It uses bearings to reduce the friction of the spool holder, which will reduce Z artifacts caused by the extruder working against the friction of the spool.

This version is designed to use two 6906Z bearings to allow the spool to spin freely. The quality of these bearings do not matter, get the cheapest you can find (or 3d print some!). The bearings have a 47mm Outer Diameter, 30mm Inner Diameter, and are 9mm thick.

The OD of the holder is 50.5mm, the ID is 26.2mm

This design is NOT optimized for horizontal stacking of multiple F-Boxes. The End Cap sticks out 2mm. If requested I can upload a modified version where it is flush but the clips will be a little weaker and harder to insert.

Please note: The Inner Cylinder is designed to be press fit onto the end cap. It is also a tight fit on the bearings. You may need to sand it slightly to get the bearings to fit. The Outer Cylinder might need a little sanding too to get the bearings to fit. If you find the clearances too tight and require too much sanding, please let me know and I will adjust the models.

Printing instructions

This is best printed with 0.2mm layer height, and the Arachne perimeter generator. The Classic perimeter generator is not recommended. No supports are required.

This print was tested and printed using PrusaSlicer v2.6.0-beta1

PLA is recommended, but PETG should also work.

Assembly

Sand the inner cylinder so the bearing will fit all the way down.

Place one 6906Z bearing in either end of the Outer Cylinder and push them in until they stop. some sanding on the inside of the cylinder may be necessary.

Push the Inner Cylinder into the two bearings until it stops, starting from the side where the bearing is inset the most.

Put the Bearing Spacer on the end of the Inner Cylinder and push it down.

Test fit the end of the Inner Cylinder onto the End Cap. Push it all the way down until the Inner Cylinder is flush with the End Cap. It should be a tight fit, but some sanding may be necessary.

Remove the Inner Cylinder assembly from the End Cap. It will need to be aligned while assembling the F-Box.

Remove the old spool holder from the F-Box. A wide flat head screwdriver, or a thin piece of metal like a coin or a washer will help with undoing the clips. Take it slow, pushing one side in at a time, working your way around and pushing the holder inwards while applying pressure to the clips.

You can reuse the rubber O-Ring or omit it. It's not really necessary, the print should fit flush enough to create an airtight seal.

Insert the End Cap into the F-Box base from the inside, taking care to align the clips while inserting. Push it all the way in until the clips latch.

With the F-Box laying on it's side, lightly put the Inner Cylinder assembly into the End Cap. DO NOT press it all the way in yet.

Align the lid of the F-Box onto the  Inner Cylinder assembly. It should align on the center and fit into the tabs. Rotate the lid with the Inner Cylinder assembly until the lid is aligned with base. Press the center of the lid down, and latch the lid into place. Press the center of the lid more until the Inner Cylinder is flush with the End Cap.